A new study, published in the Journal of Glaucoma, has attempted to determine “whether adherence is better with morning or evening administration of a once-daily glaucoma medication in the treatment of patients with glaucoma or ocular hypertension.” The Journal of Glaucoma provides a forum for discussion of clinical, scientific, and socioeconomic issues of concern to clinicians who care for persons with glaucoma.
The study, entitled Morning Dosing of Once-Daily Glaucoma Medication is More Convenient and May Lead to Greater Adherence than Evening Dosing, was authored by Bryce A. Ford, Malcolm Gooi, Anthony Carlsson, and Andrew Crichton, all of whom are affiliated with the Department of Surgery, Division of Ophthalmology, University of Calgary, Alberta, Canada.
More about the Research
From the article introduction:
It has been demonstrated that lowering of intraocular pressure (IOP) can decrease the risk of visual field loss from glaucoma. One of the most common initial interventions in the treatment of glaucoma is the prescription of topical ocular antihypertensive medications in the form of eye drops.
Of these medications, prostaglandin analogues (PGAs) such as travoprost are among the most frequently prescribed medications used to lower IOP, and are administered once daily. In order for the medication to have the desired effect of lowering IOP, consistent adherence to daily administration of the medication is essential.
Compounding barriers to adherence is the asymptomatic nature of the disease, and the perception that eye drops are not “real” medications because they are not dosed orally. Thus, any modification to a treatment regimen which improves adherence would be beneficial in the management of patients with glaucoma.
Recently, a dosing aid from Alcon for use with travoprost has been developed that allows precise recording of the date and time at which the bottle of medication is squeezed to dispense a drop. This allows measurement of adherence when the medication is prescribed for different dosing schedules within the day.
About Prostaglandin Analogues
Prostaglandin is a naturally-occurring blood protein that can lower intraocular pressure, in addition to having many other therapeutic effects. Analogue, or “analogous,” means that the drug is comparable, or similar, to prostaglandin, but has a slightly different chemical composition.
Thus, prostaglandin analogues (PGAs) are drugs that are used in the treatment of open-angle glaucoma or ocular hypertension. At specific dosages, they lower intraocular pressure by increasing the outflow of aqueous humor from the eye. Some of the more common PGAs include travoprost, latanoprost, and bimatoprost.
More about Open-Angle Glaucoma
Glaucoma is a group of eye diseases that damage the optic nerve and is one of the leading causes of vision loss and blindness. Open-angle glaucoma is the most common form of glaucoma.
The eye continuously produces a fluid, called the aqueous (or aqueous humor), that must drain from the eye in order to maintain healthy eye pressure. Aqueous humor is a clear, watery fluid that flows continuously into, and out of, the anterior chamber of the eye, which is the fluid-filled space between the iris and the cornea. It is the aqueous that helps to bring nutrients to the various parts of the eye.
Aqueous fluid drains from the anterior chamber through a filtering meshwork of spongy tissue along the outer edge of the iris (the trabecular meshwork), where the iris and cornea meet, and into a series of tubes, called Schlemm’s canal, that drain the fluid out of the eye. Problems with the flow of aqueous fluid can lead to elevated pressure within the eye.
In primary open-angle glaucoma, the filtering meshwork may become blocked or may drain too slowly. If the aqueous fluid cannot flow out of the eye, or flow out quickly enough, pressure builds inside the eye and can rise to levels that may damage the optic nerve, resulting in vision loss.
The Study Results and Conclusions
The authors summarized the study results as follows:
Patients and Methods: Thirty patients, newly diagnosed with glaucoma or ocular hypertension requiring intraocular (i.e., within the eye) pressure reduction, were started on travoprost eye drops and [randomly assigned] to either morning or evening administration for one month. They were then crossed over to the opposite dosing schedule for the following month. Adherence was monitored using an automated dosing aid.
Results: Patient adherence overall was good (89.3%). There was no statistically significant difference in adherence between morning dosing (90.9%) and evening dosing (87.3%). Adherence in the first month (91.7%) was superior to the second month (86.5%). There was no significant difference in IOP response between morning and evening dosing. Patients found morning dosing more convenient than evening dosing.
Conclusions: Early adherence to treatment with a prostaglandin analogue is good, but patients prefer morning administration to evening administration. This may lead to greater adherence with morning administration, particularly among men. Adherence decreases from the first to the second month after initiation of treatment. IOP response to this treatment is not significantly affected by morning versus evening administration.
In order to further determine the effect of timing of medication administration on adherence to glaucoma therapy, a larger and more long-term study will be required.
VisionAware will continue to provide updates for ongoing glaucoma research as they become available. You can read more information on VisionAware.org about medication concerns at Tips for Taking Glaucoma Eye Drops, Medication Management and Organization, and Medication Labeling Techniques.