The macula, also called ” yellow spot ,” is a small area in the middle of the retina. This spot, only a few square millimeters large, is responsible for essential visual performance such as reading, recognizing faces and distinguishing colors. The rest of the retina mainly perceives outlines and bright-dark contrasts.
The macula has a high metabolic rate. Its degradation products are disposed by the underlying tissue layer. With higher age, usually with 60, this result in disorders that lead to deposits under the retina and thus to functional impairments. This process is called macular degeneration with the result that the patient has a blurred central vision seeing distorted or a thick patch. Since only the center of the retina is affected, the external field of vision is maintained. This means that one can see a clock but not read the time.
Macular degeneration is distinguished between two forms: the dry and the wet macular degeneration. When dry, it leads to deposits in the retina while wet, liquid enters the retina.
We can detect changes in the central retina before deteriorating vision is being noticed. For this purpose, the posterior eye is mirrored by using a special microscope and tested with optotypes viewing a special eye chart. With fluorescein angiography, abnormal vessels in the posterior eye are shown in photographs after injection of a dye.
In the treatment of macular degeneration, the photodynamic therapy is the preferred in addition to medication. An injected dye accumulates in the pathological vessels in the retina and makes them sensitive to laser light. Specifically, the affected vessels can be destroyed with a laser treatment without harming healthy tissue.