CENTRAL CORNEAL THICKNESS

Abstract

Objectives: To compare central corneal thickness in myopic and keratoconuseyes by ultrasound pachymetry and pentacam HR. Study Design: Cross sectional study.Setting: Qassim University, Optometry Clinics, Kingdom of Saudi Arabia. Period: October2016 to April 2017. Methodology: One hundred myopic and keratoconus participants. CentralCorneal Thickness (CCT) were measured with two techniques by ultrasonic pachymetry andpentacam HR in two groups. Group one consisted of 80 myopic participants and group two of 20Keratoconuspatients.Pentacamreadings were recorded first. CCT were compared and analyzedstatistically using unpaired t-test and histogram. Results: One hundred participants (100) wereincluded in which 80 participants were myopic and 20 with keratoconus. Both eyes (200) of allthe participants were examined. Age of the myopics ranged from 18-30 years (Mean=23.03).The mean value with ultrasound pachymetery was 555μm (SD±32.021) and with pentacam566μm (SD±37.367). We observed a tendency of overestimation of CCT measurements withpentacam. Statistically a significant difference of reading between two devices (P<0.001) wasfound. In keratoconus participants, the mean age was 23.7 years (21- 26). The mean CCT takenwith Pentacam HR and US Pachymetry was 476μm (SD± 16.980) and 465μm (SD± 35.868)respectively. The t-test showed no statistical difference between thepentacam HR andultrasound pachymetry (p>0.214). Conclusion: Measurements of central corneal thicknessdone with Ultrasound Pachymeter and Pentacam HR are closely related to each other andare interchangeable when used in normal refractive error cases. While in Keratonus patientsultrasound pachymetry is preferred because of its reliability.