The Retina And Normal Vision
In normal vision, the eye works much like a camera, in which the lens in the front allows light through to the film, creating a picture. The eye functions in a similar fashion. Light enters through the cornea and lens, and is focused on the retina, which serves as the “film” in the eye.
The retina is a thin layer of delicate nerve tissue which lines the back portion of the eye. It has two main parts – the macula, responsible for central and color vision, and the peripheral retina, which is responsible for side vision and night vision.
One of the most common diseases of the retina, diabetic retinopathy, occurs in people with diabetes. It can cause permanent loss of sight and is the leading cause of blindness among adults aged 25 to 55 in the United States.
Approximately 25% of diabetics have some form of this disease. Most people who have had Type I diabetes for many years have some retinopathy, however, if blood sugar levels have been well controlled it may not be severe. In Type II diabetes, the retinopathy may be discovered shortly after, or sometimes before, the diabetes is diagnosed.
Diabetic Retinopathy occurs when blood vessels which nourish the retina begin to malfunction. Small leaks can develop in the blood vessels causing fluid or blood to seep into the retina. The retina then becomes wet and swollen and cannot function properly. Diabetic retinopathy can also occur when the blood vessels close, stimulating the growth of new blood vessels. These abnormal blood vessels can cause bleeding and scar tissue that may result in a total loss of vision.
How Is It Treated?
Diabetic retinopathy is treated in many ways depending on the stage of the disease and the specific problem that requires attention, and options include laser and traditional surgery. The goal of treatment is to arrest the progression of the disease.
The macula is a small tissue in the center of the retina which is responsible for our central vision. Macula Degeneration is a degenerative disorder usually associated with the aging process, and makes tasks such as reading, threading a needle, driving and watching TV more difficult.
The condition occurs in two forms – wet and dry. The dry form can be slowly progressive but it is less likely to lead to severe visual loss. The wet form is less common, but can lead to severe visual loss. Dr. Maizel was an investigator for Visudyne therapy now used nationwide as a treatment for some patients with the wet form of the disorder and has been asked to continue as an investigator to study expanded uses for Visudyne therapy.
Why Does That Happen?
Because one eye will naturally compensate for the loss of detail in the other eye, macula degeneration can go unnoticed until it starts to affect both eyes. Dr. Maizel can provide information and home tests to assist the patient with early detection.
How Is It Treated?
Dr. Maizel is on the forefront of the study of macular degeneration, and offers the latest, most-advanced treatment available for this disease. Although there is no proven medical therapy for dry macular degeneration, different therapies are available & may be used to treat the wet form of macular degeneration in some individuals.
The retina is very delicate, and a tear can occur when shrinkage of the vitreous fluid – the clear, gel-like substance which fills the center of the eye – pulls on the retina. The vitreous fluid can escape through this tear into a space between the retina and the back of the eye, causing the retina to detach. A blur or blind spot will occur where the retina has detached.
How Are They Treated?
There are a number of ways to treat retinal detachment, and the appropriate treatment depends on the type, severity and location of the detachment. One treatment requires insertion of a small gas bubble into the vitreous (fluid) which flattens the retina back into place. Sometimes, a tiny band made of silicone, called a scleral buckle, is attached to the outside of the eye, pressing inward and holding the retina in position.
Scar tissue can grow on the surface of the retina directly over the macula, and is called an epiretinal membrane or macular pucker. It can cause the retina to wrinkle and distort vision. This may result from surgery or another retinal problem. Or, as in most cases, it can occur in an otherwise healthy eye following a posterior vitreous detachment.
How Are They Treated?
Surgery to remove the membrane is the only way to treat this type of vision loss but, if vision is only mildly affected, surgery is not recommended. After surgery, about half the vision that was lost due to the epiretinal membrane is restored.
Other problems can occur when the fluid that fills the inner cavity of the eye (vitreous fluid) begins to shrink. Flashes appear as flashing lights or lightning streaks in the field of vision, although no light is actually flashing. These are most often noticed at night or in a dark room and can be a sign of retinal detachment.
Floaters can cause dots or lines, or appear to be cobwebs or spiders in the field of vision. They are formed from the reorganization of the vitreous material or by bleeding.
How Are They Treated?
Although they are usually just an annoyance, floaters and flashes may be signs of a retinal tear or detachment. Dr. Maizel will perform a thorough exam to determine if they require treatment. Surgery is rarely indicated, except when the floaters obscure the vision or when they or flashes are related to a serious problem.
Download this printable image of an Amsler Grid for your home use.
The Amsler Grid is one tool used to help detect vision problems resulting from damage to the macula (the central part of the retina) or the optic nerve. The damage may be caused by macular degeneration, glaucoma or other eye diseases. Early diagnosis and treatment may limit or slow vision loss.
If you are at risk for macular degeneration or other eye diseases, using this chart at home is not a substitute for regularly scheduled visits with Dr. Maizel.
- Wear your reading glasses if you use them.
- Look at the grid from about 14" away (normal reading distance).
- Cover one eye, and focus on the dot in the center. Do any lines look wavy, blurred or distorted? Are there missing or dark areas?
- Repeat the test with the other eye.
Lines should be straight and at right angles to each other. Contact us right away if you notice any problem.
Introducing New FDA Approved Drug EYLEA ™
Ray Maizel, MD is excited to bring the lastest in treatment options for Age-Related Macular Degeneration to his patients. EYLEA ™ was FDA approved in November 2011 to treat AMD. Patients benefit with bi-monthly injections rather than monthly injections. Make your appointment today with Dr. Maizel to see if EYLEA™ is right for you!
Who Is Mid-Florida Eye’s Retinal Specialist?