According to the Ocular Trauma Classification Group system for open-globe injuries, an injury whose posterior extent lies more than 5 mm behind the limbus in the sclera falls into which zone, and what prognostic significance does it carry?

• A Zone I, best prognosis
• B Zone III, worst prognosis ✓
• C Zone II, intermediate prognosis
• D Zone IV, reserved for perforating injuries only

Explanation

The classification defines Zone I as corneal and limbal involvement, Zone II as involvement extending 5 mm posterior to the limbus, and Zone III as any injury posterior to that point. Posterior wounds involve the retina and uvea, carry higher rates of retinal detachment, proliferative vitreoretinopathy, and endophthalmitis, and therefore have the worst prognosis. There are only three zones, so Zone IV does not exist in this system.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

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Written and medically reviewed by the StethoPrep medical team.