Goldmann Applanation Tonometer Research Articles

Evaluation of a new transpalpebral tonometer for self-measuring intraocular pressure.

We developed a novel transpalpebral self-tonometer called the TapEye tonometer (TET) based on palpation of the upper eyelid. Our goal was to evaluate a method for improving the accuracy of measuring intraocular pressure (IOP) through the eyelid. Participants underwent standardized training by technicians and were required to be able to use the TET for study inclusion. Subsequently, a noncontact tonometer and Goldmann applanation tonometer (GAT) were used. All participants were instructed to measure their IOPs using the three tonometers at baseline (visit 1) and at 1 month (visit 2). At visit 2, the corrected IOP value measured by the TET (c-TET) was calculated using the difference between the TET and GAT measurements obtained at visit 1. No significant correlations were found between the TET and GAT measurements at any visit, but the correlation between the c-TET and GAT measurements at visit 2 was significant. The mean difference between the c-TET and GAT measurements was 0.4 ± 3.7 mmHg in the right eye and 0.5 ± 3.4 mmHg in the left eye. After correcting the IOP based on the difference between the TET and GAT measurements at the initial visit, the corrected IOP value of the TET was correlated with that of the GAT at the second visit. The TET has the potential to address an unmet need by providing a tool for minimally invasive IOP measurements. Clinical trial registration number: jRCTs032220268.

Effect of Dorzolamide-Timolol fixed dose combination on central Corneal Thickness in patients of Primary Open Angle Glaucoma Versus Normal Tension Glaucoma

PURPOSE: To evaluate the effect of dorzolamide/timolol fixed dose combination on central corneal thickness in primary open-angle and normal tension glaucoma. METHOD: This retrospective cohort study was approved by the Ethical Review Board of College of Ophthalmology and Allied vision Sciences (1469/23) and was conducted at Diagnostic clinic Mayo Hospital, Lahore from March, 2023 to September, 2023. Sample size was calculated by a formula whose level of significance (????) was 5%, standard deviation (????) 30.9 and test values of population mean (µ̥) was 540. Using non-probability convenient sampling method total sample size was 80 patients of age group 30 to 60 which divided into normal tension and primary open angle glaucoma of 40 each. Patients with corneal edema, diabetes, and allergic to dorzolamide-timolol fixed dose combination were excluded. Data was analyzed using SPSS version 25.00. Wilcoxon signed ranks test and chi-square test were used for the significance of the study. Data p-value <0.005 considered significant. All the tests were performed after patient’s informed consent. Intraocular pressure (IOP) and central corneal thickness (CCT) were measured by Goldmann applanation tonometer and ultrasound Pachymeter respectively. RESULTS: IOP and CCT in right eye 16.17± 7.05 (p=0.000) and 545.50± 22.2 (p=0.098) respectively and of left eye 16.56± 7.00 (p=0.003) and 549.16± 20.0 (p=0.133) respectively. This illustrates significant difference in intraocular pressure after treatment in both eyes but insignificance difference in central corneal thickness. CONCLUSION: Dorzolamide-Timolol combination successfully reduces IOP as intended and leads to no statistically significant change in central corneal thickness.

ACCURACY OF MEASUREMENT RESULTS ON SCHIOTZ TONOMETER TOWARDS GOLDMANN APPLANATION TONOMETER IN TYPE II DIABETES MELLITUS PATIENTS IN MOHAMMAD HOESIN HOSPITAL, PALEMBANG

Introduction & ObjectivesThe Goldmann Applanation Tonometer is now the most accurate gold standard compared to othertonometers. IOP measurement errors using the Schiotz Tonometer can be caused by ocular rigidity,where the IOP is read higher in eyes with higher ocular rigidity and vice versa. Type II DiabetesMellitus (DM) patients are at risk for increased ocular rigidity
 MethodsThis research is a cross-sectional study with a diagnostic test design regarding the accuracy ofintraocular pressure results on the Schiotz Tonometer against the Goldmann Applanation Tonometerin type II Diabetes Mellitus patients with 35 research samples. The research was conducted at theMohammad Hoesin Hospital in Palembang from April 2022 – September 2022 until the sample sizewas met
 ResultsIntraocular pressure (IOP) as measured by The average Goldmann Applanation Tonometer was 15.5± 2.4 mmHg, with a Schiotz load of 7.5 grams the average was 16.2 ± 2.3 mmHg. Ocular rigidityhad a median of 0.0242 (0.0176 – 0.0341) From the results of this study the IOP examination withthe Schiotz Tonometer had a sensitivity of 92.9%, a specificity of 80.9%, a positive predictive valueof 76.5%, a negative predictive value of 94.4% and an accuracy value of 92.3% indicating astatistically strong level of accuracy
 ConclusionThe Schiotz tonometer has an accuracy rate of 92.3% in examining intraocular pressure using a loadof 7.5 type II diabetes patients which can replace the Goldmann Applanation Tonometer as the goldstandard if normal ocular rigidity is found

The effect of 1% tropicamide on central corneal thickness and intraocular pressure

Background: Dilating the eye with tropicamide may alter the intraocular pressure (IOP) because of an obstruction of the iridocorneal angle, resulting in decreased aqueous outflow drainage. Also, the repeated application of eyedrops and instrumentation could lead to increased central corneal thickness (CCT), consequently affecting IOP.Aim: This study aimed to determine the effect of 1% tropicamide on CCT and IOP post-mydriasis among the University of Limpopo optometry students.Setting: The data were collected at the optometry clinic of the University of Limpopo.Methods: A within-subject experimental study was conducted on 59 healthy subjects aged 18 years – 28 years. A computer assisted simple random probability sampling was used to identify a sample of participants from the study population (N = 200). Baseline and post-mydriasis IOP (20 min, 30 min, and 45 min intervals) were measured with a Goldmann applanation tonometer. Central corneal thickness and IOP were analysed using means, correlations and paired t-tests.Results: The mean CCT pre-mydriasis was 504.68 μm, and post-dilation was 507.90 μm, 510.08 μm and 509.25 μm at 20 min, 30 min, and 45 min, P = 026, p = 0.033, P = 0.004, respectively. Moreover, the mean IOP pre-mydriasis was 15.97 mmHg, and post-dilation was 16.85 mmHg, 16.46 mmHg and 16.85 mmHg over 20 min, 30 min, and 45 min of followed-up time, p = 0.140, p = 0.432, and p = 0.183, respectively.Conclusion: Measuring IOP post-dilation is still valid; however, CCT should be measured before the instillation of tropicamide.Contribution: This study analysed the effect of 1% tropicamide on CCT and IOP post-mydriasis in a clinical South African context.

Advances and Challenges in Wearable Glaucoma Diagnostics and Therapeutics.

Glaucoma is a leading cause of irreversible blindness, and early detection and treatment are crucial for preventing vision loss. This review aims to provide an overview of current diagnostic and treatment standards, recent medical and technological advances, and current challenges and future outlook for wearable glaucoma diagnostics and therapeutics. Conventional diagnostic techniques, including the rebound tonometer and Goldmann Applanation Tonometer, provide reliable intraocular pressure (IOP) measurement data at single-interval visits. The Sensimed Triggerfish and other emerging contact lenses provide continuous IOP tracking, which can improve diagnostic IOP monitoring for glaucoma. Conventional therapeutic techniques include eye drops and laser therapies, while emerging drug-eluting contact lenses can solve patient noncompliance with eye medications. Theranostic platforms combine diagnostic and therapeutic capabilities into a single device. Advantages of these platforms include real-time monitoring and personalized medication dosing. While there are many challenges to the development of wearable glaucoma diagnostics and therapeutics, wearable technologies hold great potential for enhancing glaucoma management by providing continuous monitoring, improving medication adherence, and reducing the disease burden on patients and healthcare systems. Further research and development of these technologies will be essential to optimizing patient outcomes.

A Comparative Study of Intraocular Pressure Measurements by Goldmann Applanation Tonometer and Schiotztonometer and the Study of Schiotz Tonometer a Screening Tool in North Karnataka Population

Background: Glaucoma is a multifactorial disease with common end point characteristics affecting the optic nerve.It is defined as an optic neuropathy characterised by specific structural findings in the optic disc (increased VerticalCup Disc Ratio (VCDR) or VCDR asymmetry >97.5 percentile) and particular functional deficits in automatedvisual field testing. It consists of three components: the optic nerve head, the visualfield, and intraocular pressure.Detecting the intraocular pressure is essential in not only initiating treatment, but also in monitoring the responseto treatment.Method: 210 purposively selected patients were subjected to three methods of tonometry – Goldmannapplanationtonometry, Schiotz indentation tonometry (with the 5.5g, 7.5g and 10 g weights). Three recordings were obtainedwith each method and the arithmetic mean taken as the intraocular pressure. The data was statistically analyzedusing the intra-class correlation coefficient. Sensitivity and specificity were also calculated for the Schiotz tonometer.Results: The Schiotz tonometer showed fair agreement with the Gold mannapplanationtonometer. The Schiotztonometer scored low as an effective screening tool.Conclusion: The current study shows that the Schiotz tonometer compares favourably with theGoldmannapplanation tonometer showing fair agreement with it. It showed good specificity and was reliable indetection of positives, excluding false positives.

Comparative study of recording intraocular pressure in adults by three different tonometers Goldmann applanation tonometer, noncontact tonometer, and tonopen

Purpose To compare and correlate the intraocular pressure (IOP) measurement obtained by Goldmann applanation tonometer (GAT), noncontact tonometer (NCT), and tonopen in normal and glaucomatous patients. Patients and methods A cross-sectional, observational, and comparative study was carried out. Two hundred eyes of 100 patients were screened, detailed history was taken, and thorough ocular examination was done. IOP was recorded using NCT (Keeler Pulsair), Tonopen (Tonopen XL), and GAT. Gonioscopy, optic disc examination, central corneal thickness, and visual field testing were done. Results The mean age of the study group was 53.25 years. Mean IOP by NCT was 19.20 mmHg, by GAT was 22.44 mmHg, and by tonopen was 19.33 mmHg. There was statistically significant difference between mean IOP with respect to method used (P<0.001). Forty-eight percent of eyes, 40% eyes, and 49% eyes had IOP less than 18 mmHg by NCT, GAT, and tonopen, respectively. In total, 35.5% eyes, 19.5% eyes, and 35.5% eyes had IOP ranging between 18 and 25 mmHg by NCT, GAT, and tonopen, respectively. In total, 16.5% eyes, 40.5% eyes, and 15.5% eyes had IOP more than 25 mmHg by NCT, GAT, and tonopen, respectively. Conclusion NCT and tonopen readings correlate well with GAT readings in physiologic IOP range up to 20 mmHg, but at higher IOP range they tend to underestimate IOP readings as compared with GAT. However, NCT and tonopen can be used for screening purpose as they are portable and easy to use.

Correlation Between Central Corneal Thickness and Intraocular Pressure with the Goldmann Applanation Tonometer

Purpose: The aim of this review is to investigate the correlation between central corneal thickness (CCT) and Intraocular pressure with the Goldmann applanation tonometer (GAT).
 Materials and Methods: A literature search using Medline database was conducted for the years 1946 to 2022 to explore the relationship between central corneal thickness and Intraocular pressure measured by the Goldmann applanation tonometer. The search was restricted to studies published in English language. The first 80 articles were reviewed and five relevant studies were selected in this analysis.
 Findings: Impacts of central corneal thickness on Intraocular pressure were investigated in five studies. Overestimation of intraocular pressure is associated with thick cornea while underestimation of intraocular pressure was associated with thin cornea
 Implications to Theory, Practice and Policy: Central corneal thickness can affect the result of Intraocular pressure measurement with the Goldmann applanation tonometer (GAT) . Assessment of central corneal thickness (CCT) is necessary for correct interpretation of IOP measurements obtained with the Goldmann applanation tonometer (GAT).

Comparison of Three Methods of Tonometry in Patients With Inactive Thyroid-Associated Orbitopathy

Introduction: Intraocular pressure (IOP) measurement in patients with thyroid-associated orbitopathy (TAO) can be difficult and misleading, particularly in patients with diplopia and eye deviation (esotropia or hypotropia). However, when measuring IOP, it is also necessary to pay sufficient attention to TAO patients without diplopia in primary gaze direction and without motility disorder that might not be readily apparent. Purpose: The aim of this study was to evaluate the accuracy of measurement of intraocular pressure (IOP) using three different types of tonometers: the rebound tonometer (iCARE), the Goldmann applanation tonometer (GAT) and the non-contact airpuff tonometer (NCT) in patients with inactive TAO. Materials and Methods: A total of 98 eyes of 49 adult patients with TAO were examined. The study group included 36 females and 13 males, with an age range of 19–70 years and a median age of 55.0. All the patients had evidence of thyroid disease, a history of mild to moderate TAO, no clinical signs or symptoms of active disease, and no diplopia in direct gaze direction. In addition to a comprehensive eye examination, all the patients underwent measurement of intraocular pressure with three tonometers: NCT, iCARE, and GAT. The measurements with these three devices were compared. Results: The mean IOP was 18.1 ± 2.4 mmHg (range 13–25 mmHg) with GAT, 22.3 ±5.0 mmHg (range 13–35 mmHg) with NCT, and 18.0 ±2.4 mmHg (range 13.3–26 mmHg) with iCARE. The mean difference between the GAT and iCARE measurements (using the Bland-Altman analysis) was -0.1 ±1.16 mmHg (limits of agreement -2.4 to 2.1). The mean difference between the GAT and NCT measurements was 4.2 ±3.6 mmHg (limits of agreement -2.8 to 11.2). The mean difference between the iCARE and NCT measurements was -4.3 ±3.7 mmHg (limits of agreement -11.6 to 2.9). No significant difference was found between GAT and iCARE (p = 1.000). However, there was a significant difference between GAT and NCT (p < 0.0001), as well as between iCARE and NCT (p < 0.0001). Conclusions: In patients with TAO, NCT significantly overestimates IOP values compared to the GAT and ICare. By contrast, the iCARE rebound tonometer provides IOP measurements comparable to the gold standard GAT in these patients.

Comparison of Goldmann applanation tonometer with Huvitz non-contact tonometer

: Glaucoma has been established as the second leading cause of blindness as blindness due to glaucoma is untreatable. Glaucoma screening is very important step to prevent visual loss and for screening intraocular pressure measurement plays an important role. : The study aims to compare the Goldmann applanation tonometer with Huvitz non-contact tonometer.: This was a cross-sectional study conducted for a period of 3 months March 2023 to May 2023. 200 patients were included in the study taking care of exclusion criteria. The study was started after getting permission from the institutional ethics committee. Patients were randomly taken and they underwent NCT and GAT. The values of both were compared and analysis was done using STATA and SPSS software.: The study includes 200 patients who underwent GAT and NCT. The age group ranges from 21-45 years. The IOP values showed that the mean value in the GAT group was 15.54 mmHg and that in the NCT group was 17.255 mmHg. So, the mean value shows that the values obtained from NCT are higher than those obtained from GAT. The mean IOP in the NCT group is 1.715 mmHg higher than that in the GAT group. The study has a p-value of 0.001.: Both the above methods are frequently used for the measurement of IOP. NCT is an easy and less time-consuming method that is used more frequently. But the study concludes that the results of NCT are not as accurate and should be rechecked with those of GAT in cases with borderline values before starting workup of glaucoma.

Influence of unilateral eyelid spasms and botulinum toxin treatment on intraocular pressure measured by transpalpebral tonometer.

Eyelid spasms might be associated with elevated intraocular pressure (IOP) in hemifacial spasm (HFS) patients. IOP assessment using a Goldmann applanation tonometer (GAT) is often compromised by eyelid spasms. This study aimed to assess the effect of HFS on IOP measurements using the transpalpebral tonometer Diaton® before and after treatment with botulinum toxin type A (BTX-A) and compared Diaton® and GAT measurements after treatment with BTX-A. IOP measurements were obtained with Diaton® in 27 patients with moderate-to-severe HFS before and after treatment with BTX-A. After treatment, the IOP was also measured using GAT and the results were compared with the ones measured with a Diaton®. The patients underwent automated perimetry, OCT, and pachymetry for screening to glaucoma. Mean IOP with Diaton® was 11 ± 3.42mmHg before treatment in the affected eye and 9 ± 2.98mmHg in the contralateral eye. This difference was statistically significant (P = 0.012). However, after treatment with BTX-A, no interocular difference was found in IOP obtained with Diaton® (P = 0.204) or GAT (P = 0.971). Comparison between GAT and Diaton® measurements showed no significant differences after BTX-A treatment between the affected (P = 0.212) and contralateral eye (P = 0.971). A significant reduction in IOP measurements on the affected side of HFS patients was observed after treatment with BTX-A, demonstrating that eyelid spasms may increase the IOP. No significant difference was observed between Diaton® and GAT measurements after the application of BTX-A. No differences were found in automated perimetry, OCT, and CCT when comparing affected eyes with contralateral eyes.

Agreement of intraocular pressure measurement with Corvis ST, non-contact tonometer, and Goldmann applanation tonometer in children with ocular hypertension and related factors.

To access the agreement of intraocular pressure (IOP) values obtained from biomechanically corrected tonometer [Corvis ST (CST)], non-contact tonometer (NCT), and Goldmann applanation tonometer (GAT) in children with NCT measured-IOP (NCT-IOP) values of 22 mm Hg or more, and related factors. A total of 51 eyes with NCT-IOP≥22 mm Hg in children aged 7 to 14y were examined and IOP was measured by CST, NCT, and GAT. Based on GAT measured IOP (GAT-IOP), ocular hypertension (OHT) group (≥22 mm Hg, 24 eyes) and the non-OHT group (<22 mm Hg, 27 eyes) were defined. We compared the agreement of the three measurements, i.e., CST measured IOP (CST-IOP), GAT-IOP, and NCT-IOP, and further analyzed the correlation between the differences in tonometry readings, central corneal thickness (CCT), axial length (AL), optic disc rim volume, and age. Compared with the OHT group, thicker CCT, larger rim volume, and higher differences between NCT-IOP and GAT-IOP, were found in the non-OHT group. The differences between CST-IOP and GAT-IOP were lower than the differences between NCT-IOP and GAT-IOP in both groups. The mean differences in CST-IOP and GAT-IOP were 1.26 mm Hg (95% limit of agreement ranged from 0.1 to 2.41 mm Hg, OHT group) and 1.20 mm Hg (95% limit of agreement ranged from -0.5 to 3.00 mm Hg, non-OHT group), and the mean differences in NCT and GAT were 3.90 mm Hg (95% limit of agreement ranged from -0.19 to 9.70 mm Hg, OHT group) and 6.00 mm Hg (95% limit of agreement ranged from 1.50 to 10.50 mm Hg, non-OHT group). The differences between CST-IOP and GAT-IOP were not related to CCT, age, and AL in both groups; while the differences between NCT-IOP and GAT-IOP were related to CCT in the OHT group (r=0.93, P<0.001) and to CCT and AL in the non-OHT group (r=0.66, P<0.001, r=-0.81, P<0.001). The accuracy of NCT in the diagnosis of pediatric OHT is low. The agreement of CST-IOP and GAT-IOP was significantly higher in children with and without OHT than in those with NCT-IOP and GAT-IOP. Therefore, CST can be used as a good alternative for IOP measurement in children. The impacts of CCT and AL on NCT measurement need to be fully considered when managing childhood IOP.

A STUDY ON ASSOCIATION OF SYSTOLIC BLOOD PRESSURE, DIASTOLIC BLOOD PRESSURE, AND PULSE PRESSURE WITH INTRAOCULAR PRESSURE IN RELATION TO PRIMARY OPEN-ANGLE GLAUCOMA

Objective: This study aims to probe the relationship among pulse pressure (PP), systolic blood pressure (SBP) and diastolic blood pressure (DBP), and the intraocular pressure (IOP) in normal persons and primary open-angle glaucoma (POAG) patients. Design: This was an institution-based observational study. Methods: This study was conducted on 240 patients attending the ophthalmology department and glaucoma clinic of a tertiary hospital. Included subjects were asked about their ocular and systemic problems and undergone detailed examination of eyelids, conjunctiva, cornea, anterior chamber by slit lamp, visual acuity, refraction, and fundus examination. IOP was measured by Goldmann applanation tonometer. Blood pressure was measured by sphygmomanometer. Results: In this study, we found that SBP, DBP, PP, and IOP – both eyes were found to be higher in subjects with POAG than normal control subjects. Among these, differences in mean SBP, DBP, and IOP – both eyes between subjects with POAG and normal subjects were statistically significant. IOP was found to be positively correlated with SBP, DBP, and PP both in subjects with POAG as well as in normal subjects. Conclusion: Although involving a limited number of eyes, the key findings of the study suggest that IOP is positively correlated with PP, SBP, and DBP. This opens up the possibility of early detection of glaucoma patients with raised PP, SBP, and DBP.

Intraocular Pressure Changes in Myopic Patients Undergoing Laser In-Situ Keratomileusis and Photorefractive Keratectomy.

To assess the variation in intraocular pressure measurements between Ocular Response Analyzer (ORA) and Goldmann Applanation Tonometer (GAT) in myopic patients undergoing laser assisted in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Quasi-experimental study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology (AFIO), National University of Medical Sciences, Rawalpindi, Pakistan, between September 2020 and 2021. Myopic patients undergoing LASIK and PRK during the study period were selected. Baseline examinations and postoperative follow-ups were carried out to measure intraocular pressure at 1, 3, and 6 months after LASIK or PRK, using Goldmann Applanation Tonometer (GAT) and Ocular Response Analyzer, corneal compensated IOP (ORA IOPcc). One hundred and thirteen eyes underwent myopic refractive surgery, LASIK (n = 60) or PRK (n = 53). Mean age of patients was 23.6 ± 4.11 years in the PRK group and 24.4 ± 5.94 years in LASIK group. For the PKR group, the GAT IOP value increased at 1-month (p <0.001), decreased at 3-month (p <0.001) and further decreased at 6-month (p <0.001) follow-up postoperatively. In the LASIK group, the GAT IOP value decreased at all time points (p <0.001). In both groups, the mean ORA IOPcc value increased at 1 month (p <0.001), decreased at 3-month (p <0.001) and further decreased at 6-month (p <0.001) follow-up postoperatively. The IOP mean values were generally found to be higher when measured using ORA as compared with GAT. Corneal refractive surgery markedly decreased IOP. This decrease in IOP was observed more after LASIK than after PRK. ORA was less likely to underestimate the intraocular pressure than GAT. Myopia, Laser in-situ keratomileusis, Photorefractive keratectomy, Tonometery ocular, Intraocular pressure.

Performance of home-based self-tonometry (iCare HOME (TA022)) for measuring intraocular pressure among healthy and glaucoma patients

Introduction: The purpose of this study was to compare iCare HOME (TA022) with Goldmann applanation tonometer and to evaluate the self-tonometry measurements among the Indian population. Methods: Eligible patients underwent iCare HOME training through guided demonstration (verbal, pictorial, video) and practised self-tonometry measures using iCare HOME. Certification for independent iCare HOME measure was provided if first iCare HOME intraocular pressure (IOP) measurement fell within ± 5 mmHg of Goldmann applanation tonometer (GAT) measurement which was measured by the trained clinician (principal investigator). Certified participants underwent simulated home self-tonometry measurements using iCare HOME, and agreement with GAT IOP measurements was assessed. Results: Seven of 83 participants (8.43%) failed to complete the study due to difficulty in performing the task, leading to non-certification. Patients who could use the iCare HOME had a mean age of 53 ± 15.55years (53% males; 46% females). Only one in 12 subjects did not qualify to use iCare HOME. The overall mean difference between iCare HOME and GAT was 0.83 mmHg (95%, 3.92 and -2.25) with 94.7% agreement. At various pressure ranges, 7-16 mmHg, 17-23 mmHg and &gt;23 mmHg, the mean difference between iCare HOME and GAT was 1.22 mmHg (95%, 4.32 and -1.86) with 97.4% agreement, 0.77 mmHg (95%,3.69 and -2.19) with 91.3% agreement, -0.11 mmHg (95%, 2.52 and -2.74) with 100% agreement respectively. The intra-class correlation coefficient of the iCare HOME device was 0.997(95% CI,0.995-0.998). Conclusions: Patients were able to perform self- tonometry using iCare HOME with good reliability and safety. iCare HOME shows good agreement with GAT. Further studies with proper home environment will be recommended to study the diurnal comparisons with GAT.

Intraocular pressure measurement using ICare rebound tonometer in different positions of eye and different locations on cornea.

Intraocular pressure (IOP) is one of the most crucial aspects for diagnosis and treatment plan among patients with glaucoma. Although the gold standard for IOP measurement is Goldmann applanation tonometer (GAT)[1], it must be mounted to a slit lamp biomicroscope. However, rebound tonometer has become popular due to its ease of operation and portable design, does not require topical anesthesia, and results do not differ significantly from those of GAT[2]. The purpose of this cross-sectional study is to investigate the difference in IOP measurement with iCare IC200 in different angles of the eye and different corneal locations. All participants underwent IOP measurement by GAT twice. Then, IOP was measured with iCare by a single physician. IOP was measured in a straight manner in the upright patient position; then participants were asked to look at fixation targets, which located in four different points. IOP was measured in upgaze, downgaze, medial gaze, and lateral gaze. Then, IOP was measured at 2 mm from limbus in superior, inferior, nasal, and temporal cornea. All methods were measured twice, and the mean was used for calculation. The physician who measured IOP by iCare was masked from GAT results. A total of 168 eyes were tested with a mean age of 62.15 ± 12.34 years. Mean IOP measured by GAT and iCare at the central cornea was 15.53 ± 5.57 and 14.78 ± 6.14 mmHg, respectively. The standardized mean difference (SMD) between iCare and GAT was 0.13 (-0.09-0.34), which is insignificant. The average IOP was 0.6, 0.47, 0.91, and 0.44 mmHg lower than the primary position in upgaze, downgaze, medial gaze, and lateral gaze 15 degrees angulated positions respectively (p<.01). IOPs at 2 mm from limbus in the inferior, nasal, and temporal cornea were 0.5, 0.69, and 0.57 mmHg lower than IOP measured at the central cornea (p=<.01). IOP measurements with iCare in different angles of eye were statistically significantly lower than in the primary position. Similarly, IOPs at different locations on cornea were lower than at the central cornea. However, the difference in IOP measurements with iCare in different angles of the eye and different corneal locations was in the trivial range and might be clinically insignificant.

Comparison of intraocular pressure measurements obtained by icare pro tonometer, non-contact tonometer and Goldmann applanation tonometer in healthy individuals

The goal of this paper was to compare the intraocular pressure (IOP) measurements obtained via iCare Pro rebound (IRT), non-contact tonometry (NCT), and Goldmann applanation (GAT) tonometry in healthy subjects. One hundred and twenty-five healthy individuals were included in this study. The participants' IOP measurements were obtained via non-contact tonometry. After routine ophthalmic examination, central corneal thickness (CCT) was measured with a topography device. Intraocular pressure was measured via iCare Pro rebound tonometry. After waiting for 5minutes, three measurements were taken with GAT under topical anaesthesia, and their means were recorded. Interdevice agreement was evaluated with the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The mean IOP measurements for NCT, IRT, and GAT were 15.97±2.99, 17.47±2.86, and 16.46±2.68mmHg, respectively. The mean difference between NCT and GAT was -0.49± 1.89mmHg, the mean difference between IRT and GAT was 1.01±1.90mmHg, and the mean difference between NCT and IRT was -1.50±2.02mmHg. Agreement between devices was found to be >0.8 for each tonometry ICC. There were significant positive correlations between the measurements obtained via these three instruments and CCT. In this study, IOP was measured slightly lower with NCT than GAT, but it was about 1mmHg higher with IRT than GAT on average. All three devices appeared to be affected by CCT, with NCT being the most affected in this regard. The three instruments can be used for routine inspection and screening. However, considering the differences in the measurements obtained by using them, it is clear that following up IOP measurements with GAT measurements is beneficial in advanced glaucoma patients.

Assessment of the iCare HOME2, a New IOP Self-Measurement Tonometer.

The iCare HOME2 tonometer generally can be considered reliable for most eyes and clinical settings, although it may produce slightly overestimated or underestimated intraocular pressure readings in thicker and thinner corneas, respectively. To evaluate the accuracy, correlation, and analysis of differences in intraocular pressure (IOP) measurements between the gold standard Goldmann applanation tonometer (GAT) and the new, self-measurement iCare HOME2 tonometer (icare, Vantaa, Finland). In this retrospective study, patients were randomly selected from those who attended for a routine examination in our clinic. After a complete ocular examination, each patient's IOP was measured and recorded with GAT (IOPG) and iCare HOME2 (IOPi). Central corneal thickness (CCT) was measured. Eyes with any corneal morbidity were excluded. Pearson's correlation coefficient was used to determine correlation between paired IOP measurements. Bland-Altman plots were graphed for the analysis of differences for IOP between the instruments. One hundred and thirty-five eyes of 70 patients were included in the study. The mean IOPG was 16.3 ±6.5mm Hg (range 3-56). The mean IOPi was 16.5 ±7.3mm Hg (range 3-55), (P=0.47). A strong, significant positive correlation was found for paired IOP measurements by the two instruments (r=0.94; P<0.0001). A small systematic proportional bias was seen for the paired IOP measurements, meaning that with higher IOPs the iCare HOME2 yielded higher IOP readings than GAT; but this difference was clinically insignificant. The instrument underestimated IOPs with corneas thinner than 522 µm while it overestimated IOPs when corneas were thicker than this. The iCare HOME2 could be a reliable tonometer for most eyes and clinical settings. CCT measurement is recommended in patients who use the instrument.

Comparison of Goldmann and ORA tonometers in newly diagnosed, untreated, POAG and OHT eyes

Background and objectiveThe corneal biomechanical properties in naïve, untreated glaucoma and ocular hypertension (OHT) eyes is interesting, because it may be a source of error in intraocular pressure (IOP) measurements by Goldmann applanation tonometer (GAT) and Ocular Response Analyzer (ORA)The main objective of this study was to evaluate the IOP values obtained using GAT and the ORA, in primary open angle glaucoma (POAG) and in OHT untreated eyes. Material and MethodsObservational, masked, cross sectional observational study. Newly diagnosed, untreated POAG and OHT eyes were included. Results51 POAG and 34 OHT eyes were analyzed. We found that IOPcc (IOP corneal-compensated) was significantly higher than GAT IOP in POAG (p = 0.0002) while we did not find any significant difference between both tonometers in OHT (p = 0.1). ConclusionsGAT seems to underestimate the real IOP in untreated POAG eyes and it seems to be quite accurate in OHT eyes.

Estudio comparativo entre tonómetros Goldmann y ORA en pacientes recién diagnosticados de GPAA o HTO, sin tratamiento

Background and objectiveThe corneal biomechanical properties in naïve, untreated glaucoma and ocular hypertension (OHT) eyes is interesting, because it may be a source of error in intraocular pressure (IOP) measurements by Goldmann applanation tonometer (GAT) and ocular response analyzer (ORA).The main objective of this study was to evaluate the IOP values obtained using GAT and the ORA, in primary open angle glaucoma (POAG) and in OHT untreated eyes. Material and methodsObservational, masked, cross sectional observational study. Newly diagnosed, untreated POAG and OHT eyes were included. ResultsFifty-one POAG and 34 OHT eyes were analyzed. We found that IOPcc (IOP corneal-compensated) was significantly higher than GAT IOP in POAG (P=.0002) while we did not find any significant difference between both tonometers in OHT (P=.1). ConclusionsGAT seems to underestimate the real IOP in untreated POAG eyes and it seems to be quite accurate in OHT eyes.