Optical Coherence Tomography May Help Distinguish Glaucoma from Suprasellar Tumor-Associated Optic Disc.

Abstract

Purpose This study aimed to differentiate patients with bilateral disc cupping associated with suprasellar tumor from patients with open-angle glaucoma by analyzing differences in optical coherence tomography (OCT) of the optic nerve. Methods In this retrospective cross-sectional study, we collected data from the eyes of 25 patients with suprasellar craniopharyngioma or pituitary macroadenomas (group 1) and 35 patients with primary open-angle glaucoma (POAG) (group 2), seen between 2001 and 2015, all with a visual acuity of ≥20/40, for whom Stratus Time-Domain (TD) optic nerve OCT scans were available. The main outcome measures were the retinal nerve fiber layer (RNFL) thickness, disc area, cup volume, cup/disc ratio, and rim area. Results A total of 31 patients met the inclusion criteria and were included in the study: 16 with suprasellar tumors and 15 with POAG. Both groups were similar in terms of gender and age (P > 0.05). The glaucoma group had a borderline greater total RNFL thickness (74.2 μm versus 62.8 μm, P=0.07), disc area (2.70 mm2 versus 2.16 mm2, P=0.004), and cup volume (0.20 mm3 versus 0.08 mm3, P=0.02). In multivariate, glaucoma was associated with increased total RNFL thickness (OR = 1.116 per μm, P=0.008), increased disc area (OR = 2.402 per 100 μm2, P=0.002), and decreased rim area (OR = 0.272 per 100 μm2, P=0.011). Of these, the parameter with the greatest AUC was the disc area (AUC = 0.79). Using the Youden index, the optimal cut-off point identified for stratification was a disc area greater than 2.33 μm2. Conclusions In patients with bilateral disc cupping, a decreased total RNFL thickness and smaller disc area seem to be associated with suprasellar tumors (when compared with open-angle glaucoma). These findings may aid in early diagnosis of cupping from suprasellar tumors, before compressive visual loss occurs.