In cystoid macular edema, basic defect is:
**Core Concept**
Cystoid macular edema (CME) is a condition characterized by the accumulation of fluid in the macula, leading to vision impairment. The basic defect in CME involves the breakdown of the blood-retinal barrier, allowing fluid and proteins to leak into the retina.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of CME, which involves the disruption of the tight junctions between retinal pigment epithelial (RPE) cells. This disruption leads to increased vascular permeability, allowing fluid and proteins to leak into the retina, causing cystoid edema. The breakdown of the blood-retinal barrier is mediated by various factors, including inflammation, oxidative stress, and vascular endothelial growth factor (VEGF) release.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the basic defect in CME.
**Option B:** This option is incorrect because it is not directly related to the pathophysiology of CME.
**Option C:** This option is incorrect because it is a treatment option for CME, not the basic defect.
**Clinical Pearl / High-Yield Fact**
The breakdown of the blood-retinal barrier in CME is often associated with inflammation and oxidative stress, making anti-inflammatory and antioxidant therapies potential treatment options.
**Correct Answer: D.**