DIABETIC RETINOPATHY

Diabetes is the most frequent cause of new cases of blindness in the age group of 20-74. There are approximately 16 million diabetics in the US with 8 million having some form of diabetic retinopathy. Of those 8 million, 700,00 have serious retinal disease. There will be 65,000 new cases of proliferative diabetic retinopathy each year with 24,000 new cases of blindness.

There are two main forms of the disease; Nonproliferative Diabetic Retinopathy and Proliferative Diabetic Retinopathy. The most frequent cause of vision loss is secondary to Clinically Significant Macular Edema.

The most important treatment for diabetic retinopathy is prevention and early detection. There was a landmark study published in the New England Journal of Medicine in 1993 called "The Diabetes Control and Complications Trial." This study followed over 1400 patients and evaluated the effects of tight blood sugar control on the development and progression of early diabetic retinal vascular complications in diabetics taking insulin. The results showed a decreased risk of developing retinopathy by 76% and slowed the progression by 54%. There was also a decreased risk of kidney disease and peripheral nerve damage.

The information gained from this study showed that the most important treatment for diabetic eye disease is good control of blood sugars. Your primary care doctor is probably aware of this information. Secondly, early detection is also very important. At Ohio Eye Alliance, we recommend at least yearly dilated eye examinations once the diagnosis of diabetes has been established.

Who gets Diabetic Retinopathy?

The longer someone has diabetes, the increased risk of developing serious eye disease. We can divide diabetics into two classes; namely Type I (diagnosis at age less than 30) and Type II (diagnosis at age greater than 30). Depending on whether the person is taking insulin or pills determines risk as well as how long the person has been diabetic. After 15 years of diabetes, approximately 65% of patients not taking insulin and 85% of patients taking insulin will develop some form of diabetic eye disease.

What causes Diabetic Retinopathy?

We know that there is a problem with the circulation to the eye in diabetics. The small blood vessels in the retina become damaged from the high blood sugars in the circulation. The blood vessels are needed to bring nutrients to the retina. The retina then becomes ischemic (a decrease in blood flow to the retina). The ischemic retina sends out a "signal" for the eye to produce new blood vessels to try and increase the circulation. These new blood vessels are abnormal and do not work properly. They leak fluids and can cause bleeding. Once these vessels develop, the diagnosis is now Proliferative Diabetic Retinopathy.

Vision is affected when the fluid or blood are present in the macula, which is a structure in the back of the eye controlling fine, straight-ahead vision. This is what an eye doctor looks for in the eye. The longer the blood and fluid remain in the eye, the worse the vision may become.

How do we treat Diabetic Retinopathy?

The definitive treatment is prevention as mentioned earlier. Once new blood vessels or fluid in the macula develops, the treatment is laser. Laser therapy is performed by the use of a light beam to make burn spots in the retina to cause the abnormal blood vessel to regress. Laser can also be used to treat fluid in the macula by sealing the blood vessels that caused the leaking fluid. The eye then naturally reabsorbs the fluid. Treatment is essentially used to prevent worsening of vision and can sometimes improve it. If laser treatment is no longer effective or retinopathy worsens, retinal surgical intervention may be needed.

What are some symptoms of Diabetic Retinopathy?

1. Blurred Vision
2. Distorted Vision
3. Floaters
4. Double Vision
5. Difficulty Reading

Other Ocular Complications of Diabetes:

1. Cataracts
2. Retinal Detachment
3. Neovascular Glaucoma

If you have any further questions, please don't hesitate to call (330) 829-3233 ext. 142

Paul A. Garfinkle, M.D.

Normal Eye

Close-up of retina with diabetic retinopathy

Laser beam in the treatment of diabetic retinopathy

MACULAR DEGENERATION (ARMD)

Age-Related Macular Degeneration (ARMD) is the leading cause of blindness in people over 65 years old. As many as 13 million people in the U.S. have some form of the disease with approximately 1.2 million having some sort of visual impairment. About 30% of people over the age of 75 have ARMD and another 23% will develop it within 5 years. Each year more than 200,000 people develop the Wet Form of ARMD.

The number of Americans over 65 will double to approximately 80 million by the year 2050, with 19 million over 85 years old. ARMD will become very prevalent in the future.

There are two main forms of the disease; the Dry Form, which makes up 90% of the cases and consists of yellowish deposits called "Drusen" and loss of pigmented tissue, both of which occur in the macular area; and the Wet Form, which consists of the development of new blood vessels, hemorrhage, deposition of fats and fluid in the macular area.

There is currently no cure for the Dry Form and less than 20% of the Wet Form is amenable to treatment, namely laser therapy.

The macula is an eccentrically located area in the eye only millimeters in diameter that is responsible for our straight-ahead, fine, and detailed vision. If this is damaged then our vision becomes blurred and distorted causing distance and especially reading vision to be affected.

Because this area is so important, it was designed for maximum protection against the damaging effects of sunlight (UV-rays). The design includes a dark pigment called melanin to absorb, specifically, the blue light which is known to be damaging to the photoreceptors (vision producing cells) and a group of chemicals that neutralize the free radicals produced by the interaction of UV light with the macula.

It was observed decades ago that certain plant bioflavenoids could reverse the degeneration of some patients with macular degeneration. Today, renewed interest is directed toward two carotenoid plant substances, lutein and zeaxanthin, which are the cardinal ingredients in the macular pigment melanin. These carotenoids have the ability to prevent macular degeneration and even significantly improve the existing disease by absorbing blue light and also by acting as antioxidants to remove free radicals.

These protective substances are highly concentrated in the center of the macula and also in the lens of the eye but decrease greatly in the periphery of the retina. This gives maximal protection to the most important part of the vision and to the site of most of the concentrated light.

There are numerous risk factors for macular degeneration, some we can control and some we cannot including: Family history, 2-fold higher risk in women, and Light iris color. The risks that are changeable include: Smoking, Alcohol use, Sun exposure, Increased lipids in the blood (cholesterol), Cardiovascular disease, and Diet. Smoking has been found to increase the risk of developing the wet form macular degeneration by lowering the carotene levels in the body and increase the free radicals in the body. Diet is a factor that can be significantly changed.

The results of another study of hundreds of patients with advanced ARMD was recently published in the Journal of the American Medical Association (JAMA).2 The study was carried out at five prestigious ophthalmic research centers in the USA. Several hundred macular degeneration patients were compared to "normal " counterparts. Everything about these people was the same except the "normal" group did not have macular degeneration. Important lifestyle factors were studied, including surgery, diet, vitamins, synthetic antioxidants and other factors.

The only factor that was favorable in decreasing the risk of developing "wet" macular degeneration was the consumption of green leafy vegetables five or more times a week. These people reduced their risk of ARMD by 43%. Patients who took synthetic vitamins and anti-oxidants, including vitamins A, C, and E had NO BENEFIT in reducing their risk.

A recent study from France, 'The POLA study"3 also supports the idea that consumption of vegetables could help macular degeneration by reducing "oxidative stress."

How about zinc and vitamins? The Age-Related Eye Disease Study (AREDS) released results in October 2001. Antioxidants and zinc were found to reduce the risk of progression of macular degeneration. Another study found the use of beta-carotene and vitamin A was related to increased incidence of lung cancer in male smokers as well as increased incidence of ischemic heart disease. The supplementation of vitamin E seemed to increase the risk of hemorrhagic strokes. I now recommend the use of antioxidants and zinc at the discretion of your physician.

Major medical organizations have shown the benefit of fresh fruits and raw vegetables. The National Cancer Institute, The American Cancer Society, The FDA, USDA, and nutritionists all recommend five helpings of fresh fruits and raw vegetables every day to reduce the risk of colon, breast, prostate, and rectal cancer. A diet such as this also helps control high fat and cholesterol levels. Uncooked fruits and vegetables are preferred because cooking causes the destruction of many of the necessary enzymes and antioxidants.

Obviously, over 95% of Americans do not eat this way and may be at an increased risk not only for macular degeneration, but for at least the four cancers mentioned above, as well as a host of other diet related disorders, such as obesity, increased cholesterol, arthritis, and high blood pressure.

Macular degeneration is painless; the "dry" form affects vision very slowly over many years, but the "wet" form can cause sudden visual loss. Almost always it affects both eyes but not always in the same manner. Symptoms include:

• Gradual blurring and/or the development of blind spots in the center of the field of vision.
• Difficulty in picking out details, near and far.
• Straight lines appear to be wavy and shapes are distorted.
• Printed words appear to be blurred.
• Dimmed color vision.

Treatment is only available for the "Wet" form of macular degeneration and includes actively destroying the abnormal blood vessels with a laser. Many studies show that treatment often preserves vision in the long run when compared to the natural course of the disease. This depends on the size of the lesion as well as the visual acuity at the time of the disease. The current treatment not only destroys the abnormal blood vessels but may also destroy nearby healthy retina. This may leave a permanent blind spot, but often stabilizes the vision when compared to not treating at all.

A newer laser treatment called photodynamic therapy will soon be available and has the ability of sparing healthy retina while destroying the abnormal blood vessels. A dye is injected into a vein over the course of 10 minutes. Then a laser beam is shone on the lesion for 83 seconds. The current studies show more stabilization of vision than current laser therapy. There is a need for treatment about every three months or so. This treatment as well as the current laser therapy is useful only in certain circumstances based on the appearance of the lesion on the fluorescein angiogram( a picture test of the circulation in the retina).

There are other treatments in the works, including, radiation, advanced laser therapies, retinal cell transplantation, macular translocation( moving the macula away from the underlying diseased tissue), surgical removal of abnormal blood vessels and hemorrhage, gene therapy, nutrition (see above), and the development of drugs to inhibit blood vessel growth. Many of these treatments are already in trials, soon to be released.

There is no treatment, as of yet, for the "Dry" form of macular degeneration. Currently, there is a trial for a type of laser treatment for this disease.

Unfortunately, once vision is lost from macular degeneration, it is permanent. There are, however, ways of maximizing your vision with low vision aids. Many associations exist such as the Lighthouse in New York (1-800-829-0500) and Macular Degeneration International (520-797-2525) to help people with this condition. There are catalogs from the Lighthouse and Maxi Aids (1-800-522-6294) which sell aids such as magnifiers, Large print clocks, and CCTV magnification systems that enlarge print of any material to a television screen.

Every day we learn new things about macular degeneration especially genetics and nutrition which is likely the next wave of treatments. Don't lose hope, there are possible treatments and devices available to help preserve your vision.

This photo represents the way a person's vision can be affected by macular degeneration.

Cross section diagram of the eye

Figure 1 - normal grid Figure 2 - abnormal grid

An eye doctor can detect early signs of ARMD through a regular eye exam which might include the use of an Amsler grid, pictured above. To a person with ARMD, the straight lines of the grid may appear to be wavy ( pictured in the bottom grid). The grid is held approximately 14 inches away. Wear reading glasses or bifocals and check each eye individually. Report any change to your eye doctor.