Elderly struggling with the advanced neovascular, or “wet”, form of age-related macular degeneration (AMD) can be treated with ranibizumab, which improves results on eye exams, allowing patients to have a driver’s license. In turn, their driver confidence is stronger and they are able to keep driving longer.
The condition often goes untreated, which makes it the most common reason the elderly lose their central vision, and a leading cause of their driver’s licenses being taken away.
The results, published in the journal Ophthalmology, suggest that these individuals should be treated with the drug, ranibizumab, a human monoclonal antibody fragment, in order to best avoid these vision problems.
Previous research indicated that dry age-related macular degeneration (AMD) could be prevented from turning into the wet form of the disease by controlling or increasing levels of the immune system component IL-18 in the retinas of patients.
The abnormal scarring and leaking of new blood vessels in the macula, or center of the retina, the light-sensitive layer of the eye that we use for reading, driving, and familiarizing faces, is the major sign of the wet form of AMD.
Individuals receive ranibizumab treatment by monthly injections (or as prescribed by a doctor) into the middle of the eye by using a tiny needle. The drug can remove or slow down the process of new scarring and leaking blood vessel formation.
Neil M. Bressler, M.D., the James P. Gills Professor of Ophthalmology and chief of the Retina Division at the Wilmer Eye Institute at Johns Hopkins Medicine and senior author, explained:
“Driving is an important measure of independence and quality of life for many people in the United States. Participants with wet AMD in our study perceived that they were not driving because of their diminished eyesight. Our study, believed to be the first of its kind to look at whether outcomes relevant to driving improve with treatment, suggests that monthly injections of ranibizumab may be an extremely helpful option in allowing the elderly to continue driving.”
The experts performed a phase III, multicentered, randomized clinical trial that lasted two years. In order to analyze the subjects’ ability to drive, their perception, and self-reported driving status, the scientists used a 25-item National Eye Institute Visual Function Questionnaire in two different studies.
Each month, the experts observed the best corrected vision in each eye of 1,126 participants, which they used to assess treatments for AMD.
The effects for patients receiving ranibizumab vs. sham (fake) injections were compared in one study, while the other experiment tested results of ranibizumab injections vs. photodynamic (laser) therapy (PDT) that can seal the leaking blood vessels.
Two prior analyses based on the results of these same studies, suggested that ranibizumab treatment was more beneficial than sham and PDT, in terms of avoiding vision loss.
This new report focused on clinically applicable outcomes relating to the impact this treatment has on driving in 3 ways:
- treatment vs. no treatment in patients who reported to be driving or not driving at the start and end of the study
- treatment vs. no treatment in those who had eyesight at the start and end of the study that would allow them to have an unrestricted driver’s license in at least 45 states
- a questionnaire examining the patients’ perceived difficulty in driving in conditions such as rain, fog, or driving at night
In order to obtain an unrestricted driver’s license, 45 of the states require correctable vision of at least 20/40 in one eye.
“What the study showed was that 85% of participants in the ranibizumab versus sham study and 88% in the ranibizumab versus PDT study read the eye chart better also achieved the level of vision required for an unrestricted license and in turn had greater confidence in driving,” added Bressler.
Further studies need to be conducted, according to the team, in order to establish whether driving safety or driving skills get better or stay the same, and whether they are the same as the abilities that the patients perceived and reported on the questionnaire.
“Our study has limitations because these two studies were not designed to directly assess the impact of ranibizumab on driving, and because there was just a small number of patients in the groups that were analyzed relative to the hundreds of thousands of patients affected by the wet form of AMD each year around the world.
One of our next steps is to look at these same outcomes when treatment is given for diabetic macular edema, swelling at the center of the retina as a result of diabetes, the most common cause of vision impairment in working-age adults in the U.S. and abroad.”
Written by Sarah Glynn