Ultrasound Biomicroscopy Studies to Evaluate Ciliary Cleft Parameters in Healthy Eyes of American Cocker Spaniels

Abstract

The purpose of the present study was to quantify ciliary cleft parameters in the healthy eyes of American Cocker Spaniels (ACSs) and assess their correlations with intraocular pressure (IOP) using ultrasound biomicroscopy (UBM) studies. We evaluated 26 healthy eyes from 13 ACSs. Iridocorneal angle (ICA), ciliary cleft area (CCA), ciliary cleft width (CCW), and angle-opening distance (AOD) were measured. All UBM studies were performed without pupil dilatation in both eyes of each dog. The IOPs of all eyes were measured using applanation tonometry. The mean IOP, ICA, CCA, CCW, and AOD values were 15.92±3.21 mmHg, 13.94±1.96°, 0.32±0.03 mm 2 , 0.33±0.06 mm, and 0.45±0.10 mm, respectively, for the entire study sample; 16.63±3.81 mmHg, 13.51±1.90°, 0.32±0.02 mm 2 , 0.32±0.06 mm, and 0.40±0.07 mm, respectively, in female dogs; and 14.80±1.48 mmHg, 14.63±1.96°, 0.35±0.07 mm 2 , 0.32±0.03 mm, and 0.53±0.09 mm, respectively, in male dogs. IOP had significant negative correlations with CCA and AOD in all eyes. There were no significant differences in IOP between male and female dogs, although there were significant differences in AOD. Our results suggest that IOP is correlated with CCA and AOD in ACSs.

Experimental protocol designed to employ Nd:YAG laser surgery for anterior chamber glaucoma detection via UBM

“…UBM can also illustrate the rotation of the ciliary body, that stops the forward flow of aqueous which press against the lens equator during the occurrence of glaucoma [23,26]. UBM gives the highresolution images with a transverse resolution of 50 mm, and an axial resolution of about 25 mm [27,28]. Unlike AS-OCT, UBM can achieve visualisation of structures posterior to the iris pigment epithelium as sound penetrates the pigment epithelium but light does not [29].…”