võrkkest

Võrkkest, known in English as the retina, is the light-sensitive neural tissue that lines the back of the eye. It converts incoming light into electrical signals that are sent to the brain to create visual perception.

Anatomy: The retina lies against the inner surface of the eye’s posterior segment and consists of several layers. The outer neural layer contains photoreceptors—rods and cones. Beneath them are bipolar, horizontal, and ganglion cell layers, whose axons form the optic nerve. The macula houses the fovea, the area responsible for high-acuity central vision. The retinal pigment epithelium supports photoreceptors and participates in the visual cycle.

Function: Photoreceptors transduce light into neural signals that are processed by inner retinal neurons and conveyed via the ganglion cell layer to the brain through the optic nerve. The retina thus converts light into the neural language the brain interprets as sight, with cones providing color and acuity and rods enabling vision in low light.

Blood supply and support: The retina receives oxygen and nutrients from the central retinal artery and the choroidal circulation. The retinal pigment epithelium also contributes to metabolic exchange and photoreceptor maintenance.

Clinical significance: The retina is affected by conditions such as diabetic retinopathy, age-related macular degeneration, retinal detachment, retinitis pigmentosa, and retinal vein occlusion. Symptoms include blurred vision, floaters, or a shadow in the visual field. Diagnosis relies on ophthalmoscopy, optical coherence tomography (OCT), and fluorescein angiography.

Treatment and research: Management includes laser therapy, anti-VEGF injections for neovascular AMD, surgical repair for detachments, and emerging gene therapies for inherited retinal diseases. The retina remains a central focus of vision science and ophthalmic care.