Corneal Thickness Measurement With Confocal Microscopy

Purpose: To determine the accuracy and reproducibility of central corneal thickness(CCT) measurement with slit scanning confocal microscope.Subjects and methods: In a prospective comparative clinical trial, 27 normal central corneas of 20 subjects were admitted for measurement of thickness with Confoscan 2.0 slit scanning confocal microscope (SSCM) and Sonomed ultrasound pachymeter(PACH).Result: central corneal thickness ( SD) of 27 corneas in 20 subjects measured by SSCM(529.6 33.9um) and by PACH(536.7 38.2um) differed (P<0.001,paired Student's t-test ),and the difference between both methods was over the range of CCT(mean difference , 7.0 7.1 urn ).The mean intrapatient SD of SSCM was 17.8um showed much greater than 1.7um of PACH, which indicated that SSCM had poorer reproducibility compared with PACH.Conclusion: The SSCM is a poorer precise technique for measuring central corneal thickness than ultrasound pachymeter.