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Abstract #45908 Published in IGR 13-2
Comparison of iCare tonometer and Goldmann applanation tonometry in normal corneas and in eyes with automated lamellar and penetrating keratoplasty
Salvetat ML; Zeppieri M; Miani F; Tosoni C; Parisi L; Brusini PEye 2011; 25: 642-650
PurposeTo compare intraocular pressure (IOP) measurements with Goldmann applanation tonometry (GAT) and iCare tonometry in normal and post-keratoplasty corneas and to assess the influence of central corneal thickness (CCT), corneal curvature (CC), and corneal astigmatism (CA) on IOP.MethodsThis prospective cross-sectional study included one eye of 101 subjects with normal corneas (58 healthy subjects, 43 glaucoma); and 90 post-keratoplasty patients: 34 penetrating keratoplasties (PK); 20 automated-lamellar-therapeutic keratoplasties (ALTK); 19 Descemet-stripping-automated-endothelial keratoplasties (DSAEK); 17 edematous grafts. All subjects underwent GAT and iCare IOP measurements in random order, and CCT, CC, and CA evaluation. The Bland-Altman method and multivariate regression analysis were used to assess inter-tonometer agreement and the influence of CCT, CC, and CA on IOP.ResultsiCare significantly underestimated IOP in all groups compared with GAT (GAT minus iCare of 3.5(plus or minus)3.5 mm Hg, P<0.001), but overestimated IOP in the edematous grafts (GAT minus iCare of 6.5(plus or minus)1.9 mm Hg, P<0.001). In normal corneas, both tonometer measurements were directly related to CCT values; iCare readings appeared inversely related to CC. There was no significant relationship between IOP and CCT, CC and CA in post-keratoplasty eyes, except between CC and iCare measurements for PK eyes.ConclusionsThe agreement between GAT and iCare was clinically acceptable in control, ALTK and DSAEK groups, and poor in PK and edematous grafts eyes. In normal corneas, GAT was significantly affected by CCT; iCare was influenced by CCT and CC. The iCare appeared less influenced by corneal edema when compared with GAT. High IOP readings taken with both tonometers in grafts should raise suspicion of true elevated IOP.
P. Brusini. Department of Ophthalmology, Azienda Ospedaliero, Universitaria Santa Maria della Misericordia, S.O.C. Oculistica, p.le S. Maria della Misericordia 15, Udine 33100, Italy. Email: brusini@libero.it
Classification:
6.1.1 Devices, techniques (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
8.4 Refractive surgical procedures (Part of: 8 Refractive errors in relation to glaucoma)