Surface tension is an important property of substances used as intraocular tamponades. The physical properties of currently available intraocular tamponades (gases, silicone oil and Healon) are compared with emphasis on surface tension. The gas/water interface surface tension is the greatest and therefore is the most effective in closing retinal breaks (70 erg/cm2). This is followed by silicone oil/water interface surface tension (50 erg/cm2). Healon is a 1% solution of water and therefore has no surface tension. Practical and theoretical considerations of various tamponades are described. Some properties of an ideal tamponade are suggested.