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Published on: June 20, 2015
Comparison of techniques for measuring anterior chamber depth: Orbscan imaging, Smith's technique, and van Herick's
Frank Eperjesi1, Claire Holden
1Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK. f.eperjesi@aston.ac.uk
Background:
Evaluation of anterior chamber depth (ACD) can potentially identify those patients at risk of angle-closure glaucoma. We aimed to: compare van Herick's limbal chamber depth (LCDvh) grades with LCDorb grades calculated from the Orbscan anterior chamber angle values; determine Smith's technique ACD and compare to Orbscan ACD; and calculate a constant for Smith's technique using Orbscan ACD.
Methods:
Eighty participants free from eye disease underwent LCDvh grading, Smith's technique ACD, and Orbscan anterior chamber angle and ACD measurement.
Results:
LCDvh overestimated grades by a mean of 0.25 (coefficient of repeatability [CR] 1.59) compared to LCDorb. Smith's technique (constant 1.40 and 1.31) overestimated ACD by a mean of 0.33 mm (CR 0.82) and 0.12 mm (CR 0.79) respectively, compared to Orbscan. Using linear regression, we determined a constant of 1.22 for Smith's slit-length method.
Conclusions:
Smith's technique (constant 1.31) provided an ACD that is closer to that found with Orbscan compared to a constant of 1.40 or LCDvh. Our findings also suggest that Smith's technique would produce values closer to that obtained with Orbscan by using a constant of 1.22.