This prospective case series provides data on a previously uninvestigated area. Eyes due to have routine phakoemulsification were divided into six groups according to ophthalmic viscosurgical device (OVD) type. After cataract extraction aphasic refraction using intraoperative aberrometry with the ocular response analyser (ORA) was conducted with anterior chamber filled with balanced salt solution (BSS) with watertight wounds and anterior chamber IOP at 20mmHg measured with application tonometry. Immediately after the BSS was replaced with an OVD aberrometry was repeated. The IOL power was selected from the BSS reading and manifest refraction performed three weeks after surgery. The mean absolute error was determined and compared with the extrapolated error if the aberrometry reading had been under OVD. There were 20 in each group; a total of 120 eyes. The IOL power was lower with OVD filling the anterior chamber. For Discovisc and Amvisc Plus (similar concentrations of hyaluronate) the IOL power was approximately 0.5D less than BSS fill. For Amvisc, Healon, Healon GV and Provisc the differences compared to BSS were insignificant. In conclusion surgeons should be aware that OVD affects aberrometry readings and suggested IOL power.