Ocular surface involvement in patients with neurofibromatosis type 1 syndrome

Purpose: The aim of this study is to evaluate ocular surface morphological and functional changes in patients with neurofibromatosis type 1 (NF1). Methods: Twenty-eight patients with NF1 and 14 healthy subjects were included in this study. All participants underwent a medical history collection, a complete ophthalmological examination including slit lamp exam and assessment of best-corrected visual acuity (BCVA), corneal sensitivity, and lacrimal function (Schirmer test and fluorescein tear break-up time test). Corneal nerves’ morphology and endothelial cells density were evaluated by in vivo corneal confocal microscopy (IVCM). Tear and conjunctiva epithelium samples were collected to evaluate nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) tear levels and conjunctival expression of their receptors TrkA and p75NTR. Results: Patients with NF1 showed a significant decrease of FTBUT when compared with healthy subjects (p < 0.001). Corneal sensitivity was ≤ 50 mm in 46% of NF1 patients. IVCM showed a significant increase of corneal nerve branching and of corneal endothelial cells density. No significant difference was observed between the two groups on NGF and BDNF tear levels and conjunctival expression of their receptors. Conclusion: This study demonstrated the presence of ocular surface changes in NF-1 patients including decrease of tear stability and of corneal sensitivity. Patients with NF1 also showed changes of corneal endothelial cells’ density.