The Central Retinal Vein Bypass Study: a trial of laser-induced chorioretinal venous anastomosis for central retinal vein occlusion

Ophthalmology. 2010 May;117(5):954-65. doi: 10.1016/j.ophtha.2009.10.026. Epub 2010 Feb 16.


Purpose: To evaluate the effectiveness of a laser-induced chorioretinal venous anastomosis (L-CRA) as a treatment for nonischemic central retinal vein occlusion (CRVO).

Design: Prospective, randomized, controlled, multicenter clinical trial.

Participants: A total of 113 consecutive patients with a nonischemic CRVO of >3 months' duration and visual acuity of < or =20/50.

Methods: Patients were randomized to L-CRA (58 patients) or conventional care (55 patients). They underwent standardized retinal photography, fluorescein angiography, and ophthalmic examinations, together with standardized assessments of best-corrected visual acuity, performed by masked visual acuity assessors using Early Treatment Diabetic Retinopathy Study protocols. Analysis was performed by intention-to-treat.

Main outcome measures: The primary outcome measure was change in visual acuity at 18 months. Secondary outcomes were progression of retinal ischemia and rates of adverse events.

Results: A total of 53 control patients and 55 treatment patients completed the study. The 2 groups were comparable for age, age- and gender-adjusted mean visual acuity, and most other parameters. In the treated group of 55 patients, 42 (76.4%) developed an L-CRA. Over the 18-month follow-up period, treated eyes had an 8.3 letter mean improvement from baseline compared with control eyes (P = 0.03). Treated eyes that developed a functional L-CRA achieved an 11.7 letter mean improvement from baseline over the control group after 18 months (P = 0.004). Conversion to the ischemic CRVO category occurred in 20.8% of control eyes and in 9.6% of treated eyes overall (P = 0.33). Of the treated group who developed an L-CRA where the retinal ischemia was due to progression of the CRVO, 4.9% progressed to the ischemic category (P = 0.03). Neovascularization developed at the site of the L-CRA in 10 of 55 treated eyes (18.2%). Vitrectomy surgery was required by 5 of 55 treated eyes (9.1%) because of macular traction or nonresolving vitreous hemorrhage.

Conclusions: Chorioretinal venous anastomosis was created in 76.4% of eyes with nonischemic CRVO in this study. Eyes that developed an anastomosis had a significant improvement (11.7 letters) in final visual acuity after 18 months, compared with eyes in the control group (P = 0.004). Complications were managed successfully with careful follow-up and early intervention.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anastomosis, Surgical
  • Choroid / blood supply*
  • Female
  • Fluorescein Angiography
  • Follow-Up Studies
  • Humans
  • Laser Therapy*
  • Lasers, Solid-State
  • Male
  • Middle Aged
  • Photography
  • Prospective Studies
  • Retinal Vein / surgery*
  • Retinal Vein Occlusion / diagnosis
  • Retinal Vein Occlusion / physiopathology
  • Retinal Vein Occlusion / surgery*
  • Treatment Outcome
  • Visual Acuity / physiology