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

Summary

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

Abstract

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 ± 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 < 0.001). Frisby stereopsis was also always significantly better than Random-dot stereopsis (p < 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.

Introduction

Amblyopia is a disorder of development of the visual system that results from abnormal visual input during the critical phase of early development, affecting between 1% and 5% of the general population^1,2,3,4. It often affects only one eye, caused by strabismus, anisometropia, or form deprivation during visual development. Persons with unilateral amblyopia are clear-sighted under normal everyday viewing conditions, but the vision is dominated by the strong eye. Webber suggested that reduced stereopsis is the most common visual deficit associ....

Protocol

The study protocol was approved by the institutional review board of Anhui Medical University. Written informed consent was obtained from each participant's parent or legal guardian after an explanation of the nature and possible consequences of the study. The methods and data collection were carried out under approved guidelines. Thirty-four individuals with unilateral amblyopia, including 21 boys and 13 girls aged 8.4 ± 2.7 years, were included in this study. They were recruited from the Department of Ophthalm.......

Discussion

Study design and participants
The 34 participants with unilateral amblyopia, including 21 boys and 13 girls aged 8.4 ± 2.7 years, were newly diagnosed and had never received any treatment (including spectacle wear or occlusion) before they participated in the study. In the 34 participants, anisometropic amblyopia was most prevalent (25/34, 74%), whereas strabismic amblyopia was least prevalent (9/34, 26%). The clinical details are shown in Table 1.

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Materials

Name	Company	Catalog Number	Comments
40 cm mark ruler
Frisby stereoscopic vision tester	Frisby Stereotest Co., UK	-	This stereopsis consists of three items:6 mm plate (340 arcsec), 3 mm (170 arcsec), 1.5 mm (55 arcsec).
Random-dot stereoscopic vision tester	Baoshijia Co., China	-	This stereopsis consists of  seven Random-dot stereograms (from 800 to 40 arcsec).
SPSS 24.0	IBM Corp., Armonk, NY		Statistical analysis software
Standard Tumbling E Chart	Bjsibote Co., China	-	Executive standard number: GB/T 11533-2011
Stopwatch
Titmus stereoscopic vision tester	Stereo Optical Co., America	SO005	This stereopsis consists of three items: the butterfly (3,000 arcsec), animals (800, 400, 200 arcsec), and circles (800–40 arcsec).