Validation of the eyeTelemed IOPvet indentation tonometer for use in dogs.

OBJECTIVE: To assess the accuracy of canine intraocular pressure (IOP) estimates from the eyeTelemed IOPvet indentation tonometer. ANIMALS STUDIED: Part 1 included 54 eyes from 28 Beagle dogs-23 ADAMTS10-mutants with open-angle glaucoma and 5 normals. Part 2 involved five normal canine ex vivo globes. PROCEDURE: Part 1 (in vivo) compared IOPvet estimates in normal and glaucomatous dogs to Reichert Tono-Vera® Vet rebound tonometry. The three IOPvet estimates were green (normal; <20 mmHg, according to the manufacturer), yellow (elevated; 20-30 mmHg), and red (high; >30 mmHg). In Part 2 (ex vivo), the pressure inside freshly enucleated normal canine eyes was progressively increased from 5 to 80 mmHg and compared to IOPvet estimates. Descriptive statistics compared IOPvet estimates to rebound tonometry and direct manometry, with the threshold from normal to glaucoma set at 30 mmHg. RESULTS: In Part 1 (in vivo), normal pressures (≤30 mmHg) were mainly identified correctly as green or yellow-110 of 111 estimates, corresponding to a specificity of 99%. Only 16 of 125 affected estimates were correctly displayed in the >30-mmHg range; the remaining 109 showed ≤30 mmHg, corresponding to a sensitivity of 13%. In Part 2 (ex vivo), all normal pressures were correctly estimated with green, but 64 of 88 manometric IOPs >30 mmHg were falsely estimated as 20-30 mmHg. CONCLUSIONS: The IOPvet is inaccurate in estimating canine IOP with a low sensitivity at identifying dogs with IOP > 30 mmHg. Canine-specific instrument revision is required to correctly identify elevated (yellow = 20-30 mmHg) and high (red >30 mmHg) IOPs.

Validation of the Reichert® Tono-Vera® Vet rebound tonometer in normal ex vivo canine eyes.

OBJECTIVE: To determine the accuracy of the Reichert® Tono-Vera® Vet rebound tonometer for canine intraocular pressure (IOP) measurement. ANIMALS STUDIED: Five normal canine ex vivo globes. PROCEDURES: The anterior chambers of five freshly enucleated normal canine eyes were cannulated and connected to a reservoir of Plasma-Lyte A and a manometer. Starting at a manometric IOP of 5 mmHg, the pressure was progressively increased to 80 mmHg by raising the reservoir. Triplicate IOP measurements were taken with the Tono-Vera® Vet from the central cornea using the dog setting and compared to the manometric pressure by linear regression analysis and Bland-Altman plots. RESULTS: There was a strong positive linear regression trend when comparing central corneal Tono-Vera® Vet IOPs to manometric pressures (r2 = .99) with solid agreement between the two methods. Compared to manometric IOPs, the Tono-Vera® Vet underestimated IOPs at higher pressures ≥70 mmHg. CONCLUSIONS: Measurement of IOPs from the central cornea with the Tono-Vera® Vet provided accurate results over a large range in normal canine globes compared to direct manometry. The mild to moderate underestimation of IOPs at high pressures was not considered clinically relevant.

A new mouse-fixation device for IOP measurement in awake mice.

Glaucoma is an irreversible blinding eye disease. The mechanisms underlying glaucoma are complex. Up to now, no successful remedy has been found to completely cure the condition. High intraocular pressure (IOP) is an established risk factor for glaucoma and the only known modifiable factor for glaucoma treatment. Mice have been widely used to study glaucoma pathogenesis. IOP measurement is an important tool for monitoring the potential development of glaucomatous phenotypes in glaucoma mouse models. Currently, there are two methods of IOP measurement in mice: invasive and non-invasive. As the invasive method can cause corneal damage and inflammation, and most of the noninvasive method involves the use of anesthetics. In the course of our research, we designed a mouse fixation device to facilitate non-invasive measurements of mouse IOPs. Using this device, mouse IOPs can be accurately measured in awake mice. This device will help researchers to accurately assess mouse IOP without the use of anesthetics.

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.

Assessing the accuracy of systolic aortic pressure estimation from a brachial cuff alone: a comparison with radial tonometry.

BACKGROUND: A novel method for estimating central systolic aortic pressure (cSAP) has emerged, relying solely on peripheral mean (MBP) and diastolic (DBP) blood pressures. We aimed to assess the accuracy of this Direct Central Blood Pressure estimation using cuff alone (DCBPcuff=MBP²/DBP) in comparison to the use of generalized transfer function to derive cSAP from radial tonometry (cSAPtono). METHODS: This retrospective analysis involved International Database of Central Arterial properties for Risk Stratification (IDCARS) data (Aparicio et al., Am J Hypertens 2022). The dataset encompassed 10,930 subjects from 13 longitudinal cohort studies worldwide (54.8%women; median age 46.0 years; office hypertension: 40.1%; treated: 61.0%), documenting cSAPtono via SphygmoCor calibrated against brachial systolic BP (SBP) and DBP. Our analysis focused on aggregate group data from 12/13 studies (89%patients) where full BP dataset was available. A 35% form factor was used to estimate MBP = (DBP+(0.35×(SBP-DBP)), from which DCBPcuff was derived. The predefined acceptable error for cSAPtono estimation was set at ≤5mmHg. RESULTS: The cSAPtono values ranged 103.8-127.0 mmHg (n=12). The error between DCBPcuff and cSAPtono was 0.2 ± 1.4 mmHg, with no influence of the mean. Errors ranged from -1.8 to 2.9 mmHg across studies. No significant difference in errors was observed between BP measurements obtained via oscillometry (n=9) vs auscultation (n=3) (p=0.50). CONCLUSIONS: Using published aggregate group data and a 35% form factor, DCBPcuff demonstrated remarkable accuracy in estimating cSAPtono, regardless of the BP measurement technique. However, given that individual BP values were unavailable, further documentation is required to establish DCBPcuff's precision.

The Effect of Surgical Therapy for Obstructive Sleep Apnea on Blood Pressure and Peripheral Arterial Tonometry.

OBJECTIVE: To determine the effect of upper airway surgery on cardiovascular function in patients with obstructive sleep apnea (OSA). STUDY DESIGN: A prospective, self-controlled study from 2018 to 2023. SETTING: Two academic medical centers. METHODS: Seventy-four patients underwent surgery for OSA, including: tonsillectomy, adenoidectomy, epiglottidectomy, modified uvulopalatopharyngoplasty, maxillary expansion, and maxillomandibular advancement. Twenty-four-hour ambulatory blood pressure (BP), peripheral arterial tonometry (PAT)-based home sleep study, and sleep-related patient-reported outcomes (PROs) were captured preoperatively and at 6 months postoperatively. Paired T-tests evaluated changes in outcomes after surgery. RESULTS: Forty-one patients successfully completed preoperative and postoperative assessments. Patients were generally middle-aged (43.8 ± 12.5 years), obese (BMI 33.0 ± 5.8 kg/m2), male (68%), White (71%), and had severe OSA (apnea-hypopnea index [AHI] 33.9 ± 29.5 events/h). The 4% oxygen desaturation index (ODI) decreased from 30.7 ± 27.1 to 12.2 ± 13.6 events/h (P < .01) after surgery. There was no significant difference in 24-h BP following surgery, though clinically meaningful reductions in nocturnal systolic (-1.95 [-5.34, 1.45] mmHg) and nocturnal diastolic (-2.30 [-5.11, 0.52] mmHg) blood pressure were observed. Stratified analysis showed patients undergoing skeletal surgery (n = 17) demonstrated larger average reductions compared to those undergoing soft tissue surgery in nocturnal systolic (-4.12 [-7.72, -0.51] vs -0.10 [-5.78, 5.58] mmHg) and nocturnal diastolic (-3.94 [-7.90, 0.01] vs -0.90 [-5.11, 3.31] mmHg) pressures. No meaningful changes were observed in PAT Autonomic Index (PAI) measurements. CONCLUSION: Surgical therapy for OSA did not demonstrate statistically significant improvements in 24-h BP. However, clinically meaningful reductions in nocturnal BP were observed, particularly in skeletal surgery patients, supporting the need for larger studies of cardiovascular outcomes following OSA surgery.

Long-term night-to-night variability of sleep-disordered breathing using a radar-based home sleep apnea test: a prospective cohort study.

STUDY OBJECTIVES: Night-to-night variability of sleep-disordered breathing (SDB) limits the diagnostic accuracy of a single measurement. Multiple recordings using a reliable, affordable method could reduce the uncertainty and avoid misdiagnosis, which could be possible with radar-based home sleep apnea testing (HSAT). METHODS: We recruited consecutive patients with suspected SDB and performed contactless radar-based HSAT with automated scoring (Sleepiz One) over ten nights. During the first night, patients were simultaneously measured with peripheral-arterial tonometry. RESULTS: Twenty-four of the 28 included patients could achieve a minimum of four measurements. The failure rate was 16% (201 of 238 measurements). The apnea-hypopnea index (AHI) and oxygen desaturation index were consistently lower with radar-based HSAT compared to peripheral arterial tonometry. The variability of the AHI was considerable, with a standard error of measurement of 5.2/h (95%CI 4.6-5.7/h) and a minimal detectable difference of 14.4/h (95%CI 12.7-15.9/h). Alcohol consumption partially accounted for the variability, with an AHI increase of 1.7/h (95%CI 0.6-2.8/h) for each standard drink. Based on a single measurement, 17% of patients were misdiagnosed, and 32% were misclassified for SDB severity. After five measurements, the mean AHI of the measured nights stabilized with no evidence of substantial changes with additional measurements. CONCLUSIONS: Night-to-night variability is considerable and stable over ten nights. HSAT using radar-based methods over multiple nights is feasible and well tolerated by patients. It could offer lower costs and allow for multiple-night testing to increase accuracy. However, validation and reducing the failure rate are necessary for implementation in the clinical routine. CLINICAL TRIAL REGISTRATION: "Recording of Multiple Nights Using a New Contactless Device (Sleepiz One Connect) in Obstructive Sleep Apnea", ClinicalTrials.gov, NCT05134402.

A Comparative Analysis of Intraocular Pressure Measurement Accuracy With Reused iCare Probes.

PURPOSE: To assess the accuracy of reused iCare probes after disinfection with 70% isopropyl alcohol and ethylene oxide gas compared to new iCare probes and Goldmann applanation tonometry (GAT). DESIGN: Prospective comparative analysis. PARTICIPANTS: A total of 118 eyes from 59 patients recruited from the Aravind Eye Hospital glaucoma clinic in Tirupati, South India. METHODS: Intraocular pressure (IOP) was measured on each eye using a new iCare tonometer probe, an iCare probe previously used and disinfected 1 time prior (once used probe) and 5 times prior (multiply used probe), as well as with GAT. Probes were disinfected after each use with 70% isopropyl alcohol swabs and ethylene oxide sterilization. MAIN OUTCOME MEASURES: Agreement demonstrated with intraclass correlation coefficients (ICCs), mean difference in IOP values with limits of agreement, and Bland-Altman plots among IOP measurement approaches. RESULTS: Compared to new iCare probes, both once used probes (ICC = 0.989, 95% confidence interval [CI] 0.985-0.993) and multiply used probes (ICC = 0.989, 95% CI 0.984-0.992) showed excellent agreement, and the mean difference in IOP was minimal for both once used probes (0.70 mmHg, 95% CI 0.29-1.11) and multiply used probes (0.75 mmHg, 95% CI 0.66-0.82) compared to new probes. Bland-Altman plots demonstrated minimal differences between new and reused probes across the spectrum of IOP. When comparing multiply used probes to once used probes, there was a high level of agreement (0.993) (95% CI 0.990-0.995) and negligible mean IOP difference 0.04 mmHg (95% CI 0.32-0.40). Additionally, ICC values for new probes (0.966, 95% CI 0.951-0.976), once used probes (0.958, 95% CI 0.940-0.971), and multiply used probes (0.957, 95% CI 0.938-0.970) compared to GAT were similar and all showed excellent agreement. Both new and reused iCare probes underestimated IOP by 2 to 3 mmHg compared to GAT. CONCLUSIONS: In this prospective comparative analysis, we found that reusing iCare probes up to 5 times does not compromise the accuracy of IOP measurements when disinfected with 70% isopropyl alcohol swabs and ethylene oxide. Reusing iCare probes has the potential to transform care by reducing cost, decreasing environmental waste, and allowing for glaucoma screening camps and increased glaucoma monitoring in low resource settings leading to earlier identification and treatment of glaucoma. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Pre-procedural Stratification by the Endothelial Function in Patients with Heart Failure Undergoing Atrial Fibrillation Ablation.

BACKGROUND: Endothelial dysfunction (ED), a well-established risk marker of cardiovascular events, is associated with heart failure (HF) and atrial fibrillation (AF). Its relationship with cardiovascular events in patients with HF undergoing AF ablation remains unclear. We aimed to elucidate the association between ED and the outcomes after AF ablation in patients with HF. METHODS: This prospective cohort study included patients with HF who underwent an endothelial function assessment using the peripheral vascular reactive hyperemia index (RHI) before first-time AF ablation. We defined AF recurrence according to the following types: the conventional form (AF≥30 seconds) and persistent form (requiring cardioversion). An RHI<2.1 indicated ED. Those with and without ED were compared in terms of the 3-year incidence of AF recurrence and cardiovascular events after AF ablation. RESULTS: Among 421 patients with HF (69 ± 9 years and 38% females), 343 (81.5%) had ED. Although the incidence of the conventional form of AF recurrence was similar between the groups, that of the persistent form was significantly higher in the ED group (25.7% vs. 15.3%, log-rank P = 0.028). The ED group also had a significantly higher rate of cardiovascular events (14.8% vs. 3.6%, log-rank P = 0.028). Pre-procedural ED was identified as an independent predictor of a persistent form of AF recurrence (adjusted hazard ratio [HR] 2.31, 95% confidence interval [CI] 1.05-5.07, P = 0.037) and that of cardiovascular events (adjusted HR 4.21, 95% CI 1.02-17.5, P = 0.048), respectively. CONCLUSIONS: The endothelial function assessment enabled the risk stratification of clinically problematic outcomes after AF ablation in patients with HF.

Association between ischemia-modified albumin (IMA) and peripheral endothelial dysfunction in rheumatoid arthritis patients.

The identification of circulating biomarkers of endothelial dysfunction (ED), a precursor to atherosclerosis, in rheumatoid arthritis (RA) would facilitate early risk stratification and prevention strategies. Ischemia-modified albumin (IMA) has emerged as a potential biomarker of oxidative stress, ischemia, and ED. However, studies examining the relationship between IMA and ED in RA patients are lacking. We measured serum IMA concentrations by using an albumin cobalt binding test and peripheral vasodilatory capacity by EndoPAT in 113 RA patients without previous cardiovascular events enrolled in the EDRA study (ClinicalTrials.gov: NCT02341066). The mean peripheral vasodilatory capacity, expressed by the log of reactive hyperemia index (logRHI), was 0.82, corresponding to 27% RA patients having ED. The mean plasma concentrations of IMA were 0.478 absorbance units. We observed a significant and inverse association between peripheral vasodilatory capacity and serum IMA concentrations (rho = - 0.22, p = 0.02). In univariate logistic regression, ED was significantly associated with serum IMA concentrations [OR 1173 (95% CI 1.3568 to 101,364), p = 0.040) and higher disease activity. In multivariate logistic regression, the independent association between ED and IMA remained significant after correction for disease activity and other RA-confounders [OR 2252 (95% CI 1.0596 to 4,787,505), p = 0.048 in Model 1; OR 7221 (95% CI 4.1539 to 12,552,859), p = 0.02 in Model 2]. Conclusions: This study suggests that IMA is a promising biomarker of ED in RA. Further research is needed to confirm our findings and determine the clinical utility of IMA in detecting and managing early atherosclerosis in RA patients.

Improving early detection of keratoconus by Non Contact Tonometry. A computational study and new biomarkers proposal.

Keratoconus is a progressive ocular disorder affecting the corneal tissue, leading to irregular astigmatism and decreased visual acuity. The architectural organization of corneal tissue is altered in keratoconus, however, data from ex vivo testing of biomechanical properties of keratoconic corneas are limited and it is unclear how their results relate to true mechanical properties in vivo. This study explores the mechanical properties of keratoconic corneas through numerical simulations of non-contact tonometry (NCT) reproducing the clinical test of the Corvis ST device. Three sensitivity analyses were conducted to assess the impact of corneal material properties, size, and location of the pathological area on NCT results. Additionally, novel asymmetry-based indices were proposed to better characterize corneal deformations and improve the diagnosis of keratoconus. Our results show that the weakening of corneal material properties leads to increased deformation amplitude and altered biomechanical response. Furthermore, asymmetry indices offer valuable information for locating the pathological tissue. These findings suggest that adjusting the Corvis ST operation, such as a camera rotation, could enhance keratoconus detection and provide insights into the relative position of the affected area. Future research could explore the application of these indices in detecting early-stage keratoconus and assessing the fellow eye's risk for developing the pathology.

Longitudinal intraocular pressure measurements in Whooping cranes (Grus americana) and Mississippi-Sandhill cranes (Grus canadensis pulla).

OBJECTIVE: To assess intraocular pressure (IOP) development in cranes and determine the impact of age, weight, species, head position, and sex. ANIMALS STUDIED: Whooping cranes (WC) (Grus americana), and Mississippi-sandhill cranes (MSC) (Grus canadensis pulla). PROCEDURES: Chicks were manually restrained on days 1-3, 7, 21, 35, 60, 75, and 120 for routine examinations. IOP was opportunistically measured utilizing the Tonovet Plus® in D setting with the head above the heart (AH) and below the heart (BH). Values were also obtained longitudinally in adults (>120 days old) upon presentation in 1 year. RESULTS: Intraocular pressure was highly correlated with age and weight in chicks. For every kilogram gained, IOP increased 2.46 ± 0.08 mmHg in WC and 2.66 ± 0.11 mmHg in MSC. Once hatched, IOP increased 1.13 ± 0.04 mmHg in WC and 0.87 ± 0.04 mmHg in MSC every 10 days. IOP was similar to adults at 120 days of age. In adult WC, mean IOP AH was 24.0 ± 0.4 mmHg, and BH was 27.9 ± 0.4 mmHg, there was a significant difference regarding head positioning and sex, females (25.3 ± 0.4 mm Hg) had lower IOP than males (26.5 ± 0.4 mmHg). In adult MSC, mean IOP AH was 20.7 ± 0.4 mmHg, and BH was 24.6 ± 0.4 mmHg. The difference between head positioning was significant. CONCLUSIONS: This study documents the correlation between IOP and weight or age during early development in cranes, as well as the importance of head positioning.

Even-number measurement bias with Goldmann applanation tonometry in patients with glaucoma and glaucoma suspects.

CLINICAL RELEVANCE: Goldmann applanation tonometry is widely used for the diagnosis and management of glaucoma and its use is considered standard of care. However, the precision of this method may be reduced by a clinician tendency to round to even numbers. BACKGROUND: Studies have previously demonstrated an even-number measurement bias with Goldmann applanation tonometry during examination of a general patient population. Since it has not been determined whether this bias persists among glaucoma suspects and patients with glaucoma, further investigation was conducted. METHODS: A retrospective analysis was conducted on a random sample from a large dataset of >69,000 patients seen during a six-year period at an urban, academic primary eye care service. Patients without suspicion of glaucoma, patients with a suspicion of glaucoma, and patients with glaucoma were selected who had Goldmann tonometry performed. Chart reviews were performed to confirm status, and even/odd-numbered Goldmann tonometry measurement frequencies were compared. RESULTS: The analysis included 961 controls, 506 glaucoma suspects, 159 ocular hypertensives not taking medication, and 314 patients taking medications who carried a diagnosis of glaucoma or ocular hypertension. Among controls the Goldmann tonometry even/odd digit proportions were 62.8%/37.2% (N = 961, p < 0.0001), and the even-number bias persisted among the other groups with specific even/odd distributions being 61.9%/38.1% (N = 506, p < 0.0001) for glaucoma suspects not taking medications, 66.0%/34.0% (N = 159, p < 0.0001) for ocular hypertensives not taking medications, and 64.3%/35.7% (N = 314, p < 0.0001) for glaucoma/ocular hypertension patients taking medications. CONCLUSION: An even-number measurement bias with Goldmann tonometry may be prevalent even when the examiner is aware of there being greater importance for intraocular pressure measurement accuracy.

Efficacy of the positioning system when measuring canine intraocular pressures with the Reichert® Tono-Vera® Vet rebound tonometer.

OBJECTIVE: To compare intraocular pressure (IOP) measurements in dogs taken with the Reichert® Tono-Vera® Vet rebound tonometer with and without the automatic positioning system. ANIMALS STUDIED: Measurements were taken on 49 eyes from 26 Beagle-derived dogs with variable genetics-four non-glaucomatous and 22 ADAMTS10-mutant dogs affected with different stages of open-angle glaucoma. Seventeen of the 26 dogs were measured 2-4 times on different days with variable intervals since IOP-lowering medications were administered. PROCEDURES: In each dog, tonometry was performed with the Tono-Vera® Vet using three different methods in a randomized order: (Method 1) Average of three readings with an automatic positioning system; (Method 2) one reading with an automatic positioning system; and (Method 3) average of three readings obtained without the automatic positioning system. Statistical analyses included one-way ANOVA, Tukey pairwise comparisons, and Bland-Altman plots (MiniTab®). RESULTS: With each of the three tonometry methods, 116 measurements were taken, resulting in 348 total IOP measurements with a range of 12.8-49.9 mmHg. The means and standard deviations for each method were 25.4 ± 6.9 mmHg (Method 1), 26.0 ± 7.2 mmHg (Method 2), and 26.9 ± 7.7 mmHg (Method 3), with no significant differences (p = .27). Mean IOP variances were also not significantly different between tonometry methods (p = .24 to .78). CONCLUSIONS: Because mean IOPs and their standard deviations were not statistically different between the three tonometry methods, we conclude that Tono-Vera® Vet measurements conducted without the aid of the positioning system still provide reliable results.

Posture-related fluctuations of intraocular pressure in healthy children with suspicion of glaucoma.

PURPOSE: Currently, there are no specific data on the circadian course of intraocular pressure (IOP) in children, especially for IOP measurements in the supine position. The study aimed to characterize the diurnal and nocturnal IOP fluctuations in supine and sitting positions in patients less than 18 years of age. METHODS: Seventy-nine eyes of 79 patients under 18 years of age with suspicious optic nerve heads or ocular hypertension could be included in this study. All included patients showed an inconspicuous retinal nerve fiber layer thickness and Bruch's membrane minimum rim width by coherence tomography. IOP measurements during the 24-h IOP profile were retrospectively evaluated. Measurements were taken at 10:00, 16:00, 20:00, and 23:00 h in the sitting position and at 6:00 h in the morning in the supine position using iCare rebound tonometry on 2 consecutive days. RESULTS: Thirty-four of 79 children (43.0%) had peak nocturnal IOP values > 25 mmHg. The mean daily IOP was 18.8 ± 5.6 mmHg, and the mean daily fluctuation was 6.1 ± 4.0 mmHg. At 6 am, supine measurements were elevated to 25.1 ± 8.0 mmHg. Extensive fluctuations with values > 40 mmHg in the nocturnal supine measurement occurred in a relevant share of patients (n = 5). CONCLUSION: There appear to be relevant diurnal and nocturnal IOP fluctuations in healthy children (< 18 years). Nocturnal IOP measurements in supine patients with risk factors for glaucoma may provide important additional information to identify critical patients for further follow-up.

Determination of intraocular pressure and Schirmer tear test and the comparison between the applanation tonometer (Tono-Pen AVIA®) and the rebound tonometer (TonoVet Plus®) in mini lionhead rabbits.

OBJECTIVE: To determine intraocular pressure (IOP) and tear production, as well as to compare the IOP obtained with the TonoVet Plus® (rebound) with the Tono-Pen Avia® (applanation) tonometers. ANIMALS: Twenty-five Mini Lionhead rabbits (n = 50 eyes). PROCEDURE: Tear production was measured at 6:00 a.m. and 6:00 p.m. by using the STT. The IOP reading was performed with the rebound tonometer, followed by the applanation tonometer, at 6:00 a.m., 9:00 a.m., 12:00 p.m., 3:00 p.m., and 6:00 p.m. Regression analysis, analysis of variance (anova) and Bland-Altman statistics were used. RESULTS: Daily tear production was 10.25 ± 3.75 mm/min, with no differences among the moments evaluated. Average daily IOP was 17.7 ± 3.08 mmHg with the TonoVet Plus® and 11.5 ± 4.56 mmHg with the Tono-Pen Avia®. IOP values were higher at the beginning and end of the day with both tonometers. CONCLUSION: The IOP values are higher with the TonoVet Plus® tonometer. The reference values of IOP and tear production obtained in this work may support the diagnosis, treatment, and monitoring of ocular disorders in pet Mini Lionhead rabbits.

Intraocular pressure changes under an atmospheric pressure spectrum in a multiplace hyperbaric chamber / Análise de alterações da pressão intraocular (PIO) sob o espectro da pressão atmosférica em uma câmara hiperbárica multi-lugar

ABSTRACT Purpose: To evaluate the influence of atmospheric pressure changes on the behavior of intraocular pressure of healthy military individuals-students and instructors of the National Navy's Diving & Rescue School at the "ARC BOLÍVAR" naval base-during a simulated immersion in the hyperbaric chamber of the Naval Hospital of Cartagena. Methods: A descriptive exploratory study was performed. The intraocular pressure was measured at different atmospheric pressures during 60-min sessions in the hyperbaric chamber while breathing compressed air. The maximum simulated depth was 60 feet. Participants were students and instructors of the Naval Base's Diving and Rescue Department. Results: A total of 48 eyes from 24 divers were studied, of which 22 (91.7%) were male. The mean age of the participants was 30.6 (SD=5.5) years, ranging from 23 to 40. No participant had a history of glaucoma or ocular hypertension. The mean base intraocular pressure at sea level was 14 mmHg, which decreased to 13.1 mmHg (decreased by 1.2 mmHg) at 60 feet deep (p=0.0012). However, during the safety stop at 30 feet, the mean IOP kept decreasing until reaching 11.9 mmHg (p<0.001). By the end of the session, the mean intraocular pressure reached 13.1 mmHg, which is inferior and statistically significant when compared with the intraocular pressure base mean (p=0.012). Conclusions: In healthy individuals, the intraocular pressure decreases when reaching a depth of 60 feet (2.8 absolute atmosphere pressure) and it decreases even more during ascension at 30 feet. Measurements at both points were significantly different when compared with base intraocular pressure. The final intraocular pressure was lower than the baseline intraocular pressure, suggesting a residual and prolonged effect of the atmospheric pressure on intraocular pressure.

RESUMO Objetivo: Avaliar a influência das alterações da pressão atmosférica no comportamento da pressão intraocular de indivíduos militares saudáveis-alunos e instrutores da Escola de Mergulho e Resgate da Marinha Nacional na base naval "ARC BOLÍVAR"-durante uma imersão simulada na câmara hiperbárica do Hospital da Marinha de Cartagena. Métodos: Realizamos um estudo exploratório descritivo. A pressão intraocular foi medida em diferentes pressões atmosféricas durante sessões de 60 minutos na câmara hiperbárica respirando ar comprimido. A profundidade máxima simulada foi de 60 pés. Os participantes eram alunos e instrutores do Departamento de Mergulho e Resgate da Base Naval. Resultados: Quarenta e oito olhos de 24 mergulhadores foram estudados. Vinte e dois participantes (91,7%) eram do sexo masculino. A média de idade dos participantes foi de 30,6 (DP=5,5) anos, variando de 23 a 40. Nenhum participante tinha histórico de glaucoma ou hipertensão ocular. A média de base da pressão intraocular ao nível do mar foi de 14 mmHg, diminuindo para 13,1 mmHg (queda de 1,2 mmHg) a 60 pés de profundidade (p=0,0012). Entretanto, durante a parada de segurança a 30 pés, a pressão intraocular média continuou diminuindo até atingir 11,9 mmHg (p<0,001). Ao final da sessão, a pressão intraocular média atingiu 13,1 mmHg, valor inferior e estatisticamente significativo quando comparada à média de base da pressão intraocular (p=0,012). Conclusões: Em indivíduos saudáveis, a pressão intraocular diminui ao atingir uma profundidade de 60 pés (2,8 de pressão atmosférica absoluta) e diminui ainda mais durante a ascensão a 30 pés. As medidas em ambos os pontos foram significativamente diferentes quando comparadas à pressão intraocular de base. A pressão intraocular final foi menor do que a pressão intraocular de base, sugerindo um efeito residual e prolongado da pressão atmosférica sobre a pressão intraocular.

Assessment of oropharyngeal respiratory volume and sleep apnoea scores using peripheral arterial tonometry may improve diagnosis and treatment planning of combined dysgnathia therapy approaches.

BACKGROUND: Increased daytime sleepiness is a frequently reported symptom in patients with pronounced dysgnathia. OBJECTIVES: This study investigated possible correlations using home peripheral arterial tonometry (PAT) and oropharyngeal airway volume determination in patients with dysgnathia and daytime sleepiness. METHODS: Twenty patients (13 male, median age 27.6 ± 6.8 years) with abnormal sleep history and 10 skeletal neutral configured controls (6 male, median age 29.5 ± 4.2 years) with normal sleep history were examined. Patients and controls were evaluated for apnoea-hypopnoea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), snoring volume (dB), total sleep time (TST) and REM-percentage (REM). Airway volumetry was measured via CBCT. Individual user experience for PAT was assessed using the User Experience Questionnaire (UEQ). RESULTS: Patients had significantly higher respiratory scores than controls. AHI increased 4.6-fold (p = .006), RDI 2.5-fold (p = .008) and ODI 6.4-fold (p < .001). Oropharyngeal volumes showed a 30% decrease (p = .003). dB, TST and REM showed no significant differences. AHI (r = -.51; p = .005), ODI (r = -.60; p < .001) and RDI (r = -.45; p = .016) correlated negatively with pharyngeal volume. Wits appraisal correlated negatively with oropharyngeal volume (r = -.47; p = .010) and positively with AHI (r = .41; p = .03) and ODI (r = .49; p = .007). dB and TST (r = -.49; p = .008) and REM and RDI (r = -.43; p = .02) correlated negatively. UEQ-KPI (2.17 ± 0.24) confirmed excellent usability of PAT. CONCLUSION: Patients with mandibular retrognathia and abnormal sleep history showed significantly higher respiratory indices and smaller oropharyngeal volumes than neutrally configured controls. The dygnathia severity directly influenced the risk of obstructive sleep apnoea.

The accuracy of radial artery applanation tonometry and intra-arterial blood pressure monitoring in critically ill patients: An evidence-based review.

The invasive intra-arterial approach is the gold standard for measuring blood pressure in intensive care units where accuracy is crucial. However, invasive procedures increase the risk of infections and mortality. This evidence-based review aimed to determine whether continuous non-invasive blood pressure (CNIBP) monitoring, using Radial Artery Applanation Tonometry (RAAT) devices, is as accurate as invasive methods. Six papers were included: three prospective cohort studies and three comparative studies. Most studies showed that mean arterial pressure is accurately recorded through RAAT monitoring; however, more research is needed to assess the accuracy of non-invasive readings of systolic and diastolic blood pressures, as data are not always concordant.