Chronic Visual Loss - Case 1

A 75 year old male complains of a gradual onset of a "dark spot" in the centre of his vision making it difficult for him to read the paper.

Case 1

What is the commonest cause of legal blindness (visual acuity < 20/200) over the age of 65?

Cataract
Diabetic Retinopathy
Macular Degeneration
Glaucoma