Background Optical coherence tomography (OCT) acquires cross-sectional retinal images with high resolution using low-coherence interferometry. Few studies have studied the effect of demographic data and ocular parameters that may affect central retinal thickness. In this study, these factors were used as parameters to analyse if any significant relationship exists with central retinal thickness. Methods Volunteers with a best-corrected visual acuity of 6/12 or better and no evidence of ocular abnormalities or interventions were recruited from October 2001 to March 2003. Body mass index (BMI), autorefraction, and keratometry recordings were measured, followed by applanation tonometry and Ascan ultrasonography. The central retinal thickness of the right eye was analysed using a scan length of 3 cm. Another 25 eyes were selected for interobserver reproducibility. Results In all, 117 normal subjects (60 male and 57 female subjects) were recruited. The mean thickness of the central retina with a diameter of 1 mm was 203723 mm for male and 189720 mm for female subjects. Age, intraocular pressure, and keratometric readings were not significantly correlated with central retinal thickness. Using multiple regression, gender, BMI, axial length, and signal-to-noise ratio (Po0.05) were significantly associated with the central retinal thickness. The intraclass correlation coefficient was 0.98 for interobserver reproducibility. Conclusion OCT has a high interobserver reproducibility. The male gender, larger BMI,

When a correction factor of 32 microm was applied to OCT measurements, the means of three devices became significantly equal. The adjusted OCT measurements were less precise within subjects but more accurate than Orbscan when compared with ultrasound pachymetry as a reference standard. The mean CCT measurement of our sample was comparable to some studies on Hong Kong Chinese, Caucasians and Japanese but higher than those on some Europeans, Asian and North Americans of African origin.

Aims To assess the vision-related quality of life of corneal transplant recipients using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25), and to identify the socio-demographic factors that associate with patients' self-assessment of perceived visual function. Methods Thirty patients who received corneal transplants were included in this prospective observational, cross-sectional study. Socio-demographic and clinical data, including age, sex, systemic health status, employment status, visual acuity, reason of corneal transplantation, laterality of corneal graft, and follow-up period were collected. NEI VFQ-25 was scored using Rasch analysis. Subgroup analyses were also performed. Results Age, sex, visual acuity, and health status had no significant correlation or association with the Rasch-transformed score. Patients who received bilateral corneal grafts were significantly less able socioemotionally than those with unilateral graft. Patients who became unemployed or retired after transplantation were also significantly less able in both visual functioning and socioemotional status. Conclusion Corneal transplant recipients had a decreased vision-related quality of life as demonstrated by the NEI VFQ-25. Apart from anatomical success and visual acuity, ophthalmologists should also consider other aspects of visual outcome. In particular, those who received bilateral grafts require more attention. Employment programmes should be part of corneal transplantation rehabilitation planning.