Optical Coherent Tomography Predicts Long-Term Visual Outcome of Pituitary Adenoma Surgery: New Perspectives From a 5-Year Follow-up Study

Abstract

Background: Compressive optic neuropathy is the most common indication for transsphenoidal surgery for pituitary adenomas. Optical coherence tomography (OCT) is a useful visual assessment tool for predicting postoperative visual field recovery.

Objective: To analyze visual parameters and their association based on long-term follow-up.

Methods: Only pituitary adenoma patients with abnormal visual field defects were selected. A total of 188 eyes from 113 patients assessed by visual field index (VFI) and 262 eyes from 155 patients assessed by mean deviation (MD) were enrolled in this study. Postoperative VFI, MD, and retinal nerve fiber layer (RNFL) thickness were evaluated and followed up. After classifying the patients into normal (>5%) and thin (<5%) RNFL groups, we investigated whether preoperative RNFL could predict visual field outcomes. We also observed how RNFL changes after surgery on a long-term basis.

Results: Both preoperative VFI and MD had a linear proportional relationship with preoperative RNFL thickness. Sustained improvement of the visual field was observed after surgery in both groups, and the degree of improvement over time in each group was similar. RNFL thickness continued to decrease until 36 mo after surgery (80.2 ± 13.3 μm to 66.6 ± 11.9 μm) while visual field continued to improve (VFI, 61.8 ± 24.5 to 84.3 ± 15.4; MD, -12.9 ± 7.3 dB to -6.3 ± 5.9 dB).

Conclusion: Patients with thin preoperative RNFL may experience visual recovery similar to those with normal preoperative RNFL; however, the probability of normalized visual fields was not comparable. RNFL thickness showed a strong correlation with preoperative visual field defect. Long-term follow-up observation revealed a discrepancy between anatomic and functional recovery.