Long term predictive ability of preoperative retinal nerve fiber layer thickness in visual prognosis after chiasmal decompression surgery

Abstract

Objective: To investigate the relationship between preoperative retinal nerve fiber layer (RNFL) thickness and the recovery of visual field (VF) and visual acuity (VA) 1 year after surgery in chiasmal compression patients presenting with visual impairment. Patients and methods: Twenty-nine eyes of 16 patients with chiasmal compression and 14 eyes of 14 control subjects were enrolled. All patients undergoing chiasmal decompression surgery via a transsphenoidal approach were prospectively evaluated before and 1 year after surgery with best corrected visual acuity (BCVA, logMAR), mean deviation (MD) value with standard automated perimetry (SAP) and RNFL thickness with optical coherence tomography. Eyes with chiasmal compression were divided into two groups according to the mean preoperative RNFL thickness: >= 100 mu m (Group 1) and < 100 mu m (Group 2). The relationship between the mean preoperative RNFL thickness and visual prognosis parameters (VF, VA) was analyzed. Results: The mean preoperative RNFL thickness was 115.92 +/- 8.97 mu m, 84.0 +/- 8.85 mu m, and 114.21 +/- 7.75 mu m in Group 1 (n = 15 eyes), Group 2 (n = 14 eyes) and the control group (n = 14 eyes), respectively. The mean preoperative BCVA was 0.15 +/- 0.3 in Group 1, and 0.41 +/- 0.39 in Group 2. The mean BCVA increased to 0.03 +/- 0.1 in Group 1 in the postoperative period but did not change in Group 2. MD value was - 6.10 +/- 5.54 in the preoperative period and - 2.59 +/- 2.23 in the postoperative period for Group 1 (p = 0.014), while it was - 18.97 +/- 4.14 in the preoperative period and - 18.57 +/- 4.51 in the postoperative period in Group 2 (p = 0.24). Conclusions: This study suggests that lower mean preoperative RNFL thickness was associated with poorer longterm visual prognosis. Preoperative RNFL thickness measurements may be helpful in predicting the recovery of VF and VA after decompression surgery in patients with chiasmal lesion presenting with visual impairment.