Retinal and Optic Nerve Integrity After Endoscopic Transorbital Skull Base Surgery Assessed by Optical Coherence Tomography.

BACKGROUND AND

OBJECTIVES

The endoscopic transorbital approach (ETOA) provides minimally invasive access to the skull base, but its orbital trajectory raises concern for subclinical optic nerve or retinal injury. We assessed the structural safety of ETOA using high-resolution optical coherence tomography as an objective neuro-ophthalmic tool, focused mainly on patients without orbital involvement.

METHODS

From 41 consecutive ETOA cases (2017-2024), 16 patients had analyzable baseline and approximately 12-month postoperative imaging and were included: a Group A without orbital involvement (n = 10) and a Group B with orbital or optic nerve involvement but interpretable scans (n = 6). Macular ganglion cell layer (GCL) and peripapillary retinal nerve fiber layer (RNFL) thickness were measured with spectral-domain optical coherence tomography. Paired analyses were prespecified for the Group A; the Group B was summarized descriptively. The contralateral eye served as an internal control.

RESULTS

Across all 16 patients, no structural or functional deterioration attributable to surgery was observed. In the Group A, GCL thickness in the operated eye decreased slightly from 81.0 µm to 80.5 µm (mean change -0.5 µm), as well as in the contralateral eye used as control (-0.2 µm). RNFL thickness in the operated eye increased from 96.4 µm to 97.3 µm (mean change +0.9 µm), while the contralateral eye decreased (-1.2 µm). These changes were not statistically significant and remained within physiological variability (±2 µm for GCL; ±3 µm for RNFL). Visual acuity, visual fields, color vision, and pupillary responses were preserved, with no signs of functional impairment. In the Group B, the operated eye showed RNFL thinning (≈-7.7 µm), while GCL remained stable. This was attributed to preexisting optic neuropathy or resolution of preoperative disc edema rather than surgical injury. Importantly, functional outcomes (visual acuity, visual fields, color vision, and pupillary responses) improved or remained stable.

CONCLUSION

ETOA does not induce subclinical retinal or optic nerve injury at late follow-up. The approach demonstrated structural and functional safety, particularly in patients without orbital involvement (Group A), where preservation of visual integrity is imperative. These findings support the neuro-ophthalmic safety of the transorbital corridor and justify larger prospective studies.