Optical coherence tomography in the evaluation of neurofibromatosis type-1 subjects with optic pathway gliomas

Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disorder, with an approximate incidence of 1 in 3,500. Optic pathway gliomas (OPGs) develop in 15% of individuals with NF1, commonly in childhood. OPGs are difficult to detect via a clinical inspection in children, often requiring magnetic resonance imaging (MRI). Given the significant visual risks associated with OPGs in NF1, there is a need for improved noninvasive techniques to diagnose OPGs in children; therefore, we studied optical coherence tomography (OCT) as a potential tool to assess optic nerve and retinal nerve fiber layer (RNFL) abnormalities. This prospective study was designed to evaluate OCT detection of RNFL loss from optic atrophy attributable to OPGs in a cohort of pediatric patients with NF1.

With the use of Stratus OCT, directed testing with the Fast Macular Thickness and Fast RNFL Thickness protocol scans were performed on 9 subjects with NF1 and known OPGs, 6 subjects with NF1 without OPGs, and 15 controls.

NF1 subjects with OPGs had thinner RNFLs and macula when compared with age-matched controls and to NF1 subjects without OPGs. After applying the equivalence equation, the average RNFL thickness and macular volume in NF1 subjects without OPGs was equivalent to controls.

Our study suggests that OCT can be used to detect RNFL thinning secondary to OPGs in NF1 subjects. This objective tool shows promise as a useful adjunct to routine clinical ophthalmologic evaluation in children with NF1.