Analysis of vitreous opacities in chronic glaucoma by vitreo‐optical coherence tomography imaging

Abstract

AbstractPurposeTo analyze the vitreous opacities of rat eyes by optical coherence tomography (OCT) in two models of chronic glaucoma. Hyperreflective opacities at the vitreoretinal interface, their dynamics over time (changes in number, size, intensity, eccentricity, and orientation) and as a function of intraocular pressure were analyzed in two different glaucoma models and compared to healthy controls.MethodsImages of the vitreoretinal interface were obtained by OCT and exported as videos (composed of cross‐sectional images acquired by means of 61 b‐scans measuring around 3 mm in length and centred on the optic nerve). These videos were analysed using a custom program implemented in Matlab. The vitreous opacities, closely related to the immune cells, were analysed.ResultsHyperreflective opacities, extrapolated as soma areas, were classified according to their size: isolated cells (<10 μm2), non‐activated cells (10–50 μm2), activated cells (50–250 μm2) and cell complexes (>250 μm2). In glaucoma models, right eyes showed significant increase of total area compared with left non‐induced eyes, and left eyes showed significant increase compared to healthy controls. The physiological number of opacities was 10–20. Glaucoma‐induced right eyes showed a mean of 70 opacities, a specular response between activated cells and non‐activated cells, and a greater variation in intensity in the smallest cells, that showed an early change in orientation compared with physiological eyes.ConclusionsOur method of analyzing vitreous opacities by OCT could serve as a reliable neuroimaging biomarker to detect disease onset and early progression applicable to glaucoma and potentially other neurodegenerative diseases impacting the retina and optic nerve.