According to the ETDRS (Early Treatment Diabetic Retinopathy Study) classification, which of the following constitutes 'clinically significant macular oedema' (CSME) requiring laser treatment?
- A Retinal thickening within 1000 μm of the centre of the fovea
- B Hard exudates within 500 μm of the foveal centre with adjacent retinal thickening ✓
- C Any intraretinal cyst on OCT regardless of location
- D Macular thickening of >300 μm on OCT at any location
Correct answer: B. Hard exudates within 500 μm of the foveal centre with adjacent retinal thickening
Explanation
ETDRS CSME criteria include: (1) retinal thickening within 500 μm of foveal centre, (2) hard exudates within 500 μm of foveal centre with associated adjacent retinal thickening, or (3) retinal thickening of 1 disc area in size, any part within 1 disc diameter of foveal centre. Option A uses the wrong distance (1000 μm), and OCT thickness alone was not part of the original ETDRS film-based clinical criteria.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.