Soft contact lenses do not increase myopia progression in kids

September 15, 2008

Clinicians who have been wary of fitting younger children with soft contact lenses may want to consider findings from a three-year study of myopic progression.

Key Points

The analysis compared contact lens wearers and spectacle wearers. While the former had statistically greater myopic progression over the study period, the difference of 0.19 D was not clinically significant, said Jeffrey J. Walline, OD, PhD, lead investigator of the Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) Study. Dr. Walline described the study results in a presentation at the annual meeting of the Association for Research in Vision and Ophthalmology. He also is assistant professor, The Ohio State University College of Optometry, Columbus, OH. Dr. Walline suggested that doctors may want to particularly consider prescribing contact lenses for younger children who are active or who are concerned about their appearance with glasses, because those children appear to benefit most from contact lenses.

Secondary endpoint

Many studies have evaluated "myopic creep" due to soft contact lenses, and because of their findings many clinicians decline to fit young children with contact lenses. "It's an important question to take a look at," Dr. Walline said, adding that studies finding myopic progression have lasted 1 year or less, while the ACHIEVE Study was much longer.

The study enrolled 484 children who had between 1 D and 6 D myopia with less than 1 D of astigmatism. All children were healthy and had healthy eyes and had not worn contact lenses on a regular basis. The study sites were 5 colleges of optometry in various U.S. locations.

As was typical of contact lens studies, more than half (59.5%) of the participants were female; the average age was 10.4 years. About one-third of the children were in the younger portion of the study population, aged 8 to 9. Approximately half of the children were white, while about one-fifth each were of black and Hispanic ethnicity, and a few were Asian.

"These children are your average myopes that come into your practice every day," he said. "They averaged about 2.5 D myopia at baseline, their astigmatism was limited, their eyes were about an inch in length, and their steep corneal curvature was rather steep-but that's what you would expect for myopic children."

Spectacle survey as basis

The randomization to contact lenses or spectacles was stratified based on spectacle satisfaction. This was measured with the Spectacle Survey, which was developed for the ACHIEVE Study. The survey quantifies satisfaction on a scale of 0 to 100, with 100 being extremely satisfied and 0 being unsatisfied. A cutoff point of > 67 was chosen following a sample conducted at eight centers in which it was found that 67 was the median spectacle satisfaction. The randomization was also stratified by myopia and gender.

All measures in the study were masked, including measurements of cycloplegic autorefraction, axial length, and corneal curvature. To assess the effectiveness of masking, the masked evaluators were asked to rate their confidence in what the child was wearing. Out of 3,755 masked measurements, the examiners reported they were very sure or somewhat sure of what the child was wearing only 353 times, or about 10%, Dr. Walline said. Of those 353 occurrences, the examiners were accurate 82.4% of the time, indicating that they could have been unmasked in about 7.7% of the procedures.