Internal anterior chamber diameter using optical coherence tomography compared with white-to-white distances using automated measurements

PURPOSE: To compare internal horizontal anterior chamber (AC) diameter determined by optical coherence tomography (OCT) and horizontal corneal diameter (white-to-white [WTW]) using automated measurements. SETTING: Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany. METHODS: Internal AC diameter and WTW distance was measured in 52 eyes of 26 patients using the Visante OCT (Carl Zeiss Meditec), IOLMaster (Carl Zeiss Meditec), and Orbscan Ilz topography system (Bausch & Lomb). Statistical evaluation was performed using the Bland-Altman method and regression analysis for comparison of measurement techniques. The Kruskal-Wallis test was used to measure the repeatability of each device. RESULTS: The mean internal AC diameter was 12.45 mm +/- 0.53 (SD) with OCT; the mean WTW distance was 12.17 +/- 0.45 mm with the IOLMaster and 11.84 +/- 0.41 mm with the Orbscan IIz. A positive regression was determined for AC diameter and both WTW measurements. Measurement values varied little between both WTW measurement systems (R-2 = 0.9384). CONCLUSIONS: Anterior chamber measurement using optical coherence tomography (Visante OCT) was easy to handle and showed good repeatability. The internal horizontal diameter of the AC was larger than the horizontal corneal diameter determined by automated WTW measurements (IOLMaster, Orbscan Ilz). Optical coherence tomography with the Visante OCT allows direct measurement of the AC width.