Mechanism and Emergency Management of Blast Eye/Orbital Injuries

Sabri T Shuker

Disclosures

Expert Rev Ophthalmol. 2008;3(2):229-246. 

In This Article

Protection

Cotter and La Piana (1991), studying data from the Vietnam War using theoretical analysis found that, had the standard current US Army 2-mm thick defense goggle been worn, 52% of eye injuries would have been prevented.[60] Projecting this figure to the Vietnam War overall, 5000 eye injuries from USA and allied forces would have been prevented.[61,62] That may also apply to the recent civilian and military eye injuries suffered from blast wave effect in most undeveloped countries. Improvements in ophthalmic care in the last 30 years offer hope that blindness in combat casualties will be less common in future wars.

Eyes comprise as little as 0.27% of the total body surface area and only 0.1% of the erect frontal profile. However, injuries to the eye are found in 10–13% of all combat casualties and, more recently, among civilians having unexpected IED injury, which has recently increased dramatically.[33]

Wearing a helmet with a visor designed to break the stress of the wave pressure will provide protection against blast-induced injuries, especially the upper-middle-third of facial skeleton. This protects the ocular–orbital region as well as the traumatic brain injury through cribriform plates. Ocular and orbital medium, safeguards against the peppers of fragments of secondary blast effects and attenuates the primary blast stress force.

On the whole, blast-wave contusions and blast fragmentation account for 68–78% of warfare ocular trauma.[112] Eye injuries caused US forces and Iraqi forces to civilians have become an increasing concern because of the blast. Eye injuries comprised 16% of injuries in 243 victims in the 2004 Madrid bombings.[102] The peppering of missiles in a blast wave-front offer no time for the blink reflex for minor protection by the lids. The blink reflex of the eye takes approximately 0.1 s.[113] This is too slow to afford protection from the main causative factor of ocular injuries of blast flying trajectory and debris, as well as overpressurized effect upon the individual eye. If eye lids have some protective effects, no doubt that visor will have a better eye protection. All these depend on size, type, shape and position of the explosion from the victim's eyes and so on.

Overpressurized wave eye/orbital protection depends on correlation of the mechanism of the stress pressure force, which is enough to rupture the eyeball or it is simulating eye physical properties. If the simulating eye physical properties need stress pressure (9.4 MPa) and dynamic properties of 23 MPa to rupture the eye globe.[105] If any one exposed to high stress force that used experimentally to rupture simulating eyeball from explosion, will lead to severe soft and hard tissue pulverization for the surrounding eye anatomical tissue in which practically no victim will survive this amount of stress force.

Wang et al. (2003) found experimentally that the values of the overpressure caused the facial bones fracture and the laceration of the soft tissues together with tissue defects and displacement, were as great as 5595.41 Mpa at the distance of 0.5 cm,[63] which was in agreement with Shuker's clinical finding in 1995.[29] The simulating eye needs stress pressure nearly double the megapascals than that used by Wang et al. to rupture the eye globe, this amount of stress pressure will cause devastation to the orbital region.

The authors understanding for ruptured eyes due to explosives are due to a grouping of the dynamic pressure of front wave force of the blast nearly half of the above megapascal stress pressure used in experimentally and the kinetic energy of small fragments and dirt flying particles that cause contusion, laceration and penetration weaken the eye globe which ruptured.

Using the visor could save many eyes from blast injuries, the author advises not only those in uniforms but civilians in unstable regions to have proper eye glasses required.

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