Can a contact lens help treat glaucoma?

by Allyson Rowley

While an undergraduate in biochemistry at McMaster, Michelle Fernandes worked as a researcher for a biotech company. Now a master's candidate in chemical engineering, she credits that co-op work experience with sparking her interest in applied science.

"I definitely knew I wanted to work in an area that involved health care or medical devices, and I thought was really interesting," she says. For her master's thesis, Fernandes is exploring one way in which we might administer drug into the eyes of glaucoma patients, using a special kind of contact lens.

Currently, when a glaucoma patient attempts to administer his or her medicine, much of the drug is wasted and will not make it past the cornea. "Only about five per cent of the drug actually gets to the intraocular tissue," says Fernandes. By using a contact lens, the aim is to increase the contact time on the cornea, which would then increase the chance of getting the drug to where it needs to be, without the patient having to worry about it.

Fernandes' thesis is titled "Silica particles for hydrophobic drug delivery from silicone hydrogels." In a nutshell, this means: Is it possible to load silica particles (which contain the drug) into a silicone hydrogel material, in order to prolong the delivery of the drug into the eyes of patients?

Fernandes chose the topic from a list provided by her thesis supervisor, Heather Sheardown, a professor of chemical engineering at McMaster and Associate Dean of Graduate Studies (Engineering). "I'd already done some particle synthesis work in that co-op experience with the ," explains Fernandes. "The idea of exploring drug delivery, through particles loaded into contact lenses, was really interesting to me."

Fernandes points out that the concept of using contact lenses for drug delivery has been around since the 1960s. Researchers in Sheardown's lab are pushing that idea further – for example, by exploring different silicone hydrogel-based materials (some of which are now used in contact lenses that can be worn overnight). "Ideally, we'd like to get the drug delivered through silicone hydrogels, because they have the potential for prolonged wear," Fernandes says. Silicone – not to be confused with "silicon" – allows oxygen to permeate the hydrogel material and pass through the cornea.

She explains that her research is somewhat different from that of her colleagues in the lab. Rather than adding the drug directly into the gel formulation, she is experimenting with incorporating drug-loaded particles into the silicone hydrogel, which may protect the drug from the synthesis procedure and act as an additional barrier to drug release – very important, so that the drug is released in a controlled manner and over a prolonged period of time. "By loading the drug into a particle, you might be able to tune particle properties to assist in controlling the drug release behaviour," Fernandes explains.

Can we look forward to a time when we can get prescription contact lenses with our own personalized formulation loaded into them? Perhaps. In the meantime, much research still needs to be done – and that's well before any testing can begin (first on cells, then animals, and then humans). Fernandes points out that, right now, her lens materials are not as transparent as they would need to be to become viable .

"As with any research, there's a lot of reading papers and reviewing the literature. You develop your protocols and you really work on your methodology to tune your system to get it to work. Sometimes things work, and a lot of the time they don't. But when they do, it's great!"

Fernandes hopes to wrap up her thesis by the end of the summer. She credits her McMaster experience with teaching her valuable skills, such as problem solving, attention to detail, and the ability to design experiments. It has also given her the opportunity to interact with experienced scientists in a collegial lab environment. Her goal is to work in industry, conducting research on medical devices or in the pharmaceutical field.

"I really enjoy this, because it's actually affecting humans and health care, and potentially improving the quality of life. I think that's really great."

Related Stories

Researchers seek to improve drug delivery with hydrogels

Nov 02, 2012

Researchers in Japan have developed a technique which allows them to control and target drug delivery to specific sites of the body at specific times, thus reducing side effects and improving treatment dramatically. ...

Contact lenses loaded with vitamin E may treat glaucoma

Mar 24, 2010

The popular dietary supplement vitamin E, loaded into special medicated contact lenses, can keep glaucoma medicine near the eye — where it can treat that common disease— almost 100 times longer than possible ...

Recommended for you

iPads detect early signs of glaucoma in Nepal eye screening

Oct 20, 2014

Using a tablet screening app could prove to be an effective method to aid in the effort to reduce the incidence of avoidable blindness in populations at high-risk for glaucoma with limited access to health care, according ...

Could reading glasses soon be a thing of the past?

Oct 19, 2014

A thin ring inserted into the eye could soon offer a reading glasses-free remedy for presbyopia, the blurriness in near vision experienced by many people over the age of 40, according to a study released today at AAO 2014, ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

PPihkala
not rated yet Jul 09, 2013
Even when lenses are not transparent they could be worn at night to deliver the drugs during sleep.