Due to a relative dearth of evidence as to whether astigmatic children without amblyopia at diagnosis would benefit from optical correction, researchers compared visual outcomes of 85 children ages one to seven years with moderate bilateral astigmatism (+1.25D to +3.25D) and normal vision at diagnosis who were treated with glasses to those who were merely observed.

Findings showed the rate of developing amblyopia or strabismus after 18 months or longer was similar in both groups. 58 children were prescribed glasses while 27 were observed. At the four-year markup, the rate of developing amblyopia was 8.3% in the observed group and 10.3% in the glasses group, while strabismus was 7.1% among those observed and 7.1% of those prescribed glasses.

The authors noted several limitations to these findings. For example, the treatment group was older and had higher amounts of astigmatism at diagnosis.

“If the older children had not yet developed amblyopia at diagnosis, it may have been less likely to ever develop,” the authors explained. “We further acknowledge the large age range of the participants in the study, and that there may be substantial differences in the visual development trajectories of a one-year-old and a six-year old. However, amblyopia was not more prevalent among the younger children in the observation group. Finally, children presenting without amblyopia at diagnosis may be less likely to develop it without optical correction, and thereby the study may be self-selecting for children at low risk of developing amblyopia.”

Additionally, the authors discussed how the prevention of amblyopia or strabismus is not the sole reason for prescribing glasses for young children with moderate bilateral astigmatism. However, one of the takeaways from this study is that some of these children who are asymptomatic may be at the risk of overtreatment.