ABSTRACT
Objective To explore the histopathological changes of the radial optic neurotomy (RON) in human eyes, and to establish the theoretical foundation for the effective RON. Methods Ten patients with unaffected eyeball or optic disc who had undergone ophthalmectomy (7 patients) or orbital exenteration (3 patients) because of intraocular or orbital tumor were gathered. A double-incision in pars plana was performed. One was inserted into illuminating fiber, and another was inserted into a standard microvitreoretinal (MVR) blade (unbent MVR blade in 4 patients and bent ones in 6; radial incision on nasal side of the optic disc in 4 patients and on both nasal and temporal side in 6). The histopathological examination was performed to observe the location and depth of the incision. Results Eleven incisions were found in 8 out of 10 patients, of which surgical spaces can be observed clearly. Three incisions were obliquely inserted into the optic nerves, 5 sieve plate lateral incisions had the surgical intervals connected with the subarachnoid spaces, and 3 incisions caused obvious damage of retinal ganglion cell axons due to the position close to the center. Nine incisions approached to the retrolaminal level, and the other 2 reached the laminal and prelaminal level respectively. Injured retina beside the optic disc in 1 incision was found. Central retinal vessels were not damaged. Conclusions An optimal incision may be in the edge of the lamina cribrosa, whose depth should be in the level of lamina cribrosa and retrolamina, with surgical intervals connected with the subarachnoid spaces.