Overnight orthokeratology: preliminary results of the Lenses and Overnight Orthokeratology (LOOK) study.

Background: The Lenses and Overnight Orthokeratology (LOOK) study is a pilot study designed to learn the procedures of orthokeratology lens fitting in preparation for a planned larger clinical trial and to obtain data with which to calculate a sample size for that larger study. Data are presented for the first 3 months of the LOOK study.

Methods: Sixty subjects were enrolled in this multicenter pilot study to evaluate the success and safety of treatment with overnight orthokeratology contact lenses. Refractive error, corneal topography, and biomicroscopic data were collected to determine the amount of refractive error change achieved, corneal changes, and a safety profile of overnight wear of reverse geometry rigid gas permeable lenses for orthokeratology.

Results: Of the 60 subjects enrolled, 46 completed the 1-month visit, and 31 completed the 3-month visit. The mean change in spherical equivalent manifest refraction from baseline to the morning 3-month visit was 2.08 +/- 1.11 D in the right eye and 2.16 +/- 1.05 D in the left eye. At the 3-month morning visit, 74% of right eyes and 61 % of left eyes had 20/20 unaided visual acuity. No corneal infiltrates or ulcers were noted in any subjects. Observations of fluorescein staining of the cornea, imprinting, and microcysts were noted in some patients at the 3-month visit.

Conclusions: The preliminary results of the LOOK study indicate that improvement in unaided visual acuity can be attained for at least 6 h after lens removal. The short-term safety and efficacy of the procedure appear to be favorable; however, future studies are needed to determine the long-term outcomes of treatment.