Name: binocular dynamic visual acuity in eyeglass-corrected myopic patients
Uploaded: 2022-03-29T15:00:00.000+00:00
Duration: 7 min 6 s
Description: Watch this Scientific Journal Video about Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients at JoVE.com

This work was supported by Natural Science Foundation of Beijing Municipality (7202229).

The present study enrolled consecutive myopia patients in the Department of Ophthalmology of Peking University Third Hospital. The research protocol was approved by the Peking University Third Hospital Ethics Committee, and informed consent was obtained from each participant.
1. Patient preparation
<ol>
	<li>Use the following initial inclusion criteria to enroll subjects: myopia subjects aged 17-45 years old.</li>
	<li>Use the following exclusion criteria: any history of ocular diseases, including keratitis, glaucoma, cataract, retinal and macular diseases, that significantly impact corrected distance visual acuity (CDVA). Evaluate uncorrected distance visual acuity (using the standard logarithmic VA chart), dominant eye, intraocular pressure, slit lamp, corneal topography, fundus photography, automatic computer optometry, cycloplegic subjective refraction, and CDVA. Exclude participants with keratoconus, cloudy cornea, or retinal abnormalities, including retinal breaks, retinal vascular inflammation, congenital retinal and macular diseases, or monocular CDVA worse than zero (based on the standard logarithmic VA chart).</li>
	<li>Set up the DVA test components, including test distance, environment, hardware, software, movement mode, and rules as follows:
	<ol>
		<li>For test distance and environment, set the test distance according to the size of the screen and examination requirements. 
		&#8203;NOTE: Here, DVA was assessed at 2.5 m in a quiet and bright room (luminance 15-30 lux).</li>
		<li>For hardware, present the optotype with a 24 inch in-plane switching (IPS) or twisted nematic (TN) screen (refresh rate, 60 to 144 Hz; response rate less than 5 ms).</li>
		<li>Ensure that the software is designed to display the optotype according to the preset velocity and size. Use the dynamic optotype as the letter E designed according to the standard logarithmic visual chart with four opening directions: upper, left, lower, and right. Ensure that the visual angle of the motion optotype presented at the test distance equals the optotype with the decimal size in the standard logarithmic visual chart. Set the color of the letter E to black, with a white background. Express the velocity of motion as the viewing angle changes per second.</li>
		<li>Movement mode: during the test, ensure that the optotype with a specific size and velocity appears in the middle of the screen&#39;s left side, moves horizontally to the right side, and then disappears.</li>
		<li>Test rule: Ask the subjects to identify the opening direction of the visual target. Test the minimum visual target at a certain speed that the subjects can recognize.</li>
	</ol>
	</li>
</ol>
2. Subjective refraction
NOTE: The result of subjective cycloplegic refraction is the basis for the eyeglasses prescription to correct the refractive error in myopia subjects.
<ol>
	<li>Perform automatic computer optometry as the primary data for subjective cycloplegic refraction and measure the pupil distance.</li>
	<li>Examine one eye at a time and occlude the other eye.
	<ol>
		<li>First, achieve the maximum plus to maximum visual acuity: fogging with +0.75 - +1.0 D lens, inducing a visual acuity of 0.3-0.5 (decimal visual acuity). Next, gradually decrease the positive lens in a 0.25 D step. Use a Lancaster red-green test to tune the accurate spherical diopter. Add more negative/positive lens if the patients report that the letter seen against the red/green background is clearer. 
		NOTE: The primary spherical diopter is obtained after the above step.</li>
	</ol>
	</li>
	<li>Refine the cylinder axis.
	<ol>
		<li>Place the Jackson cross cylinder device in the &#34;axis&#34; position so that the thumb-wheel&#39;s connecting line is parallel to the axis of the astigmatism. Rotate the thumb-wheel and ask the subject to compare the clearness between both sides. Turn the cylinder axis toward the red dots on the cross cylinder in the side with clearer vision. Repeat the binary comparison until the endpoint.</li>
	</ol>
	</li>
	<li>Refine cylinder power.
	<ol>
		<li>Turn the Jackson cross cylinder device so that the thumb-wheel&#39;s connecting line is at 45&#176; to the astigmatism axis. Rotating the thumb-wheel, ask the subject to compare the clearness between both sides. If the patient reports clearer placement of the cross cylinder red/white dots connecting line along the cylinder axis, add a negative/positive lens, respectively. Repeat the binary comparison until the endpoint.</li>
	</ol>
	</li>
	<li>For the second maximum plus to maximum visual acuity, repeat the Lancaster red-green test to tune the accurate spherical diopter.</li>
	<li>For binocular balance, apply a vertical prism of 6&#916; before one eye to dissociate the binocular vision. Balance the clearness of the optotypes between both eyes.</li>
</ol>
3. Dynamic visual acuity test
NOTE: DVA was measured binocularly with refractive errors fully corrected with eyeglasses in the present study.
<ol>
	<li>Test settings
	<ol>
		<li>Adjust the test distance according to the requirements. Adjust the seat to make the subject&#39;s sight at the screen&#39;s midpoint level. Ensure the subject wears the distance vision corrected eyeglasses binocularly.</li>
	</ol>
	</li>
	<li>Test parameter configurations
	<ol>
		<li>Set the optotype moving velocity and the initial optotype size.</li>
	</ol>
	</li>
	<li>For the pretest, display five optotypes with a randomized opening direction to guide the subjects to understand the test mode.</li>
	<li>Formal test
	<ol>
		<li>Start the test at the size 3-4 lines bigger than the best-corrected distance visual acuity. Display the optotype with randomized opening directions.</li>
		<li>Ask the subject to identify the opening direction of the moving optotype. Present the next optotype after the subject&#39;s response. Present eight optotypes for a certain size. If five out of eight optotypes are identified correctly, adjust the optotype to one size smaller. Repeat the above procedures until the size for which the subject can identify less than five optotypes is obtained.</li>
	</ol>
	</li>
	<li>Record the minimum size (A, decimal VA) that subjects can recognize (five out of eight optotypes are identified correctly) and the number (b) of optotypes recognized for one size smaller than A.</li>
	<li>DVA calculation
	<ol>
		<li>Present eight optotypes for each size so that each identified optotype gains 0.1/8 visual acuity. Calculate DVA according to the algorithm of logarithmic visual acuity, as shown by Eq (1); see step 3.5 for an explanation of A and b: 
		<img alt="Equation 1" src="/files/ftp_upload/63864/63864eq01v2.jpg" style="margin: auto;" /> (1) 
		NOTE: In the present study, optotypes of 40 and 80 dps were examined in order. Previous studies have reported that people could apply smooth pursuit when observing dynamic objects moving at 30-60 dps, whereas observing objects moving faster than 60 dps involves head movement and saccade16,17. Thus, two motion speeds of 40 and 80 dps were selected.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Nakatsuka, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+static+visual+acuity+on+dynamic+visual+acuity:+a+pilot+study.">Effect of static visual acuity on dynamic visual acuity: a pilot study.</a> Perceptual and Motor Skills. 103 (1), 160-164 (2006).</li><li>Ueda, T., Nawa, Y., Okamoto, M., Hara, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pupil+size+on+dynamic+visual+acuity.">Effect of pupil size on dynamic visual acuity.</a> Perceptual and Motor Skills. 104 (1), 267-272 (2007).</li><li>Ao, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Significant+improvement+in+dynamic+visual+acuity+after+cataract+surgery:+a+promising+potential+parameter+for+functional+vision.">Significant improvement in dynamic visual acuity after cataract surgery: a promising potential parameter for functional vision.</a> PLoS One. 9 (12), 115812 (2014).</li><li>Ren, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+standardized+test+system+to+evaluate+dynamic+visual+acuity+post+trifocal+or+monofocal+intraocular+lens+implantation:+a+multicenter+study.">A novel standardized test system to evaluate dynamic visual acuity post trifocal or monofocal intraocular lens implantation: a multicenter study.</a> Eye. 34 (12), 2235-2241 (2020).</li><li>Dacey, D. M., Peterson, B. B., Robinson, F. R., Gamlin, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fireworks+in+the+primate+retina:+in+vitro+photodynamics+reveals+diverse+LGN-projecting+ganglion+cell+types.">Fireworks in the primate retina: in vitro photodynamics reveals diverse LGN-projecting ganglion cell types.</a> Neuron. 37 (1), 15-27 (2003).</li><li>Skottun, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+few+words+on+differentiating+magno-+and+parvocellular+contributions+to+vision+on+the+basis+of+temporal+frequency.">A few words on differentiating magno- and parvocellular contributions to vision on the basis of temporal frequency.</a> Neuroscience and Biobehavioral Reviews. 71, 756-760 (2016).</li><li>Janky, K. L., Zuniga, M. G., Ward, B., Carey, J. P., Schubert, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Canal+plane+dynamic+visual+acuity+in+superior+canal+dehiscence.">Canal plane dynamic visual acuity in superior canal dehiscence.</a> Otology &amp; Neurotology. 35 (5), 844-849 (2014).</li><li>Gimmon, Y., Schubert, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vestibular+testing-rotary+chair+and+dynamic+visual+acuity+tests.">Vestibular testing-rotary chair and dynamic visual acuity tests.</a> Advances in Oto-Rhino-Laryngology. 82, 39-46 (2019).</li><li>Verbecque, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+visual+acuity+test+while+walking+or+running+on+treadmill:+Reliability+and+normative+data.">Dynamic visual acuity test while walking or running on treadmill: Reliability and normative data.</a> Gait &amp; Posture. 65, 137-142 (2018).</li><li>Verbecque, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feasibility+of+the+clinical+dynamic+visual+acuity+test+in+typically+developing+preschoolers.">Feasibility of the clinical dynamic visual acuity test in typically developing preschoolers.</a> European Archives of Oto-Rhino-Laryngology. 275 (5), 1343-1348 (2018).</li><li>Morgan, I. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+epidemics+of+myopia:+Aetiology+and+prevention.">The epidemics of myopia: Aetiology and prevention.</a> Progress in Retinal and Eye Research. 62, 134-149 (2018).</li><li>Lewerenz, D., Blanco, D., Ratzlaff, C., Zodrow, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+prism+on+preferred+retinal+locus.">The effect of prism on preferred retinal locus.</a> Clinical and Experimental Optometry. 101 (2), 260-266 (2018).</li><li>Lin, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peripheral+defocus+with+single-vision+eyeglass+lenses+in+myopic+children.">Peripheral defocus with single-vision eyeglass lenses in myopic children.</a> Optometry and Vision Science. 87 (1), 4-9 (2010).</li><li>Backhouse, S., Fox, S., Ibrahim, B., Phillips, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peripheral+refraction+in+myopia+corrected+with+eyeglasss+versus+contact+lenses.">Peripheral refraction in myopia corrected with eyeglasss versus contact lenses.</a> Ophthalmic and Physiological Optics. 32 (4), 294-303 (2012).</li><li>Bakaraju, R. C., Ehrmann, K., Ho, A., Papas, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pantoscopic+tilt+in+eyeglass-corrected+myopia+and+its+effect+on+peripheral+refraction.">Pantoscopic tilt in eyeglass-corrected myopia and its effect on peripheral refraction.</a> Ophthalmic and Physiological Optics. 28 (6), 538-549 (2008).</li><li>Hasegawa, T., Yamashita, M., Suzuki, T., Hisa, Y., Wada, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Active+linear+head+motion+improves+dynamic+visual+acuity+in+pursuing+a+high-speed+moving+object.">Active linear head motion improves dynamic visual acuity in pursuing a high-speed moving object.</a> Experimental Brain Research. 194 (4), 505-516 (2009).</li><li>Meyer, C. H., Lasker, A. G., Robinson, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+upper+limit+of+human+smooth+pursuit+velocity.">The upper limit of human smooth pursuit velocity.</a> Vision Research. 25 (4), 561-563 (1985).</li><li>Fogt, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+negative+directional+aftereffect+associated+with+adaptation+to+the+prismatic+effects+of+eyeglass+lenses.">The negative directional aftereffect associated with adaptation to the prismatic effects of eyeglass lenses.</a> Optometry and Vision Science. 77 (2), 96-101 (2000).</li><li>Chang, S. T., Liu, Y. H., Lee, J. S., See, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparing+sports+vision+among+three+groups+of+soft+tennis+adolescent+athletes:+Normal+vision,+refractive+errors+with+and+without+correction.">Comparing sports vision among three groups of soft tennis adolescent athletes: Normal vision, refractive errors with and without correction.</a> Indian Journal of Ophthalmology. 63 (9), 716-721 (2015).</li><li>Dacey, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiology,+morphology+and+spatial+densities+of+identified+ganglion+cell+types+in+primate+retina.">Physiology, morphology and spatial densities of identified ganglion cell types in primate retina.</a> Ciba Foundation Symposium. 184, 12-34 (1994).</li><li>Lee, M. W., Nam, K. Y., Park, H. J., Lim, H. B., Kim, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Longitudinal+changes+in+the+ganglion+cell-inner+plexiform+layer+thickness+in+high+myopia:+a+prospective+observational+study.">Longitudinal changes in the ganglion cell-inner plexiform layer thickness in high myopia: a prospective observational study.</a> British Journal of Ophthalmology. 104 (5), 604-609 (2020).</li><li>Seo, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ganglion+cell-inner+plexiform+layer+and+retinal+nerve+fiber+layer+thickness+according+to+myopia+and+optic+disc+area:+a+quantitative+and+three-dimensional+analysis.">Ganglion cell-inner plexiform layer and retinal nerve fiber layer thickness according to myopia and optic disc area: a quantitative and three-dimensional analysis.</a> BMC Ophthalmology. 17 (1), 22 (2017).</li><li>Zhang, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=eyeglass+wear,+and+risk+of+bicycle+accidents+among+rural+Chinese+secondary+school+students:+the+Xichang+Pediatric+Refractive+Error+Study+report+no.+7.">eyeglass wear, and risk of bicycle accidents among rural Chinese secondary school students: the Xichang Pediatric Refractive Error Study report no. 7.</a> Archives of Ophthalmology. 127 (6), 776-783 (2009).</li></ol>

The authors declare that they have no competing interests.

DVA is a promising indicator to assess visual function, which might better reflect actual vision in daily life. Myopic patients could have corrected, normal SVA, but their DVA might be affected. This study demonstrates a method to examine the DVA in myopic subjects with eyeglass correction accurately and analyzes its correlation with optometric parameters, including refraction, accommodation, and the dominant eye. The results indicated that DVA at 40 dps was superior to that at 80 dps. The closer the refraction state is to emmetropia, the better the eyeglass-corrected DVA at 40 and 80 dps. No correlation was found between DVA and accommodation function parameters and the dominant eye.
In the present study, the SVA was corrected completely with eyeglasses for all subjects. However, the DVA value differs from person to person. The single-factor linear mixed model results indicated that monocular and binocular mean sphere and SE are all significant influential factors for DVA, which means that the closer the refractive state is to emmetropia, the better the DVA at 40 and 80 dps. The results suggested that the decrease in DVA caused by ametropia may be challenging to completely correct with eyeglasses. Several mechanisms might be able to explain the results. The prism effect is stronger in larger diopter eyeglasses, which has a displacement effect on the object image18. Robust DVA depends on an accurate prediction of the target's motion trajectory to form an effective pursuit and saccade16,17. Thus, the prism effect may affect the subjects' prediction of the movement of dynamic visual targets and affect the pursuit, resulting in worse DVA18. Previous research demonstrates no significant difference in DVA among tennis athletes with normal vision or refractive errors with and without correction19. The difference in the results might be attributed to the difference in the test distance. The DVA test in that study was performed at a near distance (45 cm), and the near visual acuity might not have been affected in subjects with refractive error.
Future studies could further apply eye-tracking tools during DVAT to record ocular movements to substantiate this assumption. Moreover, the visual clarity in the peripheral region of eyeglasses is less clear than that in the central region due to peripheral defocus12. While observing moving targets, objects could not image constantly through the central zone20. Thus, unclear vision through the paracentral or peripheral visual field could impact DVA. Moreover, previous research has demonstrated that myopic eyes have a thinner GC-IPL and retinal nerve fiber layer (RNFL) than emmetropic eyes21,22. RNFL thickness and ganglion cell density decrease with increasing myopia diopter22. The decrease in ganglion cell density in myopic eyes may decrease the function of visual signal transmission and management, leading to a decrease in DVA conduction function.
The present study found that the diopter of eyeglasses influenced DVA with SVA correction, and the larger the diopter was, the worse the DVA. A previous study has shown that people wearing eyeglasses tend to experience a higher risk of traffic accidents23, which may be related to the impact of peripheral vision damage of eyeglasses on DVA. Thus, DVAT might better reflect functional vision in daily life to provide information for driving safety and sports performance. Since the diopter of eyeglasses significantly impacts the DVA, highly myopic subjects who have a higher demand for dynamic vision might choose to correct the refractive error with methods other than eyeglasses or have substantial career planning. In the future, the influence of other myopia correction methods on DVA, including contact lenses and refractive surgeries, can be further explored for occupational-based recommendations, including drivers and athletes. Moreover, considering the impact of age and refractive error correction on DVA, different ranges of normal values should be set according to age, and the impact of refractive error diopter should be considered when applying DVAT in the clinical setting.
Certain limitations exist in the present study. First, this study only investigated the impact of myopia on DVA in eyeglass-corrected patients. Other static distance visual acuity correction methods, including contact lenses and surgeries, might also influence DVA, which should be further investigated in the future. Second, only a single mode of optotype movement was applied in the test. More movement directions need to be explored in the future. A DVAT that can change the observation depth of the field can be designed to better reflect real-life scenes such as driving. Third, DVA is associated with eye tracking, including smooth pursuit and saccade. The present research lacks accessibility to eye-tracking devices, which is helpful for these kinds of studies. Further research could collect eye-tracking data during DVAT to substantiate ocular movement during the test. Fourth, compared with parvocellular (P) ganglion cells, magnocellular (M) ganglion cells primarily transmit high temporal frequency signals, which might be responsible for the visualization of the motion optotype in the test, which remains to be explored in future research.
In summary, the study evaluated and analyzed optometric influential factors in binocular DVA in myopic subjects whose vision was corrected to normal with eyeglasses. The results provided the normal values and distributions of DVA at 40 and 80 dps, and demonstrated that the binocular DVA at 40 dps was significantly superior to that at 80 dps. DVA improves first and then declines with aging. With SVA corrected with eyeglasses, the worse the monocular and binocular sphere and SE, the worse the DVA. No correlation was found between the dominant eye, accommodation function and DVA. The present research provides a standard and efficient protocol to examine DVA in eyeglass-corrected myopia patients, and provides the basis for better interpreting DVAT in clinical ophthalmology and evidence on the impact of eyeglass correction on motion-related activities.

Current visual assessment mainly focuses on static vision, including static visual acuity (SVA), visual field, and contrast sensitivity. In daily life, either the object or the observer is often in motion rather than being stationary. Therefore, SVA may not sufficiently reflect visual function in daily lives, especially when objects are moving at high speeds, such as during sports and driving1. DVA defines the ability to identify the details of moving optotypes1,2, which might reflect real-life situations better and be more sensitive to visual disturbance and improvement3,4. Moreover, as magnocellular (M) ganglion cells located mainly in the peripheral retina primarily transmit high temporal frequency signals, DVA might reflect visual signal transmission differently from SVA5,6. The DVA test (DVAT) can be mainly divided into two types: static- and moving-object DVATs. While the static-object DVAT demonstrates the vestibule-ocular reflex7,8,9,10, the moving-object DVAT is commonly applied in clinical ophthalmology to detect visual acuity in the identification of moving targets3,4.
The prevalence of myopia has rapidly increased in recent decades, especially in Asian countries11. Myopia has an essential impact on static uncorrected distance visual acuity, which could be corrected with various lenses. Eyeglasses are mostly used among myopia patients due to accessibility and convenience. However, eyeglasses, especially high myopia lenses, have obvious peripheral defocus and prism effects that cause unclear and skewed images to be observed through the peripheral region12,13,14,15. For a static optotype, the subject commonly uses the central area of eyeglasses that could obtain a clear vision. However, the moving target could easily move out of the eyeglasses&#39; clearest point. Thus, with eyeglass correction, myopic subjects might have normal SVA and affected DVA. However, no research has been performed to investigate the impact of myopia diopter on DVA in populations with eyeglasses.
This study demonstrates a method to examine DVA in eyeglass-corrected myopia patients and aimed to explore the impact of myopia diopter on moving-object binocular DVA in eyeglass-corrected patients. The research provides a basis for accurately interpreting DVAT in clinical ophthalmology considering the impact of eyeglasses and evidence on the influence of corrected myopia on motion-related activities.

<table><tbody><tr><td>Automatic computer optometry</td><td>TOPCON</td><td>KR8100</td><td></td></tr><tr><td>Corneal topography</td><td>OCULUS</td><td>Pentacam</td><td></td></tr><tr><td>Dynamic visual acuity test design software</td><td>Mathworks</td><td>matlab 2017b</td><td></td></tr><tr><td>Fundus photography</td><td>Optos</td><td>Daytona</td><td></td></tr><tr><td>Matlab</td><td>Mathworks</td><td>2017b</td><td></td></tr><tr><td>Noncontact tonometry</td><td>CANON</td><td>TX-20</td><td></td></tr><tr><td>Phoropter</td><td>&amp;nbsp;NIDEK</td><td>RT-5100</td><td></td></tr><tr><td>scientific statistical software</td><td>IBM</td><td>SPSS 26.0</td><td></td></tr><tr><td>Slit lamp</td><td>Koniz</td><td>IM 900</td><td></td></tr></tbody></table>

binocular dynamic visual acuity in eyeglass-corrected myopic patients

Current clinical visual assessment mainly focuses on static vision. However, static vision may not sufficiently reflect real-life visual function as moving optotypes are frequently observed daily. Dynamic visual acuity (DVA) might reflect real-life situations better, especially when objects are moving at high speeds. Myopia impacts static uncorrected distance visual acuity, conveniently corrected with eyeglasses. However, due to peripheral defocus and prism effects, eyeglass correction might affect DVA. The present research demonstrates a standard method to examine eyeglass-corrected DVA in myopia patients, and aimed to explore the influence of eyeglass correction on DVA. 
Initially, standard subjective refraction was performed to provide the eyeglass prescription to correct the refractive error. Then, binocular distance vision-corrected DVA was examined using the object-moving DVA protocol. Software was designed to display the moving optotypes according to the preset velocity and size on a screen. The optotype was the standard logarithmic visual chart letter E and moves from the middle of the left to the right side horizontally during the test. Moving optotypes with randomized opening direction for each size are displayed. The subjects were required to identify the opening direction of the optotype, and the DVA is defined as the minimum optotype that subjects could recognize, calculated according to the algorithm of logarithmic visual acuity.
Then, the method was applied in 181 young myopic subjects with eyeglass-corrected-to-normal static visual acuity. Dominant eye, cycloplegic subjective refraction (sphere and cylinder), accommodation function (negative and positive relative accommodation, binocular cross-cylinder), and binocular DVA at 40 and 80 degrees per second (dps) were examined. The results showed that with increasing age, DVA first increased and then decreased. When myopia was fully corrected with eyeglasses, a worse binocular DVA was associated with more significant myopic refractive error. There was no correlation between the dominant eye, accommodation function, and binocular DVA.

Subject examinations 
For the enrolled subjects, accommodation function, including negative relative accommodation (NRA), accommodation response (binocular cross-cylinder (BCC)), and positive relative accommodation (PRA), were examined in the mentioned order. Binocular DVA at 40 dps and 80 dps was tested with distance visual acuity-corrected eyeglasses based on subjective refraction.
Statistical analysis 
Statistical analysis was performed using scientific statistical software. Descriptive statistics of continuous variables were reported as the mean and standard deviation, and numbers and proportions were applied for categorical variables. The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes, and the binocular difference (D/ND) was calculated as the value of the nondominant eye subtracted from that of the dominant eye.
A paired t-test was used to compare the DVA at 40 dps and 80 dps. Curve estimation, including linear, quadratic, and cubic models, was used to fit the correlation between DVA and age. To analyze the potentially influential factors, linear mixed models were established to fit with DVA as the dependent variable and included the random effect at the subject level. First, single-factor linear mixed models were applied to estimate the effect of each variable as a covariant or factor according to the type of the variable. The following variables were tested as potential influential factors for DVA: refraction parameters, including the monocular and mean binocular sphere; cylinder and spherical equivalent (SE); and the absolute value of the difference in the binocular sphere; cylinder and SE; dominant-eye parameters, including dominant and nondominant-eye sphere; cylinder and SE; and the difference in the sphere, cylinder, and SE between the dominant and nondominant eye and accommodation function parameters, including NRA, BCC, and PRA.
Next, a multifactor linear mixed model was established to include several potential influential factors in one model. For a preparatory step, collinearity analysis was conducted with the included variables. A variance inflation factor greater than 10 was considered to indicate multicollinearity. Redundant variables were excluded based on clinical significance. Based on the influential factors used, two different models were fitted: the full and dominant-eye models. For the full model, the following variables were included: age; sex; accommodation function parameters (NRA, BCC, and PRA); mean binocular SE and the absolute value of the difference in the binocular cylinder and SE, dominant eye, dominant-eye cylinder, and the difference in cylinder and SE between the dominant and nondominant eyes following the preparatory collinearity analysis. For the dominant-eye model, only dominant-eye parameters were included as influential factors. P &#60; 0.05 denotes a significant difference.
The demographic and main clinical data of the included subjects are shown in Table 1. This study included 181 subjects, with an average age of 27.1 &#177; 6.3 years old, and males accounted for 37.6% of the subjects. The right eye was the dominant eye for 60.2% of subjects. The mean binocular sphere and cylinder were -5.26 &#177; 2.06 D and -0.99 &#177; 0.82 D, respectively. The absolute values of the difference in the binocular sphere and cylinder were 0.85 &#177; 0.91 D and 0.39 &#177; 0.34 D, respectively.
The cumulative LogMAR visual acuity of DVA at 40 and 80 dps and the histogram are presented in Figure 1. The cumulative results demonstrated that 75% of subjects possessed better than 0.2 LogMAR DVA for 40 dps and 62% for 80 dps DVA. The percentage of the subjects with better than 0.1 logMAR 40 dps binocular DVA was 22%, and for 80 dps, the percentage was 12%. The average binocular DVA values at 40 dps and 80 dps were 0.161 &#177; 0.072 and 0.189 &#177; 0.076, respectively, and the 40 dps DVA was significantly better than the 80 dps DVA (P &#60; 0.001).
The results of curve estimation between DVA and age are demonstrated in Figure 2. Significant results were obtained fitting an age-DVA of 40 dps with a quadratic (R2 = 0.38, P = 0.031) and cubic curve (R2 = 0.38, P = 0.030), but not a linear model (R2 = 0.21, P = 0.051). For 80 dps DVA, all the linear (R2 = 0.24, P = 0.035), quadratic (R2 = 0.43, P = 0.019), and cubic (R2 = 0.43, P = 0.020) curves could appropriately fit the age-DVA scatter plot.
Figure 3 demonstrates the effect of each potential influential factor for 40 and 80 dps DVA in single-factor linear mixed models, and the statistical results are summarized in Table 2 and Table 3. Larger right (estimate, -0.012), left (estimate, -0.010), dominant (estimate, -0.010), and nondominant (estimate, -0.010) eye spheres; larger right (estimate, -0.012), left (estimate, -0.010), dominant (estimate, -0.010) and nondominant (estimate, -0.010) eye SEs; and larger mean binocular spheres (estimate, -0.012) and SEs (estimate, -0.012) were significant negative influential factors of 40 dps DVA (P &#60; 0.001 for each variable). For DVA of 80 dps, larger monocular sphere and SE (estimate, -0.012, -0.010, -0.010, -0.010 for right, left, dominant, and nondominant eye, respectively; P &#60; 0.001 for each variable), larger left eye cylinder (estimate, -0.013; P = 0.04), larger nondominant eye cylinder (estimate, -0.016; P = 0.01), smaller binocular cylinder difference between dominant and nondominant eye (estimate, 0.027; P = 0.015), larger mean binocular sphere (estimate, -0.012; P &#60; 0.001) and SE (estimate, -0.012; P &#60; 0.001) were significant negative influential factors. Accommodation function parameters, including NRA, BCC, and PRA, were not significant influential factors for either 40 or 80 dps DVA.
Figure 4 illustrates the effects of factors and covariates for the full variables linear mixed model for 40 and 80 dps DVA, and the results are summarized in Table 4. When 40 dps DVA was used to measure variability, only a larger binocular mean SE (estimate, -0.012; 95% CI, -0.017 to -0.006; P &#60; 0.001) was a significant negative influential factor. Larger mean binocular SE (estimate, -0.011; 95% CI, -0.016 to -0.005; P &#60; 0.001) and older age (estimate, 0.002; 95% CI, 0.00002 to -0.004; P &#60; 0.048) were significant negative influential factors for 80 dps DVA.
Figure 5 shows the effect of factors and covariates for the dominant-eye multifactor linear mixed model, and the results are summarized in Table 5. Variables selected in the dominant-eye model included the dominant eye, dominant eye SE, dominant eye cylinder, binocular cylinder, and SE difference between the dominant and nondominant eyes based on collinearity analysis. When 40 and 80 dps DVA were used to measure variability, only larger dominant-eye SE (estimate, -0.010; 95% CI, -0.015 to -0.005; P &#60; 0.001 for 40 and 80 dps analysis) was a significant negative influential factor.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63864/63864fig01.jpg" /> 
Figure 1: Dynamic visual acuity distribution. (A) Histogram of DVA at 40 dps; (B) Histogram of DVA at 80 dps; (C) Cumulative percentage of DVA at 40 and 80 dps H. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/63864fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63864/63864fig02.jpg" /> 
Figure 2: Scatter plots and fitting curves showing the curve estimation between age and DVA. (A) Linear model for 40 dps DVA; (B) Quadratic model for 40 dps DVA; (C) Cubic model for 40 dps DVA; (D) Linear model for 80 dps DVA; (E) Quadratic model for 80 dps DVA; (F) Cubic model for 80 dps DVA. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/63864fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/63864/63864fig03.jpg" /> 
Figure 3: Forest plot showing the single-factor model. The central short stick indicates the estimates; bars indicate the 95% confidence interval. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/63864fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/63864/63864fig04.jpg" /> 
Figure 4: Forest plot showing the full model. The central short stick indicates the estimates; bars indicate the 95% confidence interval. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/63864fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/63864/63864fig05.jpg" /> 
Figure 5: Forest plot showing the dominant-eye model. The central short stick indicates the estimates; bars indicate the 95% confidence interval. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/63864fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Table 1: Demographic and main clinical data of the study population. The demographic data, refraction parameters, dominant eye parameters, and accommodation function of the study population are shown. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second; BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/Table 1 (18).xlsx" target="_blank">Please click here to download this Table.</a>
Table 2: Results of single-factor linear mixed model for 40 dps DVA variability. The statistical results of a linear mixed model are demonstrated with DVA of 40 dps as the dependent variable. The refraction, dominant eye, and accommodation function parameters serve as independent variables. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second; BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/Table 2 (6).xlsx" target="_blank">Please click here to download this Table.</a>
Table 3: Results of single-factor linear mixed model for 80 dps DVA variability. The statistical results of a linear mixed model are demonstrated with DVA of 80 dps as the dependent variable. The refraction, dominant eye, and accommodation function parameters serve as independent variables. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second; BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/Table 3 (3).xlsx" target="_blank">Please click here to download this Table.</a>
Table 4: Results of full model for 40 and 80 dps DVA variability. The statistical results of a multifactor linear mixed model are demonstrated with DVA of 40 or 80 dps as the dependent variable. The variables include age, sex, accommodation function parameters, mean SE, and the absolute value of the difference in the binocular cylinder and SE, dominant eye, dominant-eye cylinder, and the difference in cylinder and SE between the dominant and nondominant eyes following the preparatory collinearity analysis. *The binocular difference (OD/OS) was the absolute value of the difference between the right and left eyes. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second; BCC = binocular cross-cylinder; NRA = negative relative accommodation; PRA = positive relative accommodation; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/Table 4 (1).xlsx" target="_blank">Please click here to download this Table.</a>
Table 5: Results of dominant-eye model for 40 and 80 dps DVA variability. The statistical results of a linear mixed model are demonstrated with DVA of 40 or 80 dps as the dependent variable. The variables include dominant eye parameters. #The binocular difference (D/ND) was calculated subtracting the nondominant eye value from the dominant eye value. Abbreviations: DVA = dynamic visual acuity; dps = degrees per second; CI = confidence interval; DVA = dynamic visual acuity; SE = spherical equivalent. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63864/Table 5 (1).xlsx" target="_blank">Please click here to download this Table.</a>

Watch this Scientific Journal Video about Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients at JoVE.com

Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients

The present research demonstrates a method to accurately examine dynamic visual acuity (DVA) in myopic subjects with eyeglass correction. Further analysis indicated that the closer the refraction state to emmetropia, the better the eyeglass-corrected binocular DVA is at both 40 and 80 degrees per second.

Current clinical visual assessment mainly focuses on static vision. However, static vision may not sufficiently reflect real-life visual function as ...

binocular-dynamic-visual-acuity-in-eyeglass-corrected-myopic-patients

Universidad San Sebastian

Research

JoVE Journal

Medicine

2.5K Views.  Peking University Third Hospital. The present research demonstrates a method to accurately examine dynamic visual acuity (DVA) in myopic subjects with eyeglass correction. Further analysis indicated that the closer the refraction state to emmetropia, the better the eyeglass-corrected binocular DVA is at both 40 and 80 degrees per second.

Video: Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients

Dynamic Visual Tests to Identify and Quantify Visual Damage and Repair Following Demyelination in Optic Neuritis Patients

In order to follow optic neuritis patients and evaluate the effectiveness of their treatment, a handy, accurate and quantifiable tool is required to assess changes in myelination at the central nervous system (CNS). However, standard measurements, including routine visual tests and MRI scans, are not sensitive enough for this purpose. We present two visual tests addressing dynamic monocular and binocular functions which may closely associate with the extent of myelination along visual pathways. These include Object From Motion (OFM) extraction and Time-constrained stereo protocols. In the OFM test, an array of dots compose an object, by moving the dots within the image rightward while moving the dots outside the image leftward or vice versa. The dot pattern generates a camouflaged object that cannot be detected when the dots are stationary or moving as a whole. Importantly, object recognition is critically dependent on motion perception. In the Time-constrained Stereo protocol, spatially disparate images are presented for a limited length of time, challenging binocular 3-dimensional integration in time. Both tests are appropriate for clinical usage and provide a simple, yet powerful, way to identify and quantify processes of demyelination and remyelination along visual pathways. These protocols may be efficient to diagnose and follow optic neuritis and multiple sclerosis patients.
In the diagnostic process, these protocols may reveal visual deficits that cannot be identified via current standard visual measurements. Moreover, these protocols sensitively identify the basis of the currently unexplained continued visual complaints of patients following recovery of visual acuity. In the longitudinal follow up course, the protocols can be used as a sensitive marker of demyelinating and remyelinating processes along time. These protocols may therefore be used to evaluate the efficacy of current and evolving therapeutic strategies, targeting myelination of the CNS.

Object From Motion (OFM) and Time-constrained stereo protocols are sensitive tools to identify monocular and binocular dynamic visual function deficits, which are uniquely affected in optic neuritis patients. Furthermore, these tests may be used as quantitative noninvasive tools to assess the extent of myelination along visual pathways.

In order to follow optic neuritis patients and evaluate the effectiveness of their treatment, a handy, accurate and quantifiable tool is required to ...

Stereoacuity Improvement using Random-Dot Video Games

Conventional amblyopia therapy involves occlusion or penalization of the dominant eye, though these methods enhance stereoscopic visual acuity in fewer than 30% of cases. To improve these results, we propose a treatment in the form of a video game, using random-dot stimuli and perceptual learning techniques to stimulate stereoacuity. The protocol is defined for stereo-deficient patients between 7-14 years of age who have already received treatment for amblyopia and have a monocular best corrected distance visual acuity of at least 0.1 logMAR. Patients are required to complete a perceptual learning program at home using the video game. While compliance is stored automatically in the cloud, periodic optometry center visits are used to track patient evolution and adjust the game&#39;s stereoscopic demand until the smallest detectable disparity is achieved. The protocol has proved to be successful, and effectiveness is gauged in terms of a two-level gain on a random stereoacuity test (global stereoacuity or cyclopean stereoacuity reference test). Moreover, the random-dot stimuli learning transfers to medial lateral stereoscopic acuity according to a Wirt Circles test, in which success criteria is a final stereoacuity of over 140&#34;, and the attained enhancement corresponds to no less than two levels of stereoscopic acuity. Six months later, a random-dot stereoacuity test recorded no reduction in the stereoacuity that was achieved.

Presented here is a protocol to improve stereoacuity using gamified perceptual learning software based on random-dot stimuli. Patients are stereo-deficient subjects without strabismus. The protocol combines optometry center visits with home exercises using software. Compliance and stereoacuity evolution are stored in the cloud.

Conventional amblyopia therapy involves occlusion or penalization of the dominant eye, though these methods enhance stereoscopic visual acuity in fewer ...

Behavior

The Optokinetic Response as a Quantitative Measure of Visual Acuity in Zebrafish

Zebrafish are a proven model for vision research, however many of the earlier methods generally focused on larval fish or demonstrated a simple response. More recently adult visual behavior in zebrafish has become of interest, but methods to measure specific responses are new coming. To address this gap, we set out to develop a methodology to repeatedly and accurately utilize the optokinetic response (OKR) to measure visual acuity in adult zebrafish. Here we show that the adult zebrafish's visual acuity can be measured, including both binocular and monocular acuities. Because the fish is not harmed during the procedure, the visual acuity can be measured and compared over short or long periods of time. The visual acuity measurements described here can also be done quickly allowing for high throughput and for additional visual procedures if desired. This type of analysis is conducive to drug intervention studies or investigations of disease progression.

Zebrafish have been a valuable tool for many research areas. Here we demonstrate a method to elicit a visual response and calculate a functional visual acuity in the adult zebrafish.

Zebrafish are a proven model for vision research, however many of the  earlier methods generally focused on larval fish or demonstrated a simple  ...

Neuroscience

Assessing Binocular Central Visual Field and Binocular Eye Movements in a Dichoptic Viewing Condition

Macular degeneration typically results in heterogeneous binocular central visual defects. Currently available approaches to assess central visual field, like the microperimetry, can test only one eye at a time. Therefore, they cannot explain how the defects in each eye affect the binocular interaction and real-world function. Dichoptic stimulus presentation with a gaze-controlled system could provide a reliable measure of monocular/binocular visual fields. However, dichoptic stimulus presentation and simultaneous eye-tracking are challenging because optical devices of instruments that present stimulus dichoptically (e.g., haploscope) always interfere with eye-trackers (e.g., infrared video-based eye-trackers). Therefore, the goals were 1) to develop a method for dichoptic stimulus presentation with simultaneous eye-tracking, using 3D-shutter glasses and 3D-ready monitors, that is not affected by interference and 2) to use this method to develop a protocol for assessing central visual field in subjects with central vision loss. The results showed that this setup provides a practical solution for reliably measuring eye-movements in dichoptic viewing condition. In addition, it was also demonstrated that this method can assess gaze-controlled binocular central visual field in subjects with central vision loss.

Presented here is a protocol for assessing binocular eye movements and gaze-controlled central visual field screening in participants with central vision loss.

Macular degeneration typically results in heterogeneous binocular central visual defects. Currently available approaches to assess central visual field, ...

Quantification of Oculomotor Responses and Accommodation Through Instrumentation and Analysis Toolboxes

Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements can be observed. VisualEyes2020 (VE2020) was developed based on the lack of customizable software-based visual stimulation available for researchers that does not rely on motors or actuators within a traditional haploscope. This new instrument and methodology have been developed for a novel haploscope configuration utilizing both eye tracking and autorefractor systems. Analysis software that enables the synchronized analysis of eye movement and accommodative responses provides vision researchers and clinicians with a reproducible environment and shareable tool. The Vision and Neural Engineering Laboratory&#39;s (VNEL) Eye Movement Analysis Program (VEMAP) was established to process recordings produced by VE2020&#39;s eye trackers, while the Accommodative Movement Analysis Program (AMAP) was created to process the recording outputs from the corresponding autorefractor system. The VNEL studies three primary stimuli: accommodation (blur-driven changes in the convexity of the intraocular lens), vergence (inward, convergent rotation and outward, divergent rotation of the eyes), and saccades (conjugate eye movements). The VEMAP and AMAP utilize similar data flow processes, manual operator interactions, and interventions where necessary; however, these analysis platforms advance the establishment of an objective software suite that minimizes operator reliance. The utility of a graphical interface and its corresponding algorithms allow for a broad range of visual experiments to be conducted with minimal required prior coding experience from its operator(s).

VisualEyes2020 (VE2020) is a custom scripting language that presents, records, and synchronizes visual eye movement stimuli. VE2020 provides stimuli for conjugate eye movements (saccades and smooth pursuit), disconjugate eye movements (vergence), accommodation, and combinations of each. Two analysis programs unify the data processing from the eye tracking and accommodation recording systems.

Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements ...

Bioengineering

Assessing Early Stage Open-Angle Glaucoma in Patients by Isolated-Check Visual Evoked Potential

Recently, the isolated-check visual evoked potential (icVEP) technique was designed and has been reported to detect glaucomatous damage earlier and faster. It creates low spatial frequency/high temporal frequency bright stimuli and records cortical activity initiated primarily by afferents in the magnocellular ON pathway. This pathway contains neurons with larger volumes and axonal diameters, and it is preferentially damaged in early glaucoma, which can result in visual field loss. The study presented here uses standard operative procedures (SOP) of icVEP to obtain reliable results. It can detect visual function loss using a signal-to-noise ratio (SNR) corresponding to the defects of retinal nerve fiber layer (RNFL) in early stage open-angle glaucoma (OAG). A setting of 10 Hz and condition of 15% positive-contrast (bright) are selected to differentiate OAG patients and control subjects, with each check containing eight runs. Each run persists for 2 s (for 20 total cycles). A flowchart is constructed, which consists of pupil size and intraocular pressure over a 30 min rest period before each examination. Additionally, the testing order of eyes is performed to obtain reliable electroencephalographic signals. VEPs are recorded and analyzed automatically by software, and SNRs are derived based on a multivariate statistic. An SNR of &#8804; 1 is considered abnormal. A receiver-operating-characteristic (ROC) curve is applied to analyze the accuracy of group classification. Then, the SOP is applied in a cross-sectional study, showing that icVEP can detect glaucomatous visual function abnormality in the central visual field in the form of SNR. This value also correlates with the thickness thinning of RNFL and produces high classification accuracy for early stage OAG. Thus, it serves as a useful and objective diagnostic technology for the early detection of glaucoma.

The isolated-check visual evoked potential (icVEP) method is implemented here to assess the magnocellular ON pathway that is initially damaged in glaucoma. The study shows standard operative procedures using icVEP to obtain reliable results. It is proved to serve as a useful objective diagnosing technology for the early detection of glaucoma.

Recently, the isolated-check visual evoked potential (icVEP) technique was designed and has been reported to detect glaucomatous damage earlier and ...

Assessing Vision via Shape Recognition in Random Dot Kinematograms

Motion-Acuity Test for Visual Field Acuity Measurement with Motion-Defined Shapes

The standard visual acuity measurements rely on stationary stimuli, either letters (Snellen charts), vertical lines (vernier acuity) or grating charts, processed by those regions of the visual system most sensitive to the stationary stimulation, receiving visual input from the central part of the visual field. Here, an acuity measurement is proposed based on discrimination of simple shapes, that are defined by motion of the dots in the random dot kinematograms (RDK) processed by visual regions sensitive to motion stimulation and receiving input also from the peripheral visual field. In the motion-acuity test, participants are asked to distinguish between a circle and an ellipse, with matching surfaces, built from RDKs, and separated from the background RDK either by coherence, direction, or velocity of dots. The acuity measurement is based on ellipse detection, which with every correct response becomes more circular until reaching the acuity threshold. The motion-acuity test can be presented in negative contrast (black dots on white background) or in positive contrast (white dots on black background). The motion defined shapes are located centrally within 8 visual degrees and are surrounded by RDK background. To test the influence of visual peripheries on centrally measured acuity, a mechanical narrowing of the visual field to 10 degrees is proposed, using opaque goggles with centrally located holes. This easy and replicable narrowing system is suitable for MRI protocols, allowing further investigations of the functions of the peripheral visual input. Here, a simple measurement of shape and motion perception simultaneously is proposed. This straightforward test assesses vision impairments depending on the central and peripheral visual field inputs. The proposed&#160;motion-acuity test advances the capability of standard tests to reveal spare or even strengthened vision functions in patients with injured visual system, that until now remained undetected.

Author Spotlight: Assessment of Visual Acuity in Central Vision Loss Through Motion-Based Peripheral Vision Testing

A novel motion-based acuity test that allows the assessment of central and peripheral visual processing in low-vision and healthy individuals, along with goggles limiting peripheral vision compatible with MRI protocols, are described here. This method offers a comprehensive vision assessment for functional impairments and dysfunctions of the visual system.

The standard visual acuity measurements rely on stationary stimuli, either letters (Snellen charts), vertical lines (vernier acuity) or grating charts, ...

Excimer Laser Multifocal Double Aspheric Ablation for Presbyopia Correction

Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of presbyopia surgery. This prospective self-control study included 20 cases and 38 eyes of patients who underwent monocular bi-aspheric ablation profile correction of myopia with presbyopia at the Eye Hospital of Shandong University of Traditional Chinese Medicine from January 2023 to January 2024. These patients were selected for observation, and each patient's preoperative and postoperative uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), spherical aberration (SA) (within 6 mm), horizontal and vertical coma (within 6 mm), and corneal aspheric index (Q-value) (within 6 mm) were evaluated. Statistical data analysis was performed at different time points before and after the operation. There were statistically significant differences in UDVA between dominant and non-dominant eyes before and after surgery (Z = -3.784, p &lt; 0.001; Z = -3.817, p &lt; 0.001). Post-operatively, 90% of the non-dominant eyes achieved UNVA of J1 and above, and 95% of the bilateral eyes achieved UNVA of J1 and above. Significant differences were found in the SA of the dominant eyes, which showed a positive increase (Z= -3.784, p &lt; 0.001); however, compared with the dominant eye, the SA of the non-dominant eye was negatively increased, but the difference was not statistically significant (p = 0.08). There was a significant difference in the vertical coma of the dominant eye before and after the operation, but there was no significant difference in non-dominant eyes. There was no significant difference in the change of binocular horizontal coma before and after the operation. There were significant changes in the Q value of both eyes before and after the operation (Z = -3.923, p &lt; 0.001; Z = -3.51, p &lt; 0.001). After the monocular bi-aspheric ablation profile, the cornea of the non-dominant eye showed a prolate shape, negative SA increased, and the UDVA and UNVA improved after the operation.

Author Spotlight: Advancements in Refractive Surgical Correction for Presbyopia and Exploring Postoperative Visual Acuity

This article provides a step-by-step guide to correcting presbyopia with a monocular bi-aspheric ablation profile.

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of ...

 Evaluating Stereopsis in Unilateral Amblyopia: A Comparative Study

Comparison of Three Clinical Stereoscopic Methods for Measuring Binocular Visual Function During Amblyopic Treatment in Unilateral Amblyopia

This study aimed to compare the measuring stereopsis results of unilateral amblyopia during amblyopic treatment by employing some of the most widely used clinical tests. Thirty-four individuals with previously untreated unilateral amblyopia, aged 8.4 &#177; 2.7 years, were included in the study. Monocular (best corrected visual acuity [BCVA] at distance) and binocular (including Titmus, Random-dot, and Frisby stereopsis) visual functions were measured at baseline and 2-month and 6-month visits after synthetical treatment.
We found that Titmus stereopsis was always significantly better than Random-dot stereopsis (p &#60; 0.001). Frisby stereopsis was also always significantly better than Random-dot stereopsis (p &#60; 0.001). However, there was no significant difference between Titmus stereopsis and Frisby stereopsis (p = 0.562). However, interestingly, there was no significant difference in the mean improvement of the three stereopsis methods from baseline to the 2-month visit, F = 1.158, p = 0.318.
Similarly, a significant difference was also lacking in the mean improvement of the three stereopsis methods from baseline to the 6-month visit, F = 0.302, p = 0.740. We conclude that there will be different results obtained from different stereopsis measuring methods used to measure amblyopia in patients. We recommend performing at least two types of stereoscopic measurements to evaluate each case of amblyopia. However, for observing therapeutic effects, each measurement method has the same performance for clinical results during amblyopic treatment.

Here, we present three common stereopsis measurement methods to measure patients with amblyopia and the comparison of the efficacy of different methods.

This study aimed to compare the measuring stereopsis results of unilateral amblyopia during amblyopic treatment by employing some of the most widely used ...

Eye Exam

Source: Richard Glickman-Simon, MD, Assistant Professor, Department of Public Health and Community Medicine, Tufts University School of Medicine, MA
Proper evaluation of the eyes in a general practice setting involves vision testing, orbit inspection, and ophthalmoscopic examination. Before beginning the exam, it is crucial to be familiar with the anatomy and physiology of the eye. The upper eyelid should be slightly over the iris, but it shouldn&#39;t cover the pupil when open; the lower lid lies below the iris. The sclera normally appears white or slightly buff in color. The appearance of conjunctiva, a transparent membrane covering the anterior sclera and the inner eyelids, is a sensitive indicator of ocular disorders, such as infections and inflammation. The tear-producing lacrimal gland lies above and lateral to the eyeball. Tears spread down and across the eye to drain medially into two lacrimal puncta before passing into the lacrimal sac and nasolacrimal duct to the nose.
The iris divides the anterior from the posterior chamber. Muscles of the iris control the size of the pupil, and muscles of the ciliary body behind it control the focal length of the lens. The ciliary body also produces aqueous humor, which largely determines intraocular pressure (Figure 1). Cranial nerves II and III control pupillary reaction and lens accommodation; cranial nerve III controls upper lid elevation; cranial nerves III, IV, and VI control eye movement. The six cardinal directions of gaze are controlled by six extraocular muscles (Figure 2) innervated by cranial nerves III, IV, and VI.
Visual testing is an essential part of the ophthalmological exam and is also performed as a part of cranial nerve II assessment during the neurological exam. A focused image is projected onto the retina after its light passes through the cornea, pupil, lens, and vitreous body. The projection is upside down and reversed right to left, which means that light entering from the lower temporal field of vision strikes the upper nasal quadrant of the retina. Photosensitive cells of the retina respond by generating electrical impulses, which are relayed to the optic nerve and passed to the visual cortex through the optic tracts. The right and left visual cortices process images entering from the left and right visual fields, respectively.
<img alt="Figure 1" src="/files/ftp_upload/10149/10149fig1.jpg" /> 
Figure 1. Anatomy of the Eye. A diagram showing a sagittal view of the human eye with the structures labeled.
<img alt="Figure 2" src="/files/ftp_upload/10149/10149fig2.jpg" />
Figure 2. Muscles of the Eye. A cartoon showing a frontal view of the human eye and the extraocular muscles (labeled).

Anatomy and Physiology of Eye; Acuity and Vision Testing

Source: Richard Glickman-Simon, MD, Assistant Professor, Department of Public Health and Community Medicine, Tufts University School of Medicine, MA
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