Most cardiovascular or metabolic disorders show up as vascular pathology on the retina. For instance, Diabetic retinopathy (DR). This is a potentially vision-threatening conditions, where patches of one's retina lose the ability to react to light. This causes patches in one's vision, and if left unchecked, can soon be an irreversible loss of vision. These disorders need to be picked up early and can be treated. However, they require two things - the ability to capture high quality photographs of one's retina, and the ability to interpret those images and diagnose conditions. The first one is done using extremely high quality machines in the market, which are usually very expensive. The second is usually done by a trained clinician (ophthalmologist). Both of these are extremely difficult to get access to in resource-constrained areas or part of large-scale public health screening programs, where they are needed the most.

On the right we have a fundus image of an individual suffering from Diabetic retinopathy. Notice the flaky white spots all over the retina. These "exudates" are deposits which causes "patches" to form in one's vision. Diagnosing this condition is impossible without a good quality fundus imaging camera, which typically costs a few thousand dollars and is extremely large and heavy - definitely not a good solution for field screening programs.