Comparison of Dynamic Contour Tonometry and Goldmann Applanation Tonometry in Deep Lamellar and Penetrating Keratoplasties

Ceruti, Piero; Morbio, Roberta; Marraffa, M.; Marchini, Giorgio

doi:10.1016/j.ajo.2007.10.003

Cited by 33 publications

(29 citation statements)

References 32 publications

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“…2,35,37 The method used to measure IOP with GAT in eyes with high astigmatism (the mean of two readings taken at the flattest and steepest meridian) 21 could have influenced the results in our cohort of patients. Moreover, studies have reported that CA has no significant effect on GAT in post-PK and post-deep LK eyes, 8 which is in accordance to our results. Unlike GAT, the iCare probe is in contact with a very small area on the corneal surface, thus theoretically less influenced by CA.…”

Section: Discussionsupporting

confidence: 82%

“…4,5 In accordance to our results, previous authors have reported that there are no correlations between CC and GAT IOP; 5,28,34 however, other studies have shown some correlation. 35 Moreover, CC has shown to have no significant effect on GAT IOP in post-PK and post-deep LK eyes, 8 which is in agreement with our data.…”

Section: Discussionsupporting

confidence: 82%

“…Our post-keratoplasty eyes did not show any statistically significant relationship between CCT and both tonometers IOP readings, which is in accordance to previous studies regarding GAT in post-PK, 8,11 post-deep anterior LK, 8 and post-DSEK. 9 It is likely that keratoplasty may alter corneal biomechanics, 9 and Figure 2 Bland-Altman plots of the agreement between GAT and iCare IOP measurements.…”

Section: Discussionsupporting

confidence: 81%

“…Goldmann applanation tonometry (GAT) is considered the gold standard for IOP measurement; 1 its accuracy is, however, influenced by corneal thickness, curvature, and biomechanical properties, such as rigidity, viscosity, elasticity, hydration, [2][3][4][5][6] which have shown to have high interindividual variability and to be affected by corneal pathology and surgery. 3,4,[7][8][9] Studies have shown erroneous postoperative IOP readings with GAT after keratoplasty. [8][9][10][11] Although not fully understood and predictable, GAT IOP errors in corneal grafts may be due to several factors including the following: surgically induced thinning or thickening of the cornea; high and/or irregular postoperative astigmatism; disruption of the mechanical integrity and remodeling of corneal tissue, which include the compliance forces present in the host eye, variable graft-host interface mechanics, changes in corneal biomechanical properties, and difficulties in aligning the tonometer head properly on the corneal surface.…”

Section: Introductionmentioning

confidence: 99%

“…[8][9][10][11] Although not fully understood and predictable, GAT IOP errors in corneal grafts may be due to several factors including the following: surgically induced thinning or thickening of the cornea; high and/or irregular postoperative astigmatism; disruption of the mechanical integrity and remodeling of corneal tissue, which include the compliance forces present in the host eye, variable graft-host interface mechanics, changes in corneal biomechanical properties, and difficulties in aligning the tonometer head properly on the corneal surface. [8][9][10][11] Several alternative tonometers have been developed that claim to provide measurements that are not influenced by corneal properties, unlike GAT. The iCare (Tiolat Oy, Helsinki, Finland) is a new handheld tonometer, which is based on the impact-induction principle also known as rebound tonometry.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Comparison of iCare tonometer and Goldmann applanation tonometry in normal corneas and in eyes with automated lamellar and penetrating keratoplasty

Salvetat

Zeppieri

Miani

et al. 2011

Eye

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Purpose To 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. Methods This 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-automatedendothelial 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.Results iCare significantly underestimated IOP in all groups compared with GAT (GAT minus iCare of 3.5±3.5 mm Hg, Po0.001), but overestimated IOP in the edematous grafts (GAT minus iCare of À6.5 ± 1.9 mm Hg, Po0.001). 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. Conclusions The 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.

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