Twenty-four hours intraocular pressure in keratoconic eyes assessed by applanation tonometry and Tono-Pen AVIA

AIM: To assess intraocular pressure (IOP) during the daily curve of intraocular pressure (DCPo) in keratoconic eyes and compare Goldmann applanation tonometer (GAT), without and with astigmatism correction (nGAT and cGAT) and Tono-Pen AVIA (TPA) assessment methods. METHODS: Thirty-nine keratoconic eyes of 24 patients were assessed. DCPo was evaluated with five IOP measurements; four were performed with a GAT (nGAT and cGAT), and a Tono-Pen AVIA (TPA) at various times throughout the day. RESULTS: Mean IOP DCPo values (mm Hg) were: nGAT, 9.9±2.6; cGAT, 11.3±2.6; TPA 12.3±3.1. Mean IOP DCPo differences (mm Hg) and Spearman's correlation coefficients were as follows: cGATc-nGAT, 1.32±1.31, rs=0.879 (P<0.01); cGAT-TPA, -1.02±2.08, rs=0.723 (P<0.01); and nGAT-TPA, -2.35±2.23, rs=0.730 (P<0.01). Bland-Altman analysis for agreement between cGAT-TPA and nGAT-TPA mean IOP DCPo measurements revealed a mean difference of 1.02 (95%CI, 0.35-1.70) and 2.35 (95%CI, 1.62-3.07) mm Hg, respectively. Regression analysis yielded the following equation: TPA IOP=5.49+0.775×cGAT-0.015×ACD-0.299×corneal astig matism, which allowed us to infer TPA IOP values from other parameters. CONCLUSION: In keratoconic eyes, IOP peaks of DCPo measurements are identified at 6 a.m., independent of the tonometer. The mean DCPo values are: TPA>cGAT>nGAT. IOP TPA measures are predictive of cGAT values, adjusted according to anterior chamber depth and corneal astigmatism.

Aortic haemodynamics: the effects of habitual endurance exercise, age and muscle sympathetic vasomotor outflow in healthy men

Purpose We determined the effect of habitual endurance exercise and age on aortic pulse wave velocity (aPWV), augmentation pressure (AP) and systolic blood pressure (aSBP), with statistical adjustments of aPWV and AP for heart rate and aortic mean arterial pressure, when appropriate. Furthermore, we assessed whether muscle sympathetic nerve activity (MSNA) correlates with AP in young and middle-aged men. Methods Aortic PWV, AP, aortic blood pressure (applanation tonometry; SphygmoCor) and MSNA (peroneal microneurography) were recorded in 46 normotensive men who were either young or middle-aged and endurance-trained runners or recreationally active nonrunners (10 nonrunners and 13 runners within each age-group). Between-group differences and relationships between variables were assessed via ANOVA/ANCOVA and Pearson product-moment correlation coefficients, respectively. Results Adjusted aPWV and adjusted AP were similar between runners and nonrunners in both age groups (all, P > 0.05), but higher with age (all, P < 0.001), with a greater effect size for the age-related difference in AP in runners (Hedges’ g, 3.6 vs 2.6). aSBP was lower in young (P = 0.009; g = 2.6), but not middle-aged (P = 0.341; g = 1.1), runners compared to nonrunners. MSNA burst frequency did not correlate with AP in either age group (young: r = 0.00, P = 0.994; middle-aged: r = − 0.11, P = 0.604). Conclusion There is an age-dependent effect of habitual exercise on aortic haemodynamics, with lower aSBP in young runners compared to nonrunners only. Statistical adjustment of aPWV and AP markedly influenced the outcomes of this study, highlighting the importance of performing these analyses. Further, peripheral sympathetic vasomotor outflow and AP were not correlated in young or middle-aged normotensive men.

Effect of acupuncture on intraocular pressure and tear production in healthy horses

ABSTRACT: Acupuncture is an ancient Chinese form of therapy that involves needle stimulation of specific points on the body for therapeutic and homeostatic effects. In ophthalmology, acupuncture helps as a conventional or adjuvant therapy for numerous eye disorders, including myopia, strabismus, dry eye, and cataracts. This study aimed to evaluate the effect of acupuncture on tear production (TP) and intraocular pressure (IOP) in horses. Ten healthy horses, females and males with ages varying between eight months and nine years, were used. Schirmer’s I test and applanation tonometry were used to evaluate the basal TP and IOP of both eyes. The measurements were taken immediately before (T10) the insertion of the needles and 5 (T5), 15 (T15), 30 (T30) and 60 (T60) minutes and 24 (T24) hours after a 20-minute acupuncture session. Mean values of both eyes were analyzed over time. TP increased in 50% of the animals at T5, T15 and T24, in 30% at T30, and in 40% at T60, with an increase of up to 8.5 mm/min at T15 and T60. In addition, there was a significant difference between T24 and T30, with a 14.1% increase in TP at T24. Meanwhile, IOP decreased in 50% of the animals at T5 and T30, in 20% at T15, in 60% at T60, and in 70% at T24. Thus, we suggest that acupuncture is a technique that can benefit horses with diseases that alter these parameters, either alone or as an adjunct in conventional therapeutic protocols.

Variation of intraocular pressure comparing rebound (TONOVET Plus®) and applanation (TONO-PEN VET®) tonometry in New Zealand rabbits treated with Amlodipine®

Rabbits have played an important role in ophthalmological research processes, however in the environment there has been a deficiency of sensitive equipment in measurement of intraocular pressure for this species. To compare intraocular pressure (IOP) measured with rebound (TONOVET Plus®) and applanation (TONO-PEN VET®) tonometry in healthy New Zealand rabbits treated with Amlodipine. Twelve healthy male New Zealand white rabbits, 5 months old; two groups with 6 individuals were used in this study. The experimental group was given Amlodipine® at a dose of 5 mg/kg, once a day for a month. Blood pressure and intraocular pressure were measurement before treatment and 6 h after treatment in a period of one month. A trend is noted where the group of animals treated with amlodipine® presents lower values than the control group, both in systolic and diastolic pressure. The systolic pressure of the control group showed an average of 116.5 ± 7.9 mmHg and 117.4 ± 8.9 mmHg and the treatment group showed an average of 113.6 ± 7.9 mmHg and 111.8 ± 10.0 mmHg (pretreatment and posttreatment respectively). Tonometry: the values obtained using the TONOVET Plus® (19 ± 3 mmHg) are on average higher than the values obtained using the TONO-PEN VET® (17 ± 3 mmHg). It was possible to demonstrate the relationship between systemic blood pressure and intraocular pressure in New Zealand white rabbits. Rebound tonometry showed less variability in results than applanation tonometry. This study confirmed that both tonometers are reliable for measuring IOP in rabbits.

Keratometry, biometry, and prediction of intraocular lens power in adult tigers (Panthera tigris)

OBJECTIVE To calculate the necessary pseudophakic intraocular lens (IOL) power to approximate emmetropia in adult tigers. ANIMALS 17 clinically normal adult tigers. PROCEDURES 33 eyes of 17 clinically normal adult tigers underwent routine ophthalmic examination and B-scan ultrasonography while anesthetized for unrelated procedures. Specific ultrasound data (globe measurements and corneal curvature) and estimated postoperative IOL positions were utilized to calculate predicted IOL power by use of Retzlaff and Binkhorst theoretical formulas. Applanation tonometry and refraction were also performed. RESULTS Mean ± SD axial globe length was 29.36 ± 0.82 mm, preoperative anterior chamber depth was 7.00 ± 0.74 mm, and crystalline lens thickness was 8.72 ± 0.56 mm. Mean net refractive error (n = 33 eyes) was +0.27 ± 0.30 diopters (D). By use of the Retzlaff formula, mean predicted IOL power for the postoperative anterior chamber depth (PACD), PACD – 2 mm, and PACD + 2 mm was 43.72 ± 4.84 D, 37.62 ± 4.19 D, and 51.57 ± 5.72 D, respectively. By use of the Binkhorst equation, these values were 45.11 ± 4.91 D, 38.84 ± 4.25 D, and 53.18 ± 5.81 D, respectively. Mean intraocular pressure for all eyes was 14.7 ± 2.69 mm Hg. CLINICAL RELEVANCE The calculated tiger IOL was lower than reported values for adult domestic felids. Further studies evaluating actual PACD and pseudophakic refraction would help determine the appropriate IOL power to achieve emmetropia in this species.

Differential impact of prostaglandin analogues on agreement of intraocular pressure measurements obtained by Goldmann applanation, rebound, and noncontact tonometry

Background To evaluate the effect of topical prostaglandin analogues on agreement of IOP measurements obtained by Goldmann applanation tonometry (GAT), rebound tonometry (RBT), and noncontact tonometry (NCT) in eyes with primary open- angle glaucoma (POAG). Methods Intraocular pressure measurements were obtained using GAT, RBT, and NCT in patients with POAG with or without prostaglandin analogues. The agreement between each tonometry was analysed using Bland-Altman analyses in those with or without prostaglandin analogues. The effect of average IOP on IOP differences was also evaluated. Results Among a total of 86 subjects included in the study, 44 patients were using prostaglandin analogues. The difference in IOP measured by GAT and RBT was marginally greater in those with (GAT-RBT: − 0.94 ± 1.63 mmHg) prostaglandin analogues than in those without (− 0.33 ± 1.22 mmHg, P = 0.06). The difference in IOP measured by GAT and NCT was significantly greater in the prostaglandin group (GAT-NCT: 2.40 ± 2.89 mmHg) than in the group without prostaglandin analogues (0.41 ± 1.63 mmHg, P < 0.01). While there was no significant relationship between the average of all tonometries and the difference between tonometries in those without prostaglandin analogues, both RBT and NCT underestimated IOP relative to GAT at higher IOP in those using prostaglandin analogues. Conclusion Intraocular pressure measured by RBT and NCT was similar to that measured by GAT in those without prostaglandin analogues. RBT overestimated and NCT underestimated IOP compared to GAT in those using prostaglandin analogues.

Relation between Oscillometric Measurement of Central Hemodynamics and Left Ventricular Hypertrophy in Hypertensive Patients

<b><i>Introduction:</i></b> The augmentation index (AIx) or central systolic blood pressure (SBP), measured by radial applanation tonometry, has been reported to be independently associated with left ventricular hypertrophy (LVH) in Japanese hypertensive patients. Cuff-based oscillometric measurement of the AIx using Mobil-O-Graph® showed a low or moderate agreement with the AIx measurement with other devices. <b><i>Methods:</i></b> The AIx measured using the Mobil-O-Graph was validated against the tonometric measurements of the radial AIx measured using HEM-9000AI in 110 normotensive healthy individuals (age, 21–76 years; 50 men). We investigated the relationship between the central hemodynamics assessed using the Mobil-O-Graph and LVH in 100 hypertensive patients (age, 54–75 years; 48 men), presenting a wall thickness of ≥11 mm and ≥10 mm in men and women, respectively. <b><i>Results:</i></b> Although the Mobil-O-Graph-measured central AIx showed no negative values, it correlated moderately with the HEM-9000AI-measured radial AIx (<i>r</i> = 0.602, <i>p</i> &#x3c; 0.001) in the normotensive individuals. The hypertensive patients did not show a significant difference in the central SBP between the sexes, but the central AIx was lower in men than in women. The independent determinants influencing left ventricle (LV) mass index (LVMI) (<i>R</i>² = 0.362; adjusted <i>R</i>² = 0.329, <i>p</i> &#x3c; 0.001) were heart rate (β = −0.568 ± 0.149, <i>p</i> &#x3c; 0.001), central SBP (β = 0.290 ± 0.100, <i>p</i> = 0.005), and aortic root diameter (β = 1.355 ± 0.344, <i>p</i> = 0.001). Age (β = −0.025 ± 0.124, <i>p</i> = 0.841) and the central AIx (β = 0.120 ± 0.131, <i>p</i> = 0.361) were not independently associated with the LVMI. The area under the receiver operator characteristic curve to evaluate the diagnostic performance of the central AIx for the presence of LVH (LVMI &#x3e;118 g/m² in men or &#x3e;108 g/m² in women) was statistically significant in men (0.875, <i>p</i> &#x3c; 0.001) but not in women (0.622, <i>p</i> = 0.132). In men, a central AIx of 28.06% had a sensitivity of 83.3% and specificity of 80.0% for detecting LVH. <b><i>Conclusions:</i></b> AIx measurement in men provided useful prognostic information for the presence of LVH. Pulse-wave analysis assessed using the Mobil-O-Graph may be a valuable tool for detecting LVH in hypertensive patients.

Safety and performance of a suprachoroidal sensor for telemetric measurement of intraocular pressure in the EYEMATE-SC trial

AimTo investigate the safety and performance of a telemetric suprachoroidal intraocular pressure (IOP) sensor (EYEMATE-SC) and the accuracy of its IOP measurements in open angle glaucoma (OAG) patients undergoing simultaneous non-penetrating glaucoma surgery (NPGS).MethodsProspective, multicentre, open-label, single-arm, interventional clinical trial. Twenty-four eyes of 24 patients with OAG regularly scheduled for NPGS (canaloplasty or deep sclerectomy) were simultaneously implanted with an EYEMATE-SC sensor. Six-month follow-up on the sensor’s safety and performance as well as on the level of agreement between the EYEMATE-SC measurements and IOP measurements with Goldmann applanation tonometry (GAT).ResultsThe eyes underwent canaloplasty (n=15) or deep sclerectomy (n=9) and achieved successful implantation of the sensor. No device migration, dislocation or serious device-related complications occurred. A total of 367 comparisons were included in the IOP agreement analysis. The overall mean difference between GAT and EYEMATE-SC measurements was 1.31 mm Hg (lower limit of agreement (LoA) 7.55 mm Hg; upper LoA –4.92 mm Hg). The maximum difference of 2.5 mm Hg ±3.96 (LoA 0.30–2.29) was reached on day 10 and continuously improved to an agreement of –0.15 mm Hg ±2.28 (LoA –1.24 to 0.89) after 6 months. Accordingly, the percentage of eyes within an IOP difference of ±5 mm Hg improved from 78% (day 3) to 100% (6 months).ConclusionsAfter 6 months, the EYEMATE-SC sensor was safe and well tolerated, and allowed continual IOP monitoring.Trial registration numberNCT03756662.