Retinal nerve fiber layer thickness and its correlation with visual symptoms and radiological features in pituitary macroadenoma

Abstract

Objective: The aim of the study was to evaluate the association of the thickness of retinal nerve fiber layer (RNFL) with (i) visual symptoms and (ii) suprasellar extension defined by magnetic resonance imaging (MRI) in patients with pituitary macroadenoma. Materials and Methods: RNFL thickness of 50 consecutive patients operated for pituitary macroadenoma between July 2019 and April 2021 were compared with standard visual examination findings and MRI measurements such as optic chiasm height, distance between the optic chiasm and adenoma, suprasellar extension, and chiasmal lift. Results: The study group included 100 eyes of 50 patients operated for pituitary adenomas with suprasellar extension. RNFL thinning predominantly involved the nasal (84.26 ± 16.43 μm) and temporal quadrants (70.72 ± 14.80 μm) and correlated well with the visual field deficit (P < 0.001). Patients with moderate-to-severe deficit in visual acuity had a mean RNFL thickness <85 μm and patients with severe disc pallor had extremely thin RNFLs (<70 μm). Suprasellar extension defined as Wilsons Grade C, D, and E and Fujimotos Grades 3 and 4 were significantly associated with thin RNFLs <85 μm (P < 0.01). Chiasmal lift more than 1 cm and tumor chiasm distance of <0.5 mm were associated with thin RNFL (P < 0.002). Conclusion: RNFL thinning correlates directly with the severity of visual deficits in patients with pituitary adenoma. Wilsons Grade D and E, Fujimoto Grade 3 and 4, chiasmal lift more than 1 cm, and chiasm tumor distance <0.5 mm are strong predictors of RNFL thinning and poor vision. Pituitary macro adenoma and other suprasellar tumors need to be excluded in patients with preserved vision but having obvious RNFL thinning.