If one is to draw a perpendicular line through the pupil and into the eye, it would land on the retina in a place called the macula. It is an area approximately 1500 micrometers and is responsible for READING/DETAILED/COLOR vision. The rest of the retina is responsible for night vision and motion detection.
Damage to the macula leads to loss of reading/central vision but one is still able to see from the side of the eye. Diabetes is a common cause of damage to the macula. One of the leading causes of damage to the macula in the developing world is AGE RELATED MACULA DEGENERATION (AMD).
AMD exists in two form.DRY and WET. There is no treatment for dry AMD. In wet AMD, there is accumulation of fluid/blood under the macula. By receiving monthly eye injections Avastin or Lucentis and or applying retina laser treatment, one can prevent visual loss from WET AMD.
Using Optical Coherence Tomography (OCT), which is the GOLD STANDARD in evaluating the macula, one can diagnose macula disease at a very early age. AMD is much more common in Asians and Europeans than in Africans. Persons 50 years and above are advised to get an AMD screening eye test at least once a year.