Incidence of AMD halved in the past decade
MedWire News: Two separate studies from Denmark and Israel published in the American Journal of Ophthalmology show that the incidence of legal blindness associated with age-related macular degeneration (AMD) and other causes has halved over the past decade.
AMD is the leading cause of legal blindness in individuals aged 50 years and older in industrialized countries. Current treatment of wet AMD consists of repeated injections of vascular endothelial growth factor (VEGF) inhibitors, verteporfin photodynamic therapy, and nonreimbursed vitamin therapy.
One of the lead study authors from the Danish study, Michael Larsen (University of Copenhagen, Denmark) commented in a press release: "The massive implementation of modern wet AMD therapy has been a challenge. It is therefore very important that we can now show an impact on public health and it is wonderful to see a reduction in severe visual loss.
"The study did not examine moderate visual loss, but there are undoubtedly also a lot of people who avoided losing their driver's license and their reading vision."
In the Danish study, Sara Bloch (Glostrup Hospital, Denmark) and colleagues investigate the incidence rates of legal blindness related to AMD and other causes from 2000 to 2010 among citizens aged 50 years or older. In total, 11,848 incident cases of legal blindness were identified from the membership register of the Danish Association of the Blind.
The incidence rate of legal blindness attributable to AMD decreased significantly from 52.2 to 25.7 cases per year per 100,000 over the 10-year period. The researchers say that the bulk of the 50% reduction occurred after 2006, which corresponds with the introduction of intravitreal injection of VEGF inhibitors.
Furthermore, legal blindness from causes other than AMD decreased significantly by 33%, with most of the reduction occurring between 2000 and 2006.
The second study, conducted in Israel, evaluated time trends in the incidence and causes of new cases of blindness between 1999 and 2008. During this period, 19,862 citizens were newly registered as legally blind in the National Registry of the Blind.
Analysis of the registry findings by Alon Skaat (Tel Aviv University, Israel) and colleagues also showed that the age-standardized incidence rate of newly registered legal blindness decreased significantly from 33.8 per 100,000 in 1999 to 16.6 per 100,000 in 2008.
The researchers note that the decline was mainly attributable to a decreased incidence of blindness resulting from AMD, glaucoma, diabetic retinopathy, and cataract.
In an associated editorial, Nina Cheung (University of Melbourne, Australia) and Tien Wong (National University of Singapore, Republic of Singapore) said the findings should be considered a public health success that is related to substantial funding for ophthalmology, but more remains to be done.
"Further funding is needed for research into cost-effective preventative, diagnostic, and therapeutic strategies. These public health endeavors must continue and should extend to the developing countries where the rate of blindness is expected to be higher," they said.
By Ingrid Grasmo