"One of the clear benefits to delivery systems in glaucoma management is patient adherence," according to Dr Erin Lavik (Department
of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA).
Patient adherence is one of the major contributing factors to failure of glaucoma medications.1 Even though the drugs prescribed are efficient at reducing a patient's intraocular pressure (IOP), administration of the
medication can be irregular or discontinued by the patient thereby reducing the efficacy. There are multiple factors that
can be attributed to a patient's lack of adherence including financial and age-related problems.
To overcome these problems several drug delivery systems are currently being developed. In a recent review Dr Erin Lavik and
colleagues looked at the benefits and limitations of several drug delivery devices.2
Controlledrelease systems"In our study we focused on controlledrelease systems for glaucoma and IOP reduction in particular because of the potential
clinical impact these would have," explained Dr Lavik. Controlledrelease systems include drugloaded contact lenses that trap
the ophthalmic drug between the lens and the cornea and allow a controlled release of the drug over time, and biodegradable
micro- or nanoparticles that can be injected onto the eye and release the active compound over a specified period of time.
Also, currently under development are surgically implantable devices (such as microstents) that can provide IOP lowering over
the course of several years.
In the paper Dr Lavik and colleagues describe a range of systems that are in clinical and preclinical trials, approaches that
are amenable to patients, fit with clinican practices and improve treatment, which are likely to have an important impact
in the field of glaucoma. "There are devices that can be loaded with a wide range of drugs, most of which involve a small
amount of surgery," she said. "The most important factor is simplicity, so, if a device or formulation is simple enough to
administer, the fact that it is optimized for one particular drug may not be an issue and should help both clinician and patient."
Exciting developments
"Historically," added Dr Lavik, "some of the devices have required substantial training of both clinicians and patients. Newer
approaches are being designed to be more amenable to clinician practices and patient needs." However, there are certain issues
that developers must overcome to create a successful delivery option including obtaining a balance between the ease of administration,
patient adherence, cost and delivery time. Once a suitable delivery method has been developed and offered to the patient it
could have a significant impact not only on the adherence of the patient but also the associated costs and the quality of
life that will result. "It's exciting that there are a range of options being developed in this area to address different
needs," she concluded.
References
1. Jonathan S. Myers, L. Jay Katz and Robert E. Fintelmann, Ophthalmology Times Europe, 2008;4(5):14–17.
2. Erin Lavik, Markus H. Keuhn and Young H. Kwon, Eye, 2011;25:578–586.
Special Contributor
Dr Erin Lavik is a researcher, an ScD, and an Elmer Lindseth associate professor of Biomedical Engineering at Case Western Reserve University,
Cleveland, Ohio, USA. She collaborates with Dr Markus Kuehn, in the department of Ophthalmology at the University of Iowa,
USA and Dr Young Kwon, a glaucoma specialist on injectable formulations. She may be reached by E-mail: erin.lavik@case.edu
