The potential of the pinhole as a visual aid in the developing world

Abstract

Purpose: Providing vision correction in communities where healthcare facilities are unavailable is problematic. Here, we explore the possibility of using pinholes as near visual aids in the developing world. Method: Uncompensated (without the pinhole) proximal visual acuities (VAs) were measured and recorded for one eye of 45 presbyopic subjects over the age of 50 years in photopic (250 lux) and scotopic (20 lux) conditions. The proximal VAs were then repeated while the subjects looked through nine different pinholes. Results: The VAs varied with the diameter of each pinhole. A comparative measure was devised to determine the relative performance of different diameter pinholes as a near visual aid. The results suggest an improvement of more than 40% in VA in about 67% of subjects in good lighting conditions and about 60% in poorer lighting conditions. Conclusion: By creating more awareness that there are other ways of improving vision that cost almost nothing, visual impairment can be reduced until spectacles become available.