The probability of blindness due to the serious eye disease glaucoma has decreased by nearly half since 1980, according to a study published last month in Ophthalmology, the journal of the American Academy of Ophthalmology. The researchers speculate that advances in diagnosis and therapy are likely causes for the decrease, but caution that a significant proportion of patients still progress to blindness.
A leading cause of irreversible blindness worldwide, glaucoma affects more than 400,000 people in Canada, more than 2.7 million individuals in the United States, and more than 60 million people globally. Significant changes in diagnostic criteria, new therapies and tools as well as improvements in glaucoma management techniques have benefited individual patients; however their effect on the rates of visual impairment on a population level has remained unclear. This study, conducted by a team based at the Mayo Clinic, was the first to assess long-term changes in the risk of progression to blindness and the population incidence of glaucoma-related blindness. By identifying epidemiologic trends in glaucoma, the researchers hope to gain insight into best practices for the distribution of health and medical resources, as well as management approaches for entire populations.
The researchers examined the medical records of all residents aged 40 or above diagnosed with glaucoma between 1981 and 2000 in Olmsted County, Minnesota,. They compared this with similar data from a previous study of patients diagnosed between 1965 and 1980. The findings: While the incidence of glaucoma in the population has not changed, the probability of going blind in at least one eye due to glaucoma dropped by half, from 25.8 percent in the earlier study, to 13.5 percent in the later period. The population incidence of blindness within 10 years of diagnosis also decreased from 8.7 per 100,000 to 5.5 per 100,000 for those groups, respectively. Yet, 15 percent of the patients diagnosed in the more recent timeframe still progressed to blindness.
“These results are extremely encouraging for both those suffering from glaucoma and the doctors who care for them, and suggest that the improvements in the diagnosis and treatment have played a key role in improving outcomes,” said Arthur J. Sit, M.D., associate professor of ophthalmology at the Mayo Clinic College of Medicine and lead researcher for the study. “Despite this good news, the rate at which people continue to go blind due to OAG is still unacceptably high. This is likely due to late diagnosis and our incomplete understanding of glaucoma, so it is critical that research into this devastating disease continues, and all eye care providers be vigilant in looking for early signs of glaucoma during routine exams.” All adults should have a routine eye health examination by an optometrist or ophthalmologist at least every two years, and seniors aged 65 and older should be examined annually. For more information about glaucoma and other eye conditions, visit http://bc.doctorsofoptometry.ca/