Abstract: In preferred aspects the invention provides an in-line humidifier, a system using such a humidifier and methods related thereto, a method for infusing a gas into an eye during retinal detachment surgical procedure and a method for treating a retinal tear. The method for infusing gas includes providing an in-line humidifier, humidifying the gas in the in-line humidifier by flowing the gas there through and infusing the humidified gas into the eye. The in-line humidifier includes a housing and a humidifier section disposed within the housing, the humidifier section including a hydroscopic material that releasably retains liquid therein. The housing includes an inlet and outlet connection in fluid communication with the housing interior.