Association of retinal nerve fibre layer thickness with quantitative magnetic resonance imaging data of the optic chiasm in pituitary adenoma patients.

To evaluate retinal nerve fibre layer (RNFL) thickness in patients with pituitary adenoma (PA) by optical coherence tomography and to compare it with magnetic resonance imaging (MRI) characteristics of pituitary extension. 154 eyes of 77 patients with PA were evaluated. Ophthalmologic evaluation was performed before surgical treatment. Average and per quadrant thickness of peripapillary RNFL (internal limiting membrane to nerve fiber layer/ganglion cell layer) were calculated. Optical coherence tomography was performed in a disc circle mode (layer distance 3.45 mm; 1024 scans). PA was confirmed by MRI scans. Characteristics of the optic chiasm in relation to the suprasellar adenoma were assessed. Suprasellar extension of PA was diagnosed in 55 patients (71.4%). The optic chiasm thickness differed significantly in the groups with and without suprasellar PA extension (p < .001). A weak positive correlation was found between the height of the optic chiasm right side, middle part, left side and visual acuity (r = 0.349; 0.276; 0.307) (p < .001). RNFL thickness around the optic nerve disc measured preoperatively was reduced significantly in all four quadrants in PA patients compared with the control group (p < .001). RNFL thickness was reduced significantly only in the temporal quadrant in PA patients with suprasellar extension compared with the patients without suprasellar extension (p = .009). The temporal RNFL thickness showed the strongest positive correlation with the distance between optic chiasm and PA (r = 0.401, p < .001), while the superior, nasal and, inferior RNFL quadrants showed a weak (r = 0.079; 0.074; 0.113) or not significant (r = 0.351; 0.380; 0.180) correlation with the distance between the optic chiasm and PA. The chiasmal right side, middle part, left side heights correlated significantly with RNFL thickness in all quadrants (p < .05). Our results indicate that suprasellar extension in PA patients causes visual disturbances.