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Comparison between newly developed scanning peripheral anterior chamber depth analyzer and conventional methods of
Kenji Kashiwagi1, Toyoaki Tsumura, Shigeo Tsukahara
1Department of Ophthalmology, University of Yamanashi Faculty of Medicine, Tamaho, Yamanashi, Japan. kenjik@yamanashi.ac.jp
Purpose:
To compare the newly developed scanning peripheral anterior chamber depth analyzer (SPAC) with the Van Herick technique, the Shaffer grading system, and ultrasound biomicroscopy (UBM), in terms of accuracy of measurement of peripheral anterior chamber depth (ACD).
Methods:
The subjects were well-controlled glaucoma patients who were being treated at the University of Yamanashi Hospital. Ten eyes from each of the 4 groups classified as Shaffer grades 1 to 4 were evaluated by SPAC, the Van Herick technique, and UBM. All measurements were performed independently on the temporal side in a masked fashion. SPAC evaluated ACD consecutively from the pupil center to the limbus at 0.4 mm intervals. UBM measurements were carried out at a depth of 500 mum (angle-opening distance 500) from the scleral spur. A dummy eye was used for evaluating SPAC measurement accuracy.
Results:
The results of SPAC measurement were well correlated with those of the Van Herick technique and the Shaffer grading system. The SPAC measurement results were also significantly correlated with angle-opening distance 500. The correlation coefficients at distances of 2, 4, 4.8, and 5.6 mm from the pupil center were r=0.68, 0.69, 0.69, and 0.61, respectively, and the P values of all the correlations were less than 0.0001. Study of the dummy eye revealed that SPAC has high accuracy for measuring ACD and that the coefficient variances were less than 1.0% at all measured points.
Conclusions:
The results of SPAC measurement correlate well with those of the conventional methods.