If your father is having age related macular degeneration whichweakens the retina then he can take anti-oxidants. In a popular study called AREDS it was shown that there is some benefit by taking such vitamins in selected patients. Inmany other studies as well, they have been found to be useful. To read more about this you can follow this link - http://www.accessexcellence.org/WN/SU/macular.php. Examples of such anti-oxidants include V-RET, Macugold etc. This is very commonly prescribed to patients with macular degeneration. I hope, that helps. Thanks.
I do not think, he will need a prescription for anti-oxidants in Africa. V-RET is a popular brand and he is likely to get that in Africa. Otherwise, he can take some other brand which is available in Africa. The pharmacist or chemist will tell him other anti-oxidants name. He can consult his ophthalmologist there as well. Thanks.