Fundus Blood Flow in Patients with Sellar Lesions with Optic Nerve Bending and Chiasmal Compression

Abstract

Background/objectives: Optic nerve bending and chiasmal compression impair vision in patients with sellar lesions; however, their effect on optic nerve head (ONH) blood flow remains unclear. This study used laser speckle flowgraphy to examine the relationship between clinical features and ONH blood flow in patients with optic nerve bending and chiasmal compression. Methods: This retrospective study included 32 eyes (16 eyes with and 16 without optic nerve bending on the contralateral side) from 16 patients with sellar lesions. The best-corrected visual acuity (BCVA), simple visual field impairment score (SVFIS), optic nerve head mean blur rate (ONH-MBR), and six-segmented macular ganglion cell layer + inner plexiform layer (GCL + IPL) thickness were examined. Results: Preoperative BCVA and SVFIS in eyes with optic nerve bending were significantly worse than those in eyes without bending, and significantly correlated with the optic nerve-canal bending angle (ONCBA). After tumor resection, BCVA and SVFIS significantly improved in both groups. Preoperative ONH-MBR was significantly lower in bending eyes but increased significantly post-treatment in both groups. Preoperative ONH-MBR correlated with ONCBA, while postoperative ONH-MBR correlated with nasal GCL + IPL thickness. Conclusions: Optic nerve bending and chiasmal compression showed reduced blood flow to the ONH. These changes in blood flow may be associated with GCL + IPL thickness and optic nerve bending angle.

Keywords: ganglion cell; laser speckle flowgraphy; optic nerve bending; optical coherence tomography; pituitary neuroendocrine tumor; sellar lesions.

Figure 1

Evaluation of best-corrected visual acuity (BCVA) in eyes with the sellar lesion. The parameters for eyes with optic nerve bending (red bars) and eyes without optic nerve bending (white bars) were compared before and after the tumor resection. (a) Comparison of BCVA in eyes with and without optic nerve bending pre- and post-tumor resection. The preoperative BCVA in eyes with optic nerve bending was significantly worse than that in those without optic nerve bending (** p < 0.01). The postoperative BCVA was significantly improved in eyes with and without optic nerve bending (** p < 0.01 and * p < 0.05). (b) Graphs showing the correlation between the optic nerve-canal bending angle (ONCBA) and preoperative BCVA in 32 eyes of 16 patients. The ONCBA was positively correlated with preoperative BCVA (r = 0.43, p = 0.013).

Figure 2

Assessment of visual field using the simple visual field impairment score (SVFIS) in patients with sellar and suprasellar tumors. The parameters for eyes with optic nerve bending (red bars) and eyes without optic nerve bending (white bars) were compared before and after the tumor resection. (a) Comparison of SVFIS between eyes with and without optic nerve bending pre- and post-surgery. The preoperative SVFIS of eyes with optic nerve bending was significantly higher than that in those without optic nerve bending (* p < 0.05). Postoperative SVFIS was significantly improved in eyes with and without optic nerve bending (** p < 0.01). (b) Graphs showing the correlation between the optic nerve-canal bending angle (ONCBA) and preoperative SVFIS in 32 eyes of 16 patients. The ONCBA was positively correlated with preoperative SVFIS (r = 0.56, p < 0.001).

Figure 3

Comparison of the mean blur rate (MBR) measured using laser speckle flowgraphy (LSFG) between eyes in patients with the sellar and suprasellar tumor. The graphs show the optic nerve head (ONH)-MBR of the overall region (MA) (a), vessel region (MV) (b), and tissue region (MT) (c), measured using LSFG. The parameters for eyes with optic nerve bending (red bars) and eyes without optic nerve bending (white bars) were compared before and after the tumor resection. The ONH-MA in eyes with optic nerve bending was significantly lower than that in eyes without bending (* p < 0.05). In addition, the preoperative ONH-MA, MV, and MT in eyes with optic nerve bending increased significantly after tumor resection (all *** p < 0.001). Similarly, the ONH-MA, MV, and MT of eyes without optic nerve bending increased significantly after tumor resection (*** p < 0.001, MA; ** p < 0.01, MV and MT).

Figure 4

A representative case of craniopharyngioma. A 57-year-old woman has optic nerve bending in her left eye caused by craniopharyngioma. Preoperative and postoperative best-corrected visual acuities (BCVAs; logarithm of the minimum angle of resolution units) are 0.30 and −0.08 in the right eye and 2.0 and −0.08 in the left eye, respectively. (a) Sagittal T2-weighted magnetic resonance images before surgery. The optic nerve-canal bending angle (ONCBA) (yellow dotted lines) is formed by the optic nerve in the optic canal and the optic nerve in the intracranial subarachnoid space at the optic canal’s exit. The yellow arrowheads indicated the optic nerve. A circle surrounding red dots indicates the tumor. The ONCBAs of this case are 10° in the right eye and 63° in the left eye. (b) Color fundus photograph of both eyes showing the normal appearance at the preoperative visit. (c) The thickness of the ganglion cell layer (GCL) + inner plexiform layer (IPL) in both eyes after tumor resection is within the normal range. (d) Goldmann perimetry before and after tumor resection. A central scotoma is detected in both eyes before tumor resection. The preoperative SVFIS score for the left eye is lower than that for the right eye (4 points for the right eye; 12 points for the left eye) (upper panels). After tumor resection, the central scotoma has disappeared in both eyes, and the SVFIS score is 0 for both eyes (lower panels). (e) Laser speckle flowgraphy (LSFG) images of the optic nerve head (ONH) before and after tumor resection. The preoperative optic nerve head-mean blur rate (OHN-MBR) of the overall region (MA), vessel region (MV), and tissue region (MT) are 23.1, 46.3 and 11.9 in the right eye, and 22.2, 37.2 and 9.3 in the left eye, respectively (upper panels). Postoperative MA, MV and MT for the right eye are 27.9, 54.9 and 12.0; for the left eye, they are 29.6, 55.0 and 11.3, respectively (bottom panels).