Rod and cones, the photoreceptor cells of the retina

Rods are a type of photoreceptor cell in the retina. They are sensitive to light levels and help give us good vision in low light. They are concentrated in the outer areas of the retina and give us peripheral vision. Rods are 500 to 1,000 times more sensitive to light than cones. The retina has approximately 120 million rods and 6 million cones.

Eye problems that can affect rods include:

  • Photokeratitis
  • Retinitis pigmentosa
  • Usher syndrome