Accommodation and Photoreceptors in the Eye

Accommodation

The ability of the lens to change shape in order to focus, with the ciliary muscle relaxing to thin the lens for far focus and contracting to thicken it for near focus.

Retina

The layer at the back of the eye containing photoreceptors (rods and cones) that convert light into neural signals.

Rods

Photoreceptor cells in the retina that function in low-intensity light, perceive black and white, and are mainly located in the periphery.

Cones

Photoreceptor cells in the retina that require high-intensity light, perceive color, and are concentrated in the fovea centralis.

Rhodopsin

A pigment in rods made of retinene (vitamin A) and opsin, which when functional releases an inhibitory neurotransmitter to prevent signals from reaching the optic nerve.

Photopsin

A pigment in cones that is less light-sensitive than rhodopsin, with each cone being sensitive to red, blue, and green light.