Worth 4 Dot App for Determining Size and Depth of Suppression.

Ann L Webber,Thomas R Mandall,Lucas J Lister,Eileen E Birch,Darcy T Molloy

doi:10.1167/tvst.9.4.9

Abstract

PurposeTo describe and evaluate an iOS application suppression test, Worth 4 Dot App (W4DApp), which was designed and developed to assess size and depth of suppression.MethodsCharacteristics of sensory fusion were evaluated in 25 participants (age 12–69 years) with normal (n = 6) and abnormal (n = 19) binocular vision. Suppression zone size and classification of fusion were determined by W4DApp and by flashlight Worth 4 Dot (W4D) responses from 33 cm to 6 m. Measures of suppression depth were compared between the W4DApp, the flashlight W4D with neutral density filter bar and the dichoptic letters contrast balance index test.ResultsThere was high agreement in classification of fusion between the W4DApp method and that derived from flashlight W4D responses from 33 cm to 6 m (α = 0.817). There were no significant differences in success rates or in reliability between the W4DApp or the flashlight W4D methods for determining suppression zone size. W4DApp suppression zone size strongly correlated to that determined with the flashlight W4D (rho = 0.964, P < 0.001). W4DApp depth of suppression measures showed significantly higher success rates (χ2 = 5.128, P = 0.043) and reliability (intraclass correlation analysis = 0.901) but no significant correlation to the depth of suppression calculated by flashlight W4D and neutral density bar (rho = 0.301, P = 0.399) or contrast balance index (rho = −0.018, P = 0.958).ConclusionsThe W4DApp has potential clinical benefit in measuring suppression zone size; however, further modifications are required to improve validity of suppression depth measures.Translational RelevanceW4DApp iOS application will be a convenient tool for clinical determination of suppression characteristics.

Highlights

The Worth 4 Dot (W4D) test was first developed to assess binocular perception by Claud Worth in 19031 and remains one of the world’s most frequently used clinical tools to evaluate unilateral suppression under binocular viewing conditions.[2,3,4] Criticism of the test includes lack of standardization in manufacture, and in spacing and subtended visual angles of the dots.[5]
We developed an iOS application suppression test, the Worth 4 Dot App (W4DApp) to address the limitations of the classic Worth 4 Dot test
In those participants with abnormal sensory fusion, the success rate, reliability and validity for determination of suppression zone size, and depth of suppression were compared between the novel W4DApp and flashlight W4D

Summary

Introduction

The Worth 4 Dot (W4D) test was first developed to assess binocular perception by Claud Worth in 19031 and remains one of the world’s most frequently used clinical tools to evaluate unilateral suppression under binocular viewing conditions.[2,3,4] Criticism of the test includes lack of standardization in manufacture, and in spacing and subtended visual angles of the dots.[5]. The use of polarized targets improved interpretable response rates and significantly decreased dissociation,[2,3] and increased success rates in young children was achieved with use of shaped targets instead of dots.[8]

Methods

Results

Conclusion