Absorption kinetics of intraocular 16% perfluoropropane gas mixtures in macular hole surgery

Purpose. To determine the absorption of intraocular 16% perfluoropropane (C3Fg) gas mixtures in 102 eyes with macular hole surgery. Methods. Retrospective review of eyes treated with pars plana vitrectomy and instillation of 16% C3Fg into the vitreous between 1992 and 1996 for treatment of a macular hole. All eyes had removal of accumulated intravitreal fluid 15 minutes after the initial fluid-gas exchange to maximize the volume of the intraocular gas bubble. The volume of the intraocular gas bubble was calculated from the meniscus height of the bubble in the eye. There were a total of 102 eyes (82 phakic, 19 pseudophakic, 1 aphakic) with a minimum of three postoperative measurements (1-2 days postop, 2 weeks postop, 6 weeks postop) included in the analysis. Results. The surgical technique resulted in a mean bubble size of 90% ±5% (3.9 ±0.4 ml, mean ±SD) on the first or second postop day, 60% ±11% (2.6 ±0.7 ml) at 14.7 days and 11 % ±8% (0.21 ±0.27 ml) at 42.3 days. The mean half life of 16% C3F8 calculated from multiple regression analysis of the first order exponential absorption of the gas bubble volume was 7.24 days in all eyes (R2=0.845), 7.05 days in phakic eyes (R2=0.848) and 8.18 days in pseudophakic/aphakic eyes (R2=0.832). The shorter half life of 16% C3F8 in phakic vs. pseudophakic/aphakic eyes was marginally significant (p=0.056). Conclusions. Eyes showed relatively uniform absorption of a 16% C3F8 intraocular gas bubble. The use of this surgical technique and 16% C3Fg result in a large, long-lasting intraocular gas bubble which may be helpful in treating macular holes.