SEP 2013

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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68 EW GLAUCOMA September 2013 February 2011 Moving away from topical glaucoma drops by Michelle Dalton EyeWorld Contributing Writer Study shows people in Singapore are willing to consider other pharmacotherapeutic options for treatment R educing intraocular pressure remains the sole modifiable factor in the effort to treat glaucoma and prevent disease progression. But with up to almost 60% of patients noncompliant with their topical drops,1 researchers and clinicians alike continue to search for alternative means to deliver pharmacologic solutions. Among the novel drug delivery systems being investigated: liposomes and nanocapsules, molecularly imprinted contact lenses, drug pumps, and subconjunctival implants. The "main drawback" of ocular pharmacotherapy in glaucoma remains ocular surface complaints, said Nathan M. Radcliffe, MD, assistant professor of ophthalmology, Weill Cornell Medical College, New York. "Other delivery methods won't have preservatives on the surface of the eye and won't have the active ingredient causing some of the familiar glaucoma eye drop side effects." Researchers with the Singapore National Eye Center analyzed patients' attitudes and perceptions about a subconjunctival implant as an alternative method to receive glaucoma medications.1 (The authors noted subconjunctival implantation is promising since it has a proven safety and efficacy record in animal studies.) These types of drug delivery devices "mean more options for medically managing glaucoma available to ophthalmologists for their patients, and also improved and better IOP control and therefore optimal therapeutic effect from the anti-glaucoma drugs because patient noncompliance is reduced or even eliminated in some cases. Looking ahead, sustained drug delivery is the future in medical management in chronic ocular conditions such as glaucoma," Tina Wong, FRCOphth, senior consultant ophthalmologist, glaucoma service, Singapore National Eye Centre (SNEC), and head of the Ocular Therapeutics and Drug Delivery Research Group, Singapore Eye Research Institute, told EyeWorld. Reay H. Brown, MD, founding partner, Atlanta Ophthalmology Associates, agreed, saying "there is no question" that longer-acting and/or implantable drug delivery systems are in the future for glaucoma patients. Patient compliance with topical medications is a major issue, in terms of treatment and postoperative care. "Not using drops correctly can cause glaucoma to progress or the glaucoma surgery to fail. Furthermore, patients don't love taking daily (or twice daily) medications," said Parag Parekh, MD, glaucoma specialist in private practice, Laurel Eye Clinic, Brookville, Pa. "Cost [also] has been identified as a factor affecting adherence toward glaucoma treatment regimens, thus it may be a factor affecting acceptance of the implant," the study authors wrote. "In our study, half were willing to pay an amount equivalent to the cost of their current treatment, and 25% were willing to pay more." Others have also shown patients are willing to spend more out of pocket to reduce the number of drops needed daily. The SNEC study found close to 71% of the patients reported incomplete adherence to their medications. Further, the groups of patients who were more likely to take up the EyeWorld @EWNews Keep up on the latest in ophthalmology! Follow EyeWorld on Twitter at twitter.com/EWNews implant "were those who had severe glaucoma and those who perceived the implant to be helpful," the authors wrote. "This study shows that there is a substantial group of glaucoma patients already who would be willing to use these systems for their medical treatment," Dr. Brown said. "However, real-life acceptance will depend on the actual ease of use, cost, and efficacy." Dr. Radcliffe said something like an implant may be welcomed, as "patients accept and actually value pharmacological therapy, even for glaucoma. One of the reasons is because patients are leery of having permanent procedures performed on or in their eye." As an example, he noted many of his patients are "hesitant" to accept laser trabeculoplasty, even though efficacy and safety have been proven. "One of the reasons that selective laser trabeculoplasty is so useful is that it can help take compliance out of the picture, and for the same reason, I think effective implantable treatments or effective injectable subconjunctival treatments would be hugely popular with patients and doctors alike," Dr. Parekh said. "Certainly, my own patients would love it, and I would predict rapid uptake and acceptance of this type of treatment." Additionally, glaucoma surgeons have found patients are particularly tolerant of combined procedures (i.e., cataract and trabecular microbypass), and as long as the additional procedure doesn't change the safety profile and cost is not exorbitant, "perhaps intraocular drug delivery is something that would go well along with cataract surgery," Dr. Radcliffe said. "Patients might like a minor procedure but one that is based on pharmacological therapy," he said. those attempts failed mainly because of issues with the drug itself, he said. "No matter how a drug gets delivered, if the molecule isn't well tolerated by the eye, there are going to be problems," he said. Sustained release using contact lenses "is achievable but its general acceptance as an alternative to eye drops for long-term glaucoma patients would be hampered by the main obstacles of risk of infection from prolonged use, and variation in release of drug due to pre-existing dry eyes in some individuals would lead to a variable clinical response," Dr. Wong said. "Drug eluting contact lenses would be a better drug delivery system for short-term indications, rather than chronic diseases such as glaucoma." Dr. Brown said "It's hard to believe that patients—or entities paying for their care—would not pay a premium for longer-acting treatments that would reduce compliance issues. But the level of premium that would be acceptable remains to be seen and will depend on many factors." Ultimately, that's what will determine which novel therapy is best accepted: a combination of clinical efficacy and safety data, Dr. Radcliffe said, and cost to patients and payers. But as the SNEC study showed, at least patients are willing to consider medical glaucoma treatments beyond eye drops. The study and its implications "have the potential to revolutionize glaucoma care, and I hope we have these types of treatments soon," Dr. Parekh said. EW Sustained release contact lenses Editors' note: Drs. Brown, Parekh, and Radcliffe have no financial interests related to this article. Dr. Wong has financial interests in the technology discussed in this article. The negative outcomes associated with patient noncompliance "have driven research to develop patientindependent sustained drug delivery methods," the study authors wrote. One such alternative, using contact lenses, "would have a place from both the patient and the physician standpoint," Dr. Radcliffe said. Earlier iterations used pilocarpine, but Reference 1. Foo RCM, Lamoureux EL, Wong RCK, et al. Acceptance, attitudes and beliefs of Singaporean Chinese toward an ocular implant for glaucoma drug delivery. Invest Ophthalmol Vis Sci. 2012;53:8240-8245. Contact information Brown: reaymary@comcast.net Parekh: parag2020@gmail.com Radcliffe: nmr9003@med.cornell.edu Wong: jacyline.koh.w.y@snec.com.sg

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