Does Radial Optic Neurotomy Alter Retinal Blood Flow in Eyes With a Central Retinal Vein Occlusion

w m e f ORIO AND HORIGUCHI1 PROSPECTIVELY EVALUated the effects of pars plana vitrectomy with radial optic neurotomy (RON) on retinal blood ow (RBF) in seven eyes with macular edema due to a entral retinal vein occlusion (CRVO). They also decribed the effect of this treatment on visual acuity, foveal hickness as measured by optical coherence tomography OCT), and the development of chorioretinal anastomoses n these seven eyes. Eyes with CRVO vary widely at presentation. They may ave a different angiographic perfusion status, visual acuty, ophthalmoscopic appearance, and duration since onet, among others, and consequently have a very different atural history. The Central Vein Occlusion Study (CVOS)2 eported natural history information; however because eyes ere lumped together with regard to disease duration at tudy entry, the visual acuity natural history outcomes in he CVOS are not entirely useful to use as a reference. nless a homogenous population is studied, then, the wide ariability in eyes with CRVO on presentation, as demnstrated in Horio and Horiguchi’s series and recognized y the authors, creates inherent difficulties in evaluating he effect of investigational imaging modalities and treatent options, particularly in small study populations. orio and Horiguchi examined a diverse group of seven yes with CRVO and attempted subgroup analyses; howver, effective subgroup analyses are not feasible because of he small sample size. In the reported series, visual acuity improved by two or ore lines in three of the seven eyes and decreased in two yes at 6 months. The phakic status of these eyes was not ncluded, and postoperative lenticular changes can alter isual outcome. It is unclear to the reader how the visual cuities were measured and whether the visual acuities ere obtained in a masked fashion. The visual acuity nformation is less meaningful without this additional nformation. Foveal thickness, as measured by OCT, initially dereased at 1 week and, despite a small increase at 1 month,