Ultrasound biomicroscopy of globes from young adult pigs

Abstract

Objective - To determine anterior chamber ocular measurements of adult porcine globes without histologic fixation by use of ultrasound biomicroscopy scanning. Sample Population - 25 porcine globes obtained at an abattoir. Procedure - Globes were packed on ice for transport. In the laboratory, globes were trimmed, rinsed with antibiotic solution, secured on a single gauze-fold in a latex holder, then were ultrasonogrammed unreformed. Ultrasound biomicroscopy scanning was done, using a 50-MHz transducer, 17-mm cup, and 2% methyl cellulose. Results - Average young adult pig external ocular measurements were: nasal-temporal corneal diameter, 16.61mm; superior-inferior corneal diameter, 14.00 mm; nasal-temporal globe diameter, 25.48 mm; superior-inferior globe diameter, 24.48 mm; and axial length 21.64 mm. Ultrasound biomicroscopy anterior chamber measurements were: iris sulcus, 30.45°; ciliary sulcus, 18.89° central corneal thickness, 0.98 mm; corneal thickness at limbus, 1.19 mm; central iris thickness, 0.58 mm; iris tip to ciliary apex, 1.73 mm; iris tip to iris sulcus origin, 3.83 mm; iris tip to ciliary sulcus origin, 2.98 mm; anterior chamber depth from iris tip to cornea, 2.21 mm; central anterior chamber depth, 2.47 mm; ciliary process mid-thickness, 0.65 mm; ciliary process apex to origin of iris sulcus, 2.32 mm; ciliary process apex to origin of ciliary sulcus, 1.34 mm; zonular bundle diameter, 0.10 mm; and interzonular bundle space, 0.11 mm. Conclusions - Anatomic anterior chamber measurements and relations in porcine globes can be used to describe trauma, confirm existence of lesions, and help explain theory. Clinical Relevance - Ultrasound biomicroscopy is a clinical decision aid facilitating noninvasive anatomic or pathologic description without histologic fixation.