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Updated: Aug 3, 2025

Optimization of the Retinal Vein Occlusion Mouse Model to Limit Variability
Published on: August 6, 2021
Benefits of a Laser Chorioretinal Anastomosis Plus Ranibizumab vs Ranibizumab Alone for Central Retinal Vein
Ian L McAllister1, Lynne A Smithies1, Fred K Chen1
1From the Centre for Ophthalmology and Visual Science (I.L.M., L.A.S., F.K.C., D.A.M., P.G.S.), Lions Eye Institute, University of Western Australia, Perth, Australia.
Purpose:
To evaluate what clinical gains can be achieved over conventional treatment with ranibizumab alone for central retinal vein occlusion (CRVO) when causal pathology is additionally addressed successfully with a laser-induced chorio-retinal anastomosis (L-CRA).
Design:
Two-year extension of prospective, randomized controlled clinical trial.
Methods:
A total of 58 patients with macular edema secondary to CRVO were randomized 1:1 to receive either an L-CRA (n = 29) or sham procedure (n = 29) at baseline and then monthly intravitreal ranibizumab 0.5 mg. Outcomes (best corrected visual acuity [BCVA], central subfield thickness [CST], injection requirements) were monitored in the monthly pro re nata (PRN) ranibizumab phase from months 7 to 48.
Results:
Injection requirements for patients with a functioning L-CRA (24 of 29) during the monthly PRN period from 7 to 24 months were a mean (95% CI) of 2.18 (1.57, 2.78) injections compared to 7.07 (6.08, 8.06) (P < .0001) for control (ranibizumab alone). These decreased further over the next 2 years to 0.29 (0.14, 0.61) compared to 2.20 (1.68, 2.88) (P < .001) for the third year and 0.25 (0.11, 0.56) and 1.84 (1.34, 2.54) for the fourth year (P < .001). Mean BCVA was statistically different at all follow-up time points from month 7 through month 48 for the group with the functioning L-CRA compared to the control monotherapy group. This improved to 14.06 letters at month 48 (P = .009). There was no difference in CST between any of the groups over the 48 months of follow-up.
Conclusion:
For CRVO patients, addressing causal pathology in addition to conventional therapy improves BCVA and reduces injection requirements.
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