Lower corneal hysteresis in glaucoma patients with acquired pit of the optic nerve (APON)

Bochmann, Frank; Ang, Ghee Soon; Azuara‐Blanco, Augusto

doi:10.1007/s00417-007-0756-5

Cited by 81 publications

(67 citation statements)

References 25 publications

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“…CH is lower in glaucoma damage, acquired optic nerve pitting, and progressive glaucoma. 2,15,[28][29][30][31] In glaucoma patients with low hysteresis, there is greater backward bowing of the lamina cribrosa in response to transient IOP elevation. 32 Furthermore, CH measurements may be useful in identifying patients with keratoconus and post-LASIK ectasia, as well as for monitoring biomechanical corneal properties before and after keratorefractive procedures.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of agreement between intraocular pressure measurements using Goldmann applanation tonometry and Goldmann correlated intraocular pressure by Reichert's ocular response analyser

Ehrlich

Haseltine

Shimmyo

et al. 2010

Eye

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Purpose To compare agreement of intraocular pressure (IOP) measurements using Goldmann applanation tonometry (GAT) and Goldmann correlated intraocular pressure generated (IOPg) by the Reichert ocular response analyser (ORA). Methods Consecutive patients presenting for glaucoma evaluation underwent ORA assessment followed by examination including GAT. For each ORA assessment, measurements were taken until a waveform score (WS) of 6.5 was obtained or until five measurements were obtained per eye. The relationship between GAT and IOPg and the influence of the WS upon this relationship was evaluated. A Bland-Altman plot and linear regression were used to determine agreement between GAT and IOPg. Results A total of 518 eyes of 260 patients were included in the final analysis. Increasing WS was found to predict a smaller difference between GAT and IOPg (b ¼ À0.2, Pp0.001). Selecting the highest WS among ORA assessments of each eye, WS continued to predict concordance between GAT and IOPg (b ¼ À0.2, P ¼ 0.006). The mean IOP difference between methods was 0.1 mm Hg (±0.3), which was found to be statistically insignificant (P ¼ 0.391). This relationship between GAT and IOPg was successfully validated using a second distinct data set of 100 eyes. GAT and IOPg measurements varied by 2 mm Hg or less in 53.9% of eyes and 5 mm Hg or less in 92.3% of eyes. Conclusion In clinical practice IOPg is strongly related to GAT. Although higher WS is indicative of greater IOPg/GAT concordance, its influence is minimal. This study does not support the use of a specific WS cutoff to determine quality of an IOPg measurement.

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Section: Discussionmentioning

confidence: 99%

Evaluation of agreement between intraocular pressure measurements using Goldmann applanation tonometry and Goldmann correlated intraocular pressure by Reichert's ocular response analyser

Ehrlich

Haseltine

Shimmyo

et al. 2010

Eye

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“…This could suggest that corneal biomechanical properties may reflect viscoelastic properties of the lamina cribrosa, for example. 46 In keratoconus eyes, both CH and CRF seem to be lower than in a normal population (10.6±2.2 versus 8.7 ± 2.2 mmHg, and 10.0±2.5 versus 6.9±2.4 mmHg, respectively). 32 There is also a significant decrease of both CH and CRF following LASIK, 47 which could probably account for the changes observed in GAT measurements as described previously.…”

Section: Perkins Handheld Tonometer (Medtronic Solan Jacksonville Fmentioning

confidence: 80%

“…As some studies have reported differences in these parameters between glaucomatous and non-glaucomatous patients, 20,31,39,45,46,71,72 we believe that in the future these parameters might prove useful to better understand the pathophysiology in different eye conditions.…”

Section: Discussionmentioning

confidence: 93%

Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

Moraes

Prata

Liebmann

et al. 2008

Journal of Optometry

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Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based on a survey of the published literature. The analysis was based on a Medline search focusing mainly on papers that have evaluated the devices' accuracy with respect to corneal thickness and irregularities. Nine device types (Goldmann tonometer, Tono-Pen, Perkins tonometer, Ocular Response Analyzer, non-contact tonometer, pneumatonometer, I-Care rebound tonometer, Pascal dynamic contour tonometer (DCT) and Phosphene tonometer) were described in detail. Moreover, the physical principles and major utility of each tonometer were compared. Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared. RESUMENAvances recientes en el campo de la tonometría han propiciado el desarrollo de diversos dispositivos con diferentes aplicaciones clíni-cas. Resulta de particular importancia el papel que juegan en el caso de espesores corneales anormales o en presencia de irregularidades en la superficie de la córnea, puesto que, en esos casos, una medida imprecisa de la presión intraocular (PIO) real puede traer como consecuencia una valoración incorrecta del caso. El objetivo de esta revisión es evaluar el grado de precisión de los dispositivos más utilizados hoy en día en casos en los que existen irregularidades en la superficie de la córnea o en el espesor corneal. Para ello, se llevó a cabo una búsqueda de datos entre los artículos publicados. El análisis estuvo basado en una búsqueda bibliográfica realizada dentro de Medline, centrándose principalmente en aquellos artícu-los científicos que habían estudiado el grado de precisión del dispositivo en función del espesor corneal del paciente y de la presencia o no de irregularidades corneales. Se describen en detalle nueve tipos de dispositivos: tonómetro de Goldmann, Tono-Pen, tonómetro de Perkins, Ocular Response Analyzer, tonómetro sin contacto, neumotonómetro, tonómetro de rebote I-Care, tonómetro de contorno dinámico Pascal y tonómetro de fosfeno. Además, se presentan de forma comparada los principios físicos en los que está basado cada tonómetro y las situaciones en las que cada uno resulta de mayor utilidad. Cada uno de los distintos tonómetros disponibles en el mercado presenta ventajas y desventajas respecto...

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“…When other covariates were considered, this correlation lost its significance. Comparing CH values in POAG patients with and without acquired pits of the ONH, Bochmann et al 36 42 was not assessed in that study. On the other hand, Wells et al 13 correlated higher CH values (but not CCT) with greater changes in ONH topography after IOP increase.…”

Section: Discussionmentioning

confidence: 94%

“…6,[22][23][24][25][26] Previous studies have suggested that systemic and ocular factors, such as ageing, [27][28][29] chronically elevated IOP, [30][31][32] level of glaucomatous damage, 1,17,33 and disc size (scleral canal diameter), 34 could influence the susceptibility of an individual ONH to a given level of IOP. More recently, it has been suggested that other factors could be either directly or indirectly related to ONH response to pressure-induced damage, such as corneal parameters (both CCT and CH) 13,[35][36][37] and diabetes. 1,37,38 In glaucoma management, it is important to identify which factors are significantly related to an individual response to pressure-induced damage.…”

Section: Introductionmentioning

confidence: 99%

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients

Prata

Lima

Moraes

et al. 2010

Eye

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Purpose To investigate factors associated with changes in optic nerve head (ONH) topography after acute intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG). Methods Untreated POAG patients (IOP 421 mm Hg) were prospectively enrolled. Systemic and ocular information were collected, including central corneal thickness (CCT) and corneal hysteresis (CH). All patients underwent confocal scanning laser ophthalmoscopy and tonometry (Goldmann) before and 1 h after pharmacological IOP reduction. The mean of three measurements was considered for analysis. Changes in each ONH topographic parameter were assessed (one eye was randomly selected), and those that changed significantly were correlated with patient's systemic and ocular characteristics. Results A total of 42 patients were included (mean age, 66.7 ± 11.8 years). After a mean IOP reduction of 47.3±11.9%, significant changes were observed in cup area and volume, and in rim area and volume (Po0.01), but not in mean cup depth (P ¼ 0.80). Multiple regression analysis (controlling for baseline IOP and magnitude of IOP reduction) showed that CH (r 2 ¼ 0.17, Po0.01) and diabetes diagnosis (r 2 X0.21, Po0.01) were negatively correlated with the magnitude of changes in ONH parameters, whereas the cup-to-disc ratio was positively correlated (r 2 ¼ 0.30, Po0.01). Age, race, disc area, and CCT were not significant (PX0.12). Including all significant factors in a multivariable model, only the presence of diabetes remained significantly associated with all ONH parameters evaluated (Po0.01). Conclusions Different systemic and ocular factors, such as diabetes, CH, and the relative size of the cup, seem to be associated with the magnitude of changes in ONH topography after acute IOP reduction in POAG patients. These associations partially explain the ONH changes observed in these patients and suggest that other factors are possibly implicated in an individual susceptibility to IOP.

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Lower corneal hysteresis in glaucoma patients with acquired pit of the optic nerve (APON)

Abstract: Corneal hysteresis in POAG patients with APON was significantly lower than in patients that did not have such structural changes of the optic disc. These findings may reflect pressure-independent mechanisms involved in the pathogenesis of such glaucomatous optic nerve changes.

Cited by 81 publications

References 25 publications

Evaluation of agreement between intraocular pressure measurements using Goldmann applanation tonometry and Goldmann correlated intraocular pressure by Reichert's ocular response analyser

Evaluation of agreement between intraocular pressure measurements using Goldmann applanation tonometry and Goldmann correlated intraocular pressure by Reichert's ocular response analyser

Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients

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