Home / Diseases / Retinal diseases

Retinal diseases

The retina is a thin tissue, lining the inside of the human eye; it consists of millions of light-sensitive cells rods and cones. Rods and cones are called photoreceptors, performing the primary processing of the optic signal. Lightwaves pass through the anterior refractive optic media (cornea and lens) and are focused in one dot on the retina, which, in its turn, ensures image perception, its transformation into the nerve impulse and transmission to the brain. The brain ensures the processing of the signal and transforms it into the integral image.

The doctor checks the retina while examining the fundus of the eye. Several anatomic regions are distinguished during the examination. The optic nerve, vessels and macular region are distinguished in the central zone. The most valuable part of the retina is the macula, the region of photoreceptors accumulation, responsible for the visual clarity, specification of objects and possibility of focusing. Due to this zone a person appreciates colors. The damage of the macular region results in considerable visual deterioration and poorer image quality. Severe changes may lead to blindness.

The peripheral part of the retina is responsible for spatial peripheral vision and determination of the visual field. Due to these zones a person can see in the twilight and darkness.

There are three possible stages of damage of photoreceptors:

  • dystrophy (impairment and slowing down of the tropism of nerve cells; usually it occurs due to vascular changes caused by age-related slowing down of the metabolism processes;
  • it leads to visual deterioration, but is treated by conservative methods);
  • atrophy (death of nerve cells, complete loss of the visual function);
  • degeneration (degeneration of eye tissues into scar tissue).