võrkkestas

The võrkkestas, known in English as the retina, is the light-sensitive sensory layer lining the back of the eye. It converts incoming light into neural signals that are processed by the brain as vision. The retina contains photoreceptors—rods for sensitivity to light and motion, and cones for color and fine detail—along with several neuronal layers such as bipolar, amacrine, and ganglion cells. The macula, and within it the fovea, provide the sharpest central vision. The retina sits on the pigmented retinal epithelium and is nourished by choroidal blood vessels, with the inner retina supplied by the central retinal artery.

Visual information travels from photoreceptors through bipolar and other interneurons to ganglion cells, whose axons form the optic nerve that transmits signals to the brain’s visual pathways. The retina thus serves as the first stage of visual processing, integrating brightness, color, and motion.

Clinical relevance includes a range of diseases affecting retinal structure or blood supply. Common conditions are age-related macular degeneration, diabetic retinopathy, retinal detachment, and inherited dystrophies such as retinitis pigmentosa. Diagnostic tools include ophthalmoscopy, optical coherence tomography (OCT), fundus photography, and fluorescein angiography to assess retinal layers, vasculature, and pathology.

Treatment varies by condition and may involve anti-VEGF injections, laser therapy, surgical repair (such as vitrectomy for detachments), or nutritional supplementation in specific forms of macular degeneration. Developmentally, the retina is part of the central nervous system, derived from the neural tube, and its health is essential for clear, reliable vision.