Uncorrected myopia affects the visual acuity of OFF-pathway more than ON-pathway

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Science

Background:

• The balance between ON and OFF visual pathways is crucial for visual function.
• Myopia, or nearsightedness, affects visual acuity and may involve disruptions in these pathways.

Purpose of the Study:

• To compare visual acuity under different contrast polarities in myopic and emmetropic children.
• To investigate the relationship between ON/OFF pathway balance and the severity of myopia.

Main Methods:

• Visual acuity was measured in myopic (corrected and uncorrected) and emmetropic children using stimuli with reversed contrast polarities.
• The ON/OFF ratio of visual acuity scores was calculated and correlated with the spherical equivalent (SEQ) of myopia.

Main Results:

• Uncorrected myopic children showed significantly better visual acuity with white letters on a black background compared to black letters on a white background.
• A higher ON/OFF ratio was observed in uncorrected myopic children, correlating with the degree of myopic blur.
• No significant polarity differences were found in corrected myopic or control children.

Conclusions:

• Uncorrected myopia in children is associated with greater difficulty in resolving black letters versus white letters.
• The ON/OFF pathway imbalance in myopia is linked to the magnitude of uncorrected refractive error.