Unlike macular degeneration, glaucoma and diabetic retinopathy can affect the retina outside of the macula. They are diseases that have a wide range of presentations, so patients will present with a wide variety of visual volumes. But there are some things that they will all have in common:
- They should all involve some degree of contrast and luminance impairment, along with acuity loss, so in many ways they should be similar to macular degeneration. (For now, I treat them in pretty much the same way in the clinic, and it seems to work pretty well).
- Diabetic macular oedema would be expected to involve the fovea, so we’d expect more acuity loss.
- Glaucoma patients tend to respond well to stronger task lighting, but the optimal level seems to be not as bright as that for macular degeneration.
- Diabetic retinopathy patients often have more glare sensitivity, especially if they have media opacities. Cataract extractions will help, but the increased risk of retinopathy worsening after cataract surgery makes it a difficult decision. Yellow filters can help minimise glare while improving contrast at high illumination, and electronic magnifiers will be helpful with reversed contrast.