Patients who will be scheduled for intravitreal injection of Ranibizumab or Bevacizumab will be recruited in this prospective self-controlled trial. Fundus photography will carried out at baseline immediately before injection and at 3, 7 days and 30 days after the first injection. Using image analysis software, measurements summarized as the central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE).

Null Hypothesis: There is no significant difference between arteriolar/venular diameter before and after injection of intravitreal ranibizumab/bevacizumab in the treated and untreated eye

Inclusion Criteria:

• Patients who wish and need bevacizumab or ranibizumab treatment for underlying disease

Exclusion Criteria:

• History of previous systemic or ocular Anti-VEGF therapy
• History of previous intravitreal injection with any drug
• Intraocular pressure ≥ 22
• Glaucoma
• History or presence of thromboembolic events
• Un-controlled blood pressure
• Blood donation during the previous 3 weeks
• Relevant media opacity of the lens