Measuring IOP in Penetrating Eye Injury
Intraocular pressure (IOP) measurement is absolutely contraindicated in cases of penetrating eye injury as it can cause extrusion of intraocular contents and worsen the injury. 1
Rationale for Contraindication
- Any technique that applies pressure to the globe in penetrating eye injuries risks expulsion of intraocular contents through the wound, potentially causing irreversible vision loss and increasing risk of endophthalmitis 1
- Both contact and non-contact tonometry methods apply force to the eye that can disturb an open globe wound 1
- In penetrating injuries, the structural integrity of the eye is already compromised, making any additional pressure potentially dangerous 2
Alternative Assessment Methods
When IOP assessment is clinically necessary in patients with suspected penetrating eye injury:
- Visual inspection for signs of hypotony or hypertony should be performed instead of direct measurement 1
- Careful slit-lamp examination to assess anterior chamber depth as an indirect indicator of pressure status 1
- Examination for conjunctival hyperemia, corneal edema, and other signs that might indirectly suggest pressure abnormalities 1
- Digital palpation through closed eyelids should also be avoided as it can still exert significant pressure on the globe 3
Management Considerations
- Prioritize immediate protection of the eye with a rigid shield (without pressure on the globe) 2
- Avoid any manipulation that could increase IOP, including Valsalva maneuvers 2
- IOP measurement should be deferred until after surgical repair of the penetrating injury 1
- Post-repair, consider alternative tonometry methods if corneal irregularity exists:
- Pneumotonometer with its silicone tip that conforms to irregular corneal surfaces 1
- Non-Goldmann applanation tonometer with microstrain gauge transducer 1
- Ocular response analyzer that uses air pulse technology without direct contact 1
- Dynamic contour tonometer that minimizes influence of corneal properties 1
Risk of Delayed IOP Monitoring
- Up to 23.3% of patients with open globe injuries develop traumatic IOP elevation 2
- 6.2% may develop traumatic glaucoma requiring long-term management 2
- The mean time to development of traumatic IOP elevation is approximately 1.5 months post-injury 2
- Regular monitoring should begin after wound closure and stability is confirmed 2
Special Considerations
- In cases where IOP assessment is absolutely necessary for clinical decision-making prior to repair, consider examination under anesthesia with surgical team ready for immediate intervention 1
- Patients with penetrating injuries should be monitored for at least 6 months post-repair for development of traumatic IOP elevation 2
- Patients with risk factors such as vitreous hemorrhage and Zone II injuries require particularly close monitoring for traumatic glaucoma 2