Case Report: Twisted subbasal corneal nerve fibers in a case of neurofibromatosis type 1

Previous studies of neurofibromatosis-related neuropathy have primarily focused on large-fiber neuropathy. We report twisted subbasal corneal nerve fibers as a descriptive corneal nerve abnormality associated with neurofibromatosis type 1 (NF1), thereby enhancing the understanding of ocular manifestations of neurofibromatosis.

A 24-year-old female patient with a history of NF1 presented with dry eye symptoms and a left orbital lesion detected on computed tomography. Slit-lamp examination showed punctate epithelial keratitis in both eyes and a ring-shaped superficial stromal scar in the right eye. Magnetic resonance imaging demonstrated lesions compatible with NF1-associated neuroglial involvement, including a left orbital/optic pathway lesion. IVCM revealed thickened and tangled subbasal corneal nerve fibers with a reticular appearance in the right eye and focal thickening and twisting of subbasal nerve branches in the left eye. Quantitative analysis showed that corneal nerve fiber density was reduced to 6.25 n/mm² in both eyes. The right eye had no detectable nerve branches (CNBD = 0), whereas the left eye had a branch density of 31.25 n/mm².

This case describes qualitative and quantitative subbasal corneal nerve abnormalities in a patient with NF1. These findings support the hypothesis that corneal nerve alterations can occur in NF1.