Influence of corneal biomechanical properties on intraocular pressure measurement

Liu, Jun; Roberts, Cynthia J.

doi:10.1016/j.jcrs.2004.09.031

Cited by 706 publications

(558 citation statements)

References 44 publications

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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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Section: Introductionmentioning

confidence: 99%

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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“…Em um modelo matemático, Liu e Roberts (5) , observaram uma maior influência de variações relacionadas com a tensão da superfície relacionadas pela resistência da córnea (módulo de Young), potencialmente determinando maior "erro" na TAG, comparando-se com os efeitos relacionados com a espessura central e com a ceratometria.…”

Section: Discussionunclassified

“…Por outro lado, quanto mais grossa a córnea, maior seria sua resistência e maior a pressão medida, valor hiperestimado por meio da TAG. Além da espessura, outras características como a curvatura da córnea, também são reconhecidamente importantes, de modo que córneas mais planas tendem a apresentar maior resistência para a aplanação e gerar valores mais elevados (4,5) . Entretanto, a medida da pressão intraocular sofre influência da córnea de forma mais complexa.…”

Section: Introductionunclassified

Avaliação da pressão intraocular através do ocular response analyzer antes e após cirurgia de facoemulsificação

Valbon¹,

Silva²,

Jardim³

et al. 2011

Rev. bras.oftalmol.

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“…These are impacted by adhesion properties and the prism material, which exert a pressure that offsets the effect of corneal resistance. 12 The acrylic Tonosafe tip may affect the adhesion properties of the tear film, leading to measurement errors as well.…”

Section: Introductionmentioning

confidence: 99%

Reliability of tonosafe disposable tonometer prisms: clinical implications from the Veterans Affairs Boston Healthcare System Quality Assurance Study

Thomas

Daly

Cakiner-Egilmez

et al. 2011

Eye

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Purpose Given the Veterans Affairs Boston Healthcare System's recent introduction of single-use Tonosafe disposable tonometer prisms as an alternative to Goldmann applanation tonometers (GATs), this study had two aims: to conduct a large-scale quality assurance trial to assess the reliability of intraocular pressure (IOP) measurements of the Tonosafe disposable tonometer compared with GAT, particularly at extremes of pressure; to evaluate the suitability of Tonosafe disposable tonometer prisms as an acceptable substitute for GATs and for clinic-wide implementation in an academic tertiary referral setting. Methods Ophthalmology resident physicians measured the IOPs of patients in general and specialty eye clinics with the Tonosafe disposable tonometer and GAT. Tonosafe test-retest reliability data were also collected. A retrospective review of patient charts and data analysis were performed to determine the reliability of measurements. Results The IOPs of 652 eyes (326 patients) were measured with both GAT and Tonosafe, with a range of 3-34 mm Hg. Linear regression analysis showed R ¼ 0.93, slope ¼ 0.91, both of which supported the proposed hypothesis, and the y-intercept ¼ À1.05 was significantly different from the hypothesized value. The Tonosafe test-retest repeatability (40 eyes of 40 patients), r ¼ 0.977, was very high, which was further supported by linear regression slope ¼ 0.993, y-intercept ¼ 0.118, and a Tonosafe repeatability coefficient of 2.06, similar to GAT repeatability. Conclusions The IOP measurements by Tonosafe disposable prisms correlated closely with Goldmann measurements, with similar repeated measurement variability to GAT. This suggests that the Tonosafe is an acceptable substitute for GAT to measure IOP in ophthalmology clinic settings.

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Influence of corneal biomechanical properties on intraocular pressure measurement

Cited by 706 publications

References 44 publications

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

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

Avaliação da pressão intraocular através do ocular response analyzer antes e após cirurgia de facoemulsificação

Reliability of tonosafe disposable tonometer prisms: clinical implications from the Veterans Affairs Boston Healthcare System Quality Assurance Study

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