Direct costs of myopia in Singapore.

AIMS: To estimate the direct costs of myopia in Singapore children. METHODS: A cross-sectional study of 377 Singaporean school children aged 12-17 years from one school in Singapore Cohort study of the Risk factors for Myopia (SCORM) was conducted. A combination of parent and self-administered questionnaires asked about the cost of each optometrist visit, spectacles, and contact lenses, transport costs, father's educational level, and total family income. RESULTS: A total of 377 subjects participated and cost data were available from 301 subjects. The mean annual direct cost of myopia was S$221.7+/-313.7 (CI, S$186.5-258.1) or US$147.8+/-209.1 (CI, US$124.3-172.1) and median annual direct cost of myopia was S$125.0 or US$83.3. The mean cost per pair of spectacles was S$123.2+/-61.2 (CI, S$116.6-129.8) or US$82.1+/-40.8 (CI, US$77.8-86.5). Sixty subjects (15.9%) wore contact lenses. The mean annual cost of contact lenses was S$567.1+/-565.7 (CI, S$422.2-712.0) or US$378.1+/-377.1 (CI, US$281.4-474.6). Subjects of families with higher total family income and those with fathers with secondary or higher education had higher annual direct expenditure (P=0.03 and P=0.001 respectively). Subjects from families with higher household incomes had higher frequency of change of spectacles (P=0.02) and shorter time since the last change of spectacles (P=0.03). CONCLUSIONS: The mean annual direct cost of myopia for Singapore school children was S$221.68 (US$148) and the median, S$125.00 (US$83.33) per subject. Myopia is associated with significant financial burden in Singapore.

Corneal biomechanics, thickness and optic disc morphology in children with optic disc tilt.

AIMS: To determine the associations between corneal biomechanical parameters as measured by the Reichert Ocular Response Analyser (ORA) and disc morphology and retinal nerve fibre layer thickness (RNFL) measured by the Heidelberg Retinal Tomograph (HRT) II in Singaporean children. METHODS: This is a cross-sectional study conducted on a subset of children enrolled in the Singapore Cohort Study of the Risk Factors of Myopia (SCORM). Corneal hysteresis (CH), corneal resistance factor (CRF) and central corneal thickness (CCT) were measured with the ORA. Optic disc morphology and RNFL thickness were assessed by the HRT II. Cycloplegic refraction and ultrasound A-scans were also performed, and disc tilt was assayed from stereo photographs. RESULTS: 102 subjects (mean age 12.01 (SD 0.57) years; range 11-14 years) were included in the study. The mean CH was 12.00 (1.40) mm Hg, the mean CRF was 11.99 (1.65) mm Hg, and the mean CCT was 581.12 (33.53) mum. Eyes with tilted discs had significantly longer axial lengths and more myopic refraction than eyes without tilted discs. There were no significant correlations between CH, CRF or CCT and the HRT II parameters, after the application of the Bonferroni correction. When stratified for disc tilt, however, the global disc area was significantly correlated with CCT (r = -0.49, p = 0.001). CONCLUSION: Corneal biomechanical properties as measured with the ORA do not vary with optic disc parameters or RNFL. Central corneal thickness is correlated with disc area in Singaporean schoolchildren with tilted discs. This relationship may influence glaucoma risk in myopic subjects.