Long-term changes in straylight induced by corneal refractive therapy: a pilot study

Abstract

PURPOSE: To assess long-term intraocular straylight changes induced by corneal refractive therapy (CRT) and to determine whether these changes persist after cessation of CRT lens wear. METHODS: A single-center, prospective, longitudinal study was performed in 22 subjects (group 1) undergoing overnight corneal refractive therapy for 1 year. Ten right eyes of 10 subjects (group 2) with emmetropia served as controls. In each subject, high contrast visual acuity (HCVA), manifest refraction and intraocular straylight were determined at several time points during treatment and 1 month after discontinuing treatment. Straylight was measured using the van den Berg straylight meter (third generation). EDTRS charts (logMAR units) were used to assess HCVA. For both groups, only data for the right eyes were analyzed. RESULTS: Straylight (mean ± standard deviation) significantly fell from baseline (0.98 ± 0.13) to values recorded after 1 month (0.88 ± 0.13, p=0.011), 3 months (0.88 ± 0.13, p=0.004), 6 months (0.88 ± 0.13, p=0.000) and 12 months (0.76 ± 0.12, p=0.003) of treatment. One month after discontinuing CRT lens wear, straylight was still significantly lower than baseline (0.89 ± 0.13, p=0.003). No correlations were observed between intraocular straylight and HCVA. CONCLUSIONS: Good refractive outcomes and reductions in straylight were observed in response to corneal refractive therapy for myopia. The reduction in straylight observed after discontinuing CRT warrents further investigation.