According to the Early Treatment Diabetic Retinopathy Study (ETDRS), clinically significant macular edema (CSME) is defined as macular thickening or hard exudates within ____ of the center of the fovea:
- A 500 microns; or retinal thickening ≥1 disc area within 1 disc diameter of center ✓
- B 250 microns; or hard exudates in the inner plexiform layer
- C 1000 microns; or new vessels on disc
- D 750 microns; or subretinal fluid under the fovea
Correct answer: A. 500 microns; or retinal thickening ≥1 disc area within 1 disc diameter of center
Explanation
CSME by ETDRS criteria includes: (1) thickening of the retina within 500 µm of the foveal center; (2) hard exudates within 500 µm of the foveal center if associated with adjacent retinal thickening; or (3) a zone of retinal thickening ≥1 disc area in size, any part of which is within 1 disc diameter of the foveal center. These criteria guide treatment decisions. The other options contain incorrect distances or structures.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.