In the original Dresden protocol for corneal collagen cross-linking, the correct combination of UV-A irradiance, exposure time and total delivered energy is:

• A 9 mW/cm² for 10 minutes, total 5.4 J/cm²
• B 5 mW/cm² for 20 minutes, total 6.0 J/cm²
• C 3 mW/cm² for 30 minutes, total 5.4 J/cm² ✓
• D 10 mW/cm² for 15 minutes, total 9.0 J/cm²

Explanation

The standard (epi-on, Dresden) protocol delivers 5.4 J/cm² using UV-A at 3 mW/cm² for 30 minutes after riboflavin soaking of a de-epithelialised cornea. Accelerated protocols shorten time by raising irradiance (for example 9 mW/cm² for 10 minutes) on the assumption of equal total energy, but the benchmark against which they are compared remains the 3 mW/cm², 30 minute regimen. Option A describes an accelerated variant, not the original protocol.

Reference: Krachmer, Cornea: Fundamentals, Diagnosis and Management, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.