During focal laser photocoagulation for clinically significant macular edema with discrete leaking microaneurysms away from the center, which set of burn parameters matches standard ETDRS technique?
- A Spot size 200 to 300 microns, duration 0.2 seconds, placed 500 microns from the foveal center
- B Spot size 50 to 100 microns, duration 0.1 seconds, avoiding treatment within 500 microns of the foveal center ✓
- C Spot size 500 microns, duration 0.5 seconds, applied directly to the foveal center
- D Spot size 1000 microns, duration 0.1 seconds, arranged in a full macular grid
Correct answer: B. Spot size 50 to 100 microns, duration 0.1 seconds, avoiding treatment within 500 microns of the foveal center
Explanation
ETDRS focal treatment uses small burns of 50 to 100 microns at 0.1 second duration, applied to leaking microaneurysms and areas of diffuse leakage, with a treatment-free zone of 500 microns around the center of the fovea. Larger spots of 200 to 500 microns belong to panretinal photocoagulation, not macular treatment. Direct foveal application is never done, and a full confluent grid is obsolete because it causes paracentral scotomas.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.