Evaluation of the agreement and reliability of Transpalpebral Tonometers compared with Goldmann Applanation Tonometer – A systematic Review and Meta-Analysis Protocol

In 2020, the global prevalence of glaucoma was estimated to be 76 million and it was projected to increase to 111.8 million by 2040. Accurate intraocular pressure (IOP) measurement is imperative in glaucoma management since it is the only modifiable risk factor. Numerous studies have compared the reliability of IOP measured using transpalpebral tonometers and Goldmann applanation tonometry (GAT). This systematic review and meta-analysis aims to update the existing literature with a reliability and agreement comparison of transpalpebral tonometers against the gold standard GAT for IOP measurement among individuals presenting for ophthalmic examinations. The data collection will be performed using a predefined search strategy through electronic databases. Prospective methods-comparison studies published between January 2000 and September 2022 will be included. Studies will be deemed eligible if they report empirical findings on the agreement between transpalpebral tonometry and Goldmann applanation tonometry. The standard deviation and limits of agreement between each study and their pooled estimate along with weights and percentage of error will be reported using a forest plot. Cochrane’s Q test and the I2 statistic will be used to assess heterogeneity, and the publication bias will be investigated using a funnel plot, Begg’s and Egger’s tests. The review results will provide additional evidence on the reliability of transpalpebral tonometers that, in turn, could possibly assist practitioners to make informed decision about using it as a screening or diagnostic device for clinical practice, outreach camps, or home-based screening. Institutional Ethics Committee registration number: RET202200390. PROSPERO Registration Number: CRD42022321693.

Reutilization of disposable rebound tonometer probes: Risk or return?

Purpose: An advantage of rebound tonometry (RT) is its ease of use so that it can also be operated by health care technicians. However, the cost of the disposable measuring probes is high and their reuse carries the risk of infection. Therefore, this study aims to objectify the potential risk of bacterial transmission by RT. Methods: Our experimental setting consisted of two experiments. The first aimed to quantify the number of bacteria on a tonometer probe after immersion in a bacterial suspension in vitro. The experiment was carried out with two different bacteria and compared with results from a Goldmann tonometer probe. The second experiment tested whether bacteria could be transmitted by simulating reuse of a nondisinfected rebound tonometer probe. Results: First experiment: After immersion of the rebound tonometer probe, we measured a bacterial count of 2.43 × 106 Escherichia coli (EC) and 1.12 × 106 Pseudomonas fluorescens. In total, 1.09 × 107 bacteria for EC and 2.61 × 106 for Pseudomonas fluorescens (PF) were measured on the Goldmann tonometer probe. Second experiment: A bacterial transmission could be detected in 36% of cases in which reuse of nondisinfected tonometer probes was simulated. Conclusion: These results show that despite the small surface of the rebound tonometer probe, there is a clear risk of bacterial transmission. Thorough disinfection according to general standards should be mandatory if the tonometer probes are to be reused.

Assessment of intraocular pressure measurement between Goldman applanation tonometer, rebound tonometer, non-contact tonometer, and its correlation with central corneal thickness

Purpose: To compare readings of intraocular pressure (IOP) taken with the Goldmann applanation tonometer (GAT), the non?contact tonometer (NCT), and the rebound tonometer (RBT), and to compare their correlation with central corneal thickness (CCT). Methods: This was a prospective, cross?sectional, observational study to which patients above 18 years of age were enrolled. A total of 400 eyes of 200 non?glaucomatous patients underwent IOP recordings using the GAT, NCT, and RBT, and CCT was also noted. Informed consent of the patients was taken. The IOP readings taken via the three methods were compared and correlated with CCT. Paired t test was used to compare the two devices. Simple and multivariate linear regression analyses were used to study the relationship between factors. A P value less than 0.05 was considered significant. Correlation was determined using the Pearson correlation coefficient, and a Bland–Altman graph was plotted. Results: Mean IOP measured by the NCT was 15.65 ± 2.80 mmHg, by the RBT was 14.23 ± 3.05 mmHg, and by the GAT was 14.69 ± 2.97 mmHg. The mean CCT was 510.61 ± 33.83 microns. The difference between mean IOP recorded by the NCT and that by the RBT was 1.41 ± 2.39 mmHg, between the NCT and GAT was 0.95 ± 2.03 mmHg, and between the GAT and RBT was 0.45 ± 2.22 mmHg. The difference between the IOP values was statistically significant (P < 0.005). All tonometers showed a statistically significant correlation with CCT, but it was observed that the NCT had a stronger correlation (0.4037). Conclusion: The IOP readings taken by all the three methods were comparable; however, RBT values were closer to GAT values. CCT did influence the IOP values, and this should be kept in mind while evaluating.

CLINICAL EVALUATION OF INTRAOCULAR PRESSURE MEASUREMENTS USING DIFFERENT TONOMETERS IN PATIENTS OF VARIOUS REFRACTIVE ERRORS

Background: Intraocular pressure (IOP)is an important ?rst indicator of probability and suspicion of Glaucoma. The virtual IOP status is grossly in?uenced by multiple factors including Refractive errors ,corneal biomechanics ,central corneal thickness(CCT) and Scleral rigidity. To compare relative IOP measurements and Aim: its variability in Emmetropes, myopic and hypermetropic patients using Schiotz, Goldmann Applanation(GAT)and I-Care Rebound tonometer to establish an equation between virtual and real time IOP. This observational Materials and Methods: prospective study comprised of 100 subjects above the age of 18 years inclusive37 Emmetropes , 31 Hypermetropes and remaining 32 belonged to myopia . Descriptive statistics were performed using SPSS for Windows Statistical Analysis : version 17.0 to calculate the demographic characteristics of the study cohort. The data were expressed as mean values including the standard deviation (SD) and the 95% con?dence interval (CI). Mean IOP measurements between Schiotz, I-Care and GAT were compared by One way ANOVA along with Individual pair wise comparison by applying Post Hoc Tukey Test for comparison of IOP measurements using a particular method of Tonometry in individuals of myopia, hypermetropia and emmetropia. The highest mean value of CCT 536.667 mum was in Hypermetropes whereas the lowest CCT value of Results: 507.031mum was in myopic eyes with statistically signi?cant (P<0.05). The mean value for IOP in Emmetropes was16.665 mm Hg for Schiotz , 15.027 Hg for GAT and 15.081 mm Hg for I –Care .Whereas Hypermetropes revealed mean value of 15.055 mm Hg for Schiotz , 14.323 mm Hg for GAT and 14.065 mm Hg for I –Care . The mean value for IOP in Myopic eyes was 16.875 mm Hg for Schiotz , 14.375 mm Hg for GAT and 14.688 mm Hg for I –Care . The study had revealed higher mean Conclusion : value of IOP in Myopic eyes as compare to Emetropic and Hypermetropic subjects.IOP measurements by the Schiotz tonometer were signi?cantly higher as compare to GAT and I-Care tonometer. Whereas recordings by GAT and I Care tonometers were almost in agreement .De?nitive correlation could not be established between pachymetry readings and adjusted IOP following GAT and I –Care tonometry .

Study-of-phacoemulsification-vs-phacotrabeculectomy-in-management-of-primary-angle-closure-glaucoma

Introduction: The study was conducted to evaluate IOP management by surgical modalities such as combined trabeculectomy and phacoemulsification and phacoemulsification surgery alone. Vision impairment is a major public health problem and the burden is increasing with increase in aged population. This study wasAims And Objectives: undertaken for study the IOP management by surgical modalities such as combined trabeculectomy and phacoemulsification and phacoemulsification surgery alone. A pre-designed prospective study was conducted at the OPD of upgraded Department of Ophthalmology at LLRM Medical College, Meerut. A total of 60 patients were divided in to two equal groups randomly and studied. Majority of the patients in both the groups wereObservation And Result: aged between 61 – 70 years. Females outnumbered males in this study which was statistically significant between the two groups. The mean pre- operative intra ocular pressure was 23.3 mm Hg in combined surgery group and 23.9 mm Hg in cataract surgery alone group. Mean Intra ocular pressure decreased regularly in each follow up more in combined group than the cataract surgery alone group. The mean intra ocular pressure after 1 years follow up in combined surgery group was 10.8 mm Hg and 13.4 mm Hg in the cataract surgery alone groups which was statistically significant. Mean BCVA before the operation was 3.2 in combined surgery group and 3.8 in cataract surgery before surgery. Mean BCVA declined after 1 year of follow up in combined surgery group was 1.9 and 2.7 in cataract surgery alone group which was statistically significant. The surgery success was complete in 80.0% of the combined surgery group and 60% of the cataract alone group. Criteria For Failure Of Surgeries Ÿ The IOP >23 MMHG at the end of 1 year or Ÿ The IOP not reduced by 20 % from base line at the end of 1 year Conclusion: This study was mainly undertaken to study the efficacy of combined trabeculectomy with cataract extraction and cataract only on primary angle closure glaucoma. This study had found that, the reduction of intra ocular pressure in both the groups but more prominent in combined surgery group than cataract alone surgery group.

The effect of wearing N95 respirator masks on intraocular pressure of health care workers

Objective@#We determined if there was a significant change in the intraocular pressure (IOP) of healthcare workers with extended use of N95 masks.@*Methods@#This was a prospective time-series study involving 58 eyes of 29 healthcare workers who were assigned to 3 groups: surgical mask (control) and 2 intervention arms consisting of valved N95 (8511, 3M, USA) and non-valved N95 (8210, 3M, USA) masks. Each participant underwent IOP measurements of both eyes by Goldmann applanation tonometry at baseline, 5 minutes, 1 and 4 hours of mask use on three separate days. The primary outcome was the difference in IOP between the N95 and surgical mask groups.@*Results@#Mean baseline IOP of the cohort was 13.85 ± 1.11 mmHg with no significant difference among the groups. Compared to surgical mask use, mean IOP was increased at the 1 hour and 4 hour time points with valved N95 use (+0.88, p<0.001; +1.48, p<0.001 respectively) and increased at the 5 minute, 1 hour and 4 hour time points with nonvalved N95 use (+0.52, p=0.01; +1.07 p<0.001; +1.62, p<0.001, respectively).@*Conclusion@#There was a statistically significant increase in IOPs with prolonged N95 mask use. However, the levels of IOP increase were less than 2 mmHg and may be not clinically significant.

Comparison of the corrected intraocular pressure by tonopachy with that of Goldmann applanation tonometry in normal and glaucomatous patients

Purpose: To compare corrected intraocular pressure (IOP) by tonopachy with that of Goldmann applanation tonometry (GAT) in normal and glaucomatous patients. Methods: In this cross-sectional study, IOP and central corneal thickness (CCT) were measured in 426 eyes (213 normal eyes and 213 glaucomatous eyes) of 426 patients by tonopachy followed by GAT and ultrasound pachymetry. IOP was corrected for CCT by in-built formula in tonopachy and Ehlers correction factor for Goldmann tonometer. Limits of agreements were assessed using Bland朅ltman plots. Intraclass correlation coefficient was calculated to estimate the absolute agreement between single and average measurements of IOP and CCT of tonopachy with that of Goldmann tonometer and ultrasound pachymetry respectively. Results: Mean corrected IOP measured with tonopachy and GAT in glaucomatous eyes was 17.63 � 5.04 mmHg and 19.42 � 5.83 mmHg, and in controls it was 13.4 � 2.5 mmHg and 16.2 � 3.1 mmHg, respectively. Limits of agreement ranged from �63 to +9.25 mmHg for total population (mean = 2.31), �01 to +9.59 mmHg (mean = 1.79) for glaucoma group and �99 to +8.65 mmHg (mean = 2.83) for controls. Intraclass correlation coefficient for IOP measurement between tonopachy and Goldmann tonometer was 0.84 for total population, 0.85 for glaucoma group, and 0.63 for controls, respectively. Conclusion: Corrected IOP obtained by tonopachy showed moderate agreement with GAT and it is more in glaucoma patients than controls. Thus, tonopachy can be used as a screening tool, but cannot replace GAT.

Accuracy of intraocular pressure measurements between non-contact tonometer and ICare rebound tonometer / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To analyze the accuracy of non-contact tonometer(NCT)and ICare rebound tonometer(RBT)in measuring intraocular pressure in glaucoma patients. <p>METHODS:A retrospective proportional control study. Totally 113 patients(185 eyes)with glaucoma were studied. Intraocular pressure was measured by RBT, NCT and Goldmann Applanation tonometer(GAT)at 9:00 and 16:00 and recorded as two sets of data, respectively. Their accuracy is evaluated by the rank sum test, and the international standard 8621 guide, Bland-Altman consistency analysis analyzed the consistency of the two groups of measurements, and the data were divided into two groups: abnormal intraocular pressure group(<10mmHg or >21mmHg)and normal intraocular pressure group(10-21mmHg). The consistency was analyzed between different groups. The spearman correlation analysis is adopted to analyze the correlation between ophthalmotonometers.<p>RESULTS: There were differences among the GAT, NCT and RBT measurements(<i>P</i><0.01). There was a strong correlation between the intraocular pressure measured value obtained by GAT and measured values obtained by RBT and NCT(<i>rs</i>=0.71, 0.77, <i>P</i><0.001). The measured values of NCT and GAT are close to each other without statistically significant differences(<i>P</i>=0.92). Compared with GAT, RBT has a higher intraocular pressure measured value, and there are significant differences(<i>P</i><0.05). However, compared with GAT, both NCT and RBT have a wide range of limits of agreement, and they are(-6.2-6.0mmHg)and(-5.2-7.6mmHg)respectively. In normal intraocular pressure groups, the ranges of limits of agreement are(-5.9-5.9mmHg)and(-4.3-7.5mmHg)respectively. In abnormal intraocular pressure groups, the ranges of limits of agreement are(-7.3-6.4mmHg)and(-7.5-5.6mmHg)respectively. The evaluation carried out in accordance with ISO 8612 guides indicates that the abnormal values more than the 95% of consistency restriction of NCT and RBT in the three groups are(3.9%, 11.3%, 12.2%)and(26.3%, 11.3%, 12.2%)respectively.<p>CONCLUSION: Both NCT and RBT cannot simply replace the GAT to measure the intraocular pressure of glaucoma patients. In glaucoma patients, with the deviation of the measured value from the normal intraocular pressure range, the measurement error of NCT and RBT also increase.

Comparison of IOP detected by three kinds of tenonometers in children with high intraocular pressure and their relations with corneal thickness / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the central corneal thickness(CCT)distribution of the children with ametropia in the non-contact tonometry(NCT), and the different intraocular pressure(IOP)measurements with Goldmann applanation tonometry(GAT)and the OCULUS Corvis ST(CST)corneal biomechanical analyzer, meanwhile, to evaluate the correlation between IOP and CCT. <p>METHODS: NCT was used to measure 39 children(78 eyes)of non-glaucomatous ametropia with single eye or binocular IOP higher than 21 mmHg. The IOP was measured again with CST and GAT. The two instruments were measured in random order and the CCT was measured by CST and corrected the IOP according to the CCT. The eyes were divided into the normal group and the thicker group according to the CCT. The three IOP values were analyzed by the ANOVA, and the IOP and CCT was analyzed by the Pearson correlation coefficient. <p>RESULTS: In the normal CCT group, the IOP by CST was lower than that the GAT and NCT measurements and the difference was statistically significant(<i>F</i>=5.12, <i>P</i>=0.01). In the thicker group, the comparison of the three intraocular pressure measurement methods was statistically significant(<i>F</i>=15.72, <i>P</i><0.001). IOP by NCT and GAT were significantly correlated with CCT(<i>r</i>_NCT=0.298, <i>P</i>_NCT=0.04; <i>r</i>_GAT=0.408, <i>P</i>_GAT=0.01). There was no significant correlation between CST corrected intraocular pressure and CCT(<i>r</i>_CST=0.062, <i>P</i>_CST=0.593). <p>CONCLUSION: The CCT of ametropia children with high IOP by Topcon tonometry were thicker. The corrected intraocular pressure of CST is lower than NCT and GAT. NCT and GAT were positively correlated with CCT. For children with thicker CCT, CST corrects intraocular pressure was closer to the real intraocular pressure value than NCT and GAT.

Rebound Tonometers versus Other Tonometers: Agreement among Readings and the Effects of Axial Length, Ocular Pulse Amplitude, and Central Corneal Thickness on Readings

OBJECTIVE: The aim of this study was to use intraocular pressure (IOP) measurements obtained via rebound tonometry (RBT, the I-care instrument), Goldmann applanation tonometry (GAT), non-contact tonometry (NCT), dynamic contour tonometry (DCT, PASCAL), and the TonoPen to investigate the consistency of readings among methods and the influence of ocular pulse amplitude (OPA), axial length (AL), and central corneal thickness (CCT) on RBT data. METHODS: We prospectively studied 123 eyes. IOP was measured via RBT, GAT, NCT, DCT, and the TonoPen. In addition, OPA was measured via DCT, AL, and CCT. Correlations among measurements using the various methods were evaluated, as were the effects of OPA, AL, and CCT on RBT data. RESULTS: RBT data were significantly correlated with data obtained via GAT, NCT, DCT, and the TonoPen; the highest correlation was with GAT. OPA was significantly correlated with IOP measured via GAT but not with IOP measured via RBT. Both AL and CCT were significantly correlated with IOP data obtained via RBT and GAT. CONCLUSION: Significant correlations were evident among IOP measurements obtained via RBT and other tonometry methods. However, the influence of AL and CCT on IOP measurements obtained via RBT requires careful consideration and interpretation. Although the IOP values obtained by GAT were correlated with OPA values obtained by DCT, this was not true of IOP data obtained by RBT. This might be associated with characteristic of RBT which has the relatively short corneal contact time.

Agreement of intraocular pressure measured by noncontact tonometer and Goldmann applanation tonometer : a Meta-analysis / 中华实验眼科杂志

Background Noncontact tonometer (NCT) is a common application in clinical ophthalmology,while its measured value is influenced by corneal parameter.In recent years,there existed some clinical trials discussing the agreement between NCT and gold standard Goldmann applanation tonometer (GAT),but there was still lack of evidence.Objective This study was to evaluate the agreement between NCT and GAT by applying evidence based medicine (EBM) method.Metbods A systematic literature retrieval was conducted from the MEDLINE,EMbase,CBM disc and CNKI database with the limitation of publishing time until June 2016.The literatures were screened according to the inclusion and exclusion criteria.The sample size,average age,sample characteristics and follow-up time were extracted.The value of intraocular pressure measured by NCT and GAT were analyzed.The overall effect size was analyzed using Review Manager 5.3 (from The Cochrane Collaboration) as weighted mean difference (WMD).There existed heterology in this study.Radom effect mode was used to evaluate and compare the difference between NCT and GAT value.Results Twenty four articles were retrieved.Six comparison studies incorporated with 478 eyes were included for Meta analysis.After random effects model was performed for correction.Intraocular pressure measured by NCT was 0.02 mmHg larger than that by GAT (1 mmHg =0.133 kPa).There was no significant difference in the measurement value of IOP between the two instruments (WMD =0.02,95％ CI:-0.59 to 0.63,P =0.95).Funnel chart method showed that literature publication bias existed in this study.Conclusions Normal persons' IOP obtained from NCT and GAT showed a good reproducibility.More comparison studies are needed to support this result.

Comparison of Intraocular Pressure via Goldmann-applanation Tonometry and TonoPen in Thyroid-associated Ophthalmopathy Accompanying Restrictive Strabismus

PURPOSE: To compare the intraocular pressure (IOP) measured using Goldmann-applanation tonometry (GAT) and Tonopen® tonometry and to evaluate the factors influencing the measurement difference in patients with thyroid-associated ophthalmopathy (TAO)-related restrictive strabismus. METHODS: In 50 eyes of 50 patients who were diagnosed with TAO, IOP measurements were taken using both GAT and a Tonopen® and were subsequently compared between the devices. Factors influencing the measurement difference between the devices were determined, including the restriction of eyeball movement, eyeball deviation, exophthalmometry, central corneal thickness, refractive errors, and blood thyroid hormone levels. RESULTS: In the TAO patients, the GAT-measured IOP was higher than for Tonopen® (16.1 ± 4.7 vs. 13.8 ± 4.5 mmHg, respectively, p < 0.001). As the restriction of vertical eyeball movement increased, the IOP difference between the devices also increased (p = 0.037). The absolute IOP difference between the devices was positively correlated with restrictions in vertical eyeball movement (p = 0.027), degree of vertical strabismus (p = 0.021), and central corneal thickness (p ≤ 0.031). CONCLUSIONS: In patients with TAO accompanying vertical eyeball movement restriction, potential errors in IOP measurements should be considered between the different IOP-measuring devices.

Can higher end tonometers be used interchangeably in routine clinical practice.

Context: Precise intraocular pressure (IOP) measurement is important in glaucoma practise. Various instruments are available today to accurately measure IOP. Thus, the question arises about which instrument to use and whether all of them can be used interchangeably. Aims: To assess the agreement between noncontact tonometer (NCT), rebound tonometer (RBT), Goldmann applanation tonometer (GAT), and dynamic contour tonometer (DCT) in measuring IOP. Subjects and Methods: 499 eyes of 250 patients were evaluated during a period of 24 months from September 2010 to August 2012 and measurement of IOP by NCT, RBT, GAT, and DCT was done in the given sequence. The agreement was assessed by use of the Bland–Altman plot keeping GAT as a gold standard technique. Results: The mean IOP value of NCT, RBT, GAT, and DCT was 15.9 ± 5.5, 15.9 ± 5.8, 15.9 ± 4.9, and 16.0 ± 4.7 mm of Hg, respectively. The limits of agreement of GAT with DCT, NCT, and RBT were found to be +5.4 to −5.2, −4.7 to +4.6, and −5.2 to +5.1 mm of Hg, respectively. Conclusions: A positive and strong correlation was found between newer tonometers and GAT, but the limit of agreement was clinically unacceptable. The use of a single tonometer should be practised at a glaucoma clinic for a patient at each follow‑up.

The relationship between central corneal thickness and intraocular pressure in healthy and glaucomatous eyes, a systematic review and Meta-analysis / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the relationship between central corneal thickness and intraocular pressure in healthy and glaucomatous eyes of adults. To make up to date summary of the results of studies done on the association of central corneal thickness measurements and intraocular pressure measurements in Glaucoma patients and in healthy subject. ●METHODS: To identify relevant studies a search of MEDLINE and Science Direct databases for studies investigating the relationship between central corneal thickness ( CCT ) and intraocular pressure ( lOP ) was conducted. The Search period was from Sep. 10th to Oct. 28th of 2015. Search key words included: central corneal thickness, intraocular pressure, glaucoma, ocular hypertension, exfoliative glaucoma, applanation tonometry, pachymetry, primary open angle glaucoma, Goldmann applanation tonometry. Ln addition, a manual search of “The Year Book of Ophthalmology” Journals 2004 to 2006 lssues in the Southern Medical University Library English language section was done. The following exclusion criteria applied:1) non-English media studies;2 ) studies done before 2005; 3 ) case series and case reviews; 4 ) studies involving treatment protocols or surgical techniques; 5 ) studies comparing glaucomatous eyes with other conditions such as diabetes, hypertension or cardiovascular disease as secondary variables; 6 ) studies with children as study subjects; 7 ) studies with animal subjects. ●RESULTS: There were 12 observational studies and 1 case control study included. Compared to control subjects, patients had significantly increased lOP ( SMD:0. 50, 95% Cl:0. 30~0. 70, Z=4. 88, P ● CONCLUSION: It has been established that glaucomatous eyes tend to have thinner CCT and higher lOP compared to normal eyes.

Reactivation of Ocular Toxoplasmosis – A Case Report

Ocular toxoplasmosis is the commonest cause of posterior uveitis and is usually the result of an acquired infection caused by the protozoan Toxoplasma gondii,here we present report of case of spontaneous reactivation of toxoplasmosis in a 14-yr old girl. with reactivation o oocular toxoplasmosis.

Comparison of two methods of tonometry in glaucoma patients:Goldmann applanation tonometer and non-contact tonometer / 国际眼科杂志(Guoji Yanke Zazhi)

? AlM: To compare the two methods for the measurement of glaucoma patients' intraocular pressure ( lOP) between Goldmann applanation tonometer ( GAT) and non-contact tonometer ( NCT) and find the laws of the two methods.?METHODS: The lOP of 108 glaucoma patients ( 206 eyes) were measured by GAT and NCT respectively.?RESULTS: ln 108 glaucoma patients, the average lOP of 206 eyes was 29. 77 ± 10. 27mmHg by GAT and 24. 59 ± 8. 58mmHg by NCT. There was significant difference between GAT and NCT (P<0. 01). The higher of lOP, the difference between GAT and NCT was greater.?CONCLUSlON: The measurement results with NCT were lower than that of GAT. The higher of lOP, the difference between GAT and NCT was greater. lt's better to measure lOP by GAT for the glaucoma patients, in order to avoid the misdiagnosis and mistreatment of glaucoma.

Comparison of Dynamic Contour Tonometry and Goldmann Applanation Tonometry in Relation to Central Corneal Thickness

PURPOSE: In this study we compared the intraocular pressures (IOPs) measured using dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) and investigated the correlation between central corneal thickness (CCT) and IOP. METHODS: In a prospective study, 178 eyes of 91 subjects with glaucoma and glaucoma suspect were enrolled. IOP was measured using DCT and GAT and CCT was measured using ultrasound pachymetry. Each eye was classified into 1 of 3 groups according to their CCT: low CCT (Group A; CCT or = 561 microm). In each group, we investigated the correlation between CCT and IOP measurement using GAT and DCT. RESULTS: A significant correlation was found between CCT and IOP measured using GAT (p < 0.001), but not between CCT and IOP measured using DCT (p = 0.108) in all patients. Subgroup analysis showed that CCT affected IOP measured with GAT only in Group A (p = 0.027) and IOP measured with DCT was not affected by CCT in all 3 groups. CONCLUSIONS: IOP measured using GAT and DCT were significantly affected by CCT, especially when the CCT was low. CCT may have no effect on DCT thus, IOP measured using DCT is more reliable than GAT in patients with thin corneas.

Comparison of Rebound Tonometry and Goldmann Applanation Tonometry in Restrictive Thyroid Eye Disease

PURPOSE: To compare the intraocular pressure (IOP) measured using the rebound tonometer (RT) and Goldmann applanation tonometer (GAT) in the primary position and upgaze in restrictive thyroid eye disease (TED). METHODS: We measured the IOP in 30 subjects (54 eyes) who visited an ophthalmologist between May 2014 and May 2015. This study included 16 healthy volunteers (32 eyes) and 14 TED patients (22 eyes). The outcome measurements were the comparison of IOP readings; both intergroup and 2 measurements using the RT and the GAT for patients with restrictive TED and the control group. Upgaze IOP was measured on the central cornea with a 20-degree chin-down posture. RESULTS: Both TED patients and controls showed an increase in IOP in upgaze compared with primary position (p < 0.001). There was a significant difference in mean differential IOP between patients and controls measured using RT and GAT, respectively (p < 0.001). In the control group, there was no significant difference between the 2 instrument readings in upgaze as well as primary position for patients with restrictive TED (p = 0.853 in TED; p = 0.260 in controls). CONCLUSIONS: Based on our results, the mean IOP in conventional upgaze was significantly increased in TED patients compared to primary position using both the RT and GAT and no difference in RT readings compared with GAT readings. The RT can be used to establish IOP since no significant difference between the upgaze and the primary position readings was observed in patients with restrictive TED and is a simple and effective diagnostic tool unrelated to the position and the direction of gaze.

Rectifying calibration error of Goldmann applanation tonometer is easy.

Purpose: Goldmann applanation tonometer (GAT) is the current Gold standard tonometer. However, its calibration error is common and can go unnoticed in clinics. Its company repair has limitations. The purpose of this report is to describe a self‑taught technique of rectifying calibration error of GAT. Materials and Methods: Twenty‑nine slit‑lamp‑mounted Haag‑Streit Goldmann tonometers (Model AT 900 C/M; Haag‑Streit, Switzerland) were included in this cross‑sectional interventional pilot study. The technique of rectification of calibration error of the tonometer involved cleaning and lubrication of the instrument followed by alignment of weights when lubrication alone didn’t suffice. We followed the South East Asia Glaucoma Interest Group’s definition of calibration error tolerance (acceptable GAT calibration error within ±2, ±3 and ±4 mm Hg at the 0, 20 and 60‑mm Hg testing levels, respectively). Results: Twelve out of 29 (41.3%) GATs were out of calibration. The range of positive and negative calibration error at the clinically most important 20‑mm Hg testing level was 0.5 to 20 mm Hg and ‑0.5 to ‑18 mm Hg, respectively. Cleaning and lubrication alone sufficed to rectify calibration error of 11 (91.6%) faulty instruments. Only one (8.3%) faulty GAT required alignment of the counter‑weight. Conclusions: Rectification of calibration error of GAT is possible in‑house. Cleaning and lubrication of GAT can be carried out even by eye care professionals and may suffice to rectify calibration error in the majority of faulty instruments. Such an exercise may drastically reduce the downtime of the Gold standard tonometer.

Comparison of Intraocular Pressure Measured by Non-Contact Tonometer, Rebound Tonometer, Tono-Pen, and Goldmann Applanation Tonometer

PURPOSE: To compare the level of accuracy of intraocular pressure (IOP) measurements attained by non-contact tonometer (NCT), rebound tonometer (RT) Icare(R), and Tono-Pen (TONO-PEN AVIA(R)), using Goldmann Applanation tonometer (GAT) as a reference value and to explore their clinical usefulness. METHODS: In a prospective study of 71 normal eyes, IOP was measured with NCT, RT, Tono-Pen and GAT. The IOP values of were then compared between the eyes. RESULTS: RT showed statistically most significant agreement with the GAT [ICC 0.811, 95%CI 0.712-0.878]. In analysis of Bland-Altman plots, NCT showed the smallest mean bias (+0.2 mm Hg) and widest CI (95%CI; +/-5.05 mm Hg), RT showed relatively small mean bias (-0.7 mm Hg) and narrowest CI (95%CI; +/-3.75 mm Hg). CONCLUSIONS: There was a significant agreement between the RT and the GAT measurements. We expect RT to be considered as a reliable alternative when IOP measurement with GAT is not feasible.