- 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
. 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
- 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
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
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.
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 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
Glaucoma in the U.S
- 11.2 million people over 40 years
- 6.48 with primary open angle
- 2.54 with primary angle-closure
- Over 3 million expected to be
- 120,000 are blind as a result of
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
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.
- 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.
- Glaucoma in India - (http://www.ncbi.nlm.nih.gov/pubmed/20711029)
- Glaucoma Facts - (http://www.glaucoma.org/glaucoma/glaucoma-facts-and-stats.php)