Abstract
Purpose :
To evaluate the efficacy of customized orthokeratology lens design on a population of myopic patients
Methods :
This is a retrospective analysis of patients consulting at Clinique Universitaire de la Vision, Université de Montréal and for whom a myopia control strategy was initiated. This study was conducted after formal approval by internal review board (ethics committee) and Commission de L’accès à l’Information, responsible for the protection of personal data and information. More specifically, the chart of every young (< 20 y.o.) myopic (>-0.50D at baseline) patient seen between 2012 and 2017, and followed for at least 5 months, was reviewed. The subjects analyzed had been managed customized orthokeratology lens design. This means that the lens parameters was fully adapted to paitent’s ocular parameters, including pupil size.
Treatment zone parameters was determined based on corneal curvatures, eccentricity, and pupil area. A double-reservoir type of orthokeratology lens was designed to generate between 75 and 90 microns in the first reservoir, regardless of the baseline refractive power. A second reservoir was designed to enhance the hydraulic pressure in the first one, and to enhance lens centration. Peripheral curves were designed to optimize tear fluid exchange and lens diameter was selected to cover between 90 and 95% of the pupil area.
Results :
The study was made on 98 subjects, 45 boys (18 Caucasian and 27 Asian) and 53 girls (20 Caucasian and 33 Asian), aged 11.4 + 2.3 years old. Lenses were worn for 7 days a week, at least 8 h00 overnight, and subjects had been followed for 5.6 + 0.7 months.
Baseline refractive error was -3.66 + 0.17 D for OD and -3.56 + 0.18 D OS. Axial length was 25.13 + 0.33 mm OD and 25.09 + 0.38 mm OS. Pupil size was 5.37 + 0.01 and 5.31 + 0.07 mm OD respectively. Myopic evolution was OD -0.06 + 0.12 D for the right eye and -0.07 D + 0.17 D for OS. Axial length elongation was -0.03 + 0.09 mm OD and -0.02 + 0.10 mm OS.
Conclusions :
Customizing Orthokeratology design seems to be more effective, compared with known data, for myopia and axial length management, at least on a short term (near 6 months follow-up). Further studies are needed to confirm this tendency.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.