Visual function tests including the role of optical coherence tomography in neurofibromatosis 1

Optic pathway glioma (OPG) is a common and significant complication of neurofibromatosis 1 (NF-1) that might lead to vision loss. The main reason to treat OPG is to preserve vision. Tumor location along the visual pathway largely dictates the presenting signs and symptoms. Clinical ophthalmic evaluation is focused on optic nerve functions including evaluation of pupils’ reaction to light, visual acuity, color vision, and visual field, as well as optic nerve appearance. An important relatively new ancillary test is optic coherence tomography (OCT) that measures the volume of retinal nerve fiber layer around the optic nerve and the ganglion cell layer-inner plexiform layer (GCL-IPL) of the macula, both proved to be strongly associated with losing vision in OPG. Accurate evaluation of vision functions plays a critical role in the decision of treatment. In this review, we describe the ophthalmological assessment including new biomarkers in clinical use. We also outline prognostic factors and current recommendations for surveillance and indications for treatment.