scholarly journals Influence of Central Corneal Thickness (CCT) on the Intraocular Pressure (IOP) Measurements Taken From Goldmann Applanation Tonometer, Tonopen, and Airpuff Tonometer.

2019 ◽  
Vol 3 (3) ◽  
pp. 532-536 ◽  
Author(s):  
Anadi Khatri ◽  
Madhu Thapa ◽  
Muna Kharel ◽  
Apoorva Sah ◽  
Kripa Bhattarai ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Linear Regression Analysis ◽  
Corneal Thickness ◽  
Mean Difference ◽  
Cross Sectional ◽  
Applanation Tonometer ◽  
Predicted Values ◽  
Replicate Measurements ◽  
Ultrasonic Pachymetry

Introduction: Intraocular pressure (IOP) is one of the basic and most important investigations. Central corneal thickness influences IOP measured by various devices. Objective: In this study, we attempt to determine the agreement and influence of the central corneal thickness in the measurement of IOP obtained by Goldman applanation tonometer, Airpuff tonometer and tonopen. Methodology: A cross-sectional analytical study of Central corneal thickness (CCT) was done using Ultrasonic pachymetry. IOP was adjusted using Ehler's formula. Mean and the standard deviation was measured using the observed and predicted values for each instrument for its accuracy irrespective of the CCT. Results: 200 eyes of 100 patients were included in the study. Mean IOP measured was 16mmHg (SD 4). Tonopen was found to have closer observed values when compared with the predicted values to IOP obtained by Goldmann's applanation tonometer after CCT adjustments with Mean difference of 0.0134 mmHg with SD of 0.814. Air Puff tonometer was found to be the least accurate with Mean difference -2.08mmHg and SD of 4.704. Linear regression analysis also predicted that while the tonopen tend to underestimate the IOP levels by 5 %, Airpuff tonometer had a tendency to overestimate the IOP by 13%.(p<0.05). Conclusion: Tonopen had the greatest agreement and significant correlation with the GAT over a range of IOP and CCT and replicate measurements that are closest to the values obtained by using GAT after CCT adjustments. CCT adjustments may not even be required or has very little influence on IOP when using Tonopen.

scholarly journals Comparison of intraocular pressure and central corneal thickness in non-glaucomatous North- East Indian tribals versus general Indians

2019 ◽  
Vol 16 (3) ◽  
pp. 144-152
Author(s):  
Tanie Natung ◽  
Prasanta Kumar Goswami ◽  
Avonuo Keditsu ◽  
Wakaru Shullai
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Linear Regression Analysis ◽  
Corneal Thickness ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
East Indian ◽  
North East ◽  
The Mean ◽  
The Difference

Purpose: To compare the intraocular pressure (IOP) and central corneal thickness (CCT) of non-glaucomatous North-East (NE) Indian tribals and general Indians.  Materials and methods: In a prospective, cross-sectional study, the IOP and CCT of non-glaucomatous NE Indian tribals (n = 50) and non-glaucomatous general Indians (n = 50) were compared. Glaucoma was ruled out by history, detailed ocular examinations, and investigations. Results: There was very good correlation between the CCT and IOP values of right and left eyes (p = 0.940 and 0.847, respectively). The difference in the IOP values in the two groups was not statistically significant (p = 0.312 for Oculus Dexter [OD], p = 0.400 for Oculus Sinister [OS]). Similarly, the difference in the CCT values in the two groups was not statistically significant (p = 0.736 for OD and 0.613 for OS). The mean CCT and IOP OD for the whole population was 530.50 ± 35.42 μm and 13.80 ± 2.760 mmHg, respectively. By linear regression analysis, the IOP OD of the whole population had good correlation with CCT OD of the whole population (adjusted r2 = 0.084, p = 0.002), but not with age (adjusted r2=0.000, p=0.314) and sex (adjusted r2 = 0.010, p = 0.163). Similarly, CCT OD for the whole population did not have good correlation with age (adjusted r2 = -0.009, p = 0.762) and sex (adjusted r2 = -0.007, p = 0.603). Conclusions: In this study of individuals with normal corneas and without glaucoma, no racial variation was found in the CCT and IOP values of the two groups. The IOP OD of whole population had good correlation with CCT, but not with age and sex. There was good correlation between OD and OS values of IOP and CCT.

Relationship between novel intraocular pressure measurement from Corvis ST and central corneal thickness and corneal hysteresis

2019 ◽  
Vol 104 (4) ◽  
pp. 563-568 ◽  
Author(s):  
Masato Matsuura ◽  
Hiroshi Murata ◽  
Yuri Fujino ◽  
Mieko Yanagisawa ◽  
Yoshitaka Nakao ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Linear Regression Analysis ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Applanation Tonometry ◽  
Corneal Hysteresis ◽  
Corneal Resistance Factor ◽  
Corvis St ◽  
The Relationship

AimsCorvis ST (CST) yields biomechanical corrected IOP (bIOP) which is purported to be less dependent on biomechanical properties. In our accompanied paper, it was suggested that the repeatability of bIOP is high. The purpose of the current study was to assess the relationship between intraocular pressure (IOP) measured with CST and central corneal thickness (CCT) and corneal hysteresis (CH), in comparison with IOP measured with Goldmann applanation tonometry (GAT) and the ocular response analyzer (ORA).MethodsA total of 141 eyes from 141 subjects (35 healthy eyes and 106 glaucomatous eyes) underwent IOP measurements with GAT, CST and ORA. The relationships between IOP measurements (ORA-IOPg, ORA-IOPcc, CST-bIOP and GAT IOP) and biomechanical properties (CCT, CH and corneal resistance factor (CRF)) were analysed using the linear regression analysis.ResultsIOPg, IOPcc and GAT IOP were significantly associated with CCT (p<0.001), whereas bIOP was not significantly associated with CCT (p=0.19). IOPg, bIOP and GAT IOP were significantly associated with CH (IOPg: p<0.001; bIOP: p<0.001; GAT IOP: p=0.0054), whereas IOPcc was not significantly associated with CH (p=0.18). All of IOP records were associated with CRF (p<0.001).ConclusionThe bIOP measurement from CST is independent from CCT, but dependent on CH and CRF.

Self-measurement with Icare HOME tonometer, patients’ feasibility and acceptability

2019 ◽  
Vol 30 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Barbara Cvenkel ◽  
Makedonka Atanasovska Velkovska ◽  
Vesna Dimovska Jordanova
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Pressure Data ◽  
Limits Of Agreement ◽  
Goldmann Applanation Tonometer ◽  
Applanation Tonometer ◽  
Perception Of Self ◽  
The Mean

Purpose: To evaluate and compare the accuracy of self-measurement of intraocular pressure using Icare Home rebound tonometer with Goldmann applanation tonometer and assess acceptability of self-tonometry in patients with glaucoma and ocular hypertension. Methods: In the study, 117 subjects were trained to use Icare Home for self-measurement. Icare Home tonometer readings were compared with Goldmann applanation tonometer, including one eye per patient. Agreement between the two methods of measurement was evaluated by Bland and Altmann analysis. Questionnaire was used to evaluate patients’ perception of self-tonometry. Results: One hundred and three out of 117 patients (88%) were able to measure their own intraocular pressure and 96 (82%) fulfilled the requirements for certification. The mean (SD) difference Goldmann applanation tonometer minus Icare Home was 1.2 (2.4) mmHg (95% limits of agreement, –3.4 to 5.9 mmHg). The magnitude of bias between the two methods depended on central corneal thickness, with greater bias at central corneal thickness <500 µm. In 65 out of 96 subjects (67.7%), Icare Home results were within 2 mmHg of the Goldmann applanation tonometer. Seventy-three out of 93 (78.5%) felt that self-tonometry was easy to use and 75 patients (80.6%) responded that they would use the device at home. Conclusion: Icare Home tonometry tends to slightly underestimate intraocular pressure compared to Goldmann applanation tonometer. Most patients were able to perform self-tonometry and found it acceptable for home use. Measurements using rebound self-tonometry could improve the quality of intraocular pressure data and optimize treatment regimen.

scholarly journals Factors Affecting the Central Corneal Thickness in Nepalese Population

1970 ◽  
Vol 1 (1) ◽  
pp. 7-10 ◽  
Author(s):  
ST Godar ◽  
KR Kaini ◽  
JB Khattri
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Cross Sectional Study ◽  
Medical Sciences ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Intra Ocular Pressure ◽  
Goldmann Tonometry ◽  
Applanation Tonometer ◽  
Ocular Pressure

Background: Intra Ocular Pressure (IOP) is an important parameter for the detection and monitoring of glaucoma. Central corneal thickness (CCT) can influence the IOP estimated with Goldmann tonometry. A thick cornea overestimates the IOP and thin underestimates it. So, decreased CCT may lead to underdiagnosis and undertreatment of glaucoma and increased CCT may lead to overdiagnosis and overtreatment of glaucoma. The aim of the study is to identify the factors affecting the CCT in Nepalese population. Methods: A hospital based cross-sectional study which enrolled 152 subjects from period of January 2009 to May 2010. All subjects underwent ophthalmological examinations. CCT was measured with ultrasonic pachymeter and intraocular pressure was measured with Goldmann applanation tonometer. Results: The mean±SD CCT of right and left eye was 538±32 and 540±30μm respectively. CCT decreased with increasing age. Age and intra ocular pressure was significantly correlated with CCT. There was no significant correlation of gender and ethnicity with CCT. Conclusion: CCT decreased with increasing age. CCT was significantly correlated with age and intra ocular pressure but not with gender and ethnicity. Keywords: Nepalese; central corneal thickness; ultrasound pachymeter DOI: http://dx.doi.org/10.3126/njms.v1i1.5788   Nepal Journal of Medical Sciences. 2012; 1(1): 7-10.

Icare versus Goldmann in a randomised middle-aged population

2020 ◽  
pp. 112067212092138
Author(s):  
Katri Stoor ◽  
Elina Karvonen ◽  
Pasi Ohtonen ◽  
M Johanna Liinamaa ◽  
Ville Saarela
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Population Based ◽  
Rebound Tonometer ◽  
Goldmann Applanation Tonometer ◽  
Applanation Tonometer ◽  
Screening Study ◽  
The Difference

Purpose The aim of this study was to compare the measurements of intraocular pressure by two tonometers, the Icare rebound tonometer and the Goldmann applanation tonometer, in a randomised screening study. The influence of refraction and central corneal thickness on the measurements was also evaluated. Methods Intraocular pressure was measured with rebound tonometer and Goldmann applanation tonometer in 1266 participants; refraction and central corneal thickness were also determined. One randomised eye of each participant was selected for this report’s analysis. A Bland–Altman plot was used to compare the values obtained with the two devices. Results The correlation between rebound tonometer and Goldmann applanation tonometer was good: the intraclass correlation coefficient (r) between the two methods was 0.735 ( p < 0.001). The mean difference (rebound tonometer–Goldmann applanation tonometer) was 0.11 ± 2.3 mmHg. The difference was not statistically significant (95% confidence interval: 0.11 to 0.13, p = 0.09). With increasing central corneal thickness, not only did intraocular pressure values with both devices increase, but the difference between them also increased. Refraction (spherical equivalent) did not influence intraocular pressure or the rebound tonometer–Goldmann applanation tonometer difference. However, high astigmatism (≥2D) exerted an influence on intraocular pressure values taken with Goldmann applanation tonometer. Conclusion Measurements with rebound tonometer and Goldmann applanation tonometer are relatively uniform although rebound tonometer slightly overestimated intraocular pressure. Both rebound tonometer and Goldmann applanation tonometer and the difference between these devices were affected by central corneal thickness but not by refraction. Higher astigmatism affected Goldmann applanation tonometer more than rebound tonometer. It is concluded that rebound tonometer is a reliable method for measuring intraocular pressure in a population-based screening study.

scholarly journals The Association of Central Corneal Thickness and Intraocular Pressure Measures by Non-Contact Tonometry and Goldmann Applanation Tonometry among Glaucoma Patients.

2020 ◽  
Vol 30 (6) ◽  
Author(s):  
Samuel Kyei ◽  
Frank Assiamah ◽  
Michael Agyemang Kwarteng ◽  
Cynthia Pakyennu Gboglu
Keyword(s):  
Intraocular Pressure ◽  
Significant Relationship ◽  
Pressure Measurement ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Applanation Tonometry ◽  
Goldmann Applanation Tonometry ◽  
Goldmann Applanation Tonometer ◽  
Applanation Tonometer ◽  
The Right

BACKGROUND፡ The aim of this study was to determine whether Central Corneal Thickness (CCT) is associated with intraocular pressure measurement (IOP) with a Non-contact tonometer and the Goldmann applanation tonometer in glaucoma patients.MATERIALS AND METHODS: The study involved two hundred and thirty-two eyes of clinically diagnosed glaucoma patients receiving care at a referral facility. IOP measurements were obtained using both the Non-Contact Tonometer (NCT) and Goldmann Applanation Tonometer (GAT). The association between age, ethnicity, and CCT, as well as CCT on the measures of NCT and GAT, were analyzed.RESULTS: There were 64(55.2%) males and 52 (44.8%) females and their ages ranged from 18 to 85 years (mean age = 47.72; SD ±15.75 years). There was a weak positive correlation between the CCT and NCT findings in the right eye (r = 0.19, n = 116, p < 0.05) and in the left eye (r = 0.25, n = 116, p < 0.05). However, there was no correlation between CCT and GAT measurements. Age had a significant correlation with CCT while gender and ethnicity had no significant correlation.CONCLUSION: The study found a significant association between CCT and NCT. However, there was no significant association between CCT and GAT. CCT had an association with age but independent of gender and ethnicity since there was no significant relationship between these variables.

scholarly journals EFFICACY AND CORRELATION OF INTRAOCULAR PRESSURE MEASURED BY NON-CONTACT, REBOUND AND GOLDMANN APPLANATION TONOMETER WITH CORNEAL THICKNESS, TRUE IOP AND CORNEAL CURVATURE IN A TERTIARY HOSPITAL.

2019 ◽  
Vol 3 (10) ◽  
Author(s):  
Santanu Das ◽  
Nayana Nagesh ◽  
Kiran Kumar L ◽  
Sundeep Shetty
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Acute Angle ◽  
Angle Closure ◽  
Corneal Curvature ◽  
Rebound Tonometer ◽  
Goldmann Applanation Tonometer ◽  
Applanation Tonometer ◽  
The Mean

ABSTRACT: AIM-To compare the intraocular pressure (IOP) measured by Non-Contact tonometer (NCT), Rebound tonometer (RBT) and Goldmann Applanation tonometer (GAT) and their correlation with central corneal thickness (CCT), true IOP and corneal curvature. Reliability of each tonometer. METHODS-500 random patients aged 18 years and above were taken up for the study. Patients with anterior and posterior segment pathologies like corneal ulcer, leukoma, staphyloma, corneal lacerations, ectatic corneal conditions, corneal dystrophies, oedema, perforations, acute angle closure glaucoma, retinal detachments, vitreous haemorrhage and unwilling patients were excluded from the study. IOP was recorded using NCT, RBT and GAT after assessing the patient's visual acuity. Following IOP measurement, central corneal thickness (CCT) of each patient was measured using pachymetry. Kvalues were measured using an autorefractometer. All the data were collected and tabulated for statistical analysis to obtain results. RESULTS: The mean CCT in males was 0.5350 mm and in females 0.5340 mm respectively. The mean IOP measured by NCT is 16.43 mm hg whereas the mean IOP measured by GAT is 15.43 mm hg. IOP measured by NCT is significantly higher than the IOP measured by GAT (p<0.001). When NCT and RBT are compared NCT values are significantly higher than that of RBT(p<0.001). Although the mean RBT IOP 15.83 mm hg is higher than the mean GAT IOP of 15.42 mm hg the values are not statistically significant. When correlated with CCT all the tonometers showed significant correlation with GAT showing the strongest correlation. NCT overestimates IOP in normal, thin and thicker corneas when compared to GAT and are statistically significant. RBT also overestimates in the normal and thick corneas when compared to GAT but their values are much closer to GAT values in thinner corneas. The IOP measured by all the 3 tonometers correlated with corrected IOP with NCT showing the best correlation followed by GAT. There was no significant correlation between K and IOP in our study. CONCLUSION-From the present study we can conclude that IOP measured by NCT and RBT is higher than GAT. NCT values are significantly higher than GAT values in thin and normal corneas whereas it overestimates more in thicker corneas. RBT values are significantly higher than that of GAT in normal and thick corneas. All the tonometers show significant correlation with CCT with GAT showing the strongest correlation. So, it is always advisable to measure the corrected IOP for each patient after considering the CCT. Keywords- Non-contact tonometer; Goldmann applanation tonometer; central corneal thickness; intraocular pressure; Rebound tonometer, true IOP, Corneal curvature.  

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