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COPYRIGHT 2002 Advanstar Communications, Inc.
When it comes to treating dry eye, ophthalmologists and patients have a plethora of products from which to choose. Relief can come in the form of eye drops, gels, and ointments, or nutritional supplements and sprays.
Ophthalmology Times talked with a number of manufacturers of dry eye products about their approach to treating the condition and the therapeutic agents in their armamentarium.
Comfort and relief
"An ophthalmologist is looking for basically two things in a tear," said Craig Smith, vice president of Accutome Rx. "One is comfort for the patient.
"Second is a product that will relieve the symptoms," Smith said. "These may seem synonymous, but they're really not. You can get relief of dry eye symptoms with a very viscous product, but you can't see very well."
The Malvern, PA company produces three products for dry eye: Accu-Tears PVA (polyvinyl alcohol 1.4%); Accu-Tears HPMC (hydroxypropyl methylcellulose); and Accu-Tears Ointment (white petrolatum and mineral oil lubricant).
For daily use, patients have a choice of two products with different viscosity. Accu-Tears HPMC has a longer duration of action than the PVA product because of its higher viscosity, but many patients find that the PVA product is more comfortable because of its lower viscosity, Smith said.
"We have a more viscous product for people who want a product that's going to stay around a longer period," Smith said. "We have a thinner product for people who are bothered by the viscosity of the thicker one and want a thinner product so that they can have better vision and more comfort.
"Tears are a very individual thing," he added. "People usually stick with what is most comfortable for them."
Many artificial tears have similar ingredients, and the choice for a particular patient depends on factors such as comfort, conditions that cause the dry eye, degree of dryness, and in some cases, cost, Smith said. Comfort is in part determined by the pH level of the tear film, which may vary from person to person.
Promotes healing
Jeffrey P. Gilbard, MD, president and chief executive officer, Advanced Vision Research, Woburn, MA, said he prefers not to classify the company's TheraTears products as being intended for cases of mild, moderate, or severe dry eye.
"With TheraTears, you can take patients with either severe or mild dry eye and they'll both get better; the difference is just the time frame," Dr. Gilbard said. "Patients with mild dry eye have a more rapid response to TheraTears and to a less frequent dose. Mild and severe dry eye are on a continuum. It's not a matter of them being different diseases."
Dr. Gilbard said TheraTears was developed over an 18-year period through a grant from the National Eye Institute. He said the product is unique in that it can both heal dry eye as well as ease the symptoms.
"TheraTears is the first eye drop for dry eyes shown in empirical studies to promote healing. Nothing else has been shown to do that," he said.
The bottled product contains a patented preservative system that converts to oxygen and water on eye contact. The preservative-free single-dose product can be used for saturation dosing.
To develop the product, Dr. Gilbard approached the challenge of dry eye based on a sequence of actions: as the eye becomes dry, the tear film loses water and becomes more concentrated.
Increased osmolarity dehydrates and damages the surface of the eye and decreases the conjunctival goblet cells. The tear film must be rehydrated, or have its osmolarity lowered, to restore the goblet cells, Dr. Gilbard said.
The living cells on the surface of the eye have no blood supply, so they need to obtain oxygen and...
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