This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Which of the following drug when given intravitreally can cause macular toxicity? 
Select and explain. 
A. Ceftazidime, B. Gentamicin, C. Vancomycin, D. Dexamethasone
B: Gentamicin
Answer: B: Gentamicin 
Explanation: Gentamicin is implicated with macular or retinal toxicity even at therapeutic and low doses and is the single best answer of choice. Intravitreal injection of gentamicin result in vision loss, with vascular changes including retinal edema, cotton wool spots, intraretinal hemorrhage, aeriolar attenuation and venous beading. Late manifestations includes widespread pigmentary retinopathy, optic atrophy and anterior segment neovascularization. Ref: Retinal Angiography and Optical Coherence Tomography By J. Fernando Arevalo, Pages 207-9.