Perkins Applanation Tonometer Research Articles

A comparison of rebound and applanation tonometry in children with and without primary congenital glaucoma

Background: Intraocular pressure (IOP) measurement should be accurate in a paediatric population with primary congenital glaucoma (PCG).Aim: This study aims to investigate the difference between the change in IOP measurements using rebound tonometry (RBT) and handheld applanation tonometry (AT) (Perkins applanation tonometer [PAT]) in patients with and without PCG.Setting: Johannesburg, South Africa.Methods: Measurements were taken under anaesthesia, using RBT and AT at 0 min, 5 min and 10 mins after induction and prior to intubation. Corneal pachymetry and corneal diameters were measured.Results: Sixty-five children were included, 19 with PCG and 46 without PCG. The mean age (standard deviation [s.d.]) was 3.2 (2.25) years and 4.8 (2.4) years, respectively. The overall mean difference in IOP between RBT and PAT across both PCG and non-PCG groups was found to be 4.92 mmHg (95% confidence interval [CI]: 2.80 – 7.03) p 0.001, with RBT having higher readings. This difference was greater in the PCG group, with the IOP difference of 9.05 mmHg (95% CI: 2.6 – 15.5) p = 0.004. Mean corneal pachymetry (s.d.) was 585.6 (81.48) µm in the PCG group and 518.31 (39.9) µm in the non-PCG group. Univariate analysis showed that IOP was significantly related to corneal pachymetry, with a 11 mmHg increase in IOP for every 100 μm change in corneal thickness for measurements done with RBT (p 0.001), compared to 4 mmHg using PAT (p = 0.008).Conclusion: Intraocular pressure measurements done with RBT in children with and without PCG were overestimated compared to PAT.Contribution: This difference was more pronounced in PCG patients. In addition, IOP was significantly related to corneal thickness.

The relationship between intraocular pressure and random blood glucose levels with open angle glaucoma

Background: Primary open-angle glaucoma (POAG) is a multifactorial chronic optic neuropathy, characterized by progressive loss of retinal ganglion cells (RGC), leading to structural damage to the optic nerve head (ONH), retinal nerve fibre layer (RNFL), with visual field defects. This study was carried out at the department of optometry GSVM Medical College, Kanpur, UP from December 2015 to September 2017. Objectives were determination of the relationship between intraocular pressure and blood glucose levels in patients with primary open-angle glaucoma. Methods: A total of 74 subjects, 28 males and 46 females were used for the study. The Accu-Chek glucometer was used to measure the random blood glucose level and the intraocular pressure was measured using the Perkins applanation tonometer. Results: The mean intraocular pressure was 16.57±3.97 while the mean random blood glucose level was 168.43±108.48. Analysis of the SPSS version 23 data using the Pearson product-moment correlation coefficient at a significance level of 0.05 and a 95% confidence interval revealed no correlation between IOP and random blood glucose (p and gt; 0.05). People with primary open-angle glaucoma are advised to have their blood sugar levels monitored frequently. Conclusions: This study showed that there was no significant correlation between intraocular pressure and random blood glucose levels in patients with primary open-angle glaucoma. This would suggest that diabetics should be monitored regularly for intraocular pressure to detect an early onset of glaucoma.

Assessment by Optical Coherence Tomography of Short-Term Changes in IOP-Related Structures Caused by Wearing Scleral Lenses.

The mechanism that could increase intraocular pressure (IOP) during scleral lens (SL) wear is not fully understood, although it may be related to compression of the landing zone on structures involved in aqueous humor drainage. Thirty healthy subjects were fitted with two SLs of different sizes (L1 = 15.8 mm, L2 = 16.8 mm) for 2 h in the right eye and left eye as a control. Central corneal thickness (CCT), parameters of iridocorneal angle (ICA), Schlemm's canal (SC), and optic nerve head were measured before and after wearing both SLs. IOP was measured with a Perkins applanation tonometer before and after lens removal and with a transpalpebral tonometer before, during (0 h, 1 h, and 2 h), and after lens wear. CCT increased after wearing L1 (8.10 ± 4.21 µm; p < 0.01) and L2 (9.17 ± 4.41 µm; p < 0.01). After L1 removal, the ICA parameters decreased significantly (p < 0.05). With L2 removal, nasal and temporal SC area and length were reduced (p < 0.05). An increased IOP with transpalpebral tonometry was observed at 2 h of wearing L1 (2.55 ± 2.04 mmHg; p < 0.01) and L2 (2.53 ± 2.22 mmHg; p < 0.01), as well as an increased IOP with Perkins applanation tonometry after wearing L1 (0.43 ± 1.07 mmHg; p = 0.02). In the short term, SL resulted in a slight increase in IOP in addition to small changes in ICA and SC parameters, although it did not seem to be clinically relevant in healthy subjects.

Easyton® transpalpebral versus Perkins applanation tonometry in different populations.

To compare intraocular pressure (IOP) measurements obtained using the new transpalpebral Easyton® tonometer and Perkins applanation tonometer (PAT) in three different clinical populations. The participants of this prospective study were 84 subjects divided into the groups: 22 healthy children (G1), 42 healthy adults (G2), and 20 adult patients with primary open angle glaucoma (G3). The data recorded in 84 eyes of these subjects were age, sex, gender, central corneal thickness (CCT), and axial length (AL). In all eyes, IOP was determined in the same examination room by the same experienced examiner using Easyton® and PAT in random order. Mean differences in IOP readings between Easyton® and PAT were 0.45 ± 1.97 (p = 0.295), -0.15 ± 2.13 (p = 0.654), -1.65 ± 3.22 (p = 0.033), and -0.018 ± 2.50mmHg (p = 0.500) in the groups G1, G2, G3, and whole sample (G4), respectively. Correlations between Easyton® and PAT IOP values were 0.668 (p = 0.001) for G1, 0.463 (p = 0.002) for G2, 0.680 (p < 0.001) for G3, and 0.605 (p < 0.001) for G4. Moderate to good agreement between the two tonometers was found in all groups according to intraclass correlation coefficients, which were 0.794 (p < 0.001) for G1, 0.632 (p < 0.001) for G2, 0.809 (p < 0.001) for G3, and 0.740 (p < 0.001) for G4. The lower and upper limits of agreement between the devices were -5.1 and 4.7mmHg, respectively, in the complete group. No correlation was noted between CCT or AL and the Easyton® IOP measurements. IOP measurements obtained with Easyton® and PAT show an acceptable level of agreement mainly in healthy individuals, recommending it for IOP screening in children and in patients in which PAT measurement may be impared as patients with hemifacial spasms, corneal irregularities, or reduced mobility. It is not recommended for glaucoma patients follow-up.

Comparison of the iCare rebound tonometer and the Perkins applanation tonometer in children under general anesthesia

The goal of the study was to compare Perkins applanation tonometry and iCare rebound tonometry, evaluating their correlation and agreement in a diverse pediatric population under general anaesthesia (GA). Children undergoing an eye examination under GA between November 2019 and March 2020 were included. Intraocular pressure (IOP) was measured successively using the Perkins applanation tonometer and the iCare IC200 rebound tonometer. Ultrasonic central pachymetry and axial length were measured. One hundred and thirty-eight eyes of 72 children were included. The mean age was 2.87years. IOP measurements obtained with the two tonometers were statistically and significantly highly correlated (r=0.8, P<0.001), although the iCare overestimated IOP by an average of 3.37mmHg (SD±4.48). The agreement between the two methods was moderate; the 95% agreement limits ranged from -5.41 to +12.15mmHg (r=0.5, P<0.001). The IOP difference between the two tonometers was weakly but significantly correlated with mean IOP (r=0.52; P=0.006). No correlation was found with axial length and pachymetry. In this study, the IOP values obtained using the Perkins applanation tonometer and the iCare IC200 rebound tonometer were well correlated. The iCare tended to overestimate the IOP, especially for high IOP values. However, no underestimation of IOP was found with this device, hence its potential for glaucoma screening in children.

Analysis of the influence of corneal properties and densitometry on applanation and rebound tonometry in primary open angle glaucoma

To evaluate the influence of corneal densitometry on portable applanation (Perkins) and rebound (iCare ic100 and PRO) tonometry. A secondary goal was to assess if there was a relationship between various corneal properties and the severity of primary open angle glaucoma (POAG). Seventy-five eyes of 75 patients with primary open angle glaucoma were studied, divided by severity into 3 groups: 25 mild, 25 moderate and 25 advanced. Intraocular pressure (IOP) was measured 3 times in each participant with a Perkins applanation tonometer (PAT), a handheld version of the Goldman applanation tonometer (GAT), an iCare PRO and an iCare ic100. Mean values were then calculated. Corneal topography with the Pentacam HR (Oculus, Wetzlar, Germany) was also performed in all individuals. Mean age and sex were comparable in all groups, as were densitometry values (P>0.05). The mean visual field defect (MD) was 2.85 (±1.23) dB in the mild glaucoma group, 8.26 (±1.90) dB in the moderate group and 15.66 (±3.46) dB in the advanced group. Three multivariate regression analyses were performed. The first and second calculations assessed the effect of IOP obtained with iCare ic100 and PAT as dependent variables with age, sex, CCT and mean keratometry (Km) within the glaucoma subgroups and the global sample. The third analysis was carried out to assess the relationship between corneal densitometry as the dependant variable and the aforementioned corneal parameters among the glaucoma groups. In the first multivariate regression analysis, a statistically significant correlation was found between ic100 rebound tonometry and CCT in the POAG global sample (coef. 0.117; IC [-0.21-(-0.01)]; P=0.025). No statistically significant correlation was found in the subgroup analyses. In the second multivariate analysis, no significant correlation was found between PAT and CCT, Km, age or sex (P>0.05). In the third analysis, densitometry was correlated with age in all glaucoma subgroups (P<0.001) and with CCT in the moderate glaucoma subgroup (coef. -0.037; IC [-0.67-(-0.01)]; P=0.021). Tonometry appeared to be minimally influenced by corneal densitometry, with a mild positive linear correlation seen (R=0.03). IOP values were similar with 3 of the tonometers: PAT 16.07 (±3.18) mmHg, PRO 16.27 (±3.42) mmHg and ic100 15.17 (±4.28) mmHg. There was, however, a significant underestimation of IOP with ic100 (-0.89mmHg) compared to PAT (P=0.007). Corneal densitometry did not show significant differences between glaucoma severity groups. A positive correlation was seen with CCT and both corneal densitometry and age. No correlation was found with keratometry or severity of glaucoma. The influence of corneal densitometry on IOP measurements appears weak, with little clinical relevance identified.

Correlation of Intraocular Pressure and Random Blood Glucose Level in Patients with Primary Open-Angle Glaucoma

Primary open angle glaucoma (POAG) is a multifactorial chronic optic neuropathy, characterized by progressive loss of retinal ganglion cells (RGC), leading to structural damage to the optic nerve head (ONH), retinal nerve fiber layer (RNFL), with visual field defects. This study was carried out at the Department of Optometry Teaching Clinic, Federal University of Technology, Owerri, Imo State, Nigeria to determine the correlation between intraocular pressure and blood glucose levels in patients with primary open-angle glaucoma. A total of 37 subjects, 14 males and 23 females were used for the study. The Accu Chek glucometer was used to measure the random blood glucose level and the intraocular pressure was measured using the Perkins applanation tonometer. Results showed that the mean intraocular pressure was 16.57±3.97 while the mean random blood glucose level was 168.43±108.48. SPSS version 23 data analysis using the Pearson Product Moment Correlation Coefficient at 0.05 level of significance and 95% confidence interval revealed that there was no correlation between intraocular pressure level and random blood glucose level (P &gt; 0.05). It was recommended that patients with primary open-angle glaucoma should frequently monitor their blood glucose levels. Keywords: Intraocular Pressure, Random Blood Glucose, Primary Open Angle Glaucoma, Diabetes Mellitus

Effectiveness of trans-scleral cyclophotocoagulation for refractory paediatric glaucoma

Background: The aim of this study was to find out the effectiveness of trans-scleral cyclophotocoagulation in lowering intraocular pressure in the paediatric population.Patients and methods: This quasi-experimental study was conducted between July 2020 and January 2021 in Department of Ophthalmology, The Children’s Hospital, Lahore. Total 45 eyes of 42 children of age 1-14 years, both genders, with glaucoma were enrolled in this study. Diode cyclophotocoagulation unit and probe of make Quantel Medical was used for cycloablation under general anesthesia. Postoperative intraocular pressure was noted by using handheld Perkins applanation tonometer Mk2 after every 3 weeks for 12 weeks. If an IOP of ≤21mmHg was achieved, then efficacy or success was labeled. Patients with an IOP of &gt;21mmHg after 12 weeks were selected for repeat cycloablation treatment. Failure was labeled to an IOP of &gt;21mmHg even after a repeat session. Data analysis was done using SPSS 24. Results: In this study, 45 eyes were included with a mean age of 4.49 ± 3.12 years. There were 21 (46.7%) males and 24 (53.3%) females. At the time of presentation, the most common diagnosis was primary congenital glaucoma [28 (62.2%)], followed by aphakic glaucoma [10 (22%)], Anterior segment dysgenesis [2 (4.4%)], Pseudophakic glaucoma [2 (4.4%)], Sturge weber syndrome [2 (4.4%)] and Post-traumatic [1 (2.2%)]. The mean IOP at baseline was 26.67±3.66 mmHg, which was reduced to 19.60±6.33 mmHg with mean change in IOP of 7.07±4.56 mmHg (p&lt;0.05). The mean anti-glaucoma drugs used at baseline was 2.91±0.42, which was reduced to 0.93±1.2 with mean change in use of anti-glaucoma drugs of 1.98±1.06 (p&lt;0.05). Success was achieved in 34 (75.56%) eyes, while 11 (24.44%) needed second session. After repeat session 2 (4.4%) eyes went into treatment failure.Conclusion: Diode cyclophotocoagulation is a useful therapy for the management of glaucoma in children.

A comparison of postural and diurnal variations in intraocular pressure using the iCare rebound tonometer and Perkins applanation tonometer in admitted adults in Kenya

Background: Elevated intraocular pressure (IOP) remained the most important known risk factor for glaucoma.Aim: To compare the postural and diurnal IOP variations using the iCare rebound tonometer (RT) and Perkins applanation tonometer (PAT).Setting: Kakamega County Hospital, Kenya.Methods: Elevated intraocular pressure measurements were taken by two (masked) examiners with two devices in the morning (06:00–09:00), midday (12:00–15:00) and evening (18:00–21:00), in the sitting followed by supine positions in one randomly selected eye of 24 oculo-visual healthy hospital-admitted patients. Effects of the time of the day and position of the body within and between devices were analysed with the Statistical Package for Social Sciences.Results: The mean IOP measured by the RT ranged from 6 mmHg to 24 millimetres of mercury (mmHg) in the sitting position and from 10 mmHg to 26 mmHg in the supine position. The mean IOP measured using PAT ranged from 6 mmHg to 21 mmHg in the sitting position and from 8 mmHg to 24 mmHg in the supine position. The IOP measured by both devices significantly varied with position (p 0.05). Perkins applanation tonometer on average gave a significantly higher IOP (1.7 mmHg [p = 0.003] and 1.3 mmHg [p = 0.034]) at 06:00 compared to that at 12:00 and 18:00, respectively. The IOP readings with the RT were on average 2.2 mmHg and 3.0 mmHg higher at 06:00 compared to that at 12:00 and 18:00, respectively (p 0.0005).Conclusion: Significant reductions were observed in postural and diurnal IOPs in the sitting positions and in the afternoon, respectively. Diurnal IOP variations were slightly higher when measured by RT compared to when measured by PAT.

A Comparative Study of Intraocular Pressure Measurement between Gold-Mann Applanation Tonometer and Perkins Applanation Tonometer in Glaucoma Patients

A Comparative Study of Intraocular Pressure Measurement between Gold-Mann Applanation Tonometer and Perkins Applanation Tonometer in Glaucoma Patients

To compare the intraocular pressure in diabetes mellitus and non diabetics individuals

Introduction: To compare the intraocular pressure in diabetes mellitus patients and non diabetics individuals. Materials and Methods: A prospective observational type of study with 100 patients, 50 diabetic and 50 non-diabetics subjects, was conducted at D.Y. Patil Medical College and Hospital Kolhapur from 1st February 2019 to 30th April 2019. All subjects underwent routine complete ophthalmological examination, intra ocular pressure was measured using Perkins applanation tonometer. Blood investigation fasting blood sugars, postprandial sugars, and HbA1c levels was done in diabetics and random blood sugars were done in non diabetic subjects. Results: The mean intraocular pressure in diabetic subjects was 16.67±2.04mmHg and in non-diabetics 13.84±2.85mmHg and difference between the two groups was clinically significant (p mean intraocular pressure was (16.88±3.09mmHg) in diabetic patients with duration of diabetes greater than 10years as compared with (16.54±2.76mmHg) in diabetic patients with duration less than 10 years, p value > 0.05 which is not statistically significant and with HbA1c >6.5% showed statistically significant higher intraocular pressure compared to HbA1c Conclusion: Diabetic subjects showed higher intraocular pressure as compared to non-diabetic subjects and also there was increase in intraocular pressure with uncontrolled diabetes independent on duration of diabetes. All diabetic patients should undergo intra-ocular pressure measurement routinely. Keywords: Intraocular pressure, Diabetes, Applanation tonometer, HbA1c.

Evaluation of influence of non-office hours diurnal variation of intraocular pressure in management of glaucoma

Aim and Objectives: This article attempts to elucidate the role of round the clock IOP control and its relevance to current glaucoma practice. Materials and Methods: A prospective observational study was carried out on 50 patients of POAG or CACG on medical management whose intraocular pressures were found to be controlled by daytime office hours IOP estimation. The diurnal IOP readings obtained with Clarkes Hand held Perkins applanation tonometer and Reicherts Tonopen at 7am, 10am, 1pm, 4pm, 7pm, 10pm, 1am and 4am. Comparison of office hours IOP, extended office hours DVT and 24 hours IOP was done. Results: Fifty patients were enrolled (mean age: 53.88 ± 8.42 years) in the study. The mean office hours IOP for both eyes was significantly less (16.31±2.46) than extended office hours (17.18±2.50) and 24 hours DVT (17.49 ±2.45). There was significant difference in IOP fluctuation in office (3.72±2.14) versus extended office hours (9.26±3.11) and 24 hours DVT (10.28±2.76). The mean office hours peak IOP was significantly lower than that of extended office hours and 24 hours DVT. Conclusion: 24-hour IOP monitoring can reveal higher peaks and wider fluctuation of IOP than those found during typical office hours, it suggests a greater role for IOP-related risk for glaucoma progression. Thus may justify a more aggressive IOP-lowering treatment strategy. Keywords: Chronic angle closure glaucoma (CACG), Clarkes hand held perkins applanation tonometer, Intraocular pressure (IOP), glaucoma, Primary open angle glaucoma (POAG), Reicherts tonopen.

Dexmedetomidine was Better at Lowering Intraocular Pressure than Magnesium when Combined with Local Anesthetics in Peribulbar Blocks for Posterior Segment Eye Surgery

Background and Aim: Many medications are combined with local anesthetics for peribulbar blocks to improve the quality of the block, however, few studies have compared the effect of dexmedetomidine and magnesium on intraocular pressure when combined with local anesthetics which was the primary endpoint of this double blinded study. Materials and Methods: A randomized controlled clinical trial was conducted on 60 ASA Physical Status (ASA PS) I-II patients scheduled for elective posterior segment eye surgeries under peribulbar anesthesia. Patients were randomly allocated to one of three groups of 20 each according to the medications they received. Local anesthetic solution was prepared using 8 ml of bupivacaine 0.5% and lidocaine 2% in a 1: 1 ratio plus 1ml of hyaluronidase (150 units) making a total volume of 9 ml: Group D received: local anesthetic + 20 µg dexmedetomidine diluted with 1 mL of normal saline. Group M received: local anesthetic + magnesium sulphate 50 mg in 1 ml normal saline. Group C received local anesthetic + 1 ml normal saline. Intraocular pressure was measured with the Perkins applanation tonometer immediately before injection and at 1, 5, 10, 15 minutes (min) after injection and then at the end of the procedure, the onset and duration of lid and globe akinesia were assessed. Postoperative analgesia and the first dose of analgesic medication were also assessed. Results: Intraocular pressure measurements were statistically lower in group D than the other two groups at 10 and 15mins. The onset of globe and lid akinesia was the most rapid in Group D compared to the other two groups. The duration of globe and lid akinesia was the longest in group D. Time to first analgesic dose request was significantly longer in group D followed by group M then group C. Visual analogue score for pain was significantly less between group D and other two groups. There were no episodes of hypotension or bradycardia in the three groups. No side effects or complications as hemorrhage, globe perforation, brain stem anesthesia sedation were observed. Conclusion: In our study addition of dexmedetomidine to a peribulbar block was statistically better at reducing IOP, increasing the duration of optic anesthesia and delaying the need for postoperative analgesic dose request than magnesium.

Icare-Pro Rebound Tonometer Versus Hand-held Applanation Tonometer for Pediatric Screening

To compare intraocular pressure (IOP) measurements obtained using the new rebound tonometer Icare-Pro (Icare, Tiolat Oy, Helsinki, Finland) and the hand-held version of the Goldmann applanation tonometer (Perkins; Clement Clarke, Haag-Streit, Harlow, United Kingdom) in healthy children during clinical practice. In this prospective study, three IOP measurements were made using each tonometer in a single session, starting with the Icare-Pro. Participants were 173 non-anesthetized patients aged 1 to 16 years. Measurements were made in both eyes but only data for the right eye were entered in the analysis. Central corneal thickness, anterior chamber depth, and axial length were also measured in each patient. Data were compared by determining interclass correlation coefficients (ICCs) for each tonometer and representing the differences detected as Bland-Altman plots. Good linear correlation was observed between IOP readings obtained using the Perkins and Icare-Pro tonometers (r = 0.87, P < .001), although the Icare-Pro readings were slightly higher (mean IOP difference: 0.26 ± 1.58 mm Hg, P = .037). The 95% limits of agreement between the two methods were 2.8 to -3.4 mm Hg. The ICC was 0.857 (95% confidence interval: 0.810 to 0.893), indicating good agreement. For both tonometers, a low but significant correlation was detected between IOP and central corneal thickness or age. However, no correlation of IOP was found with axial length or anterior chamber depth. Pediatric IOP measurements determined using the new Icare-Pro rebound tonometer showed good correlation with those obtained using the hand-held Perkins applanation tonometer in a routine clinical examination with no need for general anesthesia. [J Pediatr Ophthalmol Strabismus. 2018;55(6):382-386.].

How does sevoflurane induction, followed by a ketamine maintenance infusion, affect intraocular pressure? Establishment of an anaesthetic protocol for paediatric glaucoma examinations under anaesthesia

Accurate measurement of intraocular pressure (IOP) is essential in paediatric glaucoma management. Children require serial measurements and examination under anaesthesia (EUA). Most anaesthetic agents reduce IOP, and the ideal time...

Central corneal thickness and intraocular pressure changes after congenital cataract surgery with intraocular lens implantation in children younger than 2 years

To evaluate the change in central corneal thickness (CCT) and intraocular pressure (IOP) preoperatively to postoperatively in children younger than 2years of age having surgery with primary intraocular lens (IOL) implantation for congenital cataract. Tertiary care institute, Chandigarh, India. Prospective case series. Children younger than 2years old who had phacoaspiration with IOL implantation were studied. The preoperative pachymetry and IOP were compared with the postoperative values at 3months, 6months, and 12months. Pachymetry was measured using an ultrasound pachymeter and IOP with a handheld Perkins applanation tonometer. Thirty-one patients (aged 3 to 24months) were analyzed. There were 24 bilateral cases and 7 unilateral cases. The CCT increased significantly from a preoperative value of 529.84μm±11.7 (SD) to apostoperative value of 553±15.5μm at 1year (P=.022). Themean increase in CCT was 23.16μm and in IOP, 2.59mm Hg. The change in CCT correlated with the change in IOP at 1year (P=.011). After cataract surgery, the CCT in pediatric eyes increased significantly. The CCT values were an important consideration in the measurement of IOP in children younger than 2years having cataract extraction with primary IOL implantation.

Does general anesthesia have a clinical impact on intraocular pressure in children?

Reliable measurement of intraocular pressure (IOP) is crucial in pediatric patients with suspected glaucoma. General anesthesia (GA) is usually needed in infants to allow a thorough examination. However, anesthesia itself may influence IOP, depending on the type used and the depth of sedation. The purpose of this study was to evaluate the normal distribution of IOP during GA in healthy children and to analyze differences in IOP relative to the anesthetics used and the measurement time point. Approval for this observational study was received from the local institutional review boards and written informed consent was obtained from the children's parents. A total of 100 pediatric patients with no history of glaucoma scheduled for nonintraocular surgery underwent general anesthesia, induced with sevoflurane (s) or propofol (p) and maintained with either sevoflurane with remifentanil (S) or propofol with remifentanil (P). The patients were grouped to one of four subgroups (sS, sP, pP, pS) depending on the anesthetics used during induction and maintenance. Hemodynamic parameters and IOP were measured in both eyes at four defined time points: before anesthesia induction (M1); in apnea immediately after induction and before insertion of a laryngeal mask airway (M2); in deep anesthesia during mechanical ventilation (M3); and after extubation (M4), using a handheld Perkins applanation tonometer. Differences in IOP in both eyes during the measurement periods were analyzed using multivariate repeated-measures analysis of variance and Tukey-HSD as a posthoc test with statistical significance set at P < 0.05. Pearson correlation coefficient was used to investigate further relationships between heart rate, systolic blood pressure, and IOP. General anesthesia reduced IOP significantly. The mean IOP was normally distributed, with a mean of 7.4 ± 2.89 mmHg at M1. It decreased significantly to a minimum of 5.6 ± 3.04 mmHg (P < 0.01) at M2 and increased significantly to 7.2 ± 2.51 mmHg (P < 0.01) at M3 and again to 8.4 ± 3.72 mmHg (P = 0.03) at M4. All four subgroups (sS, sP, pP, pS) showed comparable decreases in IOP between M1 and M2. During deep anesthesia (M3) and during reversal (M4), the IOP increased again in all groups. During reversal (M4), however, the sS group had a significantly lower IOP than the pP group (P = 0.001) and sP group (P = 0.02). There were no correlations between changes in IOP and gender, age, or type of surgery. Sevoflurane and propofol, both in combination with remifentanil, significantly lower IOP in children. Individual IOP levels rise and fall during anesthesia, depending on the time point of measurement. The lowest IOP can be measured immediately after induction of anesthesia. This needs to be taken into account when measuring IOP in children.

Normal values of intraocular pressure in full-term Nigerian newborns

PurposeTo determine the normative range of intraocular pressure (IOP) in full-term newborns and possible association with birth parameters during the first week of life. MethodsThis was an observational cross sectional study in which IOP was measured in 1000 eyes of 500 normal full-term newborns using the Perkins applanation tonometer under topical anesthesia. An average of three readings was taken as the IOP value. The relationship between IOP and birth parameters was analyzed. ResultsThe male to female ratio was 1:1 with 254 (50.8%) male and 246 (49.2%) female babies. The (mean±SD) value of IOP in the right eyes was 11.93±1.80mmHg, ranging between 9.00 and 16mmHg. In the left eyes, the mean value of IOP was 11.84±1.77mmHg with a range of 8.00–15.00mmHg. IOP in males (12.02±1.84mmHg) was not significantly different from that in females (11.89±1.75mmHg). There was no significant difference between right and left eyes (p=0.42). The 95% range (mean±2 SD) was 15.53mmHg for the right eye and 15.38mmHg for the left. Correlational analysis showed that birth weight and gestational age were positively correlated with IOP. ConclusionThis study provides useful normative data on IOP among Nigerian full-term newborns. Further studies on possible ethnic/geographic variations of IOP in children may be beneficial.

A New Provocative Test for Glaucoma.

ABSTRACTPurpose: To compare the effects of the water-drinking test (WDT) with the 30° inverted body position test on intraocular pressure (IOP) in normal patients, suspected glaucoma patients and glaucoma patients.Materials and methods: Based on clinical evaluation of the optic disk, IOP, and standard achromatic perimetry (SAP) of 71 eyes, 18 were “normal” (normal SAP and optic disk evaluation, and IOP < 21 mm Hg), 30 were “glaucoma suspect” (GS; normal SAP, cup/disk (C/D) ratio > 0.5 or asymmetry > 0.2 and/or ocular hypertension), and 31 had “early glaucoma” (MD < -6 dB, glaucomatous optic neuropathy). Standard achromatic perimetry was performed with the Octopus 3.1.1 Dynamic 24-2 program. Patients fasted before the WDT, and four measurements were performed at basal, 15’, 30, and 45’ after drinking 1 liter of water (WDT) in 5 minutes. In the 30° inverted position, IOP measurement with Perkins applanation tonometer was taken after 5 minutes lying down.Results: There was a statistical difference in all groups between the basal IOP and peak IOP during the WDT (p < 0.001) and in the inverted position IOP (p < 0.001). Controls (p = 0.50), suspects (p = 0.41) and glaucoma patients (p = 1.0) did not exhibit a difference between WDT-IOP and inverted position IOP.Conclusion: The 30° inverted position test was as efficient as WDT in detecting peak IOP. This new provocative test is easier, faster and more comfortable for both patients and doctors.How to cite this article: Kanadani FN, Moreira TCA, Campos LF, Vianello MP, Corradi J, Dorairaj SK, Freitas ALA, Ritch R. A New Provocative Test for Glaucoma. J Curr Glaucoma Pract 2016;10(1): 1-3.

The Icare-Pro Rebound Tonometer Versus the Hand-held Applanation Tonometer in Congenital Glaucoma

To compare intraocular pressure (IOP) measurements obtained using the new rebound tonometer Icare-Pro and the hand-held version of Goldmann Applanation Tonometer (Perkins tonometer) in children with primary congenital glaucoma (PCG) under general anesthesia. Using both tonometers, 3 IOP measurements were prospectively determined in 1 single session. Icare-Pro was always used first, and then Perkins. All measurements were recruited in 50 eyes of 50 patients with PCG under general anesthesia. Central corneal thickness, anterior chamber depth, and axial length were also measured in each patient. Data were compared by determining interclass correlation coefficient for each tonometer and representing the differences detected as Bland-Altman plots. Good linear correlation was observed between IOP readings obtained using the Perkins and Icare-Pro (r=0.75, P<0.001), although the Icare-Pro readings were slightly higher (mean IOP difference 0.42 ± 3.69 mm Hg, P=0.41). A Bland-Altman plot revealed the 95% limits of agreement between the 2 methods: 7.7 to -6.8 mm Hg (slope=0.109, P=0.32). Intraclass correlation coefficient was 0.74 (95% confidence interval, 0.59-0.84) showing good agreement. For both tonometers, no correlation was detected between IOP measurements and central corneal thickness and axial length, but positive relation was found with anterior chamber depth. IOP measurements determined using the new Icare-Pro rebound tonometer showed good correlation with those obtained using the hand-held Perkins applanation tonometer in children with PCG under general anesthesia.