Chorioretinal Anastomosis After Radial Optic Neurotomy for Central Retinal Vein Occlusion

Abstract

To evaluate the incidence of chorioretinal anastomosis after radial optic neurotomy and to determine its effect on visual acuity and foveal thickness in patients with central retinal vein occlusion. Methods: We conducted a prospective, uncontrolled, interventional study of 14 patients with preoperative visual acuities below 20/125. Pars plana vitrectomy and radial optic neurotomy were performed. Fluorescein angiography and optical coherence tomography were used to monitor the evolution of macular edema. Results: All patients underwent radial optic neurotomy with no major complications. Eight patients (57.1%) gained 1 or more lines of visual acuity while the visual acuity of 6 patients (42.9%) improved by 2 or more lines (mean visual acuity, 20/80; PϽ.001) (mean visual acuity gain, 3 lines). The decrease in macular thickness was shown to be statistically significant (PϽ.001) (median, 282 µm). Retinochoroidal shunts developed in 6 eyes (42.9%) at the site of the radial optic neurotomy. Main Outcome Measures: Improvement in visual acuity and a decrease in foveal thickness seen on optical coherence tomography. Conclusions: Surgical decompression of central retinal vein occlusion via radial optic neurotomy seems to be a promising technique that improves or at least stabilizes the course of severe central retinal vein occlusion. Improvement may occur because of optic nerve decompression, vitrectomy, and by inducing new chorioretinal shunts that drain retinal circulation to the choroid and accelerate resolution of retinal edema.

Radial Optic Neurotomy for Central Retinal Vein Occlusion: Long-Term Retinal Perfusion Outcome

“…However, we have no reliable data on how frequently spontaneous anastomosis occurs after an occlusion. Fuller et al [20 ]described a 46% incidence of spontaneous CRA after CRVO, and in the literature, the incidence of CRA after RON ranges from 42.9 to 60% [7, 21, 22]. In our study, 16 (57.1%) cases developed CRA after surgery compared to 2 (5.7%) controls.…”

“…However, the reported positive influence of vitrectomy and removal of the posterior hyaloid in increasing the diffusion between retina and vitreous cavity should also be considered [16, 17]. Another recent hypothesis presented the development of CRA after RON and its consequent retinal blood flow improvement as the main therapeutic mechanism induced by neurotomy [7]. Regarding the importance of good preoperative visual acuity for a favorable visual outcome as shown by the CVOSG, preoperative BCVA of 0.32 or worse was our criterion to perform surgical treatment (RON) [8].…”

“…In our study, 16 (57.1%) cases developed CRA after surgery compared to 2 (5.7%) controls. Studies by Garcia-Arumí et al [7 ]and Nomoto et al [21] reported that 83 and 86%, respectively, of patients who developed CRA had NICRVO. In our series, 55.5% of nonischemic and 57.9% of ischemic cases developed postoperative CRA, and consequently we found no correlation between the type of CRVO and the development of CRA.…”

“…Radial optic neurotomy (RON) was thought to improve blood flow by relieving pressure on the vein. More recently, however, it has been reported that new chorioretinal shunts induced by RON may drain the retinal circulation to the choroid, improving blood flow [7]. …”

Fibrinolytic and Surgical Treatment Approaches for Retinal Vein Occlusion

“…Moreover, while improvements in visual acuity after RON have been confirmed by several other reports [61][62][63][64] , some studies found a resolution of macular edema that was not accompanied by an improvement in visual acuity in all eyes following RON [65,66] . On the other hand, some studies revealed that RON induce the development of retinochoroidal shunt vessels in 46.7-83.3% of patients and this may represent the mechanism of any beneficial effect this surgical procedure [67][68][69][70][71] . In addition, several authors suggested that the creation of RON involves a PPV and the beneficial effects of RON are due to this alone [72,73] .…”