Comparison between different tonometers following intrastromal corneal ring segments implantation.

IOP measurements taken by air puff tonometer were significantly lower than those taken by GAT and ORA-IOPcc. These differences were not constant across the pressure range but increased as the pressure values determined using GAT and ORA increased. ORA-IOPcc and GAT showed similar readings. No correlation was found between any of the IOP readings taken by the three tonometers and the central corneal thickness.