Quantifying Suppression in Anisometropic Amblyopia With VTS4 (Vision Therapy System 4)

Abstract

Visual acuity (VA) of the amblyopic eye is usually considered for monitoring improvement with therapy. However, participation of the amblyopic eye under binocular viewing conditions is also important. This study investigated the use of a clinically available tool VTS4 (Vision Therapy System 4) to quantify the participation or suppression of the amblyopic eye under binocular viewing conditions. Methods: A cross-sectional study on patients with anisometropic amblyopia was undertaken. Monocular VA was thresholded. Stereo acuity was measured with Randot stereo test. Simultaneous macular perception (SMP) targets in VTS4 were dichoptically presented. SMP target size was reduced till the amblyopic eye's target disappeared (suppression scotoma size). An average of three measurements was taken for the suppression scotoma size. Results: Twenty-eight patients participated (aged 6 to 21 years). The mean interocular VA difference was 0.50 ± 0.27 logMAR. The mean scotoma size was 8.2°± 5.4°. Mean stereo acuity was 2.06 ± 0.34 log arc seconds from 21 patients on whom stereopsis could be measured. Suppression scotoma size showed a significant (P < 0.001) positive correlation with both interocular VA difference (r = 0.59) and stereoacuity (r = 0.72). Conclusions: Participation of the amblyopic eye under binocular viewing condition can be assessed by measuring the suppression scotoma size in VTS4, even when stereoacuity is poor or not measurable. Smaller the suppression scotoma, better is the amblyopic eye's participation. Translational Relevance: VTS4 can be used in monitoring amblyopia therapy by quantifying suppression of the amblyopic eye.

Relationship Between Suppression Scotomas and Stereoacuity in Anisometropic Amblyopia With Successfully Treated Visual Acuity

“…Available reports showed no studies in which the patients were younger than those in the present study ( Table 3 ). 10 – 14 , 27 , 28 , 44 The quantitative measurement of suppression scotomas using P4D is one of the valid methods for children.…”

“…Few reports are available regarding trials on the quantitative measurement of suppression scotomas with protocols that may be applied to children. 27 , 28 However, the number of cases in children younger than 6 years of age are at most 20. 27 , 28 Thus, the clinical significance of scotoma suppression remains poorly understood in children.…”

“… 27 , 28 However, the number of cases in children younger than 6 years of age are at most 20. 27 , 28 Thus, the clinical significance of scotoma suppression remains poorly understood in children.…”

Serious Games for Vision Training Exercises with Eye-Tracking Technologies: Lessons from Developing a Prototype

“…A common vision problem in early childhood is amblyopia. This issue is associated with abnormal visual acuity in or between two eyes that disrupts visual function [19]. The treatment of amblyopia is limited by age, and it is recommended to begin amblyopia treatment as early as possible [20].…”

The Association Between Improvement of Stereoacuity and Suppression in the Treatment of Anisometropic Amblyopia

“…Suppression is one of the factors that affects stereoacuity in patients with unilateral amblyopia. Several studies have reported the presence of suppression in anisometropic amblyopia [11][12][13][14][15][16][17][18] and its association with decreased stereoacuity. [11][12][13]15,16 These studies suggest that the key to treating amblyopia lies not only in improving VA but also in eliminating suppression and enhancing binocular function to acquire stereoacuity.…”