Detection of three visual impairments: Strabismus, blind spots, and blurry vision in rural areas using Raspberry PI by implementing hirschberg, visual field, and visual acuity tests

Abstract

This paper introduces an integrated way of detecting common visual impairments namely: Strabismus, Blind Spots and Blurry Vision. According to the Chairman of National Committee on Site Preservation, 70% of ophthalmologists are found in urban areas while the remaining 30% is scattered to rural areas. Thus, a low cost and portable product that can efficiently and effectively detect the said impairments is necessary. In addition to this, the device need not be operated by a medical practitioner. A Raspberry Pi with a monitor and camera would be used to implement Hirschberg Test for Strabismus, Visual Field Test for Blind Spot and Visual Acuity Tests for Blurry Vision. Hirschberg Test is implemented by taking the Central Corneal Light Reflex Ratio (CCLRR) of the patient through a picture taken from them. Visual Field test is done by presenting stimuli at different area of the visual field and recording the patient's response through a button press. The Visual Acuity test is done by using a Landolt C optotype and recording the patient's response through an 8 button keypad. The results from the Hirschberg Test were computed to have an accuracy of 90% by using z-test. For the Visual Field test and Visual Acuity test, the Mann Whitney Test proved that the data gathered from the patients had no significant difference with that from the medical records of patients.