Abstract
Purpose :
Orthokeratology (ortho-k) is a convenient, effective method of refractive error correction, and has been shown to play an important role in myopia control. However, there is substantial inter-patient variation in treatment response, which has been attributed to corneal biomechanical factors. Evaluation of the influence of age, ethnicity, eye size (axial length), body size (height/weight) and diet on corneal biomechanics may allow prediction of treatment outcome and aid patient selection.
Methods :
One hundred and fifty-eight healthy volunteers were recruited (mean±SD age: 32.4±12.3 years, range 19 to 63 years; mean±SD; mean spherical equivalent, MSE: -1.46±2.25 D, range -11.81 to 3.60 D). Axial length was measured using and an optical biometer (IOL Master 500). Height and weight measurements were taken using a stadiometer and a mechanical scale. Food consumption data were recorded, using an adapted 90 item Food Frequency Questionnaire (FFQ). Corneal biomechanics were measured using the Ocular Response Analyser.
Results :
Corneal hysteresis (CH) and corneal resistance factor (CRF) were not influenced by age (CH: p=0.586; CRF: p=0.173), ethnicity (CH: p=0.586; CRF: p=0.493), diet (CH: p=0.681; CRF: p=0.952), height/weight (CH: p=0.35; CRF: p=0.394) or axial length (CH: p=0.256; CRF: p=0.866). However, other ORA derived metrics were significantly influenced by axial length, height/weight, and higher meat intake (all p<0.005).
Conclusions :
Whereas ethnicity and age have no influence corneal biomechanics, axial length, height/weight and higher meat intake do influence a number of ORA-derived corneal biomechanical metrics; but not CH or CRF. Variations in the additional ORA-derived parameters reflect the complex nature of corneal biomechanical response, and suggest that they should be considered alongside CH and CRF, when investigating/predicting corneal biomechanical response to orthokeratology.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.