Light is essential to vision. The quality and quantity of the light needed for comfortable, useful vision varies and becomes particularly important when vision is impaired. Fortunately, proper light for maximum vision can be achieved based on an understanding of your needs. Let's try to separate lighting truth from lighting fiction.
Impaired vision is highly variable and lighting needs are highly individual.
For instance, on average, older people need about three times as much light as younger people. But few people are average. Three times the light may be a good starting point for adjusting the amount of light, but ultimately the individual must be comfortable and must be able to accomplish visual tasks under those conditions. It's important to evaluate visual performance and comfort under varying lighting conditions to decide what works best for you. For instance, people with glaucoma often require much higher light levels, while there are conditions such as central cataract where lower light may be better.