PURPOSE: To compare measurements of central corneal thickness obtained using a Haag-Streit optic pachymeter and a DGH 500 (Pachette Ttm ) ultrasonic pachymeter in normal patients. METHODS: An evaluation was made of 200 eyes of 100 patients using Optic (PO) and Ultrasonic (PU) pachymeters. Measurements were made in the area of the central cornea (ECC) respecting the 3.0 mm territory, in patients with normal corneas of hypermetropic, emetropic and myopic eyes. Patients with ocular diseases, ocular surgeries, and contact lens wearers, were excluded. A statistical analysis was performed using a Paired Student's t test to compare measurements between instruments at the 5% level of significance. RESULTS: The mean thickness of the ECC measured by the PO was 603.8±32.6µm and by the PU, 568.2±40.5µm. The difference between the two instruments was 35.7±26.4µm. Applying the t test with p = <5%, the difference was significant. We had no statistical difference in ECC between hypermetropic, emetropic and myopic eyes using the PU. CONCLUSION: The measurement of ECC is an over-estimate using the PO as compared with the PU.
Cornea; Corneal topography; Techniques, measures, measurement equipment; Glaucoma; Ultrasonography
