Pseudoexfoliation prevalence low in Malay population

Findings consistent with Southeast Asian studies, lower than populations around the world.

ByAndrew Kelly

People of Malay ethnicity show a low prevalence of pseudoexfoliation, according to a recent study.

Tin Aung

Tin Aung, MD, PhD, and colleagues examined data from the population-based study, known as the Singapore Malay Eye Study (SiMES), because people of Malay ethnicity make up roughly 300 million to 400 million living in Malaysia, Singapore, Indonesia and other Southeast Asia countries.

“Data from the SiMES may offer further insights into the etiology, ethnic differences and public health impact of the most common age-related eye diseases affecting urban Malay people living in Asia,” Dr. Aung said in an e-mail interview with Ocular Surgery News.

Study methods and results

The SiMES was conducted between August 2004 and June 2006 and looked at 3,280 Malay people aged 40 to 80 years. The presence of pseudoexfoliation was diagnosed at the slit lamp examination as the presence of white, fluffy material in the pupillary margin before pupil dilatation, on the anterior lens capsule after pupil dilatation, on the trabecular meshwork during gonioscopy or a combination thereof.

According to the study, 15 subjects (24 eyes) had pseudoexfoliation, an overall prevalence of 0.46%. Dr. Aung said he was not surprised by the results of the study but was intrigued at the prevalence of pseudoexfoliation in the Indian population in Singapore.

“I do not see many Malay people with pseudoexfoliation in my practice. The prevalance of pseudoexfoliation in Chinese people is also low (0.32% from the Tanjong Pagar Survey, also conducted in Singapore),” he said. “Singapore is a multiracial country, with the Chinese being the majority, followed by the Malays and Indians. What’s interesting is that the prevalence of pseudoexfoliation is high in Indians in contrast to the Chinese and Malays. This has been confirmed in several population-based studies conducted in South India.”

Dr. Aung also referenced a pseudoexfoliation study conducted on Greek participants, which found that 11.9% of participants had pseudoexfoliation, with 15.2% having pseudoexfoliation glaucoma.

Pseudoexfoliation and glaucoma

According to the study, the mean IOP in patients with pseudoexfoliation was higher than those without pseudoexfoliation (19.2 ± 5.4 mm Hg vs. 15.4 ± 3.7 mm Hg; P < .001, comparing right eyes).

“Pseudoexfoliation is important because there are associated complications in the eye, notably cataract and glaucoma. Pseudoexfoliation is the most common identifiable cause of open-angle glaucoma worldwide,” Dr. Aung explained. “In our study, 40% of Malays with pseudoexfoliation in SiMES had glaucoma. This rate is higher than most population studies, which found about 5% to 15% prevalence of glaucoma among subjects with pseudoexfoliation. … It is important for ophthalmologists to look out for signs of glaucoma in subjects with pseudoexfoliation.”

Dr. Aung also mentioned the recent interest in the genetic basis of pseudoexfoliation. He said polymorphisms in the LOXL1 gene have been found to be associated with pseudoexfoliation in some populations, including Scandinavia, Japan, the United States, Australia and India. His team is currently investigating these new findings in an attempt to find similar associations in the Malays and other Asian populations.

For more information:

Tin Aung, MD, PhD, can be reached at Singapore National Eye Centre, 11 Third Hospital Ave., Singapore 168751; +65-6227-7255; fax: +65-6226-3395; e-mail: aung_tin@yahoo.co.uk.

References:

Sumasri K, Raju P, Aung T, Wong TY. Prevalence of pseudoexfoliation in Malay population in Singapore. Am J Ophthalmol. 2008;145:766-767.

Topouzis F, Wilson MR, Harris A. Prevalence of open-angle glaucoma in Greece: the Thessaloniki Eye Study. Am J Ophthalmol. 2007;144:511-519.

Andrew Kelly is an OSN Correspondent based in Philadelphia, U.S.A.