Ranibizumab Treatment for Macular Edema Secondary to Retinal Vein Occlusion

Retinal vein occlusion (RVO) may lead to series of complications including retinal ischemia, macular edema (ME) and induce vision impairment. Intravitreal injection of Ranibizumab (0.5mg) has been proved to be a safe and effective method for the treatment of RVO-ME. In this study, different treatment regimens of Ranibizumab is applied and the effects is observed at 1-6 months to explore the best regimen for RVO. After 6 months, anti-VEGF therapy and/or laser photocoagulation is used to explore whether laser photocoagulation can maintain the therapeutic effect of Ranibizumab or reduce the injection number.

Retinal vein occlusion (RVO) may lead to series of complications including retinal ischemia, macular edema (ME) and so on. Retinal vein occlusion (RVO) can be classified as branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). Retinal vein occlusion with macular edema (RVO-ME) is the main cause of RVO induced vision impairment. Intravitreal injection of Ranibizumab (0.5mg) has been proved to be a safe and effective method for the treatment of RVO-ME. Although multiple injections of anti-vascular endothelial growth factor (anti-VEGF) drugs are beneficial to the therapeutic results of RVO-ME, they may also increase the risk of systemic or ocular complications and at the same time increase the economic burden of patients to a certain extent. Different studies have shown that anti-VEGF therapy with low frequency injection (2-5 doses) is also effective for RVO-related ME. However, there are still different views on which option is better. Meanwhile, the effect of laser photocoagulation in the non-perfusion area of the retina, and whether the number of subsequent anti-VEGF injections can be reduced accordingly, is still uncertain. Therefore, in this study, different treatment regimens will be applied and the effects will be observed at 1-6 months. After 6 months, anti-VEGF therapy and/or laser photocoagulation will be used to explore whether laser photocoagulation can maintain the therapeutic effect or reduce the injection number of Ranibizumab. This study intends to explore the therapeutic effects of different treatment regimens on RVO-ME, and meanwhile to investigate the dynamic changes in retinal morphology, microcirculation and visual function during RVO treatment by means of angiography-optical coherence tomography (angio-OCT), microperimetry, electroretinogram (ERG) examination and other methods.

Eligibility Criteria:
Inclusion Criteria:

1. Patients with RVO-ME diagnosed definitely by FFA and OCT, with CMT \> 300μm; BCVA from 20/200 to 20/40 (including 20/200 and 20/40), with a degree of myopia ≤-6 diopter (diopter, D);
2. Patients with a course of RVO ≤ 12 weeks; Patients who have not received laser, intraocular or systemic anti-VEGF treatments or long-acting hormone intraocular, periocular or systemic treatments since the onset of RVO;
3. Patients who are voluntary to sign and date the informed consent form approved by the Ethics Review Committee prior to the conduct of the relevant study steps.

Exclusion Criteria:

1. Patients with a course of disease \> 12 weeks;
2. Patients treated with any anti-angiogenic medicines for either eye within 3 months before the baseline; or patients currently in treatment with systemic anti-angiogenic drugs;
3. Patients with their study eyes treated with panretinal photocoagulation (PRP) previously;
4. Patients previously participating in other clinical trials 3 months before the baseline;
5. Patients with severely opacity of refractive media affecting laser treatment and observation;
6. Patients with other ophthalmic diseases affecting visual prognosis, such as corneal disease, glaucoma, severe cataract, uveitis, other fundus diseases, etc.
7. Patients with in any condition where intravitreal injection is unacceptable;
8. Patients identified by the investigator to be medically or mentally unstable: complicated with cardiovascular, cerebrovascular, liver, kidney and hematopoietic system and other serious primary diseases or mental disease; Women who are pregnant or preparing for pregnancy or in lactation, etc.
9. Patients with any history may interfere with the results of the trial or increase the risk of the patient (assessed by the investigator) ;
10. Patients who are in poor compliance and unable to strictly implement the protocol (assessed by the investigator).