Efficacy of an Amblyopia Treatment Program with Both Eyes Open: A Functional Near-Infrared Spectroscopy Study

Abstract

Introduction and Purpose To investigate the efficacy of an amblyopia treatment program with both eyes open. Methods Ten subjects (mean age 20.5 ±1.5 years) were enrolled. All subjects had unremarkable ophthalmic examinations, but several subjects had minor refractive errors. Vision function was evaluated using the 3-D visual function trainer-ORTe. Brain measurements were made using functional near-infrared spectroscopy (fNIRS) to examine the oxygenated hemoglobin (HbO2) concentration change upon visual stimulus presentation. The three conditions were as follows: both eyes open and both eyes stimulated, both eyes open and only one eye stimulated, and one eye open and one eye stimulated. Results Changes in HbO2 between the rest and stimulation phases were not statistically different between the unilateral and bilateral stimulation conditions with both eyes open. However, HbO2 change was significantly higher in subjects with both eyes open than in subjects with one eye closed (P < 0.001, all comparisons). Conclusion Greater activation of the visual cortex is achieved when subjects are treated with both eyes open as compared to subjects with one eye occluded. From a perspective of functional brain activation, amblyopia treatment administered without occluding the healthy eye may provide the greatest therapeutic benefit.