A 30-year-old man presents 8 hours after an alkali chemical splash to the right eye. After immediate irrigation at the scene, pH is now 7.2. The cornea shows 2+ stromal oedema with visible iris details, and limbal ischaemia involves 180 degrees of the limbal circumference. According to the Dua classification, what grade is this injury?
- A Grade I
- B Grade III ✓
- C Grade V
- D Grade VI
Correct answer: B. Grade III
Explanation
The Dua classification grades chemical injuries from I to VI based on clock hours of limbal involvement and corneal clarity. Grade III corresponds to 3 to 6 clock hours (90 to 180 degrees) of limbal involvement with oedema causing obscuration of iris details, or up to 180 degrees with good corneal clarity. Grade IV is more than 6 clock hours with total corneal involvement.
Reference: AAO BCSC Section 8: External Disease and Cornea, 2023-2024 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.