In general, a person's rod cells are first affected by RP. Rod cells help with peripheral (side) vision and seeing in dim light or dark places. The first symptom is often "night blindness," which is difficulty seeing in dim light, such as in a darkened room or outdoors at dusk. Healthy eyes naturally adapt to dark light, but eyes affected with RP take much longer to do this or don’t do it all. Some people are also bothered by the glare from sunlight or bright lights.
Trouble with your peripheral vision is also a common early symptom of RP. Peripheral vision is what you see on the sides, rather than straight ahead of you.
In some people, the central cone cells are affected first, and the disease is called cone-rod dystrophy (CRD) instead of RP. Central cone cells help with central vision, which is needed for detailed tasks such as reading, writing, driving, discriminating colors and seeing other fine details clearly.
Reviewed by health care specialists at UCSF Medical Center.