AGEING POPULATION WILL LEAD TO INCREASE IN GLAUCOMA PREVALENCE

An ageing world population will lead to an increasing worldwide prevalence of glaucoma, warned Roger Hitchings MD, Moorfields Eye Hospital in a keynote address at the 10th European Glaucoma Society Congress. “With increasing age there is a steady increase, and in some countries and some ethnic groups, a dramatic increase, in the prevalence of glaucoma. The older you are the more likely you are to get the disease,†he reported.

There are, according to current estimates, roughly 39 million blind people in the world today, around 80 per cent of whom are above the age of 50 and around 12 per cent of whom lost their vision because of glaucoma. In fact, glaucoma is second only to cataract as a cause of blindness. At present there are about 60 million people with openangle and angle closure glaucoma. By 2020 that number will likely increase to around 80 million, with prevalence in different regions varying according to the age distribution of their populations, Dr Hitchings said.

Currently, the greatest number of patients with glaucoma live in China, where there are around 16 million people with the disease, followed by Europe and India with 12 million each, and Africa with six-and-a-half million. In addition, there are an estimated six million people with glaucoma in Latin America, four million in Southeast Asia and around three million in Japan, he said. He noted that blindness has a particularly severe impact on people in the developing world, where 90 per cent of blind people are unemployed and where blindness reduces life expectancy by about one-third.

Blindness also reduces an individual’s social standing, along with their authority in the community and in the home. In all regions of the world, the prevalence of glaucoma rises gradually with age staying at below one per cent of the population below the age of 50 of most ethnicities and rising to around five or six per cent in Europe, Japan and India by age 65, but reaching over 10 per cent in Africa, Latin America and China. Among those reaching 80 years of age in those latter regions, the prevalence increases to around 15 per cent. Generally speaking the ratio of glaucoma patients to the population over the age of 40 ranges from around two per cent to four per cent. Since 1950 the shape of the age distribution of world’s population has been changing in a dramatic fashion.

In 1950 it resembled a pyramid, with the greatest numbers at the youngest ages and the lowest numbers at the oldest ages. It has since been changing to resemble a tower, with a more even age distribution. However, the change in age distribution has not been uniform throughout the world. Some countries, like India, continue to have a pyramid-shaped age distribution; other countries like the US and China have sort of a bulge in the middle because of a trend towards a reduction in family sizes in more recent decades.

Dr Hitchings pointed out that if the world’s top 10 most populous countries were placed on a graph in a logarithmic style, India and China would be two major outliers, between them accounting for 2.6 billion of the world’s approximate seven billion population. Dr Hitchings noted if current projections are correct, by 2020 there will be further increases in the older age groups in China and India, a trend which is likely to continue well into the century. Moreover, by 2020, in China the number of people with glaucoma will have risen from 17 million to 22 million and in India it will have risen from 12 million to 16 million.

In addition, the number of people with glaucoma will increase by about a half to around six million in Southeast Asia and by around one-third in Latin America to eight million. Africa will probably see its population of glaucoma patients rise by about two million to nearly eight and half million. There will be only fairly modest increases in Europe and Japan. However, the Middle East will become one of the top-ranking countries with the disease, with over two million affected individuals. “Over the next 20 years there'll be a big increase in the world population, what actually happens will depend on fertility rates, gross domestic product and politics. The expected increase in longevity will mean an inevitable increase in the prevalence of glaucoma and a disproportionate increase in the Middle Eastern countries,†he concluded.