Vitamin C helps the blood vessels of the eye, which includes the retinal vessels, and also has beneficial antioxidant properties for retinal health. Citrus fruits such as oranges and grapefruit contain vitamin C, and other foods include spinach, tomatoes and bananas.
Actually there is no special supplements that are good after treatment of retinal detachment, but it is good to keep a nutritive diet combining vitamins and minerals with lutein, quercetin, eyebright, zeaxanthin and bilberry to improve eye health.
You can have healthy foods which rich in Vitamin C , Vitamin A, Beta Carotene, Vitamin E, and Vitamin B2, which can help you keep your eyes healthy. Or you can take these supplements, too. However, you'd better check with your doctor.