Abstract
Purpose :
To investigate the correlation between pre-treatment cycloplegic spherical refraction and change in central corneal thickness after 6-months of orthokeratology lens usage in Danish children aged 6-12 years.
Methods :
This was a sub-study of the Danish CONTROL and CONTROL2 studies. CONTROL study was a 1:1 randomized controlled trial of the efficacy and adverse events of orthokeratology (OKL) compared to single-vision spectacles (SVS). The study population consisted of Danish children aged 6 to 12 years and the follow-up period was 18 months. Hereafter the SVS groups was crossed-over to OKL treatment while the original OKL group continued using OKL with a follow-up of both groups for additionally 18 months, this part was called CONTROL2. For the current study, the pre-treatment cycloplegic spherical refraction (cSEQ) and the 6-month pre- and post-treatment CCT from both studies were used. cSEQ was measured by Shin-Nippon Nvision-K 5001 autore- fractor (Rexxam Co, Kagawa, Japan) and CCT was measured by Lenstar LS900 (Haag-Streit, Koeniz, Switzerland). The OKL used was DreamLite® (CooperVision, San Ramon, California, USA), a four-zone reverse geometry lens with a 6 mm aspherical optic zone diameter, and 0.75 diopter (D) compression factor. Data from subjects who dropped out before 6-months post treatment was not included. To allow data from both eyes in the analysis a nested mixed model was applied using Stata® (Version 18.0; StataCorp, College Station, TX, USA).
Thirty-nine children with a mean age of 10.5 ± 0.8 years and a baseline mean SEQ of –2.67± 1.37 D and –2.65 ± 1.37 D in the right and left eye, respectively, were included in the study.
Results :
The pre-treatment CCT was 557.62 ± 31.56 µm in the right eye and 558.79 ± 30.99 µm in the left eye. During the 6-month treatment, CCT decreased by 13.4 ± 0.7 µm in the right eye and ± 13.5 µm in the left eye. For each diopter of baseline cSEQ a CTT decrease of 1.16 µm was found. However, this correlation did not reach statistical significance (p = 0.09, 95% CI –2.51 to 0.19 nested mixed model, Figure 1).
Conclusions :
The decrease in the central corneal thickness by 6-months of orthokeratology use was not significantly influenced by the pre-treatment cycloplegic spherical refraction in myopic Danish children aged 6-12 years.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.