IOP, air tamponade duration affect re-bubbling rate in DMEK
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Bubble-induced IOP and duration of air tamponade significantly affect graft attachment and re-bubbling rate in Descemet’s membrane endothelial keratoplasty, according to a study.
In a prospective series of 117 patients undergoing DMEK, IOP was measured immediately after filling the anterior chamber with an air bubble and categorized as low (less 10 mm Hg), normal (10 mm Hg to 20 mm Hg) and high (greater than 20 mm Hg). Duration of air tamponade was measured between the end of surgery and partial removal of the air, and categorized as less or more than 2 hours. Re-bubbling rate and endothelial cell loss were recorded over a 3-month follow-up period.
Re-bubbling was required in 32 patients (27%), at an average time of 11 days after DMEK. The re-bubbling rate was significantly higher in both the low and high pressure groups as compared with the normal pressure group, and it was higher in the group in which the air tamponade had remained in the eye for less than 2 hours.
Nine patients (7%) required more than one re-bubbling. All were in the low or high IOP groups, with a higher percentage in the group with the shorter air tamponade duration.
Overall, patients with air tamponade-induced IOP above or below normal level had a 10-fold increased risk of requiring re-bubbling. Air tamponade duration of more than 2 hours reduced the risk to almost one-fourth as compared with duration of less than 2 hours.
“An air tamponade with physiological eye pressure and duration of at least 2 hours could help to increase graft attachment and might reduce re-bubbling rates,” the authors said. However, they noted that endothelial cell loss at 1 month and 3 months after surgery was higher in the group with longer duration tamponade, “suggesting that prolonged exposure to air causes stress to the endothelium.” – by Michela Cimberle
Disclosures: The authors report no relevant financial disclosures.