Hands-Free Drug Dispensing for Eye Pressure Using Special Contact Lens

Highlights

• Contact lens that delivers drug for glaucoma patients for 6 months developed by researchers.
• Increased concentration of the drug in the lens is found to be more effective in controlling eye pressure than eye drops.
• This method of drug delivery eliminates hindrances associated with eye drops.

A team of researchers have identified a novel method of dispensing eye drops for patients with eye pressure - drug dispensing contact lens. Patients, especially senior citizens, would benefit immensely if this development enters the market soon. Dr. Joseph B. Ciolino from Massachusetts Eye and Ear, who also works as a researcher at The Harvard medical School, and his team of researchers have developed a contact lens that can dispense drug for eye pressure. A carefully placed drug polymer film has been designed to provide medication for glaucoma for a period of 6 months.

Before the advent of this method of drug delivery, patients have been relying on eye drops that have been associated with certain dilemmas.

Difficulty Faced With Using Eye Drops

The addition of eye drops seems like a simple procedure but there are a lot of hurdles that need to be crossed, especially if it involves a senior citizen.

• Some senior citizens find it hard to position the bottle above the eye, with a gentle quivering of the hand adding to the problem.
• The correct amount of medication is rarely administered into the eye.
• In most instances, senior citizens depend on caregivers to administer the eye drops who may not always be available.
• People tend to forget or miss administering the drops at the right time.

The hindrances faced with applying eye drops that prevent optimal drug delivery might be overcome by the development of drug dispensing contact lenses.

Glaucoma specialist Dr. Janet B. Serle from Mount Sinai’s Icahn School of Medicine “This promising delivery system removes the burden of administration from the patient and ensures consistent delivery of medication to the eye, eliminating the ongoing concern of patient compliance with dosing”

Drug Delivering Contact Lens

The concept of using a contact lens to deliver medication is not new and research into this method of drug delivery has been ongoing for the past 50 years but an effective solution has not been reached, till now. The earlier models delivered the medication too fast and too quick.

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The same group of researchers designed a contact lens that could deliver medication for a period of one month in 2014, this current variant has been found to deliver medication for 6 months.

Design of the Drug Delivering Contact Lens

The researchers used drug encapsulated thin film of polymers at the periphery of the contact lens, that left the center of the lens clear for good vision. The polymer present at the periphery retards the delivery of the drug.

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Boston Children’s Hospital’s Director of the Laboratory for Biomaterials and Drug Delivery, Dr. Daniel S. Kohane says "Instead of taking a contact lens and allowing it to absorb a drug and release it quickly, our lens uses a polymer film to house the drug, and the film has a large ratio of surface area to volume, allowing the drug to release more slowly"

Glaucoma

Glaucoma is a term used for a group of diseases that lead to increased pressure on the optic nerve, resulting in a partial or complete loss of vision. Early detection of glaucoma will aid in treatment and lower risk of complete vision loss.

Glaucoma produces no symptoms and is noticed only when vision loss begins. Once the vision is lost, it cannot be restored. The medication that is used to treat glaucoma either make the eye produce less fluid or drain the fluid that is produced.

Medication for glaucoma is usually in the form of eye drops or pills.

Glaucoma Prevalence in India

According to a study by George R and colleagues titled “Glaucoma in India: estimated burden of disease’ and published in the Journal of Glaucoma, the following are the statistics in India

• 11.2 million people over 40 years have glaucoma
• 6.48 with primary open angle glaucoma
• 2.54 with primary angle-closure glaucoma

Glaucoma in the U.S

• Over 3 million expected to be affected.
• 120,000 are blind as a result of glaucoma.

The serious nature of the disease, increased incidence and absence of symptoms before the start of vision loss necessitates a more effective treatment measure that can control vision loss. The current development in the field of glaucoma management in the form of drug delivering contact lenses provides greater support for patients.

Study on Effectiveness of the Drug Delivering Contact Lens

Boston Children's Hospital Technology and Innovation Development Office supported a study that detailed the effectiveness of the drug delivering contact lens. For this study 4 glaucomatous monkeys were administered with the drug delivering contact lenses. The researchers studied the effectiveness of the latanoprost drug delivering contact lenses with the eye drops of the same drug.

The results showed that when the concentration of latanoprost in the drug delivering contact lens was the same as in the eye drops, the effectiveness was comparable. However, higher concentration of latanoprost in the contact lenses resulted in greater reduction in pressure.

Advantages

• The drug is delivered without the need for a caregiver or self administration.
• Higher concentration of the drug latanoprost found to control eye pressure better than eye drops.
• The drug polymer is present at the periphery so the central part of the lens is clear, this allows vision acuity, hydration and breathability.
• The lens can also be used to correct refractive error in the individual.

The use of drug delivering contact lenses raises the hope for a better treatment modality for glaucoma that would ensure the optimum release of the drug. Human trials are being carried out at this stage to test for side efficacy.

References:

1. Glaucoma in India - (http://www.ncbi.nlm.nih.gov/pubmed/20711029)
2. Glaucoma Facts - (http://www.glaucoma.org/glaucoma/glaucoma-facts-and-stats.php)

Source-Medindia