COMPARISON OF GONIOSCOPY AND ULTRASOUND BIOMICROSCOPY FOR EVALUATING THE IRIDOCORNEAL ANGLE IN DOGS

Objective-To compare iridocorneal angle grading systems on the basis o f gonioscopy and ultrasound biomicroscopy (UBM). Design-Original cross -sectional observational study. Animals-22 dogs. Procedure-Gonioscopy, goniophotography, and UBM were performed on 38 eyes from dogs without clinical evidence of glaucoma in the eyes examined. Results-Predomina nt gonioscopic grades derived from goniophotographs were considered no rmal (n = 26) and mild (12), Ultrasound biomicroscopy angle measuremen ts ranged from 16 to 38 degrees (mean +/- SD, 26.2 +/- 4.5 degrees). C iliary clefts depicted on UBM images were graded as open (n = 4), comp act/narrow (23), and closed (11). Significant differences were not fou nd between UBM-derived ciliary cleft grades and goniophotography-deriv ed dysgenesis grades, nor between UBM-derived ciliary cleft grades and subjective gonioscopic grades. Clinical Implications-Because goniosco py allows evaluation of the anterior face of the ciliary cleft, wherea s UBM provides cross-sectional information of the iridocorneal filtrat ion angle, UBM may yield more information regarding pathogenesis and p rognosis of, and preferred management approaches to, glaucoma. Ultraso und biomicroscopy may also be useful as a predictor of glaucoma or to diagnose early stages of glaucoma.