The long term side effects of refractive surgery have been a concern for all patients and doctors alike. When Radial Keratotomy(RK) was being performed; there were many unknowns. Flattening the corneas with radial corneal incisions stretched the endothelial layer decreasing its’ ability to pump water out of the cornea. While most RK surgeons were not worried about the long term corneal hydration, questions did remain as to what would occur years after the procedure.

These RK patients do have corneal issues 10 plus years later. Their corneas often display a brownish line in the bottom half indicating iron left behind when the endothelial pump removes fluid from the cornea. In addition, most of these patients are far sighted with astigmatism and their prescription gets stronger later in the day. This makes it difficult to have an accurate eye glass prescription. Weakness of the cornea also increases the risk of corneal rupture when exposed to trauma.

LASIK and PRK do not flatten out the entire width of the cornea thus leaving the endothelial layer intact. This does not affect the pump or the functioning of the physiology of the corneal tissue. Therefore negative corneal changes that are displayed in RK patients should not occur in the LASIK and PRK patients.

According to an article published in the November issue of the Archives of Ophthalmology, there are no long term destructive corneal effects following LASIK and PRK. The study examined 29 myopic LASIK and PRK patients 9 years after the surgery and found them to display no abnormal changes. There was a 5.3% decrease in the endothelial cell density which corresponds to a normal cell decrease in individuals that never had the refractive procedure.

While the study did not examine far sighted post operative patients, they concluded that the results would be similar to the near sighted patients. Whereas post operative RK patients displayed corneal changes after 5 years, the LASIK and PRK patients did not show any signs after 9 years. Further studies must be conducted at longer post op intervals to fully examine the long term effects, but this initial study is very encouraging.

As the cold wintery weather seeps into our bones, thoughts of warm weather vacations dance in our heads. While packing for these vacations is often a pain in the back side, the final destinations makes it all worth while. These suitcases, which now must pay their own airfare, usually include the required bathing suits, suntan lotions and clothes saved for just such locations that never get out of the closet any other time of years.
One of the most important items which should be packed, but is often over looked is the sunglasses. Clinical studies have shown for many years that the high energy sunlight causes cataracts, Pterygia, solar ocular burns and Macular Degeneration. Yet, while we all are quick to put on the suntan lotion, many of us forget the sunglasses, or don’t want them on because they will leave tan lines on our face. Not a good decision, but a common one.

The question then comes up as to what type of sunglasses are the best. I generally go by the rule that if a pair of sunglasses tells you how good they are, then they are not. The best pairs are those of the quality sunglass manufacturers. The good quality sunglasses are those that serve two functions. The first is to filter out all the high energy UV light of all wavelengths. This removes the catalyst that creates the ocular damage on and in the eye.

The second is providing good quality optics. The lesser expensive sunglasses usually sacrifice optical quality which decreases one’s vision and increases glare and distortion. Comparing the good and bad sunglasses is dramatic.

The better quality sunglasses permit perfectly clear, sharp vision while giving 100% protection. The least expensive of the good quality glasses are the Ray Ban collection. The two best quality and most expensive lines are Maui Jim and Oakley. Frame style frequently determines which line a patient will wear and that is fine as long as the quality of the sunglasses is good. Serengeti, Revo, Bolle and Nikes are also among the lines that are good for ocular protection.

Have a happy healthy holiday season and a happy new year. AND WEAR YOUR SUNGLASSES.

Nutritional supplements are ubiquitous and highly recommended for many individuals. Some are more important then others and all can become toxic if over used. One of the most important elements is Zinc.

Zinc is an essential cofactor that is required in more then 300 enzymatic reactions. It is important in cellular ATP production, as well as brain and retinal growth and function. While Zinc binds to DNA aiding in gene expression, it also plays a role in cell death.

Good sources of Zinc are meats, eggs, many seafood, some peas and wheat germ. The recommended dosage (RDA) is 11 mg per day, but more may be recommended for ocular conditions such as Macular Degeneration. Larger dosages can interfere with copper bioavailability.

Unlike most nutrients, the average diet does not provide the RDA for zinc, especially with vegetarians. Zinc deficiencies are common in alcoholics, chronic kidney disease sickle cell anemia and all malabsorption patients. It is related to decreased vision, poor wound healing and an increased susceptibility to infections. In addition, poor night vision has been linked to low levels of zinc.

More then 50 mg of zinc per day are reserved for macular degeneration patients and must be closely followed by an eye doctor. Levels exceeding 300 mg will cause a decrease in the immune system, blood formation and copper deficiency anemia.

All nutritional supplements must be monitored and interactions between then regulated. The thought that if some is good, more is better does not work with anything ingested.

Color blindness and deficiencies are genetically transferred, and affect the cones in the retina. The treatment to date has been with the use of special contact lenses called X Chrome lenses. These lenses are a deep red color and are worn on the non dominant eye. This lens improves, but not completely, ones’ ability to differentiate colors. It is an aid not a cure.

Research being conducted at the Universities of Washington and Florida have reached a possible cure for color blindness in squirrel monkeys. Through the use of a gene transfer technique that added a third cone pigment replacing the one missing from their retinas. Over a period of 5 weeks these monkeys had acquired full color vision. The color identification was measured using the Cambridge color tests.

This gene transfer technique adds the missing color sensitivity to the retinas that were deficient at birth. The researchers employed human DNA which means when the procedure is used on humans no changes in the clinical therapy would be needed.

This revolutionary technique is the first step in curing color blindness and may mean and end to this common condition.

Clinical studies have shown that carotenoids are very important in maintaining good over all health and ocular health in particular. Zeaxanthin is one of the important carotenoids. It is the pigment that gives many of the fruits and vegetables their brilliant colors. Green leafy vegetables like spinach and kale as well as corn are great sources of this valuable nutrient. The best source of it are Goji berries. While the US dietary recommendation for carotenoids is about 2 mg/ day, there are no specific advisories for Zeaxanthin.

Zeaxanthin is a strong antioxidant that minimizes phototoxic stress. Systemic use of Zeaxanthin helps protect against dementia, skin conditions and certain cancers. With regard to the eyes, it is present in the natural lens. Oxidative stress causes cataracts and increases the likelihood of macular degeneration. Zeaxanthin is involved along with Lutein in increasing the density of macular pigment especially in the central fovea.

Macular pigment absorbs excess light and reduces free radicals that are responsible for oxidative stress. By absorbing the light the pigment protects the outer layer of the retina from this potential damage. Thus, Zeaxanthins’ ability to increase retinal pigment directly results in a protective action that will reduce the likelihood of macular degeneration. Epidemiological studies have supported this fact demonstrating an inverse relationship between AMD and macular pigment.

Obviously, a Zeazanthin deficiency will lead to a decreased retinal pigment concentration which can lead to more oxidative stress and therefore macular degeneration. This deprivation can also result in cataractogenesis in susceptible individuals. No studies have been conducted as to the potential affects of Zeaxanthin excess, but there have been no reported reactions in patients who have taken this supplement in large quantities. It is therefore considered relatively safe.

While Zeaxanthin does not satisfy current criteria as a essential nutrient, it may be used to fulfill the need for this category.

Damage to one’s eye is often permanent and results in poor that can not be improved by any optical means. The development of new optical aids has dramatically impacted a patient’s ability to see after trauma or accidents affecting the eye. One such change has been small telescopes that can enlarge the image onto a damaged retina, or move an image to a better or more sensitive part of the retinal tissue.

One problem with such devices has been the patient’s ability to actually wear and use this complex instrument. They are unsightly and cumbersome to use and frequently result in lack of use. Thus the need to better deliver this optical aid became a priority within the low vision field of practitioners.

A new procedure called Osteo-odonto-keratoprosthesis was performed on a Mississippi woman to help her see after losing sight due to Stevens Johnson Syndrome. Dr Victor Perez of the Bascom Palmer Eye Institute employed an extracted tooth from the patient, shaved, sculptured and modified it to hold and optical cylinder with a telescope. This tooth/telescope unit was then implanted under the patient’s skin so it could bond and give time for the body’s immune system to get used to. It was left there for 1 month during which time the eye was prepared for its’ surgical insertion.

This unit was then implanted in the eye at the iris plain. Two weeks post op, the patient was able to read 20/70, and Dr Perez expected her vision to further improve as the swelling decreased.

This patient used her own tooth as prosthesis in her eye and may serve as a model for further such procedures. She has a gap in her smile, but can finally see again.

Toxicologist John Draize, 65 years ago, invented the “rabbit test” as a standard for measuring eye damage when exposed to chemical agents. The rabbits are held in a brace preventing them from moving their bodies or heads for 21 days or longer after the chemical has been introduced into their eyes. The eyes are then evaluated for redness, corneal damage, structural changes and alterations in the anterior section of the eyes. The animals are then useless to the researchers since the eyes have been compromised.

This practice subjects the rabbits to pain and suffering and treats them like disposable tissues. It is a terrible, heartless method that demonstrates a total lack of respect for other living creatures that feel pain and fear as much as we do. Fortunately, there is an alternative method utilizing cow and chicken corneas from dead animals. This procedure has been approved by both the US and Europe. The dead tissues are exposed to the same irritants and studies instead of the live subjects. There is NO pain and NO suffering!

According to Thomas Hartung who is director of the Center for Alternatives to Animal Testing at John’s Hopkins University, the Draize eye test should become history as this and other alternative become available. The germ killing cleaning products no longer have to be tested on live rabbit eyes to see if they are safe.

We as humans have an obligation to safeguard the safety of animals. They are at our mercy and using them for this kind of testing shows a lack of respect for other life. We must employ methods that do not put animals at risk and expose them to pain. Only lab tests should be permitted and when safety and efficacy have been determined then human volunteers can be used. Animal testing never gives us the actual response anyway, so why torture these poor living creatures.

Drugs are manufactured for treating specific conditions and the FDA tests and approve them for that use. Frequently, during the use of a medicine other benefits are discovered by accident. For example, the new class of glaucoma drugs have been shown to increase eye lash growth. Thus the manufacture now makes a separate form of the drug called Latisse to apply directly on to the lashes.

According to the July 2nd issue of The New England Journal of Medicine, antihypertensive medications can slow the progress of diabetic retinopathy. A clinical study was performed on type 1 diabetics receiving either Cozaar 100mg 4 times per day, Vasotec 20 mg once per day or a placebo all for a period of 5 years.

The results were outstanding and demonstrated a definite link between these medications and reduction in diabetic retinopathy. The group taking Cozaar demonstrated a 70% reduction in retinopathy while the Vasotec group showed a 65% decrease in the progression of the disease. These results were compared to the placebo group that should no change in the expected retinopathy changes.

Research has shown that patients with moderate to severe diabetic retinopathy present with high levels of angiotensin conversion factor and angiotensin II in their vitreous and retina. Therefore, it makes sense that blocking these factors with anti hypertension medications would reduce the progression of diabetic retinopathy.

More studies must be conducted to determine the dosage and best medication for this therapy, but it certainly shows that there are other treatments in the future to preserve sight in the always difficult to treat diabetic patient.

Decreased tear production is a common occurrence as we all age and may occur secondary to many ocular surgeries. The symptoms may include but are not limited to a dry burning feeling, red eyes, and a sandy, gritty sensation. When patients enter our offices we usually categorize their disorders based on a variety of factors including age. Dry eye patients are not usually children and as a result this very common condition may go undiagnosed.

When a child rubs his/her eyes there may be a number of reasons, but while dry eyes are not often included in the differential diagnosis, it should be. The underlying causes of their symptoms and thus eye rubbing may be dry eyes caused by several anomalies. Inflammatory disease caused by such conditions as Sjogren’s, juvenile rheumatoid arthritis and viral disease may be just a few causes. Congenital disorders and poor nutrition including vitamin deficiencies can also cause dry eyes in the young. More serious diseases like diabetes and other vascular conditions may also be the reason.

In short, we must always consider dry eyes when a child enters our office with ocular symptoms. Excluding this common condition simply because of age will result in a misdiagnosis and very unhappy child and parent.