Dear reader: This page is part of a series of articles written for vision professionals. If that’s not you, it might not make much sense. If you’d like to learn all about eyes, vision impairment and what you can do about it, I strongly recommend you start by reading the article series I wrote for everyone, which starts here (click).

Contrast Sensitivity

Almost all forms of eye pathology result in impaired low contrast vision, well before they affect high contrast vision. The effect is to take away the subtlety, richness and texture of the scene. I tend to describe it to patients as being like an underexposed or overexposed photo, in that you can generally see what the scene is, but you’d never say it was a good photo.

Note: Impaired contrast sensitivity can be a falls risk. When we’re on uneven ground, the way we can see subtle changes of contour is by detecting subtle shadows. Patients will low vision often can’t detect such subtleties, so uneven areas on surfaces such as footpaths, gravel paths and grass lawns can be invisible to them. The same applies to going down stairs — if the edges aren’t well marked, many patients simply can’t see where one step ends and the next one begins.