What is diabetic macular edema and why is it clinically significant?

• A. Fluid accumulation in the optic nerve head due to increased intracranial pressure; vision loss.
• B. Leakage from retinal vessels causing peripheral vision loss.
• C. Fluid accumulation in the macula due to breakdown of the blood-retinal barrier, leading to central vision loss.
• D. Detachment of the retina causing curtain-like vision loss.

Answer: (C)