Airbag Eye Injury varying from minor abrasions to traumatic hyphaema and secondary glaucoma may result from automobile airbags. Airbags reduce the risk of injury and death from motor vehicle accident, however, injuries attributed to airbag use have been reported. There may be damage to virtually every structure of the eye and adnexa. Most injuries are self- limited and do not significantly affect vision, some result in severe visual loss. Damage to anterior structures of eye is commoner than injury to posterior segment. Posterior segment trauma is generally more visually devastating because of the involvement of optic nerve or retina.
A closer look of the type of eye injuries showed a statistically significant increased risk of corneal abrasion for occupants exposed to airbag deployment. However, occupants from car accidents without airbag deployment sustained a greater number of severe eye injuries. Characteristics of car occupants and crashes, such as seat belt, contact lens, eyeglasses, crash velocity, age and height, are not significantly correlated with the risk of airbag- induced injury.
Rising proportion of airbag- equipped cars as well as the increasing number of people electing for corrective vision surgery are the trends that may increase risk and severity of airbag- induced eye injury.
Awareness of airbag associated eye injuries help in recognising these problems early and help in their management.
Symptoms of automobile airbag trauma varies from the structure of eye and adnexa affected. Eye injuries may lead to
- Minor abrasions
- Chemical keratitis
- Blurring of vision
- Traumatic hyphaema
- Lens opacity
- Secondary glaucoma
- Vitreous haemorrhage
- Retinal haemorrhage
- Commotio retinae
- Choroidal rupture
- Traumatic optic neuropathy
- Fracture of orbit
A motor vehicle crash may produce four collisions
- First : Between vehicle and other object
- Second : Between unrestrained occupant and the interior of vehicle
- Third : Between organs of occupant and the enclosing body wall or cavity e.g. chest wall or skull.
- Fourth : Between the occupant and loose objects in the vehicle.
Deceleration forces are dependent on the deforming ability of vehicle. Newer vehicles are designed to deform extensively on impact to reduce forces applied on the occupant.
A deflated balloon stored in the steering wheel is rapidly inflated under high pressure to protect the occupant from steering wheel impact. Other airbags provide protection against striking the dashboard or side panels.
Airbag inflation occurs via a deceleration sensor. Once inflated, vents in the bag permit immediate deflation. Furthermore, timing of the airbag must be adjusted so that it is inflated to its maximum as the occupant impacts on it.
There is evidence that airbags provide excellent protection against serious injury. However, there is increasing data on injuries directly attributable to airbags.
The mechanism of eye injury, in addition to blunt impact from the airbag, includes chemical keratitis from the alkaline products of it.
Diagnosis depends upon the history of motor vehicle accident and clinical findings attributable to the eye injury sustained due to airbag.
Motor vehicle crashes are a leading cause of morbidity and mortality. Airbags drastically reduce both morbidity and mortality from accidents. But with increased use of airbags, there has been a corresponding increase in the number of injuries attributable to it.
There may be damage to virtually every structure of the eye and adnexa. Most injuries do not significantly affect vision.
Alkaline by-products of combustion in airbag expansion may produce chemical keratitis and inflammation of eyes.
Management depends upon the type and severity of injury caused by airbag.
Most eye injuries are self- limited and do not significantly affect vision, some result in severe visual loss. Damage to anterior structures of eye is commoner than posterior segment. Posterior segment trauma is generally more visually devastating because of the involvement of optic nerve or retina.
Patient presenting with ocular inflammation after airbag deployment should have their eyes irrigated with normal saline to remove any alkaline particulate foreign body.
Due to increased risk and severity of airbag induced eye injuries, innovation of airbag and eyewear protection design is needed. One such innovation is the possibility of airbags that would inflate at different speeds depending upon the severity of collision, and the physical characteristics of the occupants.