Interocular Shift of Visual Attention Enhances Stereopsis and Visual Acuities of Anisometropic Amblyopes beyond the Critical Period of Visual Development: A Novel Approach.

Liwen Huang,Hong Liu,Xinghuai Sun,Rui Liu,Vicky Wing Lai Wong,Gang Luo,Ai-Hou Wang,Shuai Liu,Behzad Mansouri,Wen Wen

doi:10.1155/2014/615213

Abstract

Aims. Increasing evidence shows that imbalanced suppressive drive prior to binocular combination may be the key factor in amblyopia. We described a novel binocular approach, interocular shift of visual attention (ISVA), for treatment of amblyopia in adult patients. Methods. Visual stimuli were presented anaglyphically on a computer screen. A square target resembling Landolt C had 2 openings, one in red and one in cyan color. Through blue-red goggles, each eye could only see one of the two openings. The patient was required to report the location of the opening presented to the amblyopic eye. It started at an opening size of 800 sec of arc, went up and down in 160 sec of arc step, and stopped when reaching the 5th reversals. Ten patients with anisometropic amblyopia older than age 14 (average age: 26.7) were recruited and received ISVA treatment for 6 weeks, with 2 training sessions per day. Results. Both Titmus stereopsis (z = −2.809, P = 0.005) and Random-dot stereopsis (z = −2.317, P = 0.018) were significantly improved. Average improvement in best corrected visual acuity (BCVA) was 0.74 line (t = 5.842, P < 0.001). Conclusions. The ISVA treatment may be effective in treating amblyopia and restoring stereoscopic function.

Highlights

Amblyopia is a developmental disorder associated with early abnormal visual experience that disrupts neuronal circuitry in the visual cortex and results in abnormal vision
Plasticity in adults with amblyopia is dramatically evident in the reports of amblyopic patients whose visual acuity spontaneously improved in the wake of visual loss due to macular degeneration in the fellow eye [3, 4]
We argue that taking a binocular approach to amblyopia treatment may offer a more principled and effective option [11, 12]

Summary

Introduction

Amblyopia is a developmental disorder associated with early abnormal visual experience that disrupts neuronal circuitry in the visual cortex and results in abnormal vision. The patients with amblyopia beyond the age of sensitive period of brain development generally received no treatments because of the long believed notion that, beyond the critical period, the neural network structure is not flexible and lacks plasticity [1]. The traditional treatments for amblyopia, for example, patching or penalizing the fellow eye, have been limited to children at critical period age only (i.e., before 10 years old). There has been accumulating evidence showing the existence of neural plasticity in the mature human visual system [2]. Plasticity in adults with amblyopia is dramatically evident in the reports of amblyopic patients whose visual acuity spontaneously improved in the wake of visual loss due to macular degeneration in the fellow eye [3, 4]. Animal study showed environmental enrichment in adult amblyopic rats restored normal visual acuity and ocular dominance [5]

Methods

Results

Conclusion