Abstract
Purpose:
Due to a relatively high rate of anterior chamber air re-injection in DMEK, a standard non-expansile concentration ophthalmic gas, 20% SF6, is recently being used for a longer tamponade effect. Until now there are no data on early postoperative intraocular pressure (IOP) safety profile of DMEK with intraocular gas. We performed a prospective cohort study of early postoperative IOP changes after DMEK surgery with SF6 anterior chamber injection.
Methods:
We measured postoperative IOP of 10 patients undergoing standard DMEK surgeries with SF6 during 2 weeks-period at the Department of Ophthalmology, University of Cologne, Germany. SF6 gas was filled at the end of the DMEK surgery to reach approximately 80% of the anterior chamber and an IOP of 15 mmHg. Postoperative IOP-changes and retained anterior chamber gas fill during the first day hourly and then early first week were analysed.
Results:
Of 10 patients, 6 underwent pseudophakic DMEK and 4 underwent triple-DMEK. Fuchs endothelial dystrophy was the main indication for surgery. Mean age was 72 years (range 56-87). Mean preoperative visual acuity was 20/80, LogMAR 0.6. Preoperative IOP, mean 14.7 ± 3.9 mmHg, increased to 15.2 ± 1.7 mmHg immediately after gas filled. While the highest IOP was measured at 1, 3, 5, and 10 hours (range 18.0-24.0 mmHg), the first 10 hours-postoperative IOP remained stable (mean range 13.0-16.0 mmHg). The first 3 days-IOPs were slightly lower than the first 24 hours. The size of gas bubble gradually reduced in the first 2 days (day 1, 70%; day 2, 60%), then rapidly reduced to 40% in the third day. Triple-DMEK appeared to have higher IOP than isolated DMEK (20.0 ± 4.8 vs 12.7 ± 4.1 mmHg at 5 hour; 20.3 ± 3.3 vs 12.4 ± 3.6 mmHg at 10 hour, p = 0.04 and 0.03 respectively) and faster gas escape from the chamber (first hour to day 3, 74% to 36% vs 64% to 49%).
Conclusions:
Anterior chamber tamponade using 20% SF6 with a set target pressure in DMEK surgery has a safe and stable IOP profile during the first day and early first week. The gas bubble retains over half of the anterior chamber volume up to day 3. Triple-DMEK seems to have higher postoperative IOP and faster gas exchange than DMEK.