What is the primary function of the retina?

What is the primary function of the retina?

• A. Converts focused photons into graded potentials and action potentials
• B. Maintains intraocular pressure
• C. Detects light intensity only
• D. Reduces optical aberrations

Answer: (A)

Light entering the eye is detected by photoreceptors in the retina, which translate photons into electrical signals. Photoreceptors respond with graded changes in membrane potential rather than all-or-none spikes, and this phototransduction starts the signal that is passed through bipolar and other interneurons to retinal ganglion cells. The retinal ganglion cells then generate action potentials that travel along the optic nerve to the brain, delivering the visual information. So the retina’s main job is to convert light into neural signals that can be transmitted and interpreted by the brain. The other options describe roles of other structures or limitations: maintaining intraocular pressure relates to aqueous humor dynamics, detecting only light intensity omits color and detail, and reducing optical aberrations is primarily a function of the eye’s optics (cornea and lens).

Light entering the eye is detected by photoreceptors in the retina, which translate photons into electrical signals. Photoreceptors respond with graded changes in membrane potential rather than all-or-none spikes, and this phototransduction starts the signal that is passed through bipolar and other interneurons to retinal ganglion cells. The retinal ganglion cells then generate action potentials that travel along the optic nerve to the brain, delivering the visual information. So the retina’s main job is to convert light into neural signals that can be transmitted and interpreted by the brain. The other options describe roles of other structures or limitations: maintaining intraocular pressure relates to aqueous humor dynamics, detecting only light intensity omits color and detail, and reducing optical aberrations is primarily a function of the eye’s optics (cornea and lens).