Descemet membrane endothelial keratoplasty

  Fitting patients with a modified cervical collar that keeps their heads tilted back after Descemet membrane endothelial keratoplasty can help prevent angle closure and formation of peripheral anterior synechiae, Joseph J K Ma MD FRCSC told the 2014 ASCRS annual meeting in Boston. Normally used to treat patients suffering neck injuries, the collar rotates the eye back along with the head, from a level position to one with the inferior portion of the eye slightly elevated. This causes the DMEK bubble to float into the inferior angle, where it pushes the iris away from the cornea. This opens the angle, allowing fluid egress through the pupil and eliminating contact between the iris and cornea that can lead to PAS formation, said Dr Ma, of the University of Toronto. “If you keep the patient in this position for five or ten minutes you can break the angle closure attack and you are left with a normal deep chamber,” Dr Ma said. The device is especially useful when using SF6 gas in eyes with floppy irises or miotic pupils, he added. In a study of 17 patients treated with SF6 and the external device, only one required re-bubbling for a 6 per cent rate. However, this patient was not compliant with the device and head positioning, Dr Ma noted. In two other patients, partial dehiscences were successfully resolved with positioning alone, suggesting the device may also be useful in this application. No peripheral iridotomies were performed and no episodes of PAS or angle closure were reported. Visual outcomes were also comparable to the literature and patients tolerated the device well, finding it especially helpful for keeping their head properly positioned during sleep, Dr Ma added. “It’s something you might consider for your armamentarium. It’s inexpensive and, at least we thought, it is efficacious