The Analysis of Central Corneal Thickness and Intraocular Pressure Measurements with Different Types of Tonometers

2017 ◽  
Vol 26 (3) ◽  
pp. 193-197
Author(s):  
Deniz MARANGOZ ◽  
Maryo Cenk KOHEN ◽  
Muhsin ALTUNSOY ◽  
Ilgaz YALVAÇ
2019 ◽  
Vol 30 (6) ◽  
pp. 1432-1439 ◽  
Author(s):  
Lisa Ramm ◽  
Robert Herber ◽  
Eberhard Spoerl ◽  
Lutz E Pillunat ◽  
Naim Terai

Purpose: To investigate the impact of diabetes mellitus–induced changes on intraocular pressure measurements using Goldmann applanation tonometry, Ocular Response Analyzer, and Corvis ST. Methods: Measurements were done using Goldmann applanation tonometry, Ocular Response Analyzer, and Corvis ST in 69 diabetic patients. Biomechanical-corrected intraocular pressure values by Ocular Response Analyzer (IOPcc) and Corvis ST (bIOP) were used. In addition, biometry and tomography were performed and information on diabetes mellitus specific factors was collected. Results were compared to an age-matched group of 68 healthy subjects. Results: In diabetes mellitus, Goldmann applanation tonometry intraocular pressure (P = 0.193) and central corneal thickness (P = 0.184) were slightly increased. Also, IOPcc (P = 0.075) and bIOP (P = 0.542) showed no significant group difference. In both groups, IOPcc was higher than Goldmann applanation tonometry intraocular pressure (P = 0.002, P < 0.001), while bIOP was nearly equal to Goldmann applanation tonometry intraocular pressure (P = 0.795, P = 0.323). Central corneal thickness showed a tendency to higher values in poorly controlled than in controlled diabetes mellitus (P = 0.059). Goldmann applanation tonometry intraocular pressure correlated to central corneal thickness, while IOPcc and bIOP were independent from central corneal thickness in both groups. All intraocular pressure values showed significant associations to corneal biomechanical parameters. Only in diabetes mellitus, bIOP was correlated to Pachy slope (P = 0.023). Conclusion: In diabetes mellitus, Goldmann applanation tonometry intraocular pressure was slightly, but not significantly, increased, which might be caused by a higher central corneal thickness and changes in corneal biomechanical properties. However, intraocular pressure values measured by Ocular Response Analyzer and Corvis ST were not significantly different between diabetes mellitus patients and healthy subjects. The bIOP showed a higher agreement with Goldmann applanation tonometry than IOPcc and was independent from central corneal thickness.


QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Fatma Gebreel Ahmed Gaber ◽  
Tamer Mohamed El- Raggal ◽  
Mohamed Gamil Metwally ◽  
Ahmed Abdelmonsef Ebeid

Abstract Background Measurement of intraocular pressure (IOP) plays a central role throughout ophthalmology. It is part of routine ophthalmologic examinations and important in the management and follow-up of patients with glaucoma. While elevated IOP remains the most important risk factor for development and progression of open angle glaucoma, at least half of the population diagnosed with open angle glaucoma is asymptomatic. Objectives The aim of our study is to compare the accuracy of intraocular pressure measurement before and after Laser in situ keratomeulsis (LASIK) surgery using three different types of Tonometers: Goldmann Applanation tonometry (GAT), Non contact tonometry (NCT) and Rebound tonometry (I care), considering the change in the central corneal thickness (CCT). Patients and Methods In this study Eighty eyes of 40 patients with mean age of 27.00±6.00 years were scheduled for LASIK..Central corneal thickness before and after surgery was obtained by Ultrasound (US) pachymetry.IOP values were measured before and after surgery using three different types of Tonometers: Goldmann Applanation tonometry, Non contact tonometry and Rebound tonometry. Results The results revealed that lower post-operative IOP measurements using all techniques. The least affected technique was Non –contact with IOP change 16%, followed by GAT with IOP change 18%, and finally Rebound with IOP change 19 %, respectively. The percentage of change in CCT between pre- and post- LASIK surgery measured with the Ultrasound pachymetry was statistically highly significant. There was a clinical significant correlation between Percentage of tissue ablation (PTA) and IOP change for GAT, NCT and rebound tonometry. Also, there was a significant correlation between Residual stromal bed (RSB) and IOP change for GAT and NCT. There was no clinical significant correlation between Ablation depth (AD) and percentage of change of IOP measurements pre and post LASIK, except for IOP measured with GAT when AD &lt; 40.00 µm. Conclusion Refractive surgery causes significant lowering of IOP as measured using Goldmann applanation tonometry, non contact tonometry and rebound tonometry. The least affected tonometry post LASIK is non contact tonometry. The reduction was correlated to the percentage of tissue ablated. The ideal method to measure IOP in post-LASIK patients would be a device that is free of corneal factors.


Medicina ◽  
2019 ◽  
Vol 55 (10) ◽  
pp. 701 ◽  
Author(s):  
De Bernardo ◽  
Borrelli ◽  
Cembalo ◽  
Rosa

Background and Objectives: It has been established that body position can play an important role in intraocular pressure (IOP) fluctuation. IOP has been previously shown to increase significantly when lying down, relative to sitting; this type of investigation has not been extensively reported for the standing (ST) position. Therefore, this study aims to look for eventual significant IOP changes while ST, sitting, and lying down. Materials and Methods: An Icare PRO was used to measure the IOP of 120 eyes of 60 healthy individuals, with age ranging from 21 to 55 years (mean 29.22 ± 9.12 years), in sitting, supine and ST positions; IOP was measured again, 5 minutes after standing (ST-5m). Results: Mean IOP difference between sitting and ST position was 0.39 ± 1.93 mmHg (95% CI: 0.04 to 0.74 mmHg) (p = 0.027); between sitting and ST-5m, it was −0.48 ± 1.79 mmHg (95% CI: −0.8 to −0.16 mmHg) (p = 0.004); between the sitting and supine position, it was −1.16±1.9 mmHg (95% CI: −1.5 to −0.82 mmHg) (p < 0.001); between the supine and ST position, it was 1.55 ± 2.04 mmHg (95% CI: 1.18 to 1.92 mmHg) (p < 0.001); between supine and ST-5m, it was 0.68 ± 1.87 mmHg (95% CI: 0.34 to 1.02 mmHg) (p < 0.001); and between ST-5m and ST, it was 0.94 ± 1.95 mmHg (95% CI: 0.58 to 1.29 mmHg) (p < 0.001). Mean axial eye length was 24.45 mm (95% CI: 24.22 to 24.69 mm), and mean central corneal thickness was 535.30 μm (95% CI: 529.44 to 541.19 μm). Conclusion: Increased IOP in the ST-5m position suggests that IOP measurements should be performed in this position too. The detection of higher IOP values in the ST-5m position than in the sitting one, may explain the presence of glaucoma damage or progression in apparently normal-tension or compensated patients.


2021 ◽  
Vol 8 (33) ◽  
pp. 3084-3089
Author(s):  
Ram Kumar Jaiswal ◽  
Ramyash Singh Yadav ◽  
Mridula Ranjan ◽  
Dipti Wahi ◽  
Chiranji Rai

BACKGROUND Myopia is a complex trait including both genetic and environmental factors as well as gene-environment interactions. It has been recognized as a risk factor for development of glaucoma. Both Myopia and raised IOP are known to increase mechanical stress at optic nerve head leading to glaucomatous nerve damage. This study intends to evaluate the clinical profile of myopic subjects and its correlation with Primary open angle glaucoma (POAG). METHODS A prospective observational study done from November 2019 to December 2020 after taking proper informed consent and ethical clearance. 164 eyes of 96 patients studied were divided into three groups, Group 1: low myopia (< -3.00D), Group 2: moderate myopia (-3.00 D to -5.75 D), Group 3: high myopia (≥ -6.00 D). A complete ocular examination was performed. Intraocular pressure was measured using Goldmann applanation tonometer. Visual field analysis using Humphrey automated perimetry was done in patients with suspected primary open angle glaucoma (POAG). Angle parameters and central corneal thickness (CCT) were measured using anterior segment optical coherence tomography (AS-OCT). RESULTS 164 eyes of 96 Myopic subjects were studied with no dropout during study period. Mean age was 46.05 yr. (range: 25-75 yr.). The refraction ranged from -0.50 DS to -17.00 DS. There was no statistically significant difference between Intraocular pressure (IOP), Central corneal thickness (CCT), corrected IOP and Nasal and Temporal Trabecular-iris Angle (TIA) between male and female of same age group. Mean IOP and mean CCT were found to vary significantly with age and with higher degree of myopia. Corrected IOP, Nasal and Temporal TIA increase significantly with higher degree of myopia. Cup-disc ratio (CDR) was found to be significantly higher in patients with moderate to high degree of Myopia. CONCLUSIONS Myopia is an important risk factor for development of primary open angle glaucoma, with its incidence increasing in patients with moderate to high myopia. KEYWORDS Myopia, Primary Open Angle Glaucoma, Intraocular Pressure, Central Corneal Thickness, Trabecular Iris Angle


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