In diabetic retinopathy, which retinal layer is most commonly associated with fluid accumulation in the macula?

• A. Outer plexiform layer
• B. Inner nuclear layer
• C. Photoreceptor layer
• D. Retinal nerve fiber layer

Answer: (A)

Fluid buildup in diabetic macular edema happens when leaking retinal vessels breach the blood-retinal barrier, causing fluid to accumulate within the retinal layers as cysts. The outer plexiform layer is the most common site for these intraretinal cysts in the macula because this region, especially in the perifoveal Henle’s fiber layer, forms a relatively spacious horizontal plane where fluid can pool and form cystic spaces. That characteristic location shows up repeatedly on imaging as the typical site of edema. While cysts can appear in other layers like the inner nuclear layer, and edema may spread, the outer plexiform layer remains the most frequently involved area in diabetic macular edema.