Retinal and Choroidal Abnormalities in Neurofibromatosis Type 1 Using 3–Dimensional Optical Coherence Tomography and Scanning Laser Ophthalmoscopy

Abstract

Abstract: : Purpose: We analyzed the retinal and choroidal abnormalities in neurofibromatosis type 1 using scanning laser ophthalmoscopy (SLO) and a new 3–dimensional (3–D) optical coherence tomography (OCT) microscopy imaging system. Methods: A 19–year–old Japanese man with neurofibromatosis type 1 was examined by conventional ophthalmoscopic and biomicroscopic fundus examinations, fluorescein angiography, indocyanine green (ICG) angiography, SLO, and 3D–OCT. A monochromatic light fundus examination using SLO with a helium–neon laser and an infrared laser was performed with a confocal aperture (direct mode) and a ring aperture (indirect mode). SLO microperimetry was done. Unlike conventional SLO, 3–D OCT can operate in a so–called "transversal" fashion (C–scan) and yields OCT images originating at the same axis and plane as the retina. The system also scans laterally along a line to the retina to produce cross–sectional longitudinal OCT images (B–scan) similar to those of the Humphrey–Zeiss system. Results: The conventional ophthalmoscopic and biomicroscopic fundus examinations were unremarkable. SLO examination showed no abnormalities with a helium–neon laser. Regions of multiple, bright patches with infrared imaging using the direct confocal mode showed two types of lesion, bright and dark patches, using the indirect mode. There were no scotomas in those regions using SLO microperimetry. Fluorescein angiography was unremarkable. ICG showed scattered porphyritic hypofluorescence in the same areas as the dark patches bilaterally. C–scan showed small, round, isolated high–intensity lesions near the optic disc. B–scan showed these lesions in the retinal nerve fiber layer. Conclusions: Infrared imaging using the indirect mode demonstrates choroidal lesions and may speculate their depth. 3D–OCT can identify undetectable microstructural changes by conventional examination. 3D–OCT and SLO techniques are useful to analyze pathologies of the retina and choroid in neurofibromatosis type 1.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • imaging/image analysis: clinical