Abstract
Purpose :
To establish reference ophthalmic findings, which include seven months follow-up data from one guinea pig diagnosed with heterotopic bone formation (HBF).
Methods :
Slit lamp biomicroscopy, gonioscopy, optical biometry, rebound tonometry, anterior segment optical coherence tomography (AS-OCT), and posterior segment spectral domain optical coherence tomography (SD-OCT) were all performed on a 3.8-year-old male guinea pig suspected of having heterotopic bone formation. The eyes of this animal underwent further evaluation 7 months after the initial evaluation.
Results :
Slit lamp biomicroscopy revealed vascularized, white masses in the anterior chamber, adjacent to the limbus, both nasally and temporally in the right eye, and both superiorly and temporally in the left eye. Their apparent locations, between the posterior corneal (endothelium) surface and anterior iris, were confirmed by gonioscopy and AS-OCT examinations. The right eye showed slightly elevated intraocular pressure compared to the left eye (18.3 vs. 13.3 mmHg) and recorded a slightly longer axial length (10.40 vs. 10.29 mm). However, SD-OCT showed no obvious differences in the shape or appearance of the optic nerve heads of the two eyes. Measurements made 7 months after the initial examination revealed significant progression in both eyes, in terms of the areal extent of the HBF lesions, as revealed by slit-lamp biomicroscopy and AS-OCT imaging. In the right eye, the lesions had extended into both superior and inferior limbal regions and in the left eye, into the nasal region. Recorded IOPs were only slightly higher than the earlier readings and still within a normal range, although a disparity between right and left eyes was again in evidence, with the right eye recording being 5.3 mmHg higher. Nonetheless, no changes in either nerve fiber layer thickness or total retinal thickness in the vicinity of the optic nerve heads were observed.
Conclusions :
Advanced ophthalmic imaging techniques including OCT can provide important clinical insights into the pathophysiological changes in HBF. This case report provides reference time course data for ocular HBF in the guinea pig.
This is a 2021 ARVO Annual Meeting abstract.