Evaluation of Corneal Pachymetry Measurements by Galilei Dual Scheimpflug Camera

Abstract

Purpose

We present an evaluation of corneal pachymetry measurements by Galilei dual Scheimpflug camera by comparing central corneal thickness measured by Galilei with Orbscan II and ultrasonic pachymetry.

Setting

Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences and Negah Eye Center, Tehran, Iran.

Materials and Methods

Central corneal thickness (CCT) was measured in 184 eyes of 92 healthy subjects using Galilei, Orbscan II, and ultrasonic (US) pachymetry. Considered as a benchmark, the measurements by US pachymetry were compared with those measured by the other 2 systems.

Results

Mean CCT was 544.4±33.4 μm, 546.7±37.9 μm, and 555.8±29.6 μm as measured by US pachymetry, Orbscan II, and Galilei systems, respectively. The mean difference of readings measured by US pachymetry with those measured by Orbscan II (acoustic coefficient 0.96) and Galilei were 2.3 μm and 10.2 μm, respectively. In spite of this discrepancy, the Galilei system had better agreement with US pachymetry than Orbscan II and US pachymetry (correlation coefficient 0.947 vs 0.817) and considering 0.98 as acoustic coefficient for Galilei CCT reading, makes its measurements identical to ultrasound pachymetry.

Conclusions

Galilei measurements of CCT are well correlated with ultrasound pachymetry in normal eyes. After considering an acoustic coefficient equal to 0.98 for Galilei, its measurements will become equal to ultrasound values.