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The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rods and cones.

The neural retina consists of several layers of neurons interconnected by synapses and is supported by an outer layer of pigmented epithelial cells. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception.

If the macula gets a central hole, there is a central blind spot.The retina (from Latin: rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. If the macula (the central portion of the retina) is wet due to AMD, diabetes, or high blood pressure, vision is blurred. If the macula (the central portion of the retina) is not smooth, vision is distorted. If the retina falls off the inside of the back of the eye (retinal detachment), vision is lost. Diseases of the choroid can cause blindness as well. The choroidal blood vessels are the source of fluid and hemorrhage in wet age-related macular degeneration (AMD).

Vascular occlusions, both vein and artery occlusion, can lead to loss of normal blood supply to the retina and lead to blindness. The inner blood vessels are the ones that are afflicted by diabetic retinopathy. In the human eye, the retina is nourished by it’s own blood vessels that feed the inner layers, and by the blood vessels of the choroid, that feed the outer layers of the retina. To function normally the retina needs to be properly nourished (see above regarding circulation) and remain attached. The retina acts like a film or digital card inside a camera – it receives the light and forms the images that are turned into electric signals which are sent to the brain. Despite the thickest and best glasses, if this tissue is not completely healthy, we will not see. In the normal situation, the retina must be healthy for us to see well. The most common problem interfering with this process is cataract, an opacification of the lens. These structures and the vitreous body that fills the center of the eye need to be clear in order for the light to get to the retina. Sometimes patients require contact lenses and glasses to help with this process. How Does the Retina Function?īoth the cornea and our natural lens focus light onto the retina. It is here that central vision and detailed vision occur. Topographically, the center of the retina is known as the macula. These cells transform the light energy into electric signals that are processed and then sent to the brain where vision is completed. The outermost layer is the photoreceptor layer, made up of rods and cones. The resulting light signals are then transmitted from this light sensitive tissue, through the optic nerve to the brain. LightĮntering the eye focuses on the retina producing images. The retina is the light sensitive tissue that lines the inside of the eye. Macular degeneration and diabetic retinopathy are diseases of the retina.