Measurements of Retinal Nerve Fiber Thickness and Ganglion Cell Complex in Neurofibromatosis Type 1, with and Without Optic Pathway Gliomas: A Case Series.

Purpose: The aim of this study was to investigate differences in retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thicknesses in neurofibromatosis 1 (NF1) cases, with and without optic pathway gliomas (OPGs). Materials and Methods: In total, 33 eyes of 33 subjects were evaluated in this prospective observational case series. Twenty-one patients with a diagnosis of NF1 were enrolled. Patients with NF1 and OPGs were included in Group 1 (n=9), and patients with NF1 without OPGs were included in Group 2 (n=12). The control group (Group 3) was comprised of 12 age- and sex-matched subjects with no history of ophthalmic or systemic diseases. All of the subjects underwent complete ophthalmic examinations, including best-corrected visual acuity (BCVA), slit lamp microscopy, and indirect ophthalmoscopy. Additionally, optical coherence tomography (OCT) measurements were obtained. Results: There were no statistically significant between-group differences in age and sex (p=0.227 and 0.986, respectively). The average RNFL thickness in Group 1 (NF1 patients with OPGs) was significantly lower than in Groups 2 and 3 (86.6 +/- 22.5, 107.4 +/- 6.65, and 108.4 +/- 5.05 mu m, respectively; p=0.001). Furthermore, the average GCC thickness in Group 1 was significantly lower than in Groups 2 and 3 (78.6 +/- 16.3, 94.8 +/- 3.55, and 94.9 +/- 3.82 mu m, respectively; p<0.001). Conclusions: Both RNFL and GCC thicknesses were significantly lower in NF1 patients with OPGs. The use of OCT to quantify damage to the visual pathway may enable earlier detection of OPGs in NF1 patients.