I’ve read that a good reading light can reduce the size of the central scotoma associated with age-related macular degeneration. Is this true?

Yes it is. Putting more light onto a page when trying to read print can help reduce the size of a central scotoma.

The reason for this is not clear. My own suggestion to explain this is that those photoceptors which are at the edge of the scotoma and have not yet been totally destroyed by the process of age-related macular degeneration but they are struggling to send information to the parts of the brain involved in vision. The extra light incident on these photoreceptors helps them function and take part in the seeing process and therefore the scotoma size is reduced.

A smaller scotoma can help improve reading as less of the print is covered and hidden by the scotoma.

Good light is readily available and inexpensive. The return on investment can be massive.