Corneal Biomechanical Properties and Retinal Vascular Caliber in Children

PURPOSE. To examine the relationship between corneal biomechanical properties and retinal vascular caliber in Singaporean children in a cross-sectional study of 257 healthy subjects from the Singapore Cohort Study of Risk Factors for Myopia. METHODS. Corneal hysteresis (CH), corneal resistance factor (CRF), central corneal thickness (CCT), and corneal compensated intraocular pressure (IOPCC) were measured with a patented dynamic bi-directional applanation device. Digital retinal photography was performed, and retinal vascular caliber was measured with custom software. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated, representing the average arteriolar and venular calibers. Spherical equivalent (SE) refraction, axial length, height, weight, and mean arterial blood pressure (MABP) were measured. RESULTS. Mean values of this study were as follows: age of study subjects, 13.97 +/- 0.90 years; CH, 11.80 +/- 1.55 mm Hg; CRF, 11.83 +/- 1.72 mm Hg; CCT, 578.76 +/- 34.47 mu m; IOPCC, 15.12 +/- 2.84 mm Hg; CRAE, 151.70 +/- 15.54 mu m; CRVE, 227.51 +/- 22.82 mu m. After controlling for age, sex, ethnicity, body mass index, father's educational level, MABP, IOP, and SE, there was a significant increase in CRAE by 1.40 mu m (95% CI: 0.17-2.61; P = 0.03) for every 1.55 mm Hg increase in CH and by 1.68 mu m (95% CI: 0.21-3.15; P = 0.03) for every 1.72 mm Hg increase in CRF. There were no significant associations between CRVE and CH, CRF, CCT, or IOP. CONCLUSIONS. Lower CH and CRF are associated with narrower retinal arterioles in Singaporean children. (Invest Ophthalmol Vis Sci. 2009; 50: 121-125) DOI: 10.1167/iovs.08-2352