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Influence of Short-Term Orthokeratology to Corneal Tangent Modulus: A Randomized Study
Andrew Kc Lam1, Stanley Yy Leung2, Ying Hon1
1a Centre for Myopia Research, School of Optometry , The Hong Kong Polytechnic University , Hong Kong , China.
Current Eye Research
|December 29, 2017
Summary
Short-term orthokeratology did not significantly alter corneal tangent modulus. Corneal hysteresis and resistance factor changes may stem from measurement variability, warranting further research into corneal biomechanics.
Area of Science:
- Ophthalmology
- Corneal Biomechanics
- Orthokeratology
Background:
- Corneal biomechanics assessment is crucial for understanding ocular responses.
- The influence of orthokeratology on corneal biomechanics requires further elucidation.
- Ocular Response Analyzer (ORA) and indentation methods offer insights into corneal properties.
Purpose of the Study:
- To investigate the short-term effects of orthokeratology on corneal biomechanics.
- To measure corneal tangent modulus using an indentation method during orthokeratology lens wear.
- To compare corneal biomechanical parameters between orthokeratology and rigid gas permeable lenses.
Main Methods:
- 16 young subjects with myopia and astigmatism were enrolled.
- One eye wore an orthokeratology lens (treatment), the fellow eye a rigid gas permeable lens (control).
- Corneal biomechanics were assessed using ORA and an indentation device after 30, 60 minutes, and overnight lens wear.
Main Results:
- Orthokeratology induced significant corneal flattening, increasing with wear time.
- Corneal resistance factor (CRF) decreased after 30 minutes of orthokeratology.
- Corneal hysteresis (CH) showed variability, with a decrease in control eyes after overnight wear.
- Baseline lower CH and higher corneal tangent modulus (E) correlated with greater corneal flattening.
Conclusions:
- Short-term orthokeratology did not significantly affect corneal tangent modulus.
- Observed changes in CH and CRF may be attributed to measurement variability.
- Corneal tangent modulus offers an additional metric for corneal biomechanics.
- Long-term studies are needed to explore the predictive value of corneal biomechanics in orthokeratology.
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