A patient presents after a metallic object penetrated the eye, with a teardrop-shaped pupil and a cloudy anterior chamber. Which diagnosis is most likely: open globe injury, corneal abrasion, or iritis?

Open Globe Injury

This patient has an open globe injury. A teardrop-shaped pupil combined with a cloudy anterior chamber after metallic object penetration are pathognomonic signs of full-thickness eyewall disruption requiring immediate ophthalmologic surgical intervention. 1

Diagnostic Reasoning

The teardrop pupil is the key diagnostic finding. This irregular pupillary shape occurs when iris tissue herniates through a full-thickness corneal or scleral defect, creating the characteristic peaked appearance toward the site of penetration. 1, 2 The cloudy anterior chamber indicates either:

• Aqueous humor leakage through the defect
• Inflammatory cells and protein from traumatic iritis
• Possible lens capsule rupture with lens material in the anterior chamber 1

Metallic foreign bodies create high-risk penetrating injuries. Sharp metallic objects commonly cause scleral lacerations that constitute full-thickness eyewall defects, the defining feature of open globe injury. 1 Scleral involvement is the most common site for open-globe injuries from sharp penetrating objects. 1

Why Not the Other Diagnoses

Corneal abrasion is definitively excluded because:

• Abrasions are superficial epithelial defects that do not cause pupillary deformity 1
• The teardrop pupil indicates full-thickness penetration, not surface injury 2
• Corneal abrasions do not produce cloudy anterior chambers from aqueous leakage 1

Isolated iritis is ruled out because:

• While iritis can cause anterior chamber cloudiness from inflammatory cells, it does not deform the pupil into a teardrop shape 1
• The mechanism (metallic penetration) and teardrop pupil indicate structural disruption, not pure inflammation 2
• Iritis may coexist with open globe injury but does not explain the complete clinical picture 1

Immediate Management Algorithm

Step 1: Protect the eye immediately

• Place a rigid eye shield over the affected eye without applying any pressure to prevent extrusion of intraocular contents 1, 3
• Do NOT manipulate the globe, perform forced duction testing, or apply pressure during examination 1, 4
• Do NOT use point-of-care ocular ultrasound, as probe pressure may cause content extrusion 1, 3

Step 2: Obtain urgent ophthalmology consultation

• Request immediate surgical exploration and primary closure 1, 5
• Do not delay consultation for imaging when the clinical diagnosis is clear 1, 4

Step 3: Imaging if patient is stable

• Order non-contrast orbital CT with thin slices and multiplanar reconstructions to detect intraocular foreign bodies 1, 2, 6
• CT demonstrates 94.9% sensitivity for detecting metallic foreign bodies 1, 6
• MRI is absolutely contraindicated when metallic intraorbital foreign body is possible due to risk of ferromagnetic movement 1, 2, 4

Step 4: Supportive measures

• Update tetanus vaccination status 3
• Administer broad-spectrum systemic antibiotics to prevent endophthalmitis 3, 5
• Prevent Valsalva maneuvers (no straining, coughing, vomiting) that could extrude ocular contents 3

Prognostic Factors

Poor visual outcomes are associated with:

• Lacerations ≥5 mm in length 1, 4
• Lens injury or dislocation 1, 4
• Vitreous hemorrhage 1, 4
• Associated extraocular injuries 1
• Severe ocular pain reflecting extensive intraocular damage 1

Critical Pitfalls to Avoid

• Never apply pressure to the globe during examination or shield placement, as this extrudes intraocular contents 1, 4
• Never perform forced duction testing when open globe is suspected 1, 4
• Never delay ophthalmology consultation for imaging when clinical diagnosis is obvious 1, 4
• Never order MRI before excluding metallic foreign body 1, 2, 4
• Recognize that CT sensitivity of 51-77% means clinical examination and surgical exploration remain definitive 7