Recently, a new chart using a dynamic target visual assessment tool was developed. This chart, called the Dynamic Optotype chart (DYOP) uses a segmented, circular figure composed of equally spaced gaps/segments that spin at a constant velocity. Our study goal was to evaluate the DYOP chart. Children were tested with the DYOP visual acuity test and the ETDRS Lea numbers chart. The results of both tests were compared.

Design and Methods:

• Prospective study.
• Consecutive patients ,ages of 4 – 17 years, presenting for eye examinations at the
Pediatric Ophthalmology section of Meir Medical Center.
• N=157: 76 males and 81 females, mean patient age: 8.4 years (±2.88 years);
range: 4–17 years
• Visual acuity in at least one eye in the range 6/4.8 to 6/60 as determined
previously with Lea numbers ETDRS chart
• Distance visual acuity was determined monocularly using both the Lea numbers
ETDRS chart and the Dyop test , alternating the order of administration between
patients; The worst-seeing eye of each patient was tested.

Conclusions:
• A strong linear correlation (r =0.88) between the
visual acuity measures was found . The mean
difference in acuity was -0.01 (95%,CI) -0.02 to
0.01.
• The 95% limits of agreement were ±1.2 lines. The
logMAR, equivalent was about less than 1 letter.
• The DYOP test underestimated vision (not clinically
significant) relative to the Lea numbers ETDRS
chart.
• The results of this study, the first prospective study
in pediatric population, support the DYOP eye chart
as a valid measure of visual acuity among pediatric
patients 4 to 17 years-of-age, with vision ranging
from 20/16 to 20/200.

References:
(1) Tsou BC, Bressler NM. Visual acuity reporting in clinical research publications. JAMA Ophthalmol. 2017;135:651-653.
(2) Cromelin CH, Candy TR, Lynn MJ, Harrington CL, Hutchinson AK. The handy eye chart: a new visual acuity test for use in children.
Ophthalmology. 2012;119:2009-13.
(3) Anstice NS, Thompson B. The measurement of visual acuity in children: an evidence-based update. Clin Exp Optom.
2014;97(1):3-11.
(4) Harris P. Validation of the DYOP Acuity Test, ARVO annual meeting, 2015.

Methods: Forty subjects with visual acuity better than 6/12 (20/40) and ages between 20 and 28 years (24.48 ± 2.01 years) were recruited at the University of Benin Optometry Clinic. Snellen and Dyop acuity charts were displayed on a monitor at a distance of 6 meters. The assessment sequence between the two acuity chart formats was alternated for every other patient to reduce potential refractionist bias. Subjective refraction was measured in both eyes, and the duration of testing for each patient and each method was recorded.

Results: There was no significant mean Thibos notations difference, M (p = 0.77), J0 (p = 0.27), and J45 (p = 0.57) using the Bland-Altman plot and 95% limits of agreement between the two charts, and there were no differences as to age or gender. There was, however, a disparity in the mean acuity of about 0.25 diopters with the mean Snellen acuity of 1.60 ± 0.21 decimal units and the mean Dyop acuity of 1.17 ± 0.14 decimal units with a linear relationship: y = 0.3121x + 0.6709 (p = 0.00). The refraction with a Dyop acuity chart also typically took half as long (339 ± 122 seconds) as the refraction with a Snellen acuity chart (680 ± 281 seconds), p = 0.00.

Conclusions: Subjective refractions with a Dyop chart were comparable to a Snellen chart. The
efficiency of a Dyop refraction, however, was typically twice that of the Snellen chart, with a
narrower variance in visual acuity measurements and an improved level of acuity of about 0.25
diopters.

Keywords: Dyop acuity chart, Snellen acuity chart, subjective refraction, visual acuity

A Dyop® (or dynamic optotype) is a spinning segmented ring visual target which uses the strobic detection of the spinning gaps/segments of the ring to measure visual function.  Dyop gap/segment color/contrast permutations have distinctive, and corresponding, acuity
endpoints. This study’s objective was to compare the qualitative acuity responses of a specific Dyop color/contrast combination to diagnosed symptoms of dyslexia.

Methods: One hundred and eighty-eight patients, ranging in age from 4 years to 44 years, were examined as patients of the Stark-Griffin Dyslexia Academy to compare their relative color/contrast
acuity endpoint perception of a spinning green-on white Dyop versus a spinning blue-on-black Dyop and the possible diagnosis of types of dyslexia. The Stark-Griffin Dyslexia Academy trains eye care professionals as to how to diagnose and treat patients with potential symptoms of dyslexia. The patients were diagnosed as to their prevalent type of dyslexia, if any, through the Stark-Griffin Dyslexia Assessment. The patients were then presented
with, as part of the Chart2020 vision test platform, a display which has an identical-diameter spinning
green-on-white Dyop and spinning blue-on-black Dyop with sufficient arc width diameter such that both Dyop rings were detected as spinning. Those identically sized Dyop rings were then reduced in arc width until spinning of each of the colored rings was not detected. The smallest diameter ring where spinning was detected for each of the
color/contrast combinations (corresponding to the acuity endpoint metric value) was recorded as the color acuity endpoint.

Results: Of the 188 patients, 166 (88% of the total) were formally diagnosed with dyslexia, and 22 patients (12% of the total) were diagnosed as not having dyslexia. Of the166 patients diagnosed with dyslexia, 151 patients (86% of that group) detected a smaller angular arc width diameter for the spinning blue-on-black Dyop, while 9 patients
(5% of that group) detected a smaller angular arc width diameter for the spinning green-on white Dyop. Of the 22 patients (12% of the total) diagnosed as not having dyslexia, 12 patients (55% of that group) detected a smaller angular arc width for the spinning green-on-white Dyop, while 9 patients (41% of that group) detected a smaller angular arc width for the spinning blue-on black Dyop. Of the 22 patients diagnosed as not having dyslexia, one was diagnosed as “cognitively challenged,” one was diagnosed as a “slow reader” (albeit not dyslexic), and one was diagnosed as having ADHD. There was an additional group of 16 patients (9% of the total) which responded by
detecting identical acuity endpoints for both the green-on-white Dyop and the blue-on-black Dyop. Of the patients who detected an identical acuity endpoint for both color options, 1 patient (5% of that group) was diagnosed as not having dyslexia, and 15 patients (95% of that group) were diagnosed with dyslexia. Of the 151 patients with a definitive color response and diagnosed dyslexia, 142 (94%) detected a smaller angular arc width for the spinning blue-on-black Dyop. Of the 21 patients with a definitive color response and diagnosed as not having dyslexia, 12 (57%) detected a smaller angular arc width for the spinning green-onwhite Dyop. While this is only a preliminary study, the correlation of detecting a smaller angular arc width for a spinning blue-on-black Dyop with the 86% association with diagnosed dyslexia definitely deserves further evaluation.

Conclusions: This preliminary evaluation of the disparity of color perception versus diagnosed symptoms of dyslexia showed a strong positive association (~86%) between color perception and diagnosed symptoms of dyslexia. The findings suggest that symptoms presented by dyslexics could be better understood or analyzed by their color perception.

Keywords: color perception, visual acuity, dyslexia, Dyop acuity chart

Methods: Fifty-nine patients (105 eyes) with senile cataracts aged 40 years or older, and with no other ocular pathologies, were evaluated as to visual acuity for pre and post cataract surgery using the Snellen acuity and Dyop acuity charts.

Results: Cataracts were nuclear in 50 eyes, nuclear and posterior sub capsular in 24 eyes, nuclear and cortical in 23 eyes, nuclear, cortical and posterior sub capsular in 4 eyes as well as nuclear, anterior and posterior sub cortical in 2 eyes, pre cataract surgery. The average spherical equivalents pre cataract surgery refractive assessments for the patients were -0.61±2.81D and -0.63±3.22D for right and left eye respectively. The mean VA measured at pre cataract surgery were significantly overestimated with Snellen (OD: 0.64 ± 0.15, OS: 0.69 ± 0.23 decimal units) versus Dyop (OD: 0.53 ± 0.25, OS: 0.55 ± 0.24 decimal units), for both eyes (OD: p = 0.01, OS: p = 0.01). The mean VA measured at post cataract surgery were also significantly overestimated with Snellen (OD: 0.88 ± 0.22, OS: 0.85 ± 0.20 decimal units) versus Dyop (OD: 0.72 ± 0.22, OS: 0.72 ± 0.23 decimal units), for both eyes (OD: p = 0.00, OS: p = 0.01). The Bland Altman plots of difference in the means for assessment of visual acuity with the two charts against the average means for assessment of visual acuity with the two charts for both eyes, were not within clinically acceptable levels, pre and post cataract surgery.

Conclusions: Visual acuity measurements for pre and post cataract surgery were different with a
Snellen acuity chart and a Dyop acuity chart in that the Dyop test was a more precise indicator of acuity resolution. These two charts cannot be used interchangeably. The apparent strength of the Dyop acuity assessment is that it primarily utilizes resolution acuity, thus preventing overestimation of visual acuity which is inherent in the recognition acuity of the Snellen test.

Keywords: Visual Acuity; Visual acuity charts; Age-Related Cataract; Cataract Surgery

Methods: A total of over sixty subjects with ages of approximately between 20 and 60 years were
selected from workers at two South African manufacturing facilities. Tumbling “E” Snellen acuity
tests and then Dyop acuity charts were utilized on a monitor and the subjects were screened for
these visual acuity thresholds at a distance of 3 metres. The subjects were first tested on
Tumbling “E” Acuity by one tester and then immediately tested by another tester on the Dual
Dyop Screening test. The scores were written down and analyzed after all subjects had been
screened. Of critical importance was the ability of the test to screen for individuals with acuity of
6/9.5 or worse in both eyes or 6/14 or worse in one eye (refer/not refer criteria).
Results: There was a high level of correlation between the acuity assessments using the two
charts. There was, however, a disparity in the mean acuity of about ‐0.5 meters (‐0.04 LogMAR
units) with a mean Tumbling “E” acuity of 6/6.4 versus a mean Dyop acuity of 6/5.8. The typical
acuity testing with a Dyop acuity chart also took half as long as the acuity with the Tumbling “E”
acuity chart.

Conclusions: Acuity testing with a Dyop chart is comparable to a Tumbling “E” Snellen chart. The
efficiency (in terms of time) of the Dyop acuity test, however, was typically twice that of the
Tumbling “E” vision chart, with a narrower variance in visual acuity measurements and an
improved level of acuity equivalent to about 0.125 diopter.

Keywords: Dyop® acuity chart, Tumbling “E” vision chart, Snellen acuity chart, visual acuity.

Conclusion:
The Dyop test has previously proven to be a more precise and efficient method of measuring visual acuity in
Adults and Children versus the Snellen test. Due to the not yet fully developed nature of the infant visual
system, the significantly more subtle methodology for Adult and Children’s testing is not simple enough. By
implementing a simpler single Dyop with a basic Black/White strobic acuity dynamic stimulus, the Dyop
Infant acuity test should prove to be a precise and efficient methodology of measuring infant vision using the
same metrics and parameters as adult vision and based on identical technology. When used with
color/contrast permutations, the Dyop Infant Acuity Test might also be a diagnostic for potential symptoms of
dyslexia, migraines, and epilepsy. It should also prove to be a far more precise, more efficient, more
convenient, and less expensive method of measuring infant acuity than use of the Teller Acuity Cards for
infant acuity testing.

References:
1. Hytowitz, Allan, Dyop Test Instructions: https://www.chart2020.com/Trial/Research/Dyop_Test_Instructions.pdf
2. Harris, PA, and Keim, E. Validation of the Dyop™ Visual Acuity Test. Investigative Ophthalmology & Visual
Science. 2015 Jun 11; 56(7): 3888-
3. Chase C, Dougherty RF, Ray N, Fowler S, Stein J. L/M speed-matching ratio predicts reading in children.
Optom Vis Sci. 2007 Mar;84(3):229-36. doi: 10.1097/OPX.0b013e31803399df. PMID: 17435537.
4. Esposito C, Harris P. Relieve Migraines with Tinted Contact Lenses, Optometry Times. 2015 Jan 15.
5. Drew S, Borsting E, Stark L, Chase C. Chromatic Aberration, Accommodation, and Color Preference in
Asthenopia. Optometry and Vision Science: July 2012 – Volume 89 – Issue 7; p 1059–1067