EyeWorld India December 2014 Issue

38 EWAP REFRACTIVE December 2014 by Audrey Chia, MD ATOM1, 2 Slow Myopia with Atropine O ver the last three decades, there has been a trend in Asia where an increasing number of children are becoming myopic at an earlier age, and achieving higher levels of myopia by adulthood. The main culprit appears to be the increased urbanization, a strong cultural emphasis on academic achievement, increased amounts of near-visual indoor recreational activity, and decreased time spent outdoors. In addressing this problem, the first step would be to try to change the environment in which our children are living, such as by encouraging our children to go outdoors to play. Aside from this, there has been increasing research into various therapeutic attempts to slow myopia including various spectacle and contact lens designs. Recent studies involving orthokeratoplasty and some contact lens designs, for example, look promising. At the Singapore Eye Research Institute (SERI), we have been studying the effects of atropine on myopia progression for the last two decades. In the first Atropine for the Treatment of Myopia (ATOM1) study (1996–2002), we randomized 400 children to either atropine 1% or a placebo agent daily in one eye. We found that atropine 1% slowed myopia progression by 80% over 2 years (from –1.20±0.69 D in placebo eyes to –0.28±0.92 D in treated eyes). The drops did, however, cause a 3-mm dilation of pupils and an 11-D loss of accommodation so that most children required photochromatic glasses and near reading add. When treatment was stopped at 2 years, there was a rapid increase in myopia especially in younger children (less than 10 years of age). The myopia progression in the atropine 1% eyes at 3 years (after a year without atropine) was –1.37±0.89 D compared to –1.56±0.89 D in placebo eyes. In the ATOM2 study (2005–12), 400 children were randomized to either atropine 0.5%, 0.1% or 0.01%, in a 2:2:1 ratio, in both eyes. After 2 years, the progression in the atropine 0.5%, 0.1% and 0.01% eyes was –0.30±0.60 D, –0.38±0.60 D and –0.49±0.63 D, respectively. Although we did not have a placebo group for comparison, we estimate that this constitutes a 75%, 70%, and 60% reduction in myopia progression. On stopping atropine, there was an increase in myopia which was more rapid in eyes previously on higher doses of atropine. At the end of 3 years, the myopia progression in the atropine 0.5%, 0.1%, and 0.01% eyes was –1.15±0.81 D, –1.04±0.83 D, and –0.72±0.72 D respectively. Pupil dilation (1 mm) and accommodation loss (4 D) was also less in the 0.01% treated eyes so that subjectively, most children (>90%) did not feel that they required photochromatic glasses or reading add. Despite the demonstrated efficacy of atropine treatment on myopia progression, some clinicians are still fearful of the long-term effects of atropine (both systemic and ocular). Some feel that atropine may adversely alter the natural growth mechanism of the eye, citing the rebound noted post-treatment. Longer term follow-up may be useful to determine if there is eventual stabilization of the myopia progression (which should occur naturally in the late teenage years). A recall of ATOM1 participants, now in their early adulthood, may help to determine this. How do we translate the findings from our ATOM studies into clinical practice? Clinically, we have been using atropine 1% to treat myopic children over the last decade. Our target group includes children at the greatest risk of developing high myopia; i.e., children aged 6–12 years presenting with myopia (more than –3.00 D) with documented progression of more than –0.75 D per year, and with parents who also have moderate or high myopia. It may be difficult for clinicians in some parts of the world to appreciate it, but in East Asia where 80–90% of children will become myopic and where 20% will develop high myopia, we do have many children who will easily satisfy these criteria. Initially, children were treated with atropine 1% daily and often the results were quickly evident with stable refraction or a hyperopic shift noted within the first 6 months. Children were routinely provided with required photochromatic and progressive near reading add. These glasses could be expensive but since myopia often remained quite Audrey Chia, MD