Prognostic value of macular ganglion cell layer thickness for visual outcome in parasellar tumors.

PURPOSE: Optic nerve compression by mass lesions at the optic chiasm leads to loss of visual function which can be recovered after decompression surgery. In this study, we evaluated the prognostic ability of macular ganglion cell layer (mGCL) thickness measured with spectral-domain optical coherence tomography (SD-OCT) for predicting postoperative visual outcome of compressive optic neuropathy (CON) related to parasellar tumors. METHODS: This observational cohort study used data from the Department of Neurosurgery and Ophthalmology, Seoul National University Bundang Hospital between 2013 and 2018. Seventy-nine eyes from 79 patients with CON due to parasellar tumors who underwent surgery were included. Patients were divided into either a visual recovery group or a non-recovery group according to the degree of postoperative visual field (VF) impairment. SD-OCT scanning with automated segmentation was performed to measure the circumpapillary retinal nerve fiber layer (cpRNFL) and the mGCL thickness in the nine macular subfields as defined by the ETDRS and 8 x 8 posterior pole grid. Correlations between preoperative cpRNFL thickness, mGCL thickness and postoperative VF sensitivity were assessed. The prognostic ability of mGCL thickness for predicting visual recovery after surgical decompression in each ETDRS subfield and posterior pole grid quadrant was evaluated. RESULTS: The central inferonasal and superonasal quadrant mGCL thicknesses measured by the 8 x 8 posterior pole grid showed the best predictability of postoperative visual outcome (AUROC = 0.963 and 0.953, respectively), which was superior to the prognostic power of the average cpRNFL. The central inferonasal quadrant mGCL thickness significantly correlated with the superotemporal quadrant VF sensitivity (R(2) = 0.589). CONCLUSIONS: The mGCL thickness in the central nasal quadrants measured by SD-OCT is an excellent predictor of visual recovery after chiasmal decompression.