Sir,

The frequency of intravitreal injections is increasing after landmark age-related macular degeneration studies,1, 2 and to a lesser extent evidence for the efficacy of intravitreal triamcinolone for diabetic maculopathy.3 Several uncommon complications are described, namely infectious and non-infectious endophthalmitis, iatrogenic lesions to the intraocular structures leading to retinal detachment or cataract and steroid-induced glaucoma.4

Two patients receiving intravitreal ranibizumab (Lucentis) for wet age-related macular degeneration complained immediately after their injection of unusual visual symptoms, ‘like looking through an hour glass,’ particularly when looking down. Ocular examination revealed multiple small intravitreal air bubbles with no entry site breaks or vitreous floaters.

This is an important observation for several reasons. Most importantly, these bubbles produced disturbing symptoms in the patients that they were not expecting. Air within the syringe could also alter the administered dose of the drug. Finally, it is well documented that intravitreal gas presents a risk during air flight.5 The volume involved here is low, but we should be aware that this is a potential complication of intravitreal injections and should take appropriate measures to avoid these symptoms and potential complications by actively checking the syringe and needle before injection to ensure that no air has been drawn up when preparing the drug for injection.