Optical coherence tomography of retinal inflammatory diseases

Purpose. OCT, a new technique for high resolution cross-sectional imaging of the retina, was used to analyze lesions from retinal inflammatory disease. Methods. Forty-one eyes of 30 patients presenting with a retinal inflammatory disease, including ocular toxoplasmosis, presumed ocular histoplasmosis syndrome (POHS), uveitis, choroiditis, inflammation of the optic nerve and HIV-related ocular disease, were examined with OCT. OCT tomograms were correlated with slit-lamp biomicroscopy, visual acuity, and fluorescein angiography. Results. OCT was successful in localizing a region of inflammation to a particular layer of the retina by delineating an area of increased reflectivity. Active ocular toxoplasmosis presented with increased backscatter from the nerve fiber layer. Progressive outer retinal necrosis was displayed as a focal area of enhanced reflectivity from the outer neurosensory retina. POHS active lesions were characterized by focal regions of increased backscatter from the choroid. OCT allowed for the quantitative assessment of intraretinal fluid accumulation associated with uveitis, choroiditis and POHS choroidal neovasculature, neurosensory detachments occurring with CMV retinitis, and changes in the peripapillary nerve fiber layer resulting from optic neuritis. Conclusion. By providing structural information, OCT may be useful in the study of the pathology of inflammatory lesions, in vivo. Quantitative measurements could be directly extracted from the images, allowing the monitoring of parameters such as retinal thickness and reflectivity before and after treatment to assess the efficacy of therapy.