letters to the editor
Credit Where it's Due
I would like to acknowledge my colleague Dianne Anderson, OD, for her involvement and support in my July article titled "Validating Corneal Topography Maps." The irregular topography images (Figures 4 through 11) were acquired while we reviewed two very challenging keratoconus cases together.
Additionally, your readers may be interested to learn that Dr. Anderson was able to successfully fit both of these highly irregular corneas with the SynergEyes KC (SynergEyes, Inc.) hybrid lens after our topographical analysis. This represents a perfect example of how practitioners and consultants can team up on very difficult cases for the benefit of the patient.
Randy Kojima, Director of Professional Affairs, Precision Technology Services
I read with interest the August Contact Lens Exam column "Association or Causation? The Corneal Staining Debate," by Loretta B. Szczotka-Flynn, OD, MS, FAAO. She correctly points out how a (Kodak Wratten No. 12) filter allows practitioners to detect subtle corneal staining that wouldn't be visible without the filter.
I would like to let your readers know that Gulden Ophthalmics sells a quality Slit Lamp Yellow Filter. Other practitioners have told us that they purchased the Kodak Yellow Filter, which is a 4-inch square piece of unprotected acetate that "lasted only six months before getting destroyed." Ours is encased in plastic and recessed to protect it from scratches and wrinkles.
Tom Cockley, President, Gulden Ophthalmics, Elkins Park, PA
EFAs and Dry Eye
I enjoyed the Dry Eye Dx and Tx article in the September issue by William Townsend, OD, on "Alternative Omega-3 Sources." He made some good and valid points.
However, I believe his assertion that it's only the omega-3 EFAs that are responsible for resolving dry eye conditions is somewhat misguided. It's actually the combination of omega-3 and omega-6 EFAs that is effective in relieving dry eyes. The omega-6 gamma-linoleic acid (GLA), while potentially pro-inflammatory by itself, is actually responsible for the conversion to PGE1, which supports mucous tissue moisture.
Regarding flax seed oil, flax is the most unstable of all the EFA vegetable oils, which causes it to oxidize and become rancid very easily. Flax does not contain GLA, nor does it contain any of the nutrient co-factors necessary to ensure its delicate conversion from linoleic acid (LA) to GLA. The most dependable source of omega-3 fatty acids are cold water fish and cod liver oil.
Also, while the polyunsaturated oils (flax seed, sunflower, sesame, etc.) are popular, it's the monounsaturated oils (olive, canola, peanut, etc.) that are the most beneficial for our health.
I'm glad to see more articles addressing the nutritional treatment of dry eyes and applaud Dr. Townsend on his efforts.
Jeffrey Anshel, OD, Encinitas, CA
Dr. Townsend's Response:
I appreciate the comments of Dr. Anshel, a recognized authority in nutrition and the eye. The benefits of both omega-6 and omega-3 polyunsaturated fatty aid are well documented. Based on articles Dr. Anshel has written, he shares my concern that as ageneral rule, the American diet contains far too much omega-6 and far too little omega-3.
My article to which he referred focused on alternatives for patients who can't or won't take the most common form of omega-3 supplementation (fish oil capsules). Many patients are willing to consume omega-3s in some of the alternative forms mentioned in the article.
Flax seed oil does not contain the long-chain omega-3s believed to be so beneficial to our eyes, but in a recent conversation with Dr. Jeffrey Gilbard, who developed TheraTears and TheraTears Nutrition (Advanced Vision Research), I learned that regular intake of flax seed oil thins meibomian gland secretions.
Our understanding of the benefits of these nutrients has increased exponentially in the past two decades, and hopefully that trend will continue. But for our patients to benefit from them, we must find a form that is readily available and palatable.
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