Evaluation of agreement of IOP measurements by Tono-Vera tonometer to Goldmann applanation tonometry.

Purpose: To evaluate the accuracy of the new Tono-Vera rebound tonometer (Reichert Inc, Buffalo, NY) compared to Goldmann Applanation Tonometry. Methods: This prospective, observational, cross-sectional study was designed in accordance with ANSI Z80.10-2014 and ISO 8612-2009 guidelines for tonometer comparison. Intraocular Pressure (IOP) was measured by Goldmann Applanation and Tono-Vera on 160 eyes of 160 subjects. Corneal Astigmatism and Central Corneal Thickness were also measured. A single investigator (CN) conducted all measurements. The average of two measurements from each tonometer was used in the analysis. Bland-Altman plots, total least squares regression analysis, and simple linear regression were used to evaluate agreement between the tonometers. Results: Average IOP values from Goldmann Applanation and Tono-Vera were not significantly different (19.17 and 19.03 respectively, p=0.40, paired t-test). The total least squares regression analysis indicated strong agreement between the two tonometers (slope +0.97, offset +0.49 mmHg, standard deviation 2.11 mmHg). There were 2 IOP measurement pairs that exceeded the ± 5 mmHg limits of agreement required in ANSI Z80.10-2014 and ISO 8612-2009, which is within the range of acceptability specified in the standards. Conclusion: We evaluated IOP measurements by Tono-Vera Rebound Tonometer vs Goldmann Applanation Tonometry for eyes with a wide range of IOP values and found no statistically significant differences in the results. Tono-Vera meets the requirements of ANSI Z80.10-2014 and ISO 8612-2009, demonstrating accuracy comparable to Goldmann tonometry.

Muscle mechanical properties of pelvic floor and paravertebral muscles in women with and without urge urinary incontinence: a case-control study.

BACKGROUND: Muscle mechanical properties (MMPs) are relevant in the pathophysiology of lumbopelvic disorders. However, they have not been described in the pelvic floor muscles (PFM) and lumbar paravertebral muscles (LPM) of women with urge urinary incontinence (UUI). OBJECTIVE: To identify differences between MMPs of PFM and LPM in patients with UUI and healthy controls. Secondarily also aimed to observe the relationship between sociodemographic and clinical variables with the PFM and LPM MMPs. METHODS: The participants of this case-control study comprised 34 women with UUI (UUI group) and 34 continent women (control group). Sociodemographic variables were obtained together with data on the clinical status of the pelvic floor. The MMPs, i.e., frequency (tone), stiffness, decrement (inverse of elasticity), and viscoelastic properties (VP), such as relaxation time and creep, of PFM and LPM were assessed with a hand-held tonometer. Between-group differences and intra-group correlations were identified. RESULTS: The UUI group presented higher frequency and stiffness, as well as lower relaxation time in PFM, whereas the LPM had lower tone and stiffness, and higher VP, compared to the control group (p < 0.05). The UUI group showed a pattern of moderate correlations (|0.403|

Expanding the invertebrate medicine toolbox: evaluation of opisthosoma tonometry as a novel diagnostic tool for arachnids.

OBJECTIVE: The objective of this study was to analyze the use of rebound tonometry, as a noninvasive diagnostic tool, in arachnids. METHODS: 5 juvenile (yearling) female and 1 juvenile male curlyhair tarantulas (Tliltocatl albopilosus, previously Brachypelma albopilosum) were used to track estimated ventral opisthosoma pressures over a 9-month period of time. Younger, growing animals were selected as they are more likely than adults to go through multiple molts throughout the 9 months of the study length. An iCare TONOVET TV01 rebound tonometer was used to measure the estimated ventral opisthosoma pressures of the spiders. Measurements were obtained from the ventral opisthosoma, 1 of the thinnest areas of exocuticle throughout the body. Readings were obtained once per week from the ventral opisthosoma for the first 2 months, then once every 2 weeks for 1 month, then back to once per week for the remainder of the study. Additional measurements were obtained following each ecdysis, after a 2% body weight sampling of hemolymph, and at the end of the study to evaluate readings in response to induction of general anesthesia with 5% isoflurane gas and oxygen flow at 2 L/min for 10 minutes. RESULTS: The average of all estimated ventral opisthosoma pressure when spiders were not in molt was 26.19 mm Hg (SD, 3.54), with a statistically significant decrease postmolt to an average of 15.31 mm Hg (SD, 3.81), followed by a gradual increase back to premolt pressures over a 3-week period with an average of 22 days (SD, 1.93). Estimated ventral opisthosoma pressures decreased post hemolymph removal. There is not sufficient evidence that estimated ventral opisthosoma pressures changed over time following the anesthesia. CLINICAL RELEVANCE: This study demonstrates that tonometry can be used to generally assess the estimated ventral opisthosoma pressure, which could correlate with where a spider is in an ecdysis cycle.

Transcatheter aortic valve implantation and its impact on endothelial function in patients with aortic stenosis.

Vascular function is impaired in patients with aortic valve stenosis (AS). The impact of transcatheter aortic valve implantation (TAVI) on endothelial function is inconclusive so far. Therefore, we sought to assess the short-term influence of TAVI on endothelial dysfunction in patients with AS. We recruited 47 patients (76.6 % male, 80.04 years old) with AS scheduled for TAVI. Endothelial function was assessed by fingertip reactive hyperemia peripheral arterial tonometry (RH-PAT). Measurements were conducted one day before and three days after TAVI. Patients were grouped according to RH-PAT change after TAVI. Overall, RH-PAT measurements did not significantly improve after TAVI (Reactive Hyperemia Index: 1.5 vs 1.6, p = 0.883; logarithm of the Reactive Hyperemia Index: 0.44 vs. 0.49, p = 0.523). Interestingly, patients with no RH-PAT improvement after TAVI displayed a more severe AS and had lower blood pressure after TAVI. This might be due to a more disturbed blood flow in patients with a smaller aortic valve area and higher peak aortic valve velocity. The relationship between AS severity, endothelial dysfunction and TAVI has to be investigated in future research that apply longitudinal study designs.

Gap Analysis of Glaucoma Examination Concept Representations within Standard SNOMED Clinical Terms.

PURPOSE: Standardization of eye care data is important for clinical interoperability and research . We aimed to address gaps in the representations of glaucoma examination concepts within Systemized Nomenclature of Medicine - Clinical Terms (SNOMED-CT), the preferred terminology of the American Academy of Ophthalmology. DESIGN: Study of data elements. METHODS: Structured eye exam data fields from two electronic health records (EHR) systems (Epic Systems and Medisoft) were compared against existing SNOMED-CT codes for concepts representing glaucoma examination findings3. Glaucoma specialists from multiple institutions were surveyed to identify high-priority gaps in representation, which were discussed among the SNOMED International Eye Care Clinical Reference Group. Proposals for new codes to address the gaps were formulated and submitted for inclusion in SNOMED-CT. MAIN OUTCOME MEASURES: Gaps in SNOMED-CT glaucoma examination concept representations RESULTS: We identified several gaps in SNOMED-CT regarding glaucoma examination concepts. A survey of glaucoma specialists identified high-priority data elements within the categories of tonometry and gonioscopy. For tonometry, there was consensus that we need to define new codes related to maximum intraocular pressure (IOP) and target IOP, and to delineate all methods of measuring IOP. These new codes were proposed and successfully added to SNOMED-CT for future use. Regarding gonioscopy, the current terminology did not include the ability to denote the gonioscopic grading system used (e.g., Shaffer or Spaeth), degree of angle pigmentation, iris configuration (except for plateau iris), and iris approach. There was also no ability to specify eye laterality or angle quadrant for gonioscopic findings. We proposed a framework for representing gonioscopic findings as observable entities in SNOMED-CT. DISCUSSION: There are existing gaps in the standardized representation of findings related to tonometry and gonioscopy within SNOMED-CT. These are important areas for evaluating clinical outcomes and enabling secondary use of EHR data for glaucoma research. This international, multi-institutional collaborative process enabled identification of gaps, prioritization, and development of data standards to address these gaps. CONCLUSION: Addressing these gaps and augmenting SNOMED-CT coverage of glaucoma examination findings could enhance clinical documentation and future research efforts related to glaucoma.

OSA diagnosis goes wearable: are the latest devices ready to shine?

STUDY OBJECTIVES: Since 2019, the FDA has cleared nine novel obstructive sleep apnea (OSA)-detecting wearables for home sleep apnea testing, with many now commercially available for sleep clinicians to integrate into their clinical practices. To help clinicians comprehend these devices and their functionalities, we meticulously reviewed their operating mechanisms, sensors, algorithms, data output, and related performance evaluation literature. METHODS: We collected information from PubMed, FDA clearance documents, ClinicalTrial.gov, and web sources, with direct industry input whenever feasible. RESULTS: In this "device-centered" review, we broadly categorized these wearables into two main groups: those that primarily harness Photoplethysmography (PPG) data and those that do not. The former include the peripheral arterial tonometry (PAT)-based devices. The latter was further broken down into two key subgroups: acoustic-based and respiratory effort-based devices. We provided a performance evaluation literature review and objectively compared device-derived metrics and specifications pertinent to sleep clinicians. Detailed demographics of study populations, exclusion criteria, and pivotal statistical analyses of the key validation studies are summarized. CONCLUSIONS: In the foreseeable future, these novel OSA-detecting wearables may emerge as primary diagnostic tools for patients at risk for moderate-to-severe OSA without significant comorbidities. While more devices are anticipated to join this category, there remains a critical need for cross-device comparison studies as well as independent performance evaluation and outcome research in diverse populations. Now is the moment for sleep clinicians to immerse themselves in understanding these emerging tools to ensure our patient-centered care is improved through the appropriate implementation and utilization of these novel sleep technologies.

Simulation techniques in optometric education: Is a model eye for tonometry a valuable instruction tool?

PURPOSE: Simulation techniques are used in healthcare education to support the development of clinical skills. The aim of this study was to investigate the perceived value of a tonometry model eye (TME) when used in teaching and learning the clinical skill of Goldmann applanation tonometry (GAT) in optometric education in the UK. METHODS: A retrospective two-armed cross-sectional study was conducted to investigate the perceived value of using a model eye for teaching and learning GAT in optometric education. Focus group discussion (FGD) was employed to explore the views of academic experts experienced in teaching GAT using a TME. Semi-structured surveys were conducted to elicit the opinions of optometry students following GAT simulation training. Qualitative thematic analysis of the FGD and open-ended survey questions was undertaken. Quantitative data based on rated student responses was assessed using Chi-square analysis to examine differences between year-group responses. RESULTS: The TME was reported to be a useful experiential tool, facilitating a safe learning environment for students to develop the technical skills required to perform GAT before moving on to real-eye experiences. Whilst limitations of the model eye were noted, these did not diminish the value of the model eye as an instructional tool. Students reported improved confidence (86%) and would highly recommend (82%) the TME to other students. CONCLUSION: The model eye for tonometry was perceived by academic tutors and optometry students to be a valuable instruction tool as part of a scaffolded process for learning GAT. Irrespective of their learning stage, students reported a range of benefits from the model eye, such as being able to make mistakes, taking repeat measurements and getting used to the equipment, all whilst not having to worry about patient safety.

Pressure-Induced Stromal Keratopathy after Surface Ablation Surgery.

Introduction: The purpose of this clinical report was to describe an unprecedented case of bilateral pressure-induced stromal keratopathy (PISK) following corneal photorefractive keratectomy, associated with presumed herpetic keratitis, and to present tomographic and biomechanical findings before and after appropriate treatment. Case Presentation: A 33-year-old male patient was referred to our clinic with suspected delayed corneal epithelial healing 3 weeks after an uncomplicated PRK. A central layer of corneal opacity with a presumed fluid-filled interface area was observed upon slit lamp biomicroscopy. Scheimpflug images from the Pentacam® revealed a hyperreflective area beneath the central cornea. Scheimpflug-based corneal tomography, biomechanical assessment using the Pentacam® AXL Wave, and the Corvis ST® were conducted. Goldmann applanation tonometry measured 23/13 mm Hg, while noncontact tonometry intraocular pressure measured with the Corvis ST® (Corvis ST IOPnct) was 40.5/43.5 mm Hg. Treatment with oral valacyclovir, combined with ocular hypotensive therapy, led to a significant reduction in IOP and improved corneal deformation parameters after 1 month. Conclusion: Surgeons should be aware of the inaccuracy of Goldmann applanation tonometry in PISK, which can occur after LASIK or surface ablation.

Carotid Arterial Compliance during Different Intensities of Submaximal Endurance Exercise.

Background: The purpose of this investigation was to determine the elastic characteristics of the common carotid artery (CCA) during endurance exercise at 3 different intensities. Methods: Twenty young healthy participants (10 males and 10 females) participated in this quasi-experimental cross-sectional study. Participants were tested in two sessions: (1) we took resting measurements of the elastic characteristics of the CCA and performed a cardiopulmonary exercise test (CPET) on a cycle ergometer to determine submaximal exercise intensities, and we conducted (2) measurements of the elastic characteristics of the CCA while exercising in a cycle ergometer at 3 intensities based on blood lactate levels of low (<2 mmol/L), moderate (2-4 mmol/L), and high (>4 mmol/L). Beta stiffness was calculated using CCA diameters during systole and diastole, measured with high-definition ultrasound imaging, and CCA systolic and diastolic pressures were measured via applanation tonometry. Results: Overall, there were no differences between males and females in terms of any of the studied variables (p > 0.05). In addition, no significant changes were found in the CCA beta stiffness and vessel diameter (p > 0.05) between exercise intensities. There was a significant exercise intensity effect on CCA systolic pressure (p < 0.05), but not on CCA diastolic pressure (p > 0.05). Conclusions: The biomechanical characteristics of the CCA, determined via compliance and beta-stiffness, do not change during cyclical aerobic exercise, regardless of exercise intensity.

A comparison of iCare and Goldmann applanation tonometry measurements during the COVID-19 pandemic: a retrospective study.

PURPOSE: To evaluate factors associated with differences in intraocular pressure (IOP) readings between iCare and Goldmann applanation tonometry (GAT) in established glaucoma patients. METHODS: This retrospective comparative study included clinical data of 350 eyes from 350 established glaucoma patients who had iCare and GAT IOP measured by an ophthalmic technician and a glaucoma specialist, respectively. The main outcome measure was the difference in IOP measurements of the right eyes with iCare and GAT. RESULTS: The intraclass correlation coefficient (ICC) between GAT and iCare was 0.90. The mean IOP difference between tonometers was - 0.18 ± 2.89 mmHg. Bland-Altman plots indicated a 95% limit of agreement of - 5.8 to 5.5 mmHg. Central corneal thickness (CCT) and age were significantly correlated with the difference in IOPs of the iCare and GAT. GAT-IOP and age were significantly associated with the absolute difference in measured IOP of the two tonometers. The difference in measurements was not significantly associated with prior glaucoma surgery, average global index of optical coherence tomography, axial length, technician years of experience and certification, and IOP range. CONCLUSION: Although there is good agreement between the iCare and GAT mean values, these devices are not interchangeable in glaucoma patients due to the wide range of the limit of agreement.

Comparing the intraocular pressure values obtained with a rebound tonometer (TONOVET Plus) and an indentation tonometer (IOPvet) in dogs with and without ocular disease.

BACKGROUND: This study aimed to compare the intraocular pressure (IOP) values obtained from two groups of dogs using the IOPvet indentation tonometer to those obtained from the same dogs using an established rebound tonometer (TONOVET Plus). METHODS: Tonometry was performed on 36 dogs with ocular diseases (70 eyes; group A) and 25 healthy dogs (49 eyes; group B). First, the TONOVET Plus rebound tonometer was used. Then, one drop of oxybuprocaine hydrochloride was applied to each eye, and 1 minute later, the IOP was estimated using the IOPvet. RESULTS: The IOPvet was safe, well tolerated and easy to use. The instrument had a high specificity (98.5%) for identifying IOPs of 20 mmHg or less. A lack of sensitivity (67.9%) was noted when evaluating eyes with an IOP between 20 and 30 mmHg. The sensitivity (33.3%) for identifying canine eyes with an IOP of greater than 30 mmHg (n = 24) was low. LIMITATIONS: This study lacks manometric work, which would be hard to justify with client-owned dogs. Quantitative numerical data were compared with qualitative values and the same investigator obtained readings using both tonometers without being masked. CONCLUSIONS: The IOPvet is highly sensitive for assessing normal IOPs, but underestimation of higher IOPs can lead to poor diagnostics. Digital tonometers remain the best way to assess IOP in veterinary clinics.

Characterization of ophthalmic lesions and normal ocular parameters in a flock of captive MacQueen's (houbara) bustards (Chlamydotis macqueenii).

OBJECTIVES: To determine normal ocular parameters of the MacQueen's bustard (Chlamydotis macqueenii) and describe ophthalmic lesions in a captive bred population. ANIMALS STUDIED: Captive breeding population of 257 Macqueen's bustards. METHODS: All birds were screened for ocular abnormalities using direct ophthalmoscopy. Abnormalities were photographed. Normative values for Schirmer tear test-1 (STT-1), applanation tonometry, aerobic and anaerobic bacterial culture, fungal culture, and transcorneal ocular ultrasonography were derived from multiple cohorts of clinically normal adult birds. Five birds with ocular pathology also underwent transcorneal ultrasonography. Statistical comparisons for normative values between OD and OS, and males and females were made using a paired t-test or Mann-Whitney U-test, with a significance level of p < .05. RESULTS: Mean tear production based on Schirmer tear test 1 (STT-1) was 10.16 ± 4.61 mm/min (3-21 mm/min). Mean intraocular pressure (IOP) was 12.42 ± 4.94 mm Hg (5-26 mm Hg). Staphylococcus species were the most isolated bacteria from the conjunctival surfaces of normal birds (85%). Significant differences were found in transcorneal ultrasonographic measurements between males and females for axial globe length (p = .032), vitreous body depth (p = .049) and lens thickness (p = .0428). Corneal fibrosis was the most observed ocular abnormality amongst eyes with pathological changes (39%). CONCLUSIONS: Schirmer tear testing, tonometry and transcorneal ultrasound can easily be utilized in MacQueen's bustards and provide reproducible results. Normal parameters for these tests were determined, and common pathological ocular changes were described in this species.

A comparison of intraocular pressure measurement using SUOER SW-500 rebound tonometer and conventional reusable Goldmann prisms.

Introduction: To determine the agreement between intraocular pressure (IOP) measurements using conventional Goldmann applanation tonometry (GA1,2T) and SUOER SW-500 Rebound Tonometer. Methods: This was a retrospective observational study where 205 eyes of 106 glaucoma patients had their IOPs measured by 2 fellowship trained ophthalmologists. Data were analyzed using the Bland-Altman method of differences. Correlation was measured using the Pearson coefficient. Results: Most of our patients were Chinese (88.7%) and female (51.9%). The average age was 66.9 years. The range of IOPs as measured by GAT was 2 to 58 mm Hg. Using the Bland-Altman method to compare GAT and SUOER SW-500 Rebound Tonometer. The tonometer overestimated the IOP by 0.5 mm Hg in the right eye and underestimated it by 0.1 mm Hg in the left eye. Overall, the tonometer overestimated the IOP by 0.2 mmHg. The Tonometer IOP correlated well with GAT, with a Pearson coefficient of correlation(r) of 0.89 (p < 0.001) for the right eye and 0.86 (p < 0.001) for the left eye, respectively. In patients with GAT IOP ≥ 21 mm Hg (n = 25), the Tonometer underestimated the IOP by 2.96 mm Hg. Discussion: The IOP measurements from the SUOER SW-500 Rebound Tonometer correlates well with the conventional GAT in measuring the IOP within normal ranges of IOP. SUOER SW-500 Rebound Tonometer may be of use, especially if the risk of transmission of infection is high considering that the probes are disposable. It is easy to use and its small size and portability makes it useful in situations where the patient is unable to be examined at the slit lamp.

Matched case-control comparison of surgical success after XEN45 Gel Stent and PRESERFLO MicroShunt implantation in a Caucasian population.

BACKGROUND: The aim of this study was to compare the outcome of implantation of a XEN45 Gel Stent with the outcome of implantation of a Preserflo MicroShunt in a matched-pair analysis in eyes being naïve to filtering surgery. METHODS: In this comparative, retrospective study, 50 eyes that had undergone XEN45 Gel Stent implantation were compared with 50 eyes after Preserflo implantation. Follow-up was at least 6 months, and surgical success was measured by criteria A (IOP < 21 mmHg, IOP reduction >20%, no repeat surgery); criteria B (IOP < 18 mmHg, IOP reduction >20%, no repeat surgery); and criteria C (IOP ≤15 mmHg, IOP reduction ≥40%, no repeat surgery). RESULTS: After a follow-up period of 12 months, mean IOP had decreased from preoperative 25.2 ± 4.8 mmHg in the XEN group to 14.5 ± 4.0 (n = 35) and from 25.3 ± 6.8 mmHg to 11.9 ± 2.9 (n = 41) in the Preserflo group, respectively. The IOP at the last follow-up of the two groups differed significantly (p < 0.01). The probability of surgical success did not differ concerning Criteria A and B, but surgical success was significantly higher in the Preserflo group for Criteria C (60%, p < 0.01). CONCLUSION: Both the Preserflo and XEN45 Gel Stent provide an effective and safe treatment option for advanced glaucoma and have a high potential to reduce intraocular pressure. Absolute IOP levels of <16 mmHg after 12 months were significantly more frequent in the Preserflo group.

Preliminary Study on Pulse Wave Changes in Patients with Inflammatory Arthropathies Treated with bDMARDs.

Background: Patients with inflammatory arthropathies exhibit an increased cardiovascular disease (CVD) risk as compared to the general population, which is not fully quantified by the conventional CVD risk scores. Biotechnological disease-modifying drugs (bDMARDs) have proved beneficial to reduce the overall CVD risk in these patients, although CVD remains a major cause of increased mortality. Since it has been shown that pulse wave parameters and in particular carotid-femoral pulse wave velocity (cfPWV) are predictors of CVD risk, the aim of this study was to evaluate their changes in patients with inflammatory arthropathies before and after bDMARD therapy. Methods: Pulse wave parameters were evaluated with applanation tonometry in patients with ankylosing spondylitis (AS), psoriatic arthritis (PsA), and rheumatoid arthritis (RA), before and after two years of bDMARD therapy. Results: At baseline, cfPWV was significantly associated with age (p < 0.001) and, among pulse wave parameters, the subendocardial viability ratio was negatively associated with C-reactive protein (CRP) (p = 0.04) and the HAQ-disability index (p = 0.03). At baseline, PsA patients showed a higher percentage of male subjects, higher CRP, and the highest cfPWV values (p = 0.048). After two years, pulse wave parameters improved in the AS and RA groups, but not in the PsA group. Conclusions: Our data confirm that pulse wave parameters are potentially reversible after bDMARD therapy, as they improved in AS and RA patients. In PsA patients, there were no changes, which may be due to the higher percentage of male subjects and higher baseline cfPWV values.

[Influence of corneal curvature and peripheral thickness on tonometry readings]. / Vliyanie krivizny i perifericheskoi tolshchiny rogovitsy na rezul'tat tonometrii.

PURPOSE: This study investigates the influence of peripheral corneal thickness (PCT) and its curvature on tonometry readings. MATERIAL AND METHODS: The study included 49 patients (49 eyes) who were indicated for glaucoma surgery. Using bidirectional applanation tonometry, the following parameters were obtained: IOPcc, IOPg - intraocular pressure (IOP) corrected for corneal compensation, taken as the most reliable indicator; IOP converted to Goldmann measurement, taken as the result of applanation tonometry, ΔIOP (IOPcc-IOPg), CH and CRF (corneal hysteresis and corneal resistance factor). During corneal topography, the corneal thickness was studied in the center, PCT at 1.5; 2, 3, 4 and 5 mm from the center in four meridians, as well as ΔPCT (PCT 3 mm - PCT 1.5 mm), the curvature of the anterior and posterior surfaces of the cornea and the depth of the anterior chamber. Aberrometry was used to obtain refractometry data and the curvature of the anterior surface of the cornea. The influence of the studied parameters on ΔIOP was evaluated. RESULTS: ΔIOP correlated with CRF (r= -0.652), CH (r= -0.873), central corneal thickness (r= -0.293), PCT at all distances except 5 mm (r= -0.297; -0.287; -0.302; -0.303), with the strong and weak meridians of the anterior surface of the cornea (r=0.328; r=0.315), with the strong and weak meridians of the posterior surface, as well as the average curvature of the posterior surface (r=0.307; r=0.332; r=0.328). After step-by-step selection of the above parameters for creating a linear regression model for ΔIOP calculation, CH, CRF and PCT1.5mm remained in the model. The model describes ΔIOP with high accuracy (R2=0.974). CONCLUSION: Biomechanical parameters of the cornea are the leading factor of applanation tonometry error. Individual linear dimensions of the cornea (thickness, curvature) have a lesser effect.

[Effect of refractive surgery on Maklakov tonometry results]. / Vliyanie keratorefraktsionnoi khirurgii na rezul'taty tonometrii po Maklakovu.

PURPOSE: The study investigates the influence of changes in keratometric parameters after refractive surgery on the results of Maklakov tonometry. MATERIAL AND METHODS: The study examined a total of 61 people (121 eyes). The patients were divided into a control group with no history of surgery (16 people, 31 eyes), a LASIK group (13 people, 26 eyes), a femtosecond-assisted LASIK (FS-LASIK) group (16 people, 32 eyes), and a photorefractive keratectomy (PRK) group (16 people, 32 eyes). The patients underwent standard examination, keratometry (Km), Maklakov tonometry with a 10 g weight, and elastotonometry with 5, 7.5, and 15 g weights. RESULTS: In the LASIK group, the indentation diameter with 5 and 7.5 g weights correlated with Km in the central and near-paracentral zone (r=0.3-0.5). Tonometry with a 10 g weight did not correlate with anything. Tonometry with a 15 g weight inversely correlated with Km in the paracentral points (4 mm) of the strong meridian (r= -0.5 ... -0.7). In the FS-LASIK group, a significant inverse correlation with Km was observed only for the indentation diameter with a 10 g weight in the paracentral (3-4 mm) zone (r= -0.4 ... -0.5). In the PRK group, weak (r<0.4) correlations were found between Km and the indentation diameter of the 7.5 and 10 g weights for the central zone (1-2 mm). No significant correlations were found for 5 and 15 g weights.In the control group, there were practically no correlations for 5 and 7.5 g weights. The indentation diameter of the 10 g weight evenly correlated with Km at all points (r= -0.38 ... -0.60), the indentation of the 15 g weight correlated mainly with the curvature of the horizontal meridian (r= -0.37 ... -0.49). CONCLUSION: Tonometry readings with the 10 g weight are the most dependent on Km in different groups, and the readings with the 5 g weight are the least dependent. LASIK is characterized by the largest scatter of dependencies for weights of different masses, FS-LASIK - by the smallest. Tonometry readings with the 5 g weight correlated with Km only in the LASIK group, and this was the only direct correlation. Considering the inverse nature of most correlations, higher Km may be associated with an overestimation of tonometry results, and lower Km - with its underestimation.

Age-related changes of intraocular pressure in Dutch belted rabbits.

This study investigated intraocular pressure (IOP) in Dutch belted rabbits using two different tonometers, rebound tonometry (TonoVet Plus; TVP) and a Tonopen (Tono-Pen AVIA Vet; TPA). Post-pubescent male Dutch belted rabbits aged 36 weeks (n = 10 animals) were used in the study. IOP measurements were conducted every 2 weeks for 22 weeks using TVP and TPA on both eyes of each rabbit. The average IOP measurements were compared by the paired Student's t-test. Pairwise Pearson's correlation coefficients and Bland-Altman statistics were used. The overall mean IOP measured with TPA was significantly higher than that with TVP (23.5 ± 4.9 vs. 21.8 ± 2.4 mmHg for the right eyes; P = 0.045, and 23.0 ± 4.7 vs. 21.5 ± 2.4 mmHg for the left eyes; P = 0.047). Both tonometers tended to show increased IOP readings with age, and positive correlations between IOP and age were observed with both TPA (r = 0.95, P < 0.001 for right eyes; r = 0.95, P < 0.001 for left eyes) and TVP (r = 0.91, P < 0.001 for right eyes; r = 0.64, P = 0.024 for left eyes). The average bias calculated by subtracting TPA from TVP was - 1.60 (95% confidence intervals - 1.927, - 1.281) mmHg. IOP in post-pubescent Dutch belted rabbits tended to increase with age throughout the 22 week study.

Susceptibility of optic nerve head in children with posture-related elevation of intraocular pressure.

BACKGROUND/AIMS: This work aimed to investigate changes in optic nerve head (ONH) morphometry based on Bruch membrane opening in children with extensive nocturnal intraocular pressure (IOP) elevations. METHODS: The course of Bruch membrane opening-based optic nerve head (ONH) morphometry was analysed in thirty-two patients younger than 18 years with evaluable SD-OCT examinations of the ONH and nocturnal posture-dependent IOP elevation above 25 mmHg. Longitudinal changes in neuroretinal rim tissue, as measured by Bruch Membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness, were assessed. RESULTS: One year after the 24 h IOP measurement, global BMO-MRW (- 1.61 ± 16.8 µm, n.s.; p = 0.611) and RNFL (+ 0.64 ± 3.17 µm; n.s.; p = 0.292) measurements were not significantly different from the baseline. No significant BMO-MRW reduction (- 3.91 ± 24.3 µm; n.s. p = 0.458) or deviation in RNFL thickness (+ 1.10 ± 3.52 µm) was observed at the four-year follow-up. Absolute IOP values measured in the supine position did not correlate with changes in global BMO-MRW or RNFL thickness. CONCLUSION: Posture-dependent IOP elevations do not seem to influence retinal nerve fibre layer thickness or Bruch membrane opening-based morphometric data in childhood.

Comparison of first, second, and third versus the average of six probe-corneal touches for intraocular measurement of two rebound tonometers in healthy horses.

The aim of this study was to evaluate the intraocular pressure (IOP) measurements obtained from first, second, and third probe-cornea touch (PCT) and compare them with the average of six PCTs using two rebound tonometers in horses. This study enrolled a total of thirty-eight stallions, comprising of 24 Arabian horses and 14 cross-breeds (with an average age of 8 ± 3 years). The IOP measurements of first, second, and third, as well as the average of six PCTs were obtained using either Tonovet (TV) or Tonovet Plus (TV+) rebound tonometers. The mean differences (95% limits of agreement) between the average of six PCTs and the first, second, and third PCTs were 0.1 (-4.8 to 5), 0.2 (-4.8 to 4.5), and 0.2 (-3.6 to 4.0) mmHg with TV, respectively. With TV+, the differences were 0.3 (-6.6 to 7.2), 1.1 (-8.6 to 10.8), and -0.2 (-3.6 to 4.0) mmHg, respectively. Compared to the average of six PCTs, only 89.5%, 92.1%, and 97.4% of IOP measurements obtained from TV and 78.9%, 73.3%, and 65.8% of IOP measurements obtained from TV+ were within 4 mmHg of the average of six PCTs for first, second, and third PCTs, respectively. In conclusion, the measurement of IOP in the first PCT achieved best agreement with the IOP measurement of six average PCTs. Therefore, the first PCT could be considered as an alternative option for measuring IOP in horses when obtaining an average of six PCTs is not feasible.