Hand-held Tonometer Research Articles

Small tidal volume hyperventilation relieves intraocular and intracranial pressure elevation in prone spinal surgery: a randomized controlled trial

To investigate the effects of different ventilation strategies on intraocular pressure (IOP) and intracranial pressure in patients undergoing spinal surgery in the prone position under general anesthesia. Seventy-two patients undergoing prone spinal surgery under general anesthesia between November, 2022 and June, 2023 were equally randomized into two groups to receive routine ventilation (with Vt of 8mL/kg, Fr of 12-15/min, and etCO2 maintained at 35-40 mmHg) or small tidal volume hyperventilation (Vt of 6 mL/kg, Fr of18-20/min, and etCO2 maintained at 30-35 mmHg) during the surgery. IOP of both eyes (measured with a handheld tonometer), optic nerve sheath diameter (ONSD; measured at 3 mm behind the eyeball with bedside real-time ultrasound), circulatory and respiratory parameters of the patients were recorded before anesthesia (T0), immediately after anesthesia induction (T1), immediately after prone positioning (T2), at 2 h during operation (T3), immediately after supine positioning after surgery (T4) and 30 min after the operation (T5). Compared with those at T1, IOP and ONSD in both groups increased significantly at T3 and T4(P < 0.05). IOP was significantly lower in hyperventilation group than in routine ventilation group at T3 and T4(P < 0.05), and ONSD was significantly lower in hyperventilation group at T4(P < 0.05). IOP was positively correlated with the length of operative time (r=0.779, P < 0.001) and inversely with intraoperative etCO2 at T3(r=-0.248, P < 0.001) and T4(r=-0.251, P < 0.001).ONSD was correlated only with operation time (r=0.561, P < 0.05) and not with IOP (r=0.178, P>0.05 at T3; r=0.165, P>0.05 at T4). Small tidal volume hyperventilation can relieve the increase of IOP and ONSD during prone spinal surgery under general anesthesia.

Influence of vaginal birth on lumbopelvic muscle mechanical properties on urinary incontinence

Objective To identify differences in the muscle mechanical properties of the pelvic floor (PF) and lumbar paravertebral (LP) muscles between young nulliparous and uni/multiparous women. Secondarily, specific behaviors, depending on the presence or absence or urinary incontinence (UI), were also researched. Design Case–control study. Setting Higher education institution. Participants One hundred young women participated, divided into two groups depending on whether they had vaginal birth (nulliparous or uni/multiparous). Each group included women with and without UI. Main measures A muscle mechanical properties (tone, stiffness, decrement—inverse of elasticity—, and viscoelastic properties: relaxation and creep) assessment of the PF and LP muscles were performed with a hand-held tonometer. Results Tone and stiffness of both sides of the PF presented group by UI interaction (p < 0.05), with uni/multiparous women with UI showing higher tone and stiffness compared to multiparous women without UI. In LP muscles, uni/multiparous women showed greater tone and stiffness on the right and left sides [−2.57 Hz (95% confidence interval −4.42,−0.72) and −79.74 N/m (−143.52,−15.97); −2.20 Hz (−3.82,−0.58) and −81.30 N/m (−140.66-,21.95), respectively], as well as a decrease in viscoelastic properties compared to nulliparous women [relaxation: 2.88 ms (0.31,5.44); creep: 0.15 (0.01,0.30); relaxation: 2.69 ms (0.13,5.25); creep: 0.14 (0,0.28), respectively]. Conclusions Vaginal birth and UI have a differential influence on the muscle mechanical properties of the PF and LP muscles. The determination of muscle mechanical properties by externally applied hand-held tonometry improves the knowledge of the lumbopelvic status, with applicability in clinical and research fields.

İntravitreal Aflibercept Uygulanan Hastalarda Topikal Antiglokomatöz Damlanın Göziçi Basıncı Değişimine Etkisi

Aim:The aim is to investigate the effect of using topical dorzolamide-timolol (DT) drops before intravitreal aflibercept (IVA) administration on intraocularpressure (IOP) changes. Materials and Methods: Forty-five eyes of 45 patients with diabetic retinopathy and macular edema who received DT drops 1 hour before IVA were considered as group 1, and 45 eyes of 45 patients without DT drops were considered as group 2. Patients who had previously undergone intravitreal injection, intraocular surgery, and who used any eye drops were excluded from the study. IOP values were measured with Tonopen contact handheld tonometer before blepharostatinsertion (BBIOP), after blepharostat insertion (ABIOP) and at 1 minute after injection (AIIOP). Results: There were 23 males and 22 females in group 1 and 22 males and 23 females in group 2 (p=0.96). The mean age was 55.23 ±7.53 years in group 1 and 55.70 ±9.78 years in group 2.(p=0. 97) In group 1, BBIOP was 18.12 ±4.18 mmHg, ABIOP 20.98 ±4.42 mmHg, AIIOP 43.20 ±15.80 mmHg, while in group 2, BBIOP 18.65 ±3.52 mmHg, ABIOP 22.80 ±3.90 mmHg, AIIOP 39.08 ±13.18 mmHg. The difference between AIIOP and BBIOP was 25.04 ±16.30 mmHg in group 1 and 20.36 ±13.82 mmHg in group 2, the difference was not statistically significant.(p=0.21) The difference between AIIOP and ABIOP was 22.32 ±16.48 mmHg in group 1 and 16.18 ±13.05 mmHg in group 2, the difference was statistically significant.(p=0.03). Conclusion: In the group using topical DT drops before IVA administration, BBIOP and ABIOP values were lower, while AIIOP values were higher.

Long-Term Decrease in Intraocular Pressure in Survivors of Ebola Virus Disease in the Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III Study.

Survivors of Ebola virus disease (EVD) experience decreased intraocular pressure (IOP) relative to unaffected close contacts during the first year of convalescence. Whether this effect persists over time and its relationship to intraocular pathology are unclear. We sought to determine whether IOP remained lower in survivors of EVD over 4 years of follow-up and to identify associated risk factors. Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III is a 5-year, longitudinal cohort study of survivors of EVD and their close contacts and is a collaboration between the Liberian Ministry of Health and the United States National Institutes of Health. Participants who enrolled in PREVAIL III at John F. Kennedy Medical Center in Liberia, West Africa from June 2015 to March 2016 who underwent comprehensive ophthalmic evaluation annually for 5 consecutive visits. Intraocular pressure was measured at each visit by a handheld rebound tonometer using sterile tips. Comparisons are made between antibody-positive survivors and antibody-negative close contacts. Intraocular pressure, measured in mmHg, at each study visit. Of 565 antibody-positive survivors and 644 antibody-negative close contacts enrolled in the study at baseline, the majority of participants returned annually, with 383 (67.8%) and 407 (63.2%) participants, respectively, presenting for the final study visit at a median of 60 months after symptom onset. A sustained, relative decrease in IOP was observed in survivors relative to close contacts, with mean difference of-0.72 mmHg (95% confidence interval [CI]-1.18 to-0.27) at the final study visit. This difference remained constant throughout the study period (P= 0.4 for interaction over time). Among survivors, physical examination findings of vitreous cell and OCT findings of vitreous opacities both demonstrated a significant association with decreasedIOP at baseline (P < 0.05 for both). After adjusting for such factors, the difference throughout the follow-up (-0.93 mmHg, 95% CI,-1.23 to-0.63) remained significant. Survivors of EVD experienced a sustained decrease in IOP relative to close contacts over a 5-year period after EVD. The results highlight the importance of considering long-term sequelae of emerging infectious diseases within a population. Proprietary or commercial disclosure may be found after the references.

Clinical Features Associated with Acute Elevated Intraocular Pressure After Intravitreal Anti-VEGF Injections.

To study the effects of intravitreal injection (IVI) of anti-VEGF (vascular endothelial growth factor) agents on intraocular pressure (IOP) and find associations with acute pressure spikes. This was a three-month, prospective study of patients receiving outpatient IVI of anti-VEGF agents for diabetic retinopathy (DR), age-related macular degeneration (AMD), and retinal vein occlusion (RVO) at the Acuity Eye Group Medical Centers. IOP was measured pre- and post-injection at 10-minute intervals up to 50 minutes after injection with a handheld tonometer. Patients with an IOP greater than 35 mmHg at 30 minutes received an anterior chamber paracentesis (ACP), while patients below 35 mmHg were monitored without intervention. A total of 617 patients (51% female, 49% male) received IVI for DR (n = 199), AMD (n = 355), and RVO (n = 63). ACP was performed in 17 patients. Average pre-injection IOP was 16 ± 4 compared to 24 ± 7 mmHg for the non-ACP vs ACP group, respectively (mean ± standard deviation), p < 0.0001. IOP returned to baseline in 98% of patients at 50 minutes. A diagnosis of glaucoma and glaucoma suspect was more prevalent in the ACP group compared to the non-ACP group, 82.3% vs 14.2% and 17.6% vs 9.0%, respectively, p < 0.0001 and p > 0.05. Patients with a pre-injection IOP >25 mmHg and a history of glaucoma had a 58.3% rate of ACP. A 31-gauge needle had a higher mean increase in IOP from baseline compared to 30-gauge needle, p < 0.0001. IOP spikes are most significant in the first 10 minutes after IVI but typically resolve within the first hour. However, utilizing a smaller 31-gauge IVI in patients with a glaucoma history and pre-injection IOP >25 mmHg may be associated with significant IOP spikes lasting longer than 30 minutes.

Analysis of influencing factors of corneal edema after phacoemulsification for diabetic cataract.

The paper aimed to explore the influence factors of corneal edema after phacoemulsification for diabetic cataracts. For this aim, 80 patients (80 eyes) with senile cataracts who underwent phacoemulsification implantation in our hospital from August 2021 to January 2022 were included in this study, including 39 males (48.75%) and 41 females (51.25%), with an average age of 70.35±5.22 years. The OCT system during ophthalmology was used to capture corneal OCT images in the center of the cornea in real time before the phacoemulsification (the phacoemulsification probe just entered the anterior chamber after the balanced saline left the separated nucleus), at the end of phacoemulsification (when the phacoemulsification ultrasound probe was still in the anterior chamber and the perfusion pressure did not change compared with that in the previous step), at the end of perfusion aspiration (after the perfusion aspiration probe left the anterior chamber), and after surgery (after the watertight incision is closed). The corneal thickness was measured at each time point using Photoshop software. AL, curvature and ACD were measured using IOL-Master bio-measurement technology, and ACD referred to the distance between the front surface of the cornea and the front surface of the lens. Endothelial cell density was measured using CIM-530 non-contact mirror microscope. A handheld rebound tonometer was used to measure intraocular pressure and optical coherence tomography was used to assess the macular area of the fundus. Fundus photography was performed with a non-diffuse fundus camera. The results indicated that the preoperative corneal thickness was 514.35±29.62 μm, and the average corneal thickness at the end of the operation was 535.26±30.29μm, which was increased by 20.91±1.67 μm compared with that before operation (P<0.05), and the increase rate of corneal thickness was 4.07%. The corneal thickness of patients tended to increase with the increase in operation time and intraocular operation time (P<0.05). The distribution of corneal edema-related features showed that 42.50% of patients had persistent edema at the time of cataract surgery. The median onset time of corneal edema in the remaining patients was 5.44 years (1.96-21.35 years for 90% CR). The higher the nuclear hardness, the more severe the cataract, and the higher APT, EPT, APE, and TST (P<0.05). The older the patient, the higher the grade of cataract nucleus, and the higher EPT, APE, and TST, the greater the intraoperative corneal thickening (P<0.05). The higher the maximum area of endothelial cells, the greater the intraoperative corneal thickness increase, the lower the corneal endothelial cell density and the greater the intraoperative corneal thickness increase (P<0.05). It was concluded that postoperative corneal edema in phacoemulsification surgery for diabetic cataracts is closely related to intraocular perfusion pressure, nuclear hardness of lens, the density of corneal endothelial cells, the energy of phacoemulsification and duration.

Evidence of Spaceflight-Induced Adverse Effects on Photoreceptors and Retinal Function in the Mouse Eye.

The goal of the present study was to characterize acute oxidative damage in ocular structure and retinal function after exposure to spaceflight, and to evaluate the efficacy of an antioxidant in reducing spaceflight-induced changes in the retina. Ten-week-old adult C57BL/6 male mice were flown aboard the ISS on Space-X 24 over 35 days, and returned to Earth alive. The mice received a weekly injection of a superoxide dismutase mimic, MnTnBuOE-2-PyP 5+ (BuOE), before launch and during their stay onboard the ISS. Ground control mice were maintained on Earth under identical environmental conditions. Before the launch, intraocular pressure (IOP) was measured using a handheld tonometer and retinal function was evaluated using electroretinogram (ERG). ERG signals were recorded when the mouse eye was under dark-adapted conditions in response to ultraviolet monochromatic light flashes. Within 20 h after splashdown, IOP and ERG assessments were repeated before euthanasia. There were significant increases in body weight for habitat control groups post-flight compared to pre-flight measurements. However, the body weights were similar among flight groups before launch and after splashdown. The IOP measurements were similar between pre- and post-flight groups with no significant differences between BuOE-treated and saline controls. Immunofluorescence evaluation showed increases in retinal oxidative stress and apoptotic cell death after spaceflight. BuOE treatment significantly decreased the level of the oxidative stress biomarker. ERG data showed that the average amplitudes of the a- and b-wave were significantly decreased (39% and 32% by spaceflight, respectively) compared to that of habitat ground controls. These data indicate that spaceflight conditions induce oxidative stress in the retina, which may lead to photoreceptor cell damage and retinal function impairment.

The Effect of Dorzolamide-timolol Eye drop on Intraocular Pressure Change in Intravitreal Ranibizumab Injected Patients.

The objective of the study was to examine the effect of dorzolamide-timolol (DT) eye drop used before intravitreal ranibizumab (IVR) injection on intraocular pressure (IOP) change. 50 eyes of 50 patients who received DT eye drops 1 h before IVR injection due to diabetic retinopathy and macular edema were considered Group 1, and 50 eyes of 50 patients who did not receive DT eye drops were considered Group 2. Those patients who had previously undergone intravitreal injection had intraocular surgery, and used any eye drops were not included in the study. Before the injection, IOP values were measured with a Tonopen contact handheld tonometer before the blepharostat was placed (BIOP), after the blepharostat was placed (AIOP), and at the 1st min after the injection (IIOP). There were 25 males and 25 females in Group 1 and 25 males and 25 females in Group 2; the mean age was 65.66 ± 9.94 years in Group 1 and 65.54 ± 7.43 years in Group 2 (P = 0.98). In Group 1, BIOP was 18.91 ± 18.91, AIOP was 21.62 ± 6.16 mmHg, and IIOP was 49.21 ± 10.95 mmHg. In Group 2, BIOP was 20.18 ± 4.19 mmHg, AIOP was 24.60 ± 4.90 mmHg, and IIOP was 49.96 ± 9.72 mmHg. IIOP-BIOP difference was 30.30 ± 9.85 mmHg in Group 1 and 29.78 ± 9.33 mmHg in Group 2 and the difference was not statistically significant (P = 0.78). In Group 1, the IIOP-AIOP difference was 27.58 ± 10.60 mmHg and in Group 2, 25.36 ± 10.46 mmHg. The difference between IIOP and AIOP was not statistically significant (P = 0.27). The use of topical DT eye drops before IVR injection does not affect the intraocular pressure change.

Comparison of four tonometers in the measurement of intraocular pressure in healthy horses.

Measurement of the intraocular pressure (IOP) is a useful diagnostic tool in equine ophthalmology. Handheld tonometers, such as Tonovet and Tonovet Plus (rebound), Tono-Pen AVIA Vet (applanation), and Kowa HA-2 (applanation using the Goldmann methodology) are used to obtain IOP measurements in veterinary medicine. To compare and evaluate the accuracy of four handheld tonometers in measuring IOP using different methodologies in healthy horses. In vivo experiment and cross-sectional survey of healthy horses. Intraocular pressure was measured in 72 eyes of 36 horses. An in vivo study was conducted on sedated horses to compare the real IOP values obtained using manometry versus those obtained using tonometry, and a field study was conducted on unsedated healthy horses with normal eyes to measure the IOP values using different tonometers. In the in vivo study, the mean IOP values using ocular manometry was 24.9± 4.0 mmHg (range, 20.0-30.0 mmHg). The mean IOP values using tonometry were: Tonovet, 25.7± 5.8 mmHg (range 19.5-33.0 mmHg); Tonovet Plus, 24.8± 7.1 mmHg (range 13.2-33.2 mmHg); Tono Pen AVIA Vet, 19.2± 4.7 mmHg (range 13.1-26.5 mmHg); and Kowa Ha-2, 24.1± 1.2 mmHg (range 22.8-25.8 mmHg). In the field study, the IOP values were: Tonovet, 30.7± 5.6 mmHg (range 21.7-38.0 mmHg); Tonovet Plus, 29.6± 6.7 mmHg (range 16.2-38.6 mmHg); Tono-Pen AVIA Vet, 27.3± 5.8 mmHg (range 14.6-37.1 mmHg); and Kowa HA-2, 23.4± 2.2 mmHg (range 20.2-28.7 mmHg). This study included only healthy horses and a limited number of animals in the in vivo study. There was a strong correlation between the IOP values and manometry for all tonometers. IOP should be estimated using the same tonometer over time, and the bias of the tonometer used, such as overestimation (rebound tonometer) and underestimation (applanation tonometer), should be acknowledged. A normal reference value for each tonometer should be established in horses.

A Prospective Analysis of the Simplified Student Sight Savers Program on Open-Angle Glaucoma Cost Burden in Underserved Communities.

(1) Background: Glaucoma is a leading cause of irreversible blindness worldwide. Unfortunately, no noticeable symptoms exist until mid- to late-stage glaucoma, leading to substantial costs to the patient and the healthcare system. (2) Methods: The Student Sight Savers Program, an initiative started at Johns Hopkins University, was designed to meet the needs of community screening for glaucoma. Several medical students at the Rocky Vista University in Saint George, Utah, were trained, and screened patients at local fairs and gathering places using a modified version of this program. Patients found to have elevated pressure (>21 mmHg) or other ocular abnormalities were referred for an ophthalmological examination. (3) Results: Individuals from medically underserved areas/populations (MUA/Ps) were nearly three times as likely to have elevated intraocular pressure as individuals not in underserved areas (p = 0.0141). A further analysis demonstrates that medical students can help reduce medical costs for patients and the healthcare system by providing referrals to ophthalmologists and reaching populations that are not usually screened for glaucoma. (4) Conclusions: Allowing medical students to perform community-based glaucoma screening events in MUA/Ps using handheld tonometers may decrease the cost burden associated with late diagnosis, and raise awareness about glaucoma, especially in underserved populations.

Ocular Hypotensive Properties and Biochemical Profile of QLS-101, a Novel ATP-Sensitive Potassium (KATP) Channel Opening Prodrug.

PurposeTo characterize the ocular hypotensive and pharmacological properties of QLS-101, a novel ATP-sensitive potassium (KATP) channel opening prodrug.MethodsOcular hypotensive properties of QLS-101 were evaluated by measuring IOP with a handheld rebound tonometer after daily topical ocular instillation of 0.2% (n = 5) or 0.4% QLS-101 (n = 10) in C57BL/6J mice. KATP channel specificity was characterized in HEK-293 cells stably expressing human Kir6.2/SUR2B subunits and assessed for off-target interactions using a receptor binding screen. Conversion of QLS-101 prodrug to its active moiety, levcromakalim, was evaluated in vitro using human ocular tissues and plasma samples and after incubation with human phosphatase enzymes (2.0 nM-1.0 µM).ResultsC57BL/6J mice treated once daily with 0.2% QLS-101 exhibited significant (P < 0.01) IOP reductions of 2.1 ± 0.4 mmHg after five days; however, a daily attenuation of the effect was noted by 23h post-dose. By comparison, treatment with 0.4% QLS-101 lowered IOP by 4.8 ± 0.7 mm Hg (P < 0.0001) which was sustained for 24 hours. Unlike levcromakalim, QLS-101 failed to induce KATP channel activity in HEK-Kir6.2/SUR2B cells consistent with its development as a prodrug. No off-target receptor effects were detected with either compound. In vitro ocular tissue conversion of QLS-101 prodrug was identified in human iris, ciliary body, trabecular meshwork, and sclera. Alkaline phosphatase was found to convert QLS-101 (mean Km = 630 µM, kcat = 15 min−1) to levcromakalim.ConclusionsQLS-101 is a novel KATP channel opening prodrug that when converted to levcromakalim shows 24-hour IOP lowering after once-daily topical ocular administration.

Ocular biometric measurements and central corneal thickness in African pediatric population

AIM: To determine the ocular biometric measurements and central corneal thickness (CCT) in Nigerian children so as to have a reference database. METHODS: A hospital-based observational study of a cross-section of children seen consecutively between November 2017 and January 2018. The socio-demographic data of patients, visual acuity (VA) was assessed with LogMAR charts and Lea charts according to age group. Examination under anesthesia (EUA) was carried out for children eight years and below. Anterior and posterior segments examination through dilated pupil were done. Corneal diameters (CD) were assessed using calipers. Intraocular pressures (IOP) were examined using handheld tonometer, CCT and axial length (AL) were measured using the ultrasonic pachymeter. Cycloplegic refraction was carried out after clinical examination. Data were entered into and analysed using SPSS version 17 to generate results through descriptive statistics. Frequencies and cross tabulations of variables were done (P&lt;0.05). RESULTS: Sixty-six children with 132 eyes of ages between 3-16y (mean: 9.13±3.70y) were studied. Male with female ratio was 1:1.7. The modal age range was 6-10y (42.4%). Most of them were primary school students (n=36, 54.5%). The predominant parents’ occupation was traders/unskilled workers (51.6%) and the professionals/civil servants (30.3%). The mean right and left VA were 0.45±0.46 and 0.45±0.44 (logMAR) respectively. The mean right and left horizontal corneal diameters (HCD) were 10.5±1.6 and 10.37±1.45 mm respectively. The mean right and left vertical corneal diameters (VCD) were 9.7±1.2 and 9.7±1.3 mm respectively. The mean right and left CCT were 556.71±2.61 and 556.47±45.53 µm respectively. Myopia (n=23, 34.8%), myopic astigmatism (n=18, 27.3%) and simple astigmatism (n=16, 24.2%) were the commonest types refractive error. No significant associations were observed between CCT and HCD (P=0.739), VA (P=0.058) and refractive error (P=0.199). However, CCT slightly significantly correlated with the age groups (P=0.055). CONCLUSION: Mean values for CCT, IOP and CD are known for the first time in Nigerian children. There is no significant association between CCT and VA, CD and refractive errors.

Contralateral Forced Eyelid Closure Increases Intraocular Pressure.

The purpose of the study was to describe the influence of contralateral forced eyelid closure on intraocular pressure (IOP). Twenty-one healthy volunteers with no ophthalmic history had their IOP measured in the supine position to simulate the intraoperative environment. Intraocular pressure was measured with a handheld tonometer over three scenarios: (1) both eyes in a relaxed state, (2) eyelid speculum in the right eye with both eyes open and relaxed, (3) eyelid speculum in the right eye with the fellow eye squeezing tightly. Intraocular pressure significantly increased with forced contralateral eyelid squeezing compared with the relaxed state by a mean of 7.71±5.08 mm Hg (95% Confidence Interval of 5.40-7.37), P<0.001. Contralateral eyelid squeezing can significantly increase intraoperative IOP measurements.

Effect of ATP-sensitive Potassium Channel Openers on Intraocular Pressure in Ocular Hypertensive Animal Models.

PurposeTo evaluate the effect of ATP-sensitive potassium channel openers cromakalim prodrug 1 (CKLP1) and diazoxide on IOP in three independent mouse models of ocular hypertension.MethodsBaseline IOP was measured in TGFβ2 overexpression, steroid-induced, and iris dispersion (DBA/2J) ocular hypertension mouse models, followed by once daily eyedrop administration with CKLP1 (5 mM) or diazoxide (5 mM). The IOP was measured in conscious animals with a handheld rebound tonometer. Aqueous humor dynamics were assessed by a constant perfusion method. Effect of treatment on ocular tissues was evaluated by transmission electron microscopy.ResultsCKLP1 decreased the IOP by 20% in TGFβ2 overexpressing mice (n = 6; P < 0.0001), 24% in steroid-induced ocular hypertensive mice (n = 8; P < 0.0001), and 43% in DBA/2J mice (n = 15; P < 0.0001). Diazoxide decreased the IOP by 32% in mice with steroid-induced ocular hypertension (n = 13; P < 0.0001) and by 41% in DBA/2J mice (n = 4; P = 0.005). An analysis of the aqueous humor dynamics revealed that CKLP1 decreased the episcleral venous pressure by 29% in TGFβ2 overexpressing mice (n = 13; P < 0.0001) and by 72% in DBA/2J mice (n = 4 control, 3 treated; P = 0.0002). Diazoxide lowered episcleral venous pressure by 35% in steroid-induced ocular hypertensive mice (n = 3; P = 0.03). Tissue histology and cell morphology appeared normal when compared with controls. Accumulation of extracellular matrix was reduced in CKLP1- and diazoxide-treated eyes in the steroid-induced ocular hypertension model.ConclusionsATP-sensitive potassium channel openers CKLP1 and diazoxide effectively decreased the IOP in ocular hypertensive animal models by decreasing the episcleral venous pressure, supporting a potential therapeutic application of these agents in ocular hypertension and glaucoma.

A comparative study of intraocular pressure and hemodynamic changes during general and regional anesthesia in abdominal and lower-limb surgeries

Context: In general anesthesia, intubation/extubation and use of succinylcholine elevate intraocular pressure (IOP). Elevation of IOP during anesthesia may be detrimental to patients with preexisting ocular conditions such as glaucoma and uveitis. Regional anesthesia (spinal) lowers mean arterial and may lead to hemodynamic changes. Aims: We aimed to study changes in IOP and mean arterial pressure (MAP) in patients undergoing abdominal and lower-limb surgery following general and regional anesthesia. Setting and Design: A prospective comparative nonrandomized study was done. One hundred and twenty patients were randomly allocated to receive either general (Group A, n = 60) or regional anesthesia (Group B, n = 60), respectively. An independent investigator recorded MAP and IOP (Perkins handheld tonometer). Statistics: A one-way repeated measures analysis of variance (ANOVA) was done to determine whether there are any significant differences between the means of three or more levels of a within-subject factor (IOP and MAP) over time. Results: In Group A, there was a significant rise in IOP (ANOVA, P = 0.007) after general anesthesia over time. In Group B, the change in IOP (ANOVA, P = 0.219) was not statistically significant over time. However, there was a significant reduction in MAP over time. Between the groups, the mean change in IOP was significantly higher in patients in Group A and mean MAP significantly lower in Group B, respectively. Conclusion: Patients with glaucoma, uveitis, and cardiovascular diseases should have IOP monitoring prior to deciding the type of anesthesia and after anesthesia for lower-limb and abdominal surgeries. Sudden loss of vision after anesthesia needs immediate attention.

Absolute and Relative Reliability of the Assessment of the Muscle Mechanical Properties of Pelvic Floor Muscles in Women with and without Urinary Incontinence.

An analysis of the muscle mechanical properties (MMPs) of the pelvic floor muscles (PFMs) is relevant for understanding the physiopathology of urinary incontinence (UI). However, there is no objective and reliable methodology currently available for quantifying the MMPs of PFMs. Thus, the objective was to determine the intra-rater and inter-rater reliability of the MMPs of PFM assessment with a hand-held tonometer device, called the MyotonPRO, in young women with and without UI. Sociodemographic and pelvic floor questionnaires, plus MMPs of PFMs were assessed in 38 nulliparous women with UI and 40 matched healthy women by two trained physiotherapists on two different occasions, 48–72 h apart. Good to excellent absolute reliability was found for tone, stiffness, and decrement of both intra- and inter-rater analyses in both study groups (Intraclass Correlation Coefficient ranged from 0.75 to 0.92), with a trend of lower values for relaxation and creep. The standard error of measurement (SEM) did not achieve 10% of the mean values for any MMPs. The minimum detectable change (MDC) values were also provided for clinical applications. In conclusion, the relative reliability of tone, stiffness, and the assessment of the decrement of PFMs with MyotonPRO is good to excellent for UI and healthy women. The SEM and MDC values were acceptable for their application in clinical settings.

Scleral Tonometry Precision During Scleral Lens Wear: A Pilot Study.

PurposeTo evaluate the reproducibility, and therefore the utility, of using traditional tonometry devices for measuring intraocular pressure (IOP), while a prosthetic replacement of the ocular surface ecosystem device (PD) or scleral lens is applied to the eye.Patients and MethodsTwenty subjects (40 eyes) with keratoconus were enrolled. With PD applied, the first 10 consecutive patients had IOP measured multiple times with a handheld tonometer (Tono-Pen AVIA, Reichert, Depew, NY) on the superotemporal sclera 1 mm posterior to the PD edge. This identical procedure was repeated for the next 10 consecutive patients with a pneumatonometer (Model 30, Reichert, Depew, NY). Once three reliable measurements, as defined by the study protocol, were obtained for an eye, the procedure was repeated with the same tonometer device on the fellow eye.ResultsThe mean standard deviation for reliable IOP measurements was ±2.92 mmHg, median (IQR) of 2.62 (1.68 to 3.53) mmHg in the handheld tonometer group and ±1.98 mmHg in the pneumatonometer group. There was no statistically significant difference between the groups (p = 0.07). The mean IOP range for the reliable IOP measurements was 5.5 ± 3.80 mmHg, median (IQR) of 5 (3 to 7) mmHg for the handheld tonometer group and 3.71 ±1.12 mmHg in the pneumatonometer group. There was no statistically significant difference between the groups (p = 0.06).ConclusionHandheld tonometry and pneumatonometry have poor reproducibility when used to measure scleral IOP in keratoconus patients, while a PD is applied to the eye. An alternative research model and methodology should be investigated and confirmed to have precision prior to proceeding with further analysis of any relationship between scleral lens wear and IOP.

Comparing posture induced intraocular pressure variations in normal subjects and glaucoma patients.

To compare the posture-induced variations in intraocular pressure (IOP) between the primary open angle glaucoma (POAG) and non-glaucomatous eyes. A case-controlled age matched study was conducted in 55 successive newly diagnosed POAG and 56 non-glaucomatous patients seen in glaucoma clinic and general outpatient eye clinic in the Alex Ekwueme University Teaching Hospital, Abakaliki. The IOPs of eligible correspondents were measured with Perkin's hand-held tonometer in the sitting, supine flat and supine with pillow positions respectively. Measurement of IOP in each position was done after 15min of assuming such posture. The IOP difference between the sitting and supine flat position was significantly higher in the POAG than non-glaucoma subjects (7.68±2.08 vs 4.03±0.13 mm Hg, P<0.001). The IOP difference between the sitting and supine with pillow positions was 2.61±1.49 mm Hg for POAG and 1.44±0.70 mm Hg in non-glaucoma (P<0.001), while difference between supine flat and supine with pillow positions was 5.07±2.24 mm Hg in POAG and 2.59±0.66 mm Hg in non-glaucomatous patients (P<0.001). Greater variations in posture induced IOP occurred in POAG patients than non-glaucomatous. The posture induced IOP variation is lowest in the sitting position and highest in the supine flat position. Evaluation of posture induced IOP changes may be an important tool in the management of glaucoma.

The Effect of Body Posture Changes and Central Corneal Thickness on Intraocular Pressure among Healthy Malays

Purpose: To study the relationship between intraocular pressure (IOP), posture, and central corneal thickness (CCT) among healthy Malays. Method: Thirty-four young adults had their IOPs measured using a handheld tonometer (Accutome, Pennsylvania, USA) after maintaining 5 min at four different postures; sitting upright, supine, supine &amp; 45° inclination, and prone positions. The sequences of the postures were made random. CCT was measured using Oculus Pentacam (Oculus, Wetzlar, Germany), and the value at the corneal apex was taken. Participants were grouped into Group A with CCT of &lt; 550 μm, and Group B of &gt; 550 μm. Results: The highest IOP was recorded at the prone position 23.77±2.71 mmHg (p &lt; 0.001), and the lowest was at sitting upright 15.43±2.67 mmHg (p &lt; 0.001). IOP at the supine position was 17.31±3.07 mmHg, and at the supine &amp; 45° inclination position was 16.00±2.80 mmHg. IOPs were significantly different between sitting upright and supine (p = 0.03), between sitting upright and prone (p &lt; 0.001), between supine and prone (p &lt; 0.001), and between supine &amp; inclined 45° and prone (p &lt; 0.001). There was no significant difference in IOPs between Group A and Group B at different postures (p &gt; 0.05). Conclusions: Change in body posture significantly affects IOP, with the lowest IOP during the sitting upright position, and the highest at the prone position. IOP change upon posture shifts was not affected by CCT.

Effects of intubation with a double-lumen endotracheal tube on intraocular pressure during rapid sequence induction using succinylcholine chloride in patients with or without underlying systemic hypertension.

BackgroundTracheal intubation is closely associated with increases in intraocular pressure (IOP); however, the effects of double-lumen tube (DLT) intubation on IOP have not been validated. Systemic hypertension (HTN) is another factor that may increase IOP. In this study, we observed differences in IOP increases between DLT and singlelumen tube (SLT) intubation, and evaluated the influence of underlying HTN during rapid sequence induction.MethodsSixty-eight patients were allocated into one of the following group: SLT/without HTN (n = 17), SLT/HTN (n = 17), DLT/without HTN (n = 17), and DLT/HTN (n = 17). An SLT was inserted for orthopedic or gynecological surgery, and a DLT was inserted for lung surgery after rapid sequence induction using succinylcholine. IOP was measured before anesthetic induction and until 10 min after intubation using a handheld tonometer (Tono-Pen AVIA®).ResultsIn the DLT/without HTN and DLT/HTN groups, the maximum increases in IOPs after tracheal intubation were 7.9 and 12.2 mmHg, respectively, compared to baseline. In the SLT/without HTN and SLT/HTN groups, the maximum increases were 5.0 and 4.9 mmHg, respectively, compared to baseline. In comparisons between patients with and without underlying HTN, the values of IOPs were comparable.ConclusionsTracheal intubation with a DLT is associated with more increases in IOPs than with an SLT in rapid sequence induction. Well-controlled underlying hypertension did not increase IOP during tracheal intubation.