UPDATING DATA FOR GLAUCOMA SURGERY RATES

There is an urgent need for updated data concerning the rates of glaucoma surgery around the world, and particularly in lower-income countries where the disease is most prevalent, according to Kaweh Mansouri MD. “At the moment intraocular pressure is the only modifiable risk factor for glaucoma, a disease which has been recognised by the World Health Organization as being the second leading cause of blindness worldwide and the first irreversible cause of blindness. Surgery is so far the ultimate treatment option and one of the weaknesses that we face in glaucoma is a general lack of epidemiological data which is the cornerstone of public health action and policy,†he said.

Dr Mansouri, a senior fellow at the Hamilton Glaucoma Center, University of California, San Diego, US, proposed using a new metric to gather data concerning glaucoma surgeries worldwide. Known as the Glaucoma Surgical Rate (GSR), this metric is the total number of surgeries performed in a country in a one-year period per one million people.

Presenting data collected from 37 countries that responded to the survey, Dr Mansouri noted that the GSR in these countries ranged from single digits in low-income, high-prevalence, developing countries to over 1,000 in Portugal.

“The data presented covers a total of 1.6 billion people or about one-fifth of the planet’s population. The lowest rates so far are from low income but high prevalence countries most affected by this disease. Based on these findings we would appeal to the World Glaucoma Association to coordinate collection of data as this would really be a significant step in fighting glaucoma-related blindness in the world,†he said.

Dr Mansouri’s survey revealed some interesting disparities in glaucoma surgery rates within and between regions. In the European region, for instance, the GSR varied from as high as 1,022 for Portugal to just 85 in the Netherlands. Similarly in the American region, the United States of America recorded the highest glaucoma surgery rate of 292 surgeries per one million population per year compared to a GSR of only 17 for Brazil. He added that other reasons for the significant disparities in data may be differences in definition or coding of interventions as well as in the quality of data collection between countries. The paucity of data from the sub-Saharan African region, the region with the highest prevalence of glaucoma, was evidenced by the fact that only two countries, Ghana, with a GSR of 7.01 and Ivory Coast with a GSR of 2.85, responded to the survey.

Looking at the data in more detail, Dr Mansouri noted a correlation between the number of ophthalmologists in a country and the number of glaucoma surgeries performed.

“This is pretty much as we might expect, but there are some notable exceptions to the rule. For instance Georgia and Pakistan have a similar GSR rate as Serbia which has almost five times more ophthalmologists per head of population,†he said.

A correlation was also found between the wealth of a country, as reflected by its GDP, and the number of surgeries performed, again with some notable exceptions. The Netherlands, for instance, performs less glaucoma surgeries than Lithuania which has a significantly lower GDP, said Dr Mansouri. In general, however, a clear trend emerged where the vast majority of low-income countries, defined by having a GDP of less than 3,000, also tended to have a GSR of less than 100.

“The new GSR metric might be useful to facilitate epidemiological research and comparison between countries and it seems that a GSR of 100 or close to 100 might be a useful target for public action,†concluded Dr Mansouri.