Retinal microvascularization can provide important informations to systemic vascular phenomena. The non-invasive quantitative description of the retinal vascularization is now possible by performing OCT-angiography and their image analysis software (vascular density and retinal perfusion). Systemic microvacular changes during the establishment of oncological treatment by targeted antiangiogenic therapy are little described in the literature. The objective of this pilot study is to describe the evolution of the retinal vascular density of patients with antiangiogenic drugs. In addition, the evolution of the retinal vascular density of patients on antiangiogenic drugs will study as a function of the response to the treatment and the toxicity of these treatments.

The main objective of this study is to describe the change in retinal vascular density of patients with first-line colorectal cancer treated with Bevacizumab.

Inclusion Criteria:

1. Patient over 18 years old starting first-line treatment for metastatic colorectal cancer including BEVACIZUMAB (AVASTIN®)
2. Systemic or intraocular anti-VEGF treatment naïve
3. ECOG ≤ 2

Exclusion Criteria:

1. Pregnant woman,
2. Minor patient or under legal protection
3. Person deprived of liberty or under guardianship
4. Inability to undergo medical monitoring of the trial
5. Impossibility of carrying out the OCT-A
6. Patient with a contraindication to Tropicamide 0.5% eye drops
7. Patient with a history of degenerative macular pathology, vascular macular pathology or presenting an epiretinal membrane with traction phenomenon.
8. Diabetes
9. Patient for whom it is not possible to schedule an ophthalmology consultation before the start of treatment.