The annual meeting of the American Academy of Ophthalmology was held from Oct. 27 to 30 in Chicago and attracted approximately 6,000 participants from around the world, including ophthalmologists, optometrists, opticians, and other eye health care professionals. The conference featured presentations focusing on the latest advances in comprehensive eye care, including medical, surgical, and optical care.
In the phase II LADDER study, Carl D. Regillo, M.D., of the Wills Eye Hospital in Philadelphia, and colleagues evaluated the durability and safety of a new reservoir-based, sustained delivery device called the port delivery system (PDS) among patients with wet age-related macular degeneration (AMD). The PDS is implanted in the eye in the operating room and then is refilled using a special needle as needed in the office with a concentrated solution of the anti-vascular endothelial growth factor (VEGF) agent ranibizumab.
"An unmet need for wet AMD is to have the effect of anti-VEGF therapy last longer. Currently, we have to administer anti-VEGF drugs by an office-based intravitreal injection every four to eight weeks to control the disease adequately and get good visual outcomes," Regillo said. "We found that the device exceeded our expectations in terms of duration of action. The median time to the first refill of the PDS in the office after implantation was 15 months in the high-concentration device arm of the study. Furthermore, the rate of adverse events was relatively low."
A phase III trial is currently underway and results are expected in a couple of years.
"This device has the potential to significantly change how we treat wet AMD in the future," Regillo concluded. "Less frequent office visits and treatments for our patients with wet AMD is not only more convenient; it also has the potential to minimize how often there is recurrent disease activity, which would maximize long-term visual outcomes."
In another study, Sharon Fekrat, M.D., from Duke University in Durham, N.C., and colleagues used optical coherence tomography (OCT) angiography, a non-invasive imaging technology, to evaluate the small blood vessels in the retina to determine if there is a difference in patients with Alzheimer's disease.
The investigators found that patients with Alzheimer's disease had significantly reduced blood vessel density in their retina compared with patients with mild cognitive impairment and compared with healthy older adults.
"Currently, there is no single test for detecting Alzheimer's disease. In fact, the diagnosis of Alzheimer's is currently based on a combination of cognitive and neuropsychological assessments, neuroimaging such as magnetic resonance imaging, and/or a spinal tap," Fekrat explained. "The results of our work demonstrate distinct changes in the retinal blood vessels in patients with Alzheimer's disease. These changes in the smaller retinal vessels are so subtle that they cannot be detected on routine clinical examination of the eye. These changes can be detected using a quick, non-invasive, and relatively inexpensive scan that can be performed in a few minutes."
According to Fekrat, this study is the largest prospective trial to demonstrate these findings and lays the groundwork for future studies to detect changes across a larger spectrum of neurocognitive impairment, including amyotrophic lateral sclerosis, Parkinson's disease, multiple sclerosis, and Huntington's disease.
"Some ophthalmologists currently do have OCT angiography in their office; however, this testing is not ready for prime time. Patients cannot yet go to their optometrist or ophthalmologist and ask to be screened for Alzheimer's disease. Before this testing can be implemented either in clinical practice or as part of the enrollment criteria of a clinical trial studying novel Alzheimer's disease medications, our findings need to be validated in larger studies," Fekrat said. "We also need to further evaluate the ability of this technology to detect changes over time and whether such changes are indicative of progression of Alzheimer's disease."
Yu-Yen Chen, M.D., Ph.D., of the Taichung Veterans General Hospital in Taiwan, and colleagues found that metformin was associated with a reduced risk for developing macular degeneration.
"Macular degeneration and diabetes are common diseases that can both lead to vision loss. Because they are so common, we are always looking for better, less expensive, and safe treatment options. Metformin meets those criteria, and it is readily available, safe, and cost-effective" said the AAO's clinical spokesperson Sunir J. Garg, M.D., of Thomas Jefferson University in Philadelphia. "The investigators identified over 65,000 diabetic patients, including two-thirds prescribed metformin and one-third not taking the medicine. The investigators found that metformin was associated with a 50 percent reduction in developing macular degeneration. The study investigators suggest that this medication may be an option for treatment of macular degeneration and may do more than just maintain glucose levels."
While these results are idea-generating, according to Garg, they will need to be evaluated prospectively to understand if this effect is reproducible.
"While metformin may prove to reduce the risk of developing macular degeneration, there are three concerns: One, when you look at large populations you can find seemingly impressive results that may not hold true when follow-up work is done. In this case, maybe patents who take metformin for their diabetes have a different metabolism compared to those who don't, or maybe they have different levels of exercise or smoking, which could affect results," Garg said. "Two, we don't know what would happen if you took metformin to slow down or prevent macular degeneration. That question, which is the question most of us would want to know, can only be done when looking at a cohort prospectively. Three, this study was performed in Taiwan and the Taiwanese patient population is different than the U.S. patient population. Taiwanese patient populations tend to be more homogeneous than the U.S. population, and the results of this study may not necessarily be generalizable to the U.S. population."