The use of the Reichert ocular response analyser to establish the relationship between ocular hysteresis, corneal resistance factor and central corneal thickness in normal eyes

Shah, Sunil; Laiquzzaman, Mohammad; Cunliffe, I A; Mantry, Sanjay

doi:10.1016/j.clae.2006.09.006

Cited by 201 publications

(179 citation statements)

References 23 publications

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“…The difference between 'inward' and 'outward' applanation pressure depends on the viscoelastic properties of the corneoscleral shell, because opposition forces absorb energy from the air impulse (corneal hysteresis). 10,11 The ORA derives two IOPs: the Goldmann-correlated IOP (IOPg), which the manufacturers have calibrated with GAT, and the corneal-compensated IOP (IOPcc), which is designed to be independent of the CCT.…”

Section: Introductionmentioning

confidence: 99%

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Carbonaro

Andrew

Mackey

et al. 2010

Eye

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Purpose The purpose of this study was to compare the reliability of the 'gold standard' Goldmann applanation tonometer (GAT), with that of the ocular response analyser (ORA), and the dynamic contour tonometer (DCT). Patients and methods A total of 694 subjects were recruited to participate from the TwinsUK (UK Adult Twin Registry) at St Thomas' Hospital, London. Intraocular pressure (IOP) was measured using GAT, ORA, and the DCT. The agreement between the three methods was assessed using the Bland-Altman method. Repeatability coefficients and coefficient of variation between first and second readings of the same eye were used to assess reliability. Results Mean age was 57.5 years (SD, 13.1; range, 16.1-88.5). The mean IOPs, calculated using the mean of two readings from the right eye were as follows: Goldmann (GAT), 14.1 ± 2.8 mm Hg; IOPg (ORA), 15.9 ± 3.2 mm Hg; IOPcc (ORA), 16.6 ± 3.2 mm Hg; and DCT, 16.9 ± 2.7 mm Hg. The 95% limits of agreement were for ORA (IOPcc): GAT, À2.07 to 7.18 mm Hg; for DCT: GAT, À0.49 to 6.21 mm Hg; and for DCT: ORA (IOPcc), À3.01 to 4.85 mm Hg. Coefficients of variation for the three tonometers were GAT, 8.3%; ORA, 8.2%; DCT, 6.3%. The repeatability coefficients were 3.4 mm Hg for GAT, 3.57 mm Hg for ORA and 3.09 mm Hg for DCT. GAT and ORA (IOPg) readings showed a positive correlation with central corneal thickness (Po0.005). Conclusions This study found similar reliability in all three tonometers. Bland-Altman plots showed the three instruments to have 95% limits of agreement outside the generally accepted limits, which means they are not interchangeable. GAT measurements were found to be significantly lower than the two newer instruments.

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Section: Introductionmentioning

confidence: 99%

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Carbonaro

Andrew

Mackey

et al. 2010

Eye

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“…7 As changes on CCT are demonstrated to occur after tamsulosin use 5 , we wondered if corneal biomechanics could also be affected by this medication. To our knowledge, no study to date has evaluated the effects of tamsulosin on the corneal biomechanics.…”

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confidence: 99%

“…However, due to the dynamic nature of the air pulse, the viscous damping in the cornea causes delays in the inward and outward applanation events, resulting in two different pressure values. 6,7 The average of these two pressure values provides a repeatable, Goldmann-correlated IOP value (IOPg). 6,7 The difference between these two pressure values is CH.…”

mentioning

confidence: 99%

“…6,7 The average of these two pressure values provides a repeatable, Goldmann-correlated IOP value (IOPg). 6,7 The difference between these two pressure values is CH. The CH measurement has been shown to be significant and useful in its own right, but in addition, the dynamic bi-directional applanation process can be used to derive other valuable information; namely corneal-compensated IOP (IOPcc) and CRF.…”

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confidence: 99%

“…The ORA utilizes a rapid air impulse to apply force to the cornea, and an advanced electro-optical system to monitor its deformation. 6,7 A precisely-metered collimated-air-pulse causes the cornea to move inwards, past applanation, and into a slight concavity. Milliseconds after applanation, the air pump shuts off and the pressure declines in a smooth fashion.…”

mentioning

confidence: 99%

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Effect of Tamsulosin on Corneal Biomechanical Features

Palamar¹,

Emre²,

Turna³

et al. 2016

Turkiye Klinikleri J Ophthalmol

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A AB BS S T TR RA AC CT T O Ob bj je ec ct ti iv ve e: : Tamsulosin (Flomax ® ) usage was reported to increase central corneal thickness (CCT). As CCT and ocular biomechanical parameters are closely related, this study was conducted to investigate the possible effects of tamsulosin on biomechanical parameters of cornea as measured with Reichert Ocular Response Analyser (ORA) in patients with benign prostate hyperplasia. M Ma at te er ri ia al l a an nd d M Me et th ho od ds s: : Besides full eye examination (best corrected visual acuity, intraocular pressure (IOP) measured with Goldmann applanation tonometry, CCT) ORA (corneal hysteresis, corneal resistance factor, corneal compensated IOP, Goldmann correlated IOP) measurements of 30 eyes of 15 male patients before and one month after tamsulosin therapy were performed. For comparisons paired t-test was used. R Re es su ul lt ts s: : Mean age in the study group was 61.50±6.10 (range 47-69) years. Pre-tamsulosin CCT was lower than post-tamsulosin values (pre-: 549.18±28.84 micrometers, post-: 556.77±24.86 micrometers; p=0.002). Although statistically insignificant corneal resistance factor after tamsulosin use was lower (pre-: 10.73±1.05 mmHg, post-: 9.45±1.51 mmHg; p=0.071). Measurements before and after tamsulosin treatment was not statistically different for any of the other parameters. C Co on nc cl lu us si io on n: : Tamsulosin seems not only to cause an increment on CCT, but also effect corneal resistance factor. The long term effects of tamsulosin on corneal biomechanical properties should further be investigated with larger group of patients. K Ke ey y W Wo or rd ds s: : Cornea; tamsulosin; eye Ö ÖZ ZE ET T A Am ma aç ç: : Tamsulosin (Flomax ® ) kullanımı sonrası merkezi kornea kalınlığında (MKK) artış olduğu bilinmektedir. Kornea kalınlığı ile korneanın biyomekanik özellikleri arasındaki yakın ilişki bulunduğundan, benign prostat hiperplazisi sebebiyle tamsulosin kullanan hastalarda korneada gelişebilecek muhtemel biyomekanik özellik değişikliklerinin Reicher Oküler Response Analiz cihaz (ORA) ile incelenmesi amacıyla bu çalışma planlanmıştır. G Ge er re eç ç v ve e Y Yö ön nt te em ml le er r: : Tamsulosin kullanılmasından önce ve kullanımından 1 ay sonra 15 hastanın 30 gözünde tam oftalmolojik muayeneye (en iyi düzeltilmiş görme keskinliği, göz içi basınç ölçümü GİB) ilaveten MKK ölçümü ve ORA (korneal histerezis, korneal rezistans faktör, kornea kompanse GIB ve Goldmann korele GIB) ölçümleri yapılmış ve sonuçlar karşılaştırılmıştır. İstatistiksel analiz için eşleştirilmiş-t testi kullanılmıştır. B Bu ul lg gu ul la ar r: : Çalışma grubundaki hastaların ortalama yaşı 61,50±6,10 (range 47-69) yıl idi. Tamsulosin öncesi ve sonrasındaki MKK sırasıyla 549,18±28,84 ve 556,77±24,86 µm (p=0,002)idi. İn-celenen parametreler içerisinde hiçbir parametre için tedavi sonrasında anlamlı değişiklik izlenmemekle beraber yalnızca korneal rezistan faktör için , bir miktar azalma eğilimi olduğu izlenmiştir (pre-: 10,73±1,05 mmHg, post-:9,45±1,51 mmHg; p=0,071). S So on n...

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Corneal Thickness and Intraocular Pressure in a Nonglaucomatous Burmese Population

Casson¹

2008

Arch Ophthalmol

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Objective: To determine correlates of central corneal thickness (CCT) and its relationship to intraocular pressure (IOP) in a Burmese population. Methods: We performed a population-based survey of inhabitants 40 years or older in Myanmar; of 2076 participants, data from 1909 nonglaucomatous subjects who underwent ultrasound pachymetry and Goldmann applanation tonometry were analyzed. Linear mixed effects models adjusting for nonindependence of right and left eye data were constructed. Results: Mean (SD) CCT was 521.9 (33.3) µm, and the mean (SD) IOP was 14.5 (3.4) mm Hg. Intraocular pressure and spherical equivalent were significant predictors of CCT (PϽ.001 and P=.01, respectively). Age, sex, body mass index, and corneal curvature were not significant pre-dictors. Central corneal thickness was the only significant predictor of IOP (ie, an increase of 100 µm in CCT predicted an increase of 1.3 mm Hg in IOP). The Spearman correlation between CCT and IOP for the right and left eyes was highly significant (PϽ.001), but the Spearman rank correlation values (R 2 =0.016 and R 2 =0.017, respectively) were weak. Conclusions: The CCT in this Burmese population was significantly associated with IOP and spherical equivalent. The weak association between CCT and IOP is consistent with that of other population-based studies. Other corneal factors are likely to influence Goldmann applanation tonometry.

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The use of the Reichert ocular response analyser to establish the relationship between ocular hysteresis, corneal resistance factor and central corneal thickness in normal eyes

Cited by 201 publications

References 23 publications

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Effect of Tamsulosin on Corneal Biomechanical Features

Corneal Thickness and Intraocular Pressure in a Nonglaucomatous Burmese Population

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