Can prone positioning cause eyeball injury?

Yes, prone positioning can cause eyeball injury, and this risk is well-documented and preventable with proper precautions.

Prone positioning carries a significant risk of ocular injury through two primary mechanisms: direct mechanical compression of the eyeball leading to central retinal artery occlusion (CRAO), and increased intraocular pressure (IOP) that can result in ischemic optic neuropathy (ION). 1

Types of Eyeball Injuries from Prone Positioning

Direct Compression Injuries (CRAO)

• Central retinal artery occlusion occurs from direct pressure on the eyeball and is typically unilateral 1
• 70% of CRAO cases show external signs of trauma to the eyeball 1
• These injuries usually follow head mobilization during procedures or incorrect initial positioning 1
• Case reports document CRAO from headrests, sheet rolls, horseshoe devices, and other positioning equipment 2

Increased Intraocular Pressure

• IOP increases sharply above normal range (<20 mmHg) within 1 hour of prone positioning and continues rising throughout the procedure 3
• IOP remains elevated even 30 minutes after returning to supine position 4
• The prone position combined with Trendelenburg positioning further increases IOP 1

Other Ocular Complications

• Chemosis and exposure keratopathy are the most frequent ocular surface manifestations 5
• Conjunctival abnormalities and corneal injuries can occur 5
• Rare but devastating complications include globe rupture 6

Prevention Algorithm

1. Use Appropriate Head Positioning Devices

Mayfield head clamps or direct bone-point application headrests are strongly recommended as they prevent direct eyeball contact 1. Notably, no CRAO cases occurred when Mayfield clamps were used 1. Avoid horseshoe headrests as they can shift and cause compression 1.

2. Position the Head Correctly

• Keep head level with or higher than the body 2
• Maintain neutral forward position without neck flexion, extension, lateral flexion, or rotation 2
• Use a 10% forward tilt rather than Trendelenburg to reduce IOP 1

3. Perform Repeated Eye Checks

Periodically verify absence of direct eyeball compression throughout the procedure 1. This is critical because compression often occurs from head movement during surgery rather than initial positioning 1.

4. Implement Eye Protection Protocols

• Use aqueous gels or humidity chambers for sedated/intubated patients 1
• Consider fluorescein testing to screen for corneal injuries in at-risk patients 1
• Establish training programs and prevention protocols in your facility 1

High-Risk Situations Requiring Extra Vigilance

• Prolonged procedures (>4 hours) 2
• Spinal surgery with substantial blood loss (>800 mL) 2
• Patients with obesity, male sex, or vascular risk factors 1
• Use of Wilson frames (associated with higher ION risk) 2
• Procedures with significant hypotension, anemia, or hypovolemia 1

Critical Pitfalls to Avoid

1. Never assume initial positioning remains correct throughout surgery - head movement is the most common cause of compression 1
2. Do not rely solely on initial eye checks - repeated assessment is essential 1
3. Avoid excessive Trendelenburg positioning in prone patients as this compounds IOP elevation 1
4. Do not use horseshoe headrests without vigilant monitoring as they frequently shift 1

Evidence Quality Note

The 2019 ASA Practice Advisory 2 and 2017 French guidelines 1 provide the strongest recommendations. Recent research confirms IOP increases occur universally in prone positioning 3, 4, though the overall incidence of serious visual complications remains relatively low when proper precautions are taken 7. However, when injuries do occur, they can be devastating and irreversible 6, making prevention paramount.