Purpose:High-resolution biometry of the anterior ocular segment is now becoming more and more important against a background of refractive surgery and the evaluation of potentially accommodative lens replacement materials.The aim of this study was a systematic investigation of the currently available non-contact methods for measuring the anterior chamber depth(ACD).Methods:The ACDs of 50 phakic eyes of 27 patients aged between 19 and 59 years were measured with the IOL-Master(Zeiss),the AC-Master(Zeiss),the Pentacam(Oculus)and slit-lamp pachymetry by Jaeger(Haag-Streit).Results:The median anterior chamber depth in the investigated eyes was 3.63 mm for the IOL-Master(minimum 2.88 mm,maximum 4.22 mm),3.802 mm for the AC-Master(2.816 mm-4.373 mm),3.915 mm for the Pentacam(minimum 2.994 mm,maximum 4.614 mm)and 3.75 mm for Jaeger(2.887 mm-4.29 mm).With a probability of error of α =0.05 there were no significant differences concerning the ACD between the methods of Jaeger and AC-Master,Jaeger and IOL-Master,or Pentacam and AC-Master(Wilcoxon and Wilcox).The intra-individual variability was ± 5.4 μ m for AC-Master,± 12.7 μ m for Pentacam,± 24.5μ m for IOL-Master and± 41.2 μ m for Jaeger.The maximum method-dependent difference in ACD determination was 285 μ m.Conclusions:All the methods allow non-contact biometry,but the results might differ due to measuring principles inherent to the system,experience of the examiner and compliance of the patient.Partial coherence interferometry with the AC-Master offers the advantage of measurement exactly along the optical axis with the highest reproducibility and patient compliance. Purpose: High-resolution biometry of the anterior ocular segment is now more and more important against a background of refractive surgery and the evaluation of potentially accommodative lens replacement materials. The AIM of this study was a systematic investigation of the currently available non-contact Methods for measuring the anterior chamber depth (ACD). Methods: The ACDs of 50 phakic eyes of 27 patients aged between 19 and 59 years were measured with the IOL-Master (Zeiss), the AC-Master (Zeiss), the Pentacam Results: The median anterior chamber depth in the investigated eyes was 3.63 mm for the IOL-Master (minimum 2.88 mm, maximum 4.22 mm), 3.802 mm for the AC-Oculus, and slit-lamp pachymetry by Jaeger (Haag-Streit) Master (2.816 mm-4.373 mm), 3.915 mm for the Pentacam (minimum 2.994 mm, maximum 4.614 mm) and 3.75 mm for Jaeger (2.887 mm-4.29 mm) .With a probability of error of a = 0.05 there were no significant differences concerning the ACD between the methods of Jaeger and AC-Master, Jaeg er and IOL-Master, or Pentacam and AC-Master (Wilcoxon and Wilcox). The intra-individual variability was ± 5.4 μm for AC-Master, ± 12.7 μm for Pentacam, ± 24.5 μm for IOL-Master and ± 41.2 μ m for Jaeger. The maximum method-dependent difference in ACD determination was 285 μ m. Conclusions: All the methods allow non-contact biometry, but the results might differ due to measuring principle inherent to the system, experience of the examiner and compliance of the patient. Partially coherence interferometry with the AC-Master offers the advantage of measurement exactly along the optical axis with the highest reproducibility and patient compliance.