Neffendorf JE, Guillemaut JY, Hutter JC, et al. - In the present study, the researchers sought to determine how the gas concentration in air needed to achieve full postoperative vitreous cavity fill varies in different aqueous outflow states. In order to estimate gas dynamics, a mathematical model was used. In an eye with normal aqueous outflow, ocular hypertension (OHT), and OHT with apraclonidine treatment,  the change in gas bubble volume over time was measured. The concentration needed was higher for all gases to achieve a full postoperative fill in OHT eyes compared with normal eyes. This is the first study demonstrating aqueous outflow affects bubble size and indicates eyes with reduced outflow are at risk of underfill. Ultimately, this can impact surgical success.