Central visual loss following a motor vehicle accident: traumatic airbag maculopathy

Our literature review on the PubMed database using the keywords airbag, trauma, macular and maculopathy yielded 12 similar cases, but none from Australia. We therefore believe this to be the first report of an Australian case of central visual loss from traumatic airbag maculopathy (TAM) without apparent external injuries. Despite saving lives, airbags have been associated with a range of ocular trauma specific to their deployment, including corneal injuries, hyphaema, intraocular haemorrhages, retinal tears and detachments.1 Other modifiable risk factors that affect the severity of the eye injuries include unfastened seatbelt, wearing spectacles and close proximity to the steering wheel.1 Newer airbags have reduced inflation force, which decreases overt manifestations of direct blunt ocular trauma; however, as our report shows, they may cause a separate pattern of occult ocular injury.

The postulated cause of the specific injury of TAM relates to the acceleration–deceleration forces resulting in retinal dehiscence.2,3 The forces involved may cause blunt trauma to the ocular tissue, due to the airbag inflating in one direction and the head moving in the opposite direction at high velocity. The traumatic mechanism causes a disruption of the connecting cilia of cones and rods in the outer segment.4

One reported case of TAM described immediate unilateral blurred central vision with no other ocular injuries, and an SD-OCT scan demonstrated foveal detachment.5 Another report described two cases of post-traumatic unilateral maculopathy with serous retinopathy on SD-OCT imaging.2,5 All three cases showed resolution of foveal subretinal fluid over 4 weeks, consistent with the pattern of resolution seen in this case; however, full retinal architecture was restored within 12 weeks. Despite substantial visual improvement and return to a normal anatomical appearance, patients can report ongoing paracentral scotomas, which are detectable only on electrophysiology testing and suggest a persisting disruption to retinal function.5 The time frame for the resolution of the subretinal fluid is important as it may coincide with the resolution of ocular injuries, such as hyphaemas or vitreous haemorrhages, which may obscure the diagnosis of the macular pathology. Therefore, clinicians need to consider TAM in patients with persisting scotomas and obtain an electrophysiology study in the context of normal clinical and SD-OCT scan findings.

In summary, significant sight-threatening ocular injuries related to airbags can occur despite the lack of apparent external trauma to the eye. The visual symptoms and visual acuity should be specifically assessed in these patients. A prompt referral to an ophthalmology service is paramount to allow detailed ocular assessment and detection of subtle maculopathy that may have long term visual consequences.