Citation information: Hon Y, Cheung SW, Cho P & Lam AKC. Repeatability of corneal biomechanical measurements in children wearing spectacles and orthokeratology lenses. Ophthalmic Physiol Opt 2012, 32, 349–354. doi: 10.1111/j.1475-1313.2012.00920.x
Purpose: To determine the repeatability of corneal hysteresis (CH) and corneal resistance factor (CRF) measurements in children wearing spectacles and children under orthokeratology (ortho-k) therapy using the Ocular Response Analyzer (ORA).
Methods: CH and CRF were measured twice at a 10-min interval using ORA on the same day in both eyes of 25 children (mean age = 10.6 ± 1.2 years) wearing spectacles and 34 children (mean age = 10.9 ± 1.0 years) wearing ortho-k lenses. Four measurements were obtained from each eye in each set of measurements. Only data from the right eyes were analyzed.
Results: No significant between-measurement differences in CH and CRF were found in either group of subjects (paired t-tests, p > 0.05) and no correlations were found between the mean differences and their means (Pearson’s correlations, −0.09 < r < 0.21, 0.24 < p < 0.85). The 95% limits of agreement (LA) were −1.87 mmHg to +2.59 mmHg and −1.53 mmHg to +1.41 mmHg for CH and −1.86 mmHg to +2.22 mmHg and −1.45 mmHg to +1.57 mmHg for CRF in the spectacle and ortho-k groups, respectively. A significant between-group difference in CRF was found (unpaired t-tests, p = 0.02).
Conclusions: Repeatability of CH and CRF measurements using the ORA is within ±2 mmHg in children wearing spectacles or ortho-k lenses. We suggest that the ORA can be used to monitor long-term corneal biomechanical changes during ortho-k treatment.