REDUCING BLINDNESS

Recent advances in treatment for ophthalmological diseases combined with widely available and universal free access to medical care seem to be powerfully effective for reducing the incidence of blindness, according to experience in Israel. At the 2012 annual meeting of the Association for Research in Vision and Ophthalmology, Alon Skaat MD, updated findings from a recently published populationbased study that assessed time trends in the incidence and causes of new cases of blindness in Israel between 1999 and 2008 [Am J Ophthalmol 2012;153:213-21].

The research was initiated by Michael Belkin MD, professor of ophthalmology, Tel Aviv University. Using patient information extracted from annual reports issued by Israel’s National Registry of the Blind, the investigators calculated annual age-standardised rates of newly registered legal blindness, defined as BCVA less than 3/60 in the better eye or visual field loss less than 20 degrees.

Almost 20,000 new cases of blindness were registered over the study period, but time trend analysis showed the age-standardised rate of blindness certification decreased continuously and fell by more than 50 per cent between 1999 and 2008 from 33.8 to 16.6 cases/100,000 residents. Analyses of disease-specific rates of blindness showed the annual age-standardised rate per 100,000 residents also decreased significantly by ≥50 per cent for all four leading causes of blindness: age-related macular degeneration (AMD), glaucoma, diabetic retinopathy and cataract.

“According to global data from the World Health Organization, there were about 161 million visually impaired people in 2002, of whom about 37 million were blind, and the number of blind people in the world is expected to continue to rise because of population growth and increasing longevity,†said Dr Skaat, clinical lecturer, Department of Ophthalmology, Goldschleger Eye Institute Sheba Medical Centre, Tel Hashomer, Israel. “The results of our study indicate that progress in eye care and its improved delivery in our clinics in Israel have been very successful in addressing this major public health issue.â€

Noting that a few other high-income countries have also reported a reduction in blindness incidence over the same time period, Dr Skaat observed that the magnitude of reduction was greater in Israel. He attributed the difference both to the universal free access to healthcare in Israel and to the density of ophthalmologists (~100 per one million people), which is higher than in most other countries.

However, specific developments in both ophthalmological care and national healthcare policy also contributed to the declining rate of blindness over time. For AMD, the reduction in annual blindness rate first began in 2004, which is the year when bevacizumab (Avastin, Genentech) treatment for exudative AMD came into widespread use in Israel, Dr Skaat said. The decreased annual rate of glaucoma-related blindness could be explained by the availability of new treatments.

In this case, the beginning of the decline followed the commercial introduction of prostaglandin analogues as first-line treatment. “We know from published studies investigating patients with other chronic diseases that medication adherence is probably higher among patients in Israel than in other countries. Our data on the decline in glaucoma-related blindness seem to exemplify the value of combining good patient compliance with good therapy,†he said.

Although there were no major advances in treatment for diabetic retinopathy over the study period, an initiative to optimise diabetic patient care was launched by the Ministry of Health in 1993-94. “As a result of this national programme, almost every diabetic patient in Israel receives regular screening for diabetic-related eye disease that is important for preventing vision loss,†Dr Skaat said. The time trend for change in cataract-related blindness showed the annual rate fell through 2004 and was stable thereafter.

Here as well, the explanation involved changes in healthcare delivery with the establishment of private ophthalmology clinics that were allowed to perform highvolume cataract surgery and the beginning of private insurance offered by the HMOs. “With these developments, the wait time for cataract surgery, which previously could be two-to-three years, was virtually eliminated,†said Dr Skaat. He said there are limitations for analyses based on registry data. However, it is believed that most blind people in Israel are both diagnosed because there is universal free access to healthcare, and entered into the registry, because persons issued with a Certificate of Blindness derive financial and social service benefits.

Furthermore, the accuracy of the registry data was validated in a 1998 study using information from other government registries. “Although the registry was started in 1990, we chose to start our study using data from 1999, the year after the validation. We believe any errors in reporting are probably due to malingering. However, that would have a negligible effect on our findings given the length of our study period,†Dr Skaat said. Dr Skaat acknowledges the contribution of the researchers Dr Ofra Kalter-leibovici and Ms Ancela Chertit from the Gertner Institute of Epidemiology and Health Policy Research, in Tel-Hashomer.