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M. W. Aschbrenner, H. B. Moss, G. W. Lyles, K. L. Cohen; Cycloplegic Anterior Chamber Depth Measurements Using Anterior Segment Optical Coherence Tomography (VisanteTM). Invest. Ophthalmol. Vis. Sci. 2010;51(13):1312.
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© ARVO (1962-2015); The Authors (2016-present)
To compare automated anterior chamber depth (aACD) measurements with manual ACD (mACD) measurements in normal, cyclopleged, phakic eyes using enhanced and single scans from the anterior segment optical coherence tomography (VisanteTM) (Carl Zeiss Meditec, Dublin, CA).
This was a prospective study of 44 normal eyes (25 patients). ACD was measured from the tear film to the anterior lens capsule. Eyes received one drop of phenylepherine (2.5%) and one drop of tropicamide (1%). Thirty minutes later, the VisanteTM captured images using enhanced and single angle scans. ACD was measured using aACD and mACD. A second mACD was measured with a different observer (mACD2). Values were compared using Pearson product correlations and paired t-tests.
Mean aACD was 3.607mm (SD=0.417) for enhanced and 3.606 mm (SD=0.415) for single scans. Mean mACD was 3.620mm (SD 0.410) for enhanced and 3.620mm (SD=0.407) for single scans. Mean mACD2 was 3.582mm (SD 0.486) for enhanced and 3.564 mm (SD= 0.444) for single scans. All ACD measurements for enhanced and single scans were correlated (range r=0.895 to r=0.999) and not significantly different (p>0.05). There was a correlation between aACD and mACD for enhanced (r=0.998) and single scans (r=0.998), despite a statistical difference between enhanced (p=0.006) and single scans (p=0.008). mACD and mACD2 were correlated and not statistically different for enhanced (r=0.977; p=0.242) and single scans (r=0.999; p=0.338).
To date, there are no known studies comparing ACD measurements between automated and manual modes from single and enhanced scans using the VisanteTM. Few studies compared ACD measurements between VisanteTM and the IOLMasterTM (Carl Zeiss Meditec, Dublin, CA), none examined in a cycloplegic state (recommended in the IOLMasterTM manual), and none compared measurement modalities among features allowed by the VisanteTM. Our study found that single and enhanced scans yield measurements that were not statistically different. aACD and mACD were correlated, but statistically different, which requires further investigation. Because pre-op ACD is important in the calculation of IOL power for the prediction of post-op refraction (Haigis formula), further comparisons of the VisanteTM with the IOLMasterTM should be performed to validate the VisanteTM measurements.
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