Temporal refractive evolution of myopia during orthokeratology treatment

Abstract

Relevance: Myopia is a refractive error in which light converges in front of the retina, producing a blurred image. Orthokeratology fully or partially compensates this ametropia through reversible corneal tissue redistribution induced by overnight wear of reverse-geometry rigid gas-permeable contact lenses.

Purpose: The aim of this retrospective study was to evaluate the average time required to neutralize myopia ranging from −0.50 D to −6.00 D of spherical equivalent.

Methods: The sample consisted of 55 eyes from young adults, 7 of which had previously undergone refractive surgery, all of legal age, with a mean age of 25.47 ± 3.17 years, who were candidates for different state security forces. All patients were fitted with Paragon CRT lenses; after confirming a correct fit, residual refraction was recorded at five time points throughout the fitting process: the feasibility study day, the first night after starting Ortho-k, the fourth night, ten nights after starting treatment, and one month of contact lens wear. In the statistical analysis, we compared the variation in refraction across the four follow-up visits, pupil diameter, and the possible variation in results depending on gender, age, and the presence of prior refractive surgery.

Results: The results obtained when analyzing gender, age, and pupil diameter showed no significant differences throughout the treatment. Statistically significant differences were observed between eyes previously treated with refractive surgery and untreated eyes during the first two follow-up visits, and from 4 nights onward the results showed no further variation.

Conclusions: Mean refractive neutralization was achieved after ten nights of use, remaining stable at one month of treatment.