Determining the mean difference in central corneal thickness measured by applanation ultrasound and oculus Wavelight Occulyzer II

Objective: The objective is to determine the mean difference of central corneal thickness measurements by using ultrasound pachymeter and oculus Wavelight Occulyzer II. Patients & Methods: This prospective cross-sectional comparative study was conducted at Department of Ophthalmology, Liaquat National Hospital, Karachi for 6 months duration, after the approval from ethical committee. Patients were included in our study on the basis of inclusion & exclusion criteria. Central corneal thickness measurements was taken by using ultrasound pachymeter & oculus Wavelight Occulyzer II. All the data was collected by single researcher. The results were plotted, compared & analyzed. Results: 130 patients attending ophthalmology department and fulfilling the inclusion criteria were assessed. One eye of each patient was measured (65 were right eye and 65 were left eye). 73(56.2%) were male and 57(43.8%) were females. Mean age of these patients was 33.9 ±8.9 years. The mean ± SD thinnest oculus Wavelight Occulyzer II measurement was 538.61±23.46 ?m and ranged between 476.0 and 619.0 ?m whereas the mean thinnest ultrasound pachymeter measurement was 535.1±21.816?m and ranged between 482 and 601 ?m. There was highly significant correlation of central corneal thickness between both the instruments. (r=0.96, p<0.001) Conclusion: According to the results of our study there is a highly correlation of central corneal thickness was found between the readings obtained from both UP and oculus Wavelight Occulyzer II. So we concluded that oculus Wavelight Occulyzer II can be used as an alternative technique to ultrasound pachymetry while assessing CCT in clinical settings to decrease the risk of procedure associated problems with UP like epithelial trauma and infection, to decrease the frequent use of topical anesthetic agents, for early detection and management of glaucoma & in anxious patients also. Keywords: Central corneal thickness, ultrasound pachymeter, oculus Wavelight Occulyzer II

Effect of Age on Individual Corneal Epithelial Thickness in Normal Eyes as Measured with Ultrasound Pachymeter

Purpose: The goal of this study was to determine age-relatedvariation in the thickness of the corneal epithelium using ultrasound pachymeter. Methods: One hundred three patients were enrolled in this study and grouped according to age: Group A (< 30 years), group B (31-40 years), group C (41-50 years), group D (51-60 years), group E (61-70), and group F (> 71). Total corneal and corneal epithelial thickness measurements were made using the SonogageCorneo-Gage Plus 2 (Cleveland, Ohio) ultrasound pachymeter. Correlations of central epithelial thickness with central total corneal thickness, age, and gender were calculated. In addition, mean central epithelial thickness (CET) was measured. One-way ANOVA testing and post hoc analysis with the Tukey test and Pearson correlation were performed to analyze data. Results: The mean epithelial thickness at the central cornea was 47.88±1.15 μm, with no statistically significant difference between right and left eyes, and no significant differences in gender or central total corneal thickness. The difference in mean epithelial thickness across age groups was statistically significant (p <0.008). The mean epithelial thickness of the > 71 years group was significantly thinner than that of the < 30 years, 31-40, 41-50, and 51-60 years age groups. Conclusions: Ultrasound pachymeter of the corneal epithelium demonstrated that the oldest age group (> 71 years) had significantly thinner central corneal epithelial thickness than the younger age groups. There was no correlation between epithelial thickness, total corneal thickness, gender, or laterality.

The relationship between central corneal thickness and corneal curvature in adult Nigerians

Purpose: The aim of this study was to provide average values for central corneal thickness (CCT) and corneal curvature (CC) and also to determine a regression model for the relationship between CCT and CC in adult Nigerians without glaucoma.Methods: A total of 95 subjects consisting of 56 males and 39 females aged between 20 and 69 years with mean age of 47.1 ± 14.1 years were recruited for the study. Central corneal thickness was measured by ultrasound pachymetry (SW-1000P ultrasound pachymeter, Tianjin Suowei Electronic Technology, China) and corneal curvature was measured by keratometry (Bausch & Lomb keratometer H-135A, USA).Results: The average values of 550.1 ± 33.1µm and 43.0 ± 1.1 D were obtained for CCT and CC respectively. CCT significantly correlated with age (p=0.01), and the regression model predicts a decrease of 6.0 µm in CCT per decade. No significant association was found between CC and age (p=0.56). Also, no significant association was found between CCT and CC (p=0.07). Female subjects had significantly steeper corneas than their male counterparts.Conclusion: Central corneal thickness decreases with increasing age. Neither CCT nor age appear to be significantly correlated with corneal curvature. (S Afr Optom 2011 70(1) 44-50)