SPECIAL CONTACT LENSES FOR GLAUCOMA PATIENTS

Ophthalmologist Carolina Valdivia, MD answers a question about special contact lenses designed to help control eye pressure in glaucoma patients.

A 23 year-old man from India writes:

Hello Dr. Valdivia. My uncle is suffering from Glaucoma. I want to know about the new research at Florida University, wherein by wearing special contact lenses, glaucoma can be cured in six months. Moreover I would like to know that where can I order these lenses from?

Thanks!

Thank you for your question and for your interest in glaucoma-eye-info.com

Carolina Valdivia, MD I am sorry to learn that your uncle is living with glaucoma. The special contact lenses to which you are referring are the product of research being conducted by a team at the University of Florida, led by Dr. Anuj Chauhan, Professor of Chemical Engineering.

Dr. Chauhan has designed a soft contact lens that in a limited test with dogs successfully delivered a sustained dose of vitamin E over a 3-5 day period. Vitamin E is thought to aid vision because of its antioxidant capacities. Several independent studies have explored the prospect that it could help combat glaucoma when used in conjunction with prescription drugs.

Although vitamin E research is exciting in its own right, the potential benefit of the special contact lenses for glaucoma patients is that they would represent a superior drug-delivery system compared to eye drops. The ultimate goal appears to be to develop contact lenses that could be worn for up to one month.

Glaucoma is the second leading cause of blindness worldwide. In its early stages, glaucoma typically does not exhibit recognizable signs and symptoms, but silently causes damage to the optic nerve that ultimately can result in a partial or complete loss of eyesight. There is no cure for glaucoma and once vision is lost, it cannot be restored. However, treatments, including medication and surgery, do slow down or halt progression of the disease.

The claim that these special contact lenses would cure glaucoma in six months is false. Moreover, Dr. Chauhan does not make any such assertion. The actual purpose of the lenses is adjunctive, meaning something that assists a primary treatment – in this case medications to reduce pressure inside the eye.

The premise behind the research project is that current eye-drop delivery systems for drugs that control intraocular pressure in glaucoma patients are inefficient for the following reasons.

Most of the eye drop is wasted and never reaches the targeted area of the eye.
Eye drops must be administered every 12-24 hours in order to maintain effective concentrations of the medication.
Medications in the eye drops are absorbed into the blood stream and sometimes can cause uncomfortable side effects.

The lens delivery system potentially could address each of these drawbacks to using conventional eye drops. Since medication would be delivered directly into the eye, less would be needed to achieve the same results achieved with eye drops. Medicines would be released by the special contact lenses through a timed-release mechanism, rendering current administration cycles unnecessary. Additionally, lower doses of medications might be able to be used. Finally, the occurrence of side effects would be diminished because most of the drug would be delivered to the targeted area.

A delivery mechanism that would immerse the eye in slow and continuous medication to control intraocular pressure has been a goal in the field of ophthalmology for many years. In this respect, Dr. Chauhan's research represents a significant step forward. However, as Dr. Chauhan notes on his website, development and calibration of the lenses is in its nascent stages. It will be at least 8 years before a product that is based upon this research will be available to the public through a doctor's prescription. Until then, it will not be possible for you to obtain these lenses for your uncle.

There also are some potential pitfalls that will have to be overcome in order for this new medication delivery system to be practical.

At present, ophthalmologists strongly advise patients not to leave contact lenses in their eyes overnight. Either this problem would have to be overcome in some way or eye drops still would have to be applied once per day prior to going to sleep. This would seem to undermine the fundamental premise of the research to make obsolete the use of eye drops as a drug-delivery system. A continued requirement for eye drops may significantly limit the attractiveness of this option for patients.
The most effective glaucoma drops available today only require application once per day. Would patients be willing to insert a contact lens in their eye when they do not otherwise use contacts?
Special contact lenses that deliver sustained dosages of glaucoma medication would have to be comparable in price to eye drops in order for them to represent a feasible and viable alternative for patients.

These reservations aside, the research is an exciting endeavor and it is worth following its progress. You can do this by going to Dr. Chauhan's website and checking for updates. Assuming that the research moves forward without any major complications in the animal trials, Dr. Chauhan should be starting human trials in the next couple of years. You might consider contacting him through the electronic mail address listed on his website and asking about the possibility of your uncle volunteering to be a participant in one of these trials.

Carolina Valdivia, MD

REFERENCES:

Gupta C and Chauhan A. Ophthalmic delivery of cyclosporine A by punctal plugs. Journal of Controlled Release. 2011; 150(1): 70-76.

Kim J, Peng CC, and Chauhan A. Extended delivery of dexamethasone from silicone-hydrogel contact lenses containing Vitamin E diffusion barriers. Journal of Controlled Release. 2010; 148: 110-116.

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My goal in answering your questions is to provide you with information, clear up misconceptions, and to explain options so that you can have an informed conversation with your doctor. However, under no circumstances should my response to your question be considered a substitute for ongoing consultation and examination with your doctor. Since I have not examined you, I only can speak in terms of generalities, whereas your doctor has sufficient clinical details to evaluate your case specifically.

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