Andrew A. Dahl, MD, is a board-certified ophthalmologist. Dr. Dahl's educational background includes a BA with Honors and Distinction from Wesleyan University, Middletown, CT, and an MD from Cornell University, where he was selected for Alpha Omega Alpha, the national medical honor society. He had an internal medical internship at the New York Hospital/Cornell Medical Center.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
The retina is an extremely thin tissue that lines the inside of the back of the eye. When we look around, light from the objects we are trying to see enters the eye. The light image is focused onto the retina by
both the cornea and the lens. This light striking the retina causes a complex biochemical change within layers of the retina and this, in turn, stimulates an electrical response in other layers of the retina. Nerve endings within the retina transmit these
electrical signals to the brain through the optic nerve. Within specific areas of the brain, this electrical energy is processed to allow us both to see and to understand what we are seeing. The retina has been compared to the film of a camera. However, film, once used, has a permanent image on it. The retina continually renews itself chemically and electrically, allowing us to see millions of different images every day without them being superimposed.
The retina is about the size of a postage stamp. It consists of a central area called the macula and a much larger peripheral
area of the retina. The light receptor cells within the retina are of two types, called the rods and the cones. Rods allow us to see in
conditions of reduced illumination. Cones provide us with sharpness of vision
and color vision. The peripheral retina allows us to see objects on either side (peripheral vision) and, therefore, provides the vision needed for a person to move about safely. However, because this part of the retina contains a lesser concentration of cones, it does not allow for perception of visual detail. Its larger concentration of rods provides better vision during conditions of darkness.
In contrast, the macula is a smaller, central area of the retina that contains a high concentration of cones. Accordingly, it enables clear central vision to see fine details for such activities as reading or threading a needle. The macula is particularly sensitive to circulatory changes, especially those that occur with aging, such as decreased blood flow. The retina contains a network of branching arteries, which supplies blood that carries the needed oxygen and nutrients to the retina, and
a network of accompanying veins, which then carry the blood away together with the waste products of retinal metabolism.
Medical Author: Sanford G. Feldman, MD
Medical Editor: Melissa Conrad Stöppler, MD
There are three main causes of retinal detachment, each with its own set of risk factors. The most common type is called a “rhegmatogenous” detachment, and is caused by a tear or hole in the retina. The retina is the thin, light-sensitive tissue that lines the back inside wall of the eye. If the retina tears, thick liquid called vitreous (which fills the back two-thirds of the hollow eyeball) can seep through the hole. The fluid accumulates underneath the retina, causing the retina to peel away from the back of the eye. Risk factors for rhegmatogenous retinal detachments include aging, cataract surgery, thinning of the outer retina known as lattice degeneration, a high degree of nearsightedness (also called high myopia), and head trauma. Let's look at each one of these causes in more detail: