The safety of orthokeratology contact lens wear in slowing the axial elongation of the eye in children

Purpose

To evaluate the safety of orthokeratology contact lens wear in slowing the axial elongation of the eye in myopic children.

Methods

Safety data from three prospective studies, which evaluated the use of orthokeratology for slowing myopia progression in children in comparison to a parallel control group of single-vision spectacle lens wearers over a 2-year period, were pooled together for analysis. The primary and secondary safety endpoints are the comparisons of adverse events and slit-lamp findings grades ≥ 2 between orthokeratology and control groups, respectively.

Results

Collectively, data from 125 orthokeratology and 118 control subjects were analyzed in this study. Of these, 101 (81 %) and 88 (75 %) orthokeratology and control subjects completed the 2-year follow-up period, respectively. Nineteen orthokeratology subjects experienced 28 adverse events, of which 6 were significant, whereas just one adverse event was found in the control group; this difference was statistically significant (p < 0.001). Most adverse events found in the orthokeratology group were corneal in nature, primarily corneal abrasion/staining, accounting for around 40 % of all adverse events. Of the 28 adverse events, only 18 (3 significant) are likely to be contact lens-related, leading to incidence rates of total and device-related adverse events per 100 patient years of lens wear (95 % confidence intervals) of 13.1 (9.2–18.2) and 8.4 (5.4–10.7), respectively. No significant differences were found between groups in the total number of silt-lamps findings with grades ≥ 2 (p > 0.05).

Conclusion

Around 13% of eyes wearing overnight orthokeratology contact lenses are likely to experience an adverse event over one year of lens wear, with this figure being lower when considering device-related adverse events alone. No serious adverse events were found, with most being non-significant. These results inform eye care practitioners on the safety of orthokeratology lenses when prescribed for slowing myopia progression to myopic children.