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

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 mu m 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.