What is the retina? The retina is a light-sensing layer of cells that forms the innermost layer of the posterior wall of the eye. The retina is comprised of photoreceptor cells, rods and cones, and glial cells. These cells respond to light by transmitting signals to the brain that allows it to perceive the image that is being seen. Rods function mostly in low light conditions and form a black and white image, while Cones are more sensitive to daylight or well-lit conditions and allow the perception of color.

The retina is 0.5mm thick and composed of ten layers that provide structural and functional support to the photoreceptor cells.  At the center of the retina is a small area containing the highest concentration of rods and cones, called the Macula.  

Disorders of the retina

The retina can be affected by a number of pathologies that vary widely, but also produce symptoms affecting vision. Common retinal diseases and conditions include:

  • Retinal detachment
  • Retinal artery occlusion 
  • Age-related macular degeneration
  • Glaucoma
  • Diabetic retinopathy
  • Retinitis pigmentosa
  • Retinoblastoma
  • Color vision deficiency

Source: Nguyen KH, Patel BC, Tadi P. Anatomy, Head and Neck, Eye Retina. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: