Measurement of the internal diameter and depth of the anterior chamber: IOLMaster versus anterior chamber optical coherence tomographer

In Brief PURPOSE: To study the internal diameter of the anterior chamber (AC), which remains a relatively subjective procedure dominated by the white-to-white technique, evaluated with a compass or using anterior segment photographs. In vivo dimensions of the AC were studied with an optical coherence tomographer (AC OCT) prototype. SETTING: Clinique Monticelli, Marseilles, France. METHODS: The dimensions in 107 normal eyes that had never had surgery were studied with the IOLMaster and AC OCT. RESULTS: The mean anterior chamber depth was 3.53 mm ± 0.35 (SD) with the IOLMaster (Carl Zeiss, Medictec) and 3.64 ± 0.33 mm with the AC OCT (Carl Zeiss, Medictec). The mean horizontal diameter of the AC was 12.12 ± 0.44 mm with the IOLMaster and 12.20 ± 0.44 mm with the AC OCT. With the AC OCT, the anterior chamber's horizontal and vertical diameter could be evaluated; in 74% of the observed eyes, the vertical diameter was larger by at least 100 μm than the horizontal diameter. DISCUSSION: The AC OCT has better reproducibility than the IOLMaster for evaluating the depth or internal diameter of the anterior chamber. This study showed that in 74% of cases, the AC was an oval with a larger vertical axis, which provides evidence of the value of the OCT preoperative examinations for phakic intraocular lens implantation. In a comparative evaluation of the quality of anterior chamber measurements (depth and internal diameter) using the IOLMaster and an anterior chamber optical coherence tomographer prototype, the anterior chamber generally appeared to be oval with a large vertical axis.