Eye and optic tract function in patients with cavernous sinus meningioma undergoing CyberKnife robotic radiosurgery

Purpose To assess 6–month radiation–related ocular side effects in patients udergoing CyberKnife Robotic Radiosurgery which enables delivery of beams of high dose radiation with extreme accuracy. Ocular side effects after radiation therapy have been reported and include: dry eye syndrome, eyelash loss, cataract formation, retinopathy, corneal changes, neovascular glaucoma, optic neuropthy. Methods We examined 9 patients undergoing CyberKnife Robotic Surgery for meningiomas located close to optic chiasm in order to assess effects of radiation on ocular tract function. Patients received 18 Gy in 3 fractions. Doses delivered to optic tract were on average 15 Gy in 3 fractions. Ocular structures involve extremely radiosensitive tissues such as natural lens as well as relatively resistant tissues:cornea, sclera and optic nerve. Slit lamp biomicroscopy with dialated fundus exam, Best Corrected Visual Acuity (BCVA), Intraocular Pressure (IOP), Endothelial Cell Count (ECD), cataract formation, Retinal Nerve Fiber Layer (RNFL) and Central Macular Thickness were obtained at a baseline and six months after radiotherapy Results No pathological changes in slit lamp examination with dialated fundus exam were revealed. No significant cataract formation or progession was observed. No statistically significant changes in measured parameters regarding eye, optic nerve and optical tract were observed (p>0,05 Wilcoxon paired test). Conclusion Our study did not show any significant inluence of radiation to eye and optic tract in patients treated with CyberKnife Robotic Radiosurgery for brain lesions in six month follow up period. Further observation of potential radiation–related ocular complications is required.