discovering dry eye
Current Dry Eye Treatments Show Promise
BY BARBARA CAFFERY, OD, MS, FAAO
Eyecare practitioners have a new and increasingly varied supply of drops for their dry eye patients. On paper they show great promise, but how they will perform clinically remains undetermined.
Is Thicker Better?
First are the new, thicker drops that are either gels or gel-like in nature. Refresh Liquigel (Allergan), Tears Naturale Forte (Alcon) and Genteal Gel (Novartis Ophthalmics) are three good examples. The manufacturers recommend these thicker drops for moderate to severe dry eye patients, and they believe that the best starting point for mild dry eye cases is the "lighter" versions of the same drops.
The thicker drops cause little blurring on instillation despite their high viscosity. Instruct patients to not use them during lens wear. To date, my dry eye patients have responded well with these drops. They report that the drops last longer, feel more soothing and that they feel that they need to use them less often.
Inflammation and Dry Eye
Whatever the cause of dry eye, it results in the presence of inflammatory mediators on the ocular surface that may arise from surface cells, the lacrimal gland or dilated conjunctival vessels. This causes poor tear composition, which worsens dry eye. Eventually this chronic cycle results in symptoms and signs of ocular surface disease and further progression of the chronic cycle.
Our goal in treating dry eye, then, is to minimize inflammation and attempt to restore the various layers of the tears while washing away inflammatory mediators that perpetuate the cycle.
Anti-inflammatory and Oil-based Drops
Refresh Endura (Allergan) is a drop that began as the vehicle used in the Restasis (Allergan) trials. Restasis, as you may know, is the recently approved cyclosporine drop. Its anti-inflammatory properties reportedly reduce the inflammatory response associated with dry eye disease. Restasis received approval based on increased Schirmer test results with its use. Yet results with Restasis showed no significant difference in other signs and symptoms of dry eye disease when compared with the vehicle.
Refresh Endura is an oil-based eyedrop that adds oil to the eye that you can see with a slit lamp after instillation. This oil may bring significant relief to patients who have poor meibomian gland function or evaporative dry eye.
Drops for Contact Lens Wearers
New in-eye cleaning drops for contact lens wearers are formulated to "de-coat" the lens surface while the contact lens is in the eye. Blink-N-Clean by Advanced Medical Optics and Clerz Plus by Alcon are examples of these formulations.
To date, my contact lens patients find these drops useful. The drops particularly help marginal dry eye patients who wear lenses less often and have trouble tolerating lens wear. These patients often wear one-day disposable lenses. If they want to wear their lenses for a few extra hours, then they use these drops to make their later wear time more comfortable.
Help in a Bottle
I am continually grateful for the innovative work by the pharmaceutical industry to improve the quality of life for our dry eye patients. These new products help eyecare practitioners better manage the tough cases.
Dr. Caffery has practiced optometry in Toronto, Canada, in a group setting dedicated to contact lens and tear film research since 1977.