Patients with the rare genetic disorder Fabry’s disease—a lysosomal storage disorders—have particular ocular needs. Specifically, they’re at elevated risk for corneal dystrophy.1 Traditionally, these patients are evaluated for epithelial deposits using a slit lamp, but with the development of in vivo corneal confocal microscopy (IVCM), researchers are wondering if this technology provides a superior method of detection for these particular patients.
What’s known is that slit-lamp exams suffer from a high number of false negative results and, consequently, low negative predictive value, according to the Italian research team. Their research, published in the British Journal of Ophthalmology, shows that microstructural changes in the cornea can be seen with IVCM technology in patients with Fabry’s disease and may assist in earlier diagnosis.2
The investigators looked at 28 eyes of 14 patients with Fabry’s and eight healthy controls using both slit-lamp exams and IVCM of central and peripheral corneal quadrants. They found cornea verticillata in 32% of eyes with Fabry’s disease at the slit lamp. Using the IVCM, 89% showed the presence of epithelial hyper-reflective deposits. Of the 19 eyes deemed negative at the slit-lamp, 16 eyes showed epithelial deposits when evaluated using IVCM. Compared with controls, Fabry’s disease patients had a significantly reduced number, density and length of nerve fibers at the level of corneal sub-basal nerve plexus, but a significantly higher grade of fibers tortuosity, the report shows.2
1. Fabry Disease. rarediseases.org/rare-diseases/fabry-disease/. NORD. Accessed November 8, 2019.
2. Leonardi A, Carraro G, Modugno R, et al. Cornea verticillata in Fabry disease: a comparative study between slit-lamp examination and in vivo corneal confocal microscopy. Br J Ophthalmol. August 10, 2019. [Epub ahead of print].