What is the significance of the optic disc?

• A. It is the blind spot, lacking photoreceptors
• B. It is the site of highest acuity
• C. It is where tears are produced
• D. It contains the fovea

Answer: (A)

The main idea is that the optic disc is where the retinal ganglion cell axons bundle to form the optic nerve and exit the eye, and this area contains no photoreceptors. Because there are no rods or cones there, light falling on the optic disc cannot be detected, creating a natural blind spot in vision. The region of highest visual acuity is the fovea, with a dense packing of cones and a thin, inner retinal layer that minimizes light scattering; that’s why the fovea, not the optic disc, is responsible for sharp central vision. Tears are produced by the lacrimal gland, not the retina or optic nerve. The fovea lies separate from the optic disc, so the optic disc does not contain it.