Early morphological recovery of the optic chiasm is associated with excellent visual outcome in patients with compressive chiasmal syndrome caused by pituitary tumors.

OBJECTIVES

The study objectives are (1) to identify factors predicting the excellent visual recovery after transsphenoidal removal of pituitary tumors and (2) to describe the association of excellent visual recovery and early restoration of symmetry of the decompressed optic chiasm.

METHODS

Thirty-five patients with visual symptoms due to pituitary tumors underwent endoscopic endonasal surgery. All patients received perioperative diagnostic magnetic resonance (MR) imaging and ophthalmological assessments within 2 weeks before surgery, within 2 weeks after surgery, and 3 months or later after surgery. Preoperative best-corrected visual acuity (BCVA ≧ 20/20), degree of visual field deficit (VFD, less than half of VF), thickness of retinal nerve fiber layer (RNFL) measured by optical coherence tomography (OCT), and thickness of ganglion cell complex (GCC) measured by OCT were considered for statistical analysis as predictive factors of VF outcome. Multivariate logistic regression models were used in statistical evaluation of data.

RESULTS

In the multivariate analysis, RNFL (odds ratio  =  62.137, P < 0.001) and preoperative VFD (odds ratio  =  8.244, P < 0.02) proved to be effective as factors predicting sufficient VF recovery. Postoperative restoration of symmetry of the optic chiasm was related to sufficient VF recovery (P < 0.0001, Fisher's exact test) and RNFL (P < 0.0001, Fisher's exact test).

DISCUSSION

Early decompression is crucial for sufficient VF recovery, in particular, while RNFL preserves normal or borderline thickness and while VFD keeps within hemianopia. Morphological reversibility is associated with functional reversibility in the optic chiasm compressed by a pituitary tumor. In particular, early morphological recovery suggests functional recovery, which indicates neurocyte reserve in the compressed optic pathway with functional recovery.