Extending the reach of anterior segment ophthalmic imaging

Abstract

Eye exams via a slit lamp are critical in screening for conditions such as cataracts, corneal opacities and pterygia early on to avert vision loss. The slit lamp, however, is a purely qualitative optical device that is bulky, expensive, can cause eye discomfort due to light sensitivity. It also requires a trained physician to operate, making it unsuitable for large-scale screening in resource-constrained settings. In this thesis, we propose a spectrum of portable anterior segment imaging solutions that can be operated by minimally trained health workers. On one end, we present a smartphone attachment with minimal optics and no electronic components beyond what is present in the smartphone itself to examine and image the anterior segment of the eye. This cost-effective, easily scalable solution would help extend the reach of anterior segment examination to extremely resource constrained settings, such as mass-screening camps, mobile ophthalmology clinics, war zones etc. On the other end, we propose purely solid-state instrumentation that employs programmable illumination and light steering optics to simulate the motion of a slit on the eye, thereby exhibiting functionality similar to that of a slit lamp with no moving parts. Finally, we discuss potential deployment strategies for two implementations of this technology in the specific cases of two contrasting healthcare systems in India.