Retinal Ischemia in Central Retinal Vein Occlusion, and the Effects of Treatment With Intravitreal Ranibizumab

Recent studies have shown a remarkably positive effect of 6 monthly injections of Ranibizumab on eyes with CRVO. The disease may cause severe sight threatening complications, partly due to restrictions in blood flow and oxygenation . Although Ranibizumab has been shown affective to reduce oedema of the retina, it is not known whether the drug ameliorates or aggravates restrictions in oxygenation.

The Oxymap oximeter allows a non-invasive measurement of the oxygen saturation in retinal vessels and thus the state of retinal oxygenation.

The primary objective of the study is to evaluate the effects of injections of Ranibizumab on the retinal oxygen saturation in eyes with newly diagnosed central retinal vein occlusion (CRVO),

The secondary objective is to evaluate the effects of injections of Ranibizumab on visual acuity and retinal oedema in eyes with different degree of ischemia.

Background and objectives

The CRUISE study has shown a remarkable positive effect of 6 monthly injections intravitreal Ranibizumab on visual function in eyes with macular edema secondary to CRVO. Eyes with CRVO are at risk of severe complications to retinal ischemia, particularly proliferative retinopathy and neovascular glaucoma. It is not known whether intravitreal anti-VEGF therapy ameliorates or aggravates retinal ischemia and thus the risk of ischemic complications is unknown. Since complications to retinal ischemia take time to develop, and are relatively infrequent, the CRUISE study was not designed, or powered, to investigate the impact of intravitreal anti-VEGF treatment on these complications.

The Oxymap oximeter allows objective non-invasive measurement of the oxygen saturation in retinal vessels and thus the degree of retinal ischemia. The rationale behind the present study is to use this instrument in order to obtain preliminary information on the effects of intravitreal anti-VEGF treatment on retinal ischemia in CRVO eyes without having to wait for ischemic complications to arise in a large study population.

The primary objective of the study is to evaluate the effects of treatment with intravitreal Ranibizumab on the retinal oxygen saturation in eyes with newly diagnosed central retinal vein occlusion (CRVO),

The secondary objective is to evaluate the effects of intravitreal Ranibizumab on visual acuity and central retinal thickness in eyes with different degree of ischemia.

Study design

The research project is a case-series study of CRVO-patients with three monthly injections of Ranibizumab and a 3 month follow-up period, during which Ranibizumab injections are provided as needed.

Eligibility Criteria:
Inclusion Criteria:

1. Central retinal vein occlusion in one eye.
2. Planned treatment with intravitreal injections of Lucentis (ranibizumab)
3. Functional fellow eye.

Exclusion Criteria:

1. Current or previous medical condition that in the opinion of the investigator may confound assessment of study results or put where the study methods may put the patient at risk.
2. Patients who are unable to receive treatment with vascular endothelial growth factor inhibitors.
3. Prior panretinal photocoagulation in the study eye.
4. Prior intraocular surgery in the study eye, other than cataract operation.
5. Any intravitreal injection 6 months prior to study baseline
6. Participation in another clinical study that, in the opinion of the investigator, may confound the assessment of study results.