Dyop® - Dynamic Optotype™

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Experimental Test

 

 

The Dyop® Test Optimizes the Refraction Process.

Dyop® tests provide Eye Care Professionals with “better patients” and less stress

The Dyop® Test reduces overminus, underminus, and doctor/patient visual stress.

 

Dyop® Professional Test

 

Chart2020 Brochure

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Chart2020 Manual

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Dyop® Refraction Procedure

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Dyop® Professional Users’ Guide

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Dyop® Clinical Trial Report – ARVO 2015

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Preliminary studies indicate that Dyop® acuity tests:

·       are more accurate than Snellen/Sloan tests,

·       are more consistent than Snellen/Sloan tests,

·       are potentially faster to use than Snellen/Sloan tests,

·       maintain greater precision as refractive power increases,

·       inherently avoid overminused and underminused refractions,

·       minimize optotype fixation and decision fatigue,

·       minimize image memorization,

·       do not require the ability to read to measure visual acuity,

·       potentially save doctors and patients’ time and money in determining visual needs.

 

Dyop® acuity tests are intended to be a more precise and faster to use replacement for Snellen, Sloan, and Landolt visual acuity/refraction tests. 

 

Dyop® tests use apparent motion detection from the strobic stimulus and refresh rate of the photoreceptors to determine the visual acuity and refraction endpoints.  Snellen letters are culturally derived, NOT proportional, and do NOT provide a consistent basis for determining visual acuity.  As a result, Dyop® tests are more accurate and efficient than the 1862 classic Snellen test, and create a visual acuity test based on physiology rather than subjective and imprecise cognition. 

 

Dyop® tests enable patients to have a visual acuity endpoint which avoids overminused refractions which seem to be inherent with static image fixation.  It is typically difficult for patients to perceive when optotypes are "too crisp" (over- minused), despite the discomfort and visual stress, which is one of the inherent inadequacies with Snellen and other static image tests. 

 

Dyop® tests determine visual acuity based upon photoreceptor physiology with a precision (approximately +/- 0.06 diopters) not previously available with traditional static image visual acuity tests.  Unlike static image tests, which may be dependent upon cognition as much as they are for visual acuity, Dyop® tests also maintain a higher level of accuracy as visual acuity decreases with increased blur. 

 

 

The response disparity between the Sloan and Dyop® tests are theoretically due to:

 

The 2013 projected Sloan optotypes are “fuzzier” than the 2013 computer generated Sloan optotypes, and thereby give a “fuzzier” acuity response.

 

The 0.54 arc minutes squared Dyop® visual stimulus area (the arc width of the gap/segments) is smaller and inherently more precise than the 1.0 arc minute squared visual stimulus area (the “Minimum Area of Resolution”) of Snellen/Sloan/Landolt optotypes.

 

The 0.54 arc minutes squared Dyop® visual stimulus area correlates to about 20 photoreceptors.

 

Fixating on static images increases accommodative stress, which leads to over-minused refractions.  The visual dissonance from over-minused refractions is a major reason for patients’ complaining about their lenses and/or not wearing their lenses at all. 

 

 

The Dyop® Acuity/Refraction Test can be used on virtually any personal computer system with minimal setup-up and training.  Dyop® vision testing should increase the accuracy of prescriptions, let patients more easily know when their vision is not proper, maintain higher practitioner testing consistency, and potentially save doctors and patients’ time and money when getting their vision checked.

 

The Dyop® concept is revolutionary, both literally and culturally.  Previous static methodologies for measuring visual acuity were culturally based and a combination of the perceptual guesses of the subject and the observational guesses of the examiner.  The 1862 Snellen test, and the 1888 Landolt ring as an attempt at a “culturally neutral” test, use static images with a limited precision increment range that is no longer adequate for a society where much of the day is spent looking at the precision of a computerized display and/or regularly travelling at speeds greater than 55 miles per hour (88.5 kilometers per hour).  Snellen letters are culturally derived, NOT proportional, and do NOT provide a consistent basis for determining visual acuity:   Snellen tests also ignore the fact that the visual stimulus is the “Minimum AREA of Resolution” rather than the “Minimum ANGLE of Resolution.”

 

Visual acuity measurement in increments of +/- 0.25 diopters was acceptable and adequate in 1862 because of the difficulty of making lenses more precisely than +/- 0.25 diopters.  Visual testing in increments of +/- 0.25 diopters was also adequate because of the small percentage of the population able to read, or needed to be able to read.

 

Varying Difficulty of Snellen Letters and Common Errors in Amblyopic and Fellow Eye

PDF File

http://archopht.ama-assn.org/cgi/content/abstract/129/2/184

 

http://archopht.jamanetwork.com/article.aspx?articleid=426887

 

Snellen test responses also are NOT equivalent to the responses from the academically preferred Landolt ring test.  Because of the increased cognition factor inherent in the non-uniformity of the Snellen letters, for them to be equivalent to the 5 arc minute size of Landolt rings, Snellen letters should actually be only 4.25 arc minutes in size (15% smaller) and NOT the currently accepted 5.0 arc minutes:

 

Correlation of Optotypes with the Landolt Ring

PDF file

 

Recognition versus Resolution

 

 

Note: Dyop® tests are for vision screening purposes only and are NOT a substitute for an examination by a licensed vision care professional.  

 

The Dyop® (Dynamic Optotype™) tests and concept are covered under U.S. Patent US 8,083,353

and International Published Patent WO 2011/022428.

For further information contact: Allan Hytowitz at Allan@Dyop.org

5035 Morton Ferry Circle, Alpharetta, GA, 30022   /   678-893-0580

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