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Long-term atropine therapy not associated with elevated IOP in myopic children

Topical atropine therapy administered to myopic children in Taiwan over a 3-year period was found to be statistically dissociated with the risk of developing increased intraocular pressure during the treatment period, according to a recent study.

In the past, atropine eye drops have been demonstrated to have clinical efficacy in curbing the progression of myopia, reportedly halving an annual myopia progression of 1 D, as well as halving the proportion of fast myopic progressor in Asian children when it is applied regularly, according to Saw and colleagues.

However, “because long-term atropine treatment is used in many school-age children to retard the progression of myopia in Taiwan, the safety of such a treatment frequently concerns clinicians, parents and even the governmental agencies,” Chen-Chang Yang, MD, MPH, DrPH, one of the study authors, told Primary Care Optometry News. The study by Dr. Yang and colleagues was recently published in Optometry and Vision Science.

Details of the study

In this study, complete ocular examination data and IOP measurements for 621 myopic children between the ages of 6 and 15 years were retrospectively reviewed. Of the children included in the study, 489 were treated with atropine. The remaining 132 children received no atropine treatment and were designated as the reference group.

The duration of treatment was calculated from the first date the patient received the atropine prescription (between 2005 and 2007) to his or her study recruitment date in 2008. Different concentrations of atropine were administered at the clinicians’ discretion based on the severity of myopia. Children were also, after a year, divided into a “good compliers” group and “bad compliers” group to account for the effects of compliance.

“The major adverse reactions associated with low dose atropine therapy are photophobia and glare, which are generally tolerated by Asian children. In western countries, however, the use of atropine as a first-line therapy is less acceptable because the prevalence of the above-mentioned side effects is usually higher,” Dr. Yang said.

While there was no statistical correlation between the risk of elevated IOP and the amount of atropine administered and/or the duration of treatment, risk factors for elevated IOP were, in contrast, positively associated with age and spherical equivalent values. This was observed regardless of whether or not the patients had been treated with atropine. As a result, the study authors concluded that clinicians should be wary of changes in IOP among older myopic children, as well as children with more severe cases of myopia, and that further studies should be conducted to prove the long-term safety of the therapy.

These findings could potentially have far-reaching clinical implications.

“The prevalence of myopia is rapidly increasing in many countries, and it has become a significant public health problem worldwide,” Dr. Yang said. “If atropine therapy is both effective and safe, then it can be considered as a first-line therapy in many countries where other treatment regimens, such as pirenzepine, are not available.”

When asked if the selective muscarinic M1-antagonist agent, pirenzepine, which has also shown promise as a viable treatment for myopia, was used in Taiwan, Dr. Yang said, “Pirenzepine, like atropine, may slow myopia progression but is less likely to produce mydriasis and cycloplegia. Unfortunately, pirenzepine gel is not yet available in Taiwan; therefore it is not used to treat myopia in Taiwan.”

Myopia treatment in Taiwan

Nearly 85% of school-age Taiwanese children develop myopia. Hence, the current practice of treating them with atropine was implemented to ameliorate the dire need for an easy, affordable and effective way to slow the progression of the condition, Dr. Yang said.

With myopia being as severe a problem as it is in Taiwan, students younger than 15 are required by the current health policy to undergo school-based vision screening each semester. In cases where myopia is diagnosed, students must receive treatment from certified ophthalmologists, who, in Taiwan, predominantly prescribe topical atropine before bed as their preferred treatment method, administering it to the myopic children until they turn 16.

Co-author Jessica Wu, MD, added that ophthalmologists in Taiwan “clinically underprescribe glasses for children when they look at near objects or use a bifocal lens to avoid the cycloplegic effect of atropine.”

The use of atropine in Taiwan has been endorsed by the Ophthalmological Society of Taiwan and, as a result, has become a first-line therapy, as well as a fully reimbursable treatment via the national health insurance system, according to Dr. Yang. – by Daniel Morgan

References:

• Wu TEJ, Yang CC, Chen HS. Does atropine use increase intraocular pressure in myopic children? Optom Vis Sci. 2012;89(2):61-67.
• Saw SM, Gazzard G, Au Eong KG, Tan DT. Myopia: Attempts to arrest progression. Br J Ophthalmol. 2002;86:1306-1311.

For more information:

• Chen-Chang Yang, MD, MPH, DrPH, can be reached at the Division of Clinical Toxicology, Department of Medicine, Taipei Veterans General Hospital; ccyang@vghtpe.gov.tw.