Mean Intraocular Pressure Measurements Research Articles

Randomized Clinical Trial of Intraocular Pressure-Lowering Medications on Preventing Spikes in Intraocular Pressure Following Intravitreal Anti-Vascular Endothelial Growth Factor Injections.

Intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents are a primary management option for retinal diseases. Acute elevation of intraocular pressure (IOP) is a complication associated with these injections that should be considered. This study investigated and compared the prophylactic effects of fixed combination anti-glaucoma medication on IOP spikes following intravitreal anti-VEGF injections. This randomized double-blind clinical trial included one eye of each participant indicated for treatment with intravitreal injection of anti-VEGF agents (bevacizumab, aflibercept, and ranibizumab) and randomly allocated to one of the three prophylactic anti-glaucoma medications, with each drug further divided into one- and two-drop regimens before intravitreal injection. Participants with allergies or contraindications to medications were excluded from the pretreatment groups and were invited to participate in the control group. The study involved 308 participants: 89 in the dorzolamide/timolol group, 86 in the brimonidine/timolol group, 101 in the brinzolamide/brimonidine group, and 32 in the control group. Baseline characteristics and IOP were comparable across all groups. In the prophylactic premedication groups, mean IOP at 30min were within 21mmHg and returned to their baseline at 1h. Mean IOP measurements between baseline and 30min in the brimonidine/timolol two-drop regimen were not significantly different: 13.72 ± 4.63 vs 15.11 ± 4.39mmHg, p = 0.096. In the control group, IOP significantly increased from baseline at 30min and 1h post-injection: 14.31 ± 4.10, 22.15 ± 8.64, and 18.36 ± 7.52mmHg, respectively, p < 0.001. Topical fixed combination anti-glaucoma medication used as a prophylactic treatment before intravitreal anti-VEGF injections significantly prevented IOP spikes post-injection, with a comparable effect among three medications. Prophylactic treatment of IOP spikes should be considered as standard care to prevent further damage in patients with compromised retinal vascular and optic nerve perfusion. TCTR20241005001, retrospectively registered.

The Agreement of Intraocular Pressure Measurement in Healthy Merinos Sheep Using Rebound Tonometer (Tonovet®) and Applanation Tonometer (Tono-Pen VetTM)

The assessment of intraocular pressure (IOP) holds significant importance in ophthalmology as a crucial diagnostic tool for various ocular disorders. This study aimed to evaluate the agreement between rebound (TonoVet®, TV) and applanation (Tono-Pen Vet™, TPV) tonometers in measuring IOP in healthy Merino sheep. 155 healthy Merinos (80 males, 75 females) with a mean weight of 54.4±8.7 kg, aged 24±6 months, were included in the study. IOP was measured between 9:00 and 11:00 am using both the rebound and applanation tonometers. The rebound tonometer was used first, followed by the applanation tonometer. A total of 620 readings (310 readings for each tonometer) were obtained from the two devices. No statistical differences were noted between the mean IOP measurements of the right and left eyes for both tonometers (p&gt;0.05). However, there was a significant difference in the mean IOP measurements between the TV (11.8±2.3 mmHg) and the TPV (13.9±2.9 mmHg) tonometers (p

Comparison of Air Puff Tonometer with Gold Standard Applanation Tonometer for Measurement of Intraocular Pressure in Adult Population

Detecting and treating glaucoma early is vital to prevent vision loss. Two main instruments, the Air Puff Tonometer and the Gold Standard Applanation Tonometer, are used to measure Intraocular Pressure (IOP). However, there is ongoing debate among ophthalmologists regarding the accuracy and reliability of these devices. Objective: To evaluate and contrast the measurements of intraocular pressure obtained through Air puff tonometry and Goldmann applanation tonometry. Methods: A cross-sectional comparative study was conducted upon 900 patients of Glaucoma, selected through purposive sampling technique, attending the Eye OPD of Isra University Hospital, Hyderabad. Patients with age more than 18 years, of both genders who provided consent for eye examination and treatment, were included in the study while patients with corneal disease or prior surgery, ocular trauma, or those presenting with active infection or ocular disease were excluded from the study. Results: 396 (44.0%) of patients were males and 504 (56.0%) were females. The results indicate that the mean IOP measurement for air puff tonometry (17.43 mm Hg) is significantly higher (p-value=0.0001) than the mean measurement obtained by Goldman tonometry (13.84 mm Hg). Overall, the distribution of IOP was similar for both types of tonometry, with a slightly higher proportion having high IOP values (19-22 mmHg) with Goldman tonometry compared to air puff tonometry. Conclusions: The findings of this research demonstrated a noteworthy contrast between the two techniques, where the air puff tonometry produced noticeably elevated intraocular pressure measurements in comparison to the widely accepted applanation tonometry

Evaluation of early period changes in intraocular pressure, ocular biometry and anterior segment after upper eyelid blepharoplasty.

To investigate the acute effects of upper eyelid blepharoplasty on intraocular pressure (IOP) and ocular biometric parameters. This prospective cross sectional study examined the eyes of 49 patients with dermatochalasis. Following a detailed ophthalmological examination, corneal topography was used to evaluate the eyes mesopic and photopic pupil diameter, anterior chamber depth, and corneal astigmatism on the day of surgery and on days first and seventh postoperatively. Ocular biometry was used to assess axial length and intraocular lens power. Goldmann applanation tonometry was used to measure intraocular pressure. Forty-nine eyes (26 males and 23 females) of 49 patients aged between 44 and 76years (mean 61 ± 7.9) were included in our study. The mean anterior chamber depth (ACD) was 2.90 ± 0.37mm preoperatively, 3.00 ± 0.29mm at postoperative day first, and 3.04 ± 0.29mm at postoperative day seventh, and the increase in anterior chamber depth was statistically significant (p < 0.001). The mean astigmatism values were measured as preoperative 0.73 ± 0.69 D, postoperative first day 0.93 ± 0.81 D, and postoperative seventh day 1.26 ± 0.90 D. The increase in astigmatism values was statistically significant (p < 0.001).The mean pupil diameter measurements in the mesopic environment were 4.20 ± 0.61mm preoperatively, 4.40 ± 0.59mm on the first postoperative day, and 4.39 ± 0.57mm on the seventh postoperative day, and there was a statistically significant difference between the three measurements (p = 0.03). The mean IOP measurements of the patients were 15.91 ± 3.51mmHg preoperatively, 16.81 ± 3.36mmHg on the first postoperative day, and 16.97 ± 3.13mmHg on the seventh postoperative day. The increase between these three measurements was statistically significant (p = 0.013). This study includes important insights into the potential acute phase impact of blepharoplasty surgery on ocular findings. Patients undergoing upper eyelid surgery should be informed about the possible change in ocular biometric parameters, intraocular pressure, and pupil diameter.

Comparison of intraocular pressure measurements obtained by icare pro tonometer, non-contact tonometer and Goldmann applanation tonometer in healthy individuals

The goal of this paper was to compare the intraocular pressure (IOP) measurements obtained via iCare Pro rebound (IRT), non-contact tonometry (NCT), and Goldmann applanation (GAT) tonometry in healthy subjects. One hundred and twenty-five healthy individuals were included in this study. The participants' IOP measurements were obtained via non-contact tonometry. After routine ophthalmic examination, central corneal thickness (CCT) was measured with a topography device. Intraocular pressure was measured via iCare Pro rebound tonometry. After waiting for 5minutes, three measurements were taken with GAT under topical anaesthesia, and their means were recorded. Interdevice agreement was evaluated with the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The mean IOP measurements for NCT, IRT, and GAT were 15.97±2.99, 17.47±2.86, and 16.46±2.68mmHg, respectively. The mean difference between NCT and GAT was -0.49± 1.89mmHg, the mean difference between IRT and GAT was 1.01±1.90mmHg, and the mean difference between NCT and IRT was -1.50±2.02mmHg. Agreement between devices was found to be >0.8 for each tonometry ICC. There were significant positive correlations between the measurements obtained via these three instruments and CCT. In this study, IOP was measured slightly lower with NCT than GAT, but it was about 1mmHg higher with IRT than GAT on average. All three devices appeared to be affected by CCT, with NCT being the most affected in this regard. The three instruments can be used for routine inspection and screening. However, considering the differences in the measurements obtained by using them, it is clear that following up IOP measurements with GAT measurements is beneficial in advanced glaucoma patients.

Real-world agreement of same-visit Tono-Pen vs Goldmann applanation intraocular pressure measurements using electronic health records

PurposeTo compare intraocular pressure (IOP) obtained with Tono-Pen (TP) and Goldmann applanation (GAT) using large-scale electronic health records (EHR). DesignRetrospective cohort study. MethodsA single pair of eligible TP/GAT IOP readings was randomly selected from the EHR for each ophthalmology patient at an academic ophthalmology center (2013–2022), yielding 4550 eligible measurements. We used Bland-Altman analysis to describe agreement between TP/GAT IOP differences and mean IOP measurements. We also used multivariable logistic regression to identify factors associated with different IOP readings in the same eye, including demographics, glaucoma diagnosis, and central corneal thickness (CCT). Primary outcome metrics were discrepant measurements between TP and GAT as defined by two methods: Outcome A (normal TP despite elevated GAT measurements), and Outcome B (TP and GAT IOP differences ≥6 mmHg). ResultThe mean TP/GAT IOP difference was 0.15 mmHg ( ± 5.49 mmHg 95% CI). There was high correlation between the measurements (r = 0.790, p < 0.001). We found that TP overestimated pressures at IOP <16.5 mmHg and underestimated at IOP >16.5 mmHg (Fig. 4). Discrepant measurements accounted for 2.6% (N = 116) and 5.2% (N = 238) for outcomes A and B respectively. Patients with thinner CCT had higher odds of discrepant IOP (OR 0.88 per 25 μm increase, CI [0.84–0.92], p < 0.0001; OR 0.88 per 25 μm increase, CI [0.84–0.92], p < 0.0001 for outcomes A and B respectively). ConclusionIn a real-world academic practice setting, TP and GAT IOP measurements demonstrated close agreement, although 2.6% of measurements showed elevated GAT IOP despite normal TP measurements, and 5.2% of measurements were ≥6 mmHg apart.

Comparison of intraocular pressure in New Zealand White rabbits measured using rebound and applanation tonometers and four different methods of physical restraint

ABSTRACT Aims To compare intraocular pressure (IOP) measurements obtained in rabbits using rebound (TV) and applanation (TPV) tonometers with four different methods of physical restraint. Methods A total of 20 New Zealand White rabbits (40 eyes) were included in this study. IOP readings were obtained from both eyes using the two different tonometers. The rabbits were placed on a table and restrained by wrapping in a cloth (Method I), by scruffing with rear support (Method II), by wrapping in a cloth and cupped in the hands (Method III), or by a box restrainer (Method IV). Results The mean IOP measurement obtained by TPV was higher than that obtained with the TV for all handling methods. Mean differences (TV−TPV, in mmHg) in IOP were −5.3 (95% Cl = −6.5 to −4.1) for Method 1, −4.7 (95% Cl = −6.2 to −3.29) for Method II, −4.9 (95% Cl = −6.2 to −3.7) for Method III and −7.6 (95% Cl = −9.2 to −5.9) for Method IV. Using the TV tonometer, mean IOP for Method IV was higher than for Method I (mean difference 2.1 (95% Cl = 1.1–3.1)), whereas using the TPV tonometer, mean IOP for Method IV was significantly higher than Method I, II, and III (mean differences: 4.4 (95% Cl = 2.6–5.9), 3.7 (95% Cl = 2–5.3) and 3.8 (95% Cl = 2–5.4), respectively). According to Bland-Altman plots, IOP readings for TPV tended to be higher than those for TV with all handling methods, but with a lack of agreement. The mean difference and 95% limits of agreement for the differences between TV and TPV were −5.4 mmHg (−12.5–1.9 mmHg), −4.7 mmHg (−12.9–3.5 mmHg), −4.9 mmHg (−12–2.2 mmHg), and −7.5 mmHg (−17.4–2.3 mmHg), with Methods I, II, III, and IV, respectively. Comparing TV and TPV, only 7.5%, 12.5%, 27.5%, and 15% of IOP measurements from 20 rabbits were within the range considered clinically acceptable for IOP (± 2 mmHg) for Method I, II, III, and IV, respectively. Conclusion and clinical relevance In conclusion, the physical restraint method should be recorded when IOP is measured in rabbits, and TV and TPV tonometers cannot be used interchangeably (high bias and low proportion of measurements within ± 2 mmHg).

CLINICAL EVALUATION OF INTRAOCULAR PRESSURE MEASUREMENTS USING DIFFERENT TONOMETERS IN PATIENTS OF VARIOUS REFRACTIVE ERRORS

Background: Intraocular pressure (IOP)is an important rst indicator of probability and suspicion of Glaucoma. The virtual IOP status is grossly inuenced by multiple factors including Refractive errors, corneal biomechanics ,central corneal thickness(CCT) and Scleral rigidity. Aim: To compare relative IOP measurements and its variability in Emmetropes, myopic and hypermetropic patients using Schiotz, Goldmann Applanation(GAT)and I-Care Rebound tonometer to establish an equation between virtual and real time IOP. Materials and Methods: This observational prospective study comprised of 100 subjects above the age of 18 years inclusive37 Emmetropes , 31 Hypermetropes and remaining 32 belonged to myopia . Statistical Analysis : Descriptive statistics were performed using SPSS for Windows version 17.0 to calculate the demographic characteristics of the study cohort. The data were expressed as mean values including the standard deviation (SD) and the 95% condence interval (CI). Mean IOP measurements between Schiotz, I-Care and GAT were compared by One way ANOVA along with Individual pair wise comparison by applying Post Hoc Tukey Test for comparison of IOP measurements using a particular method of Tonometry in individuals of myopia, hypermetropia and emmetropia. Results: The highest mean value of CCT 536.667 mum was in Hypermetropes whereas the lowest CCT value of 507.031mum was in myopic eyes with statistically signicant (P&lt;0.05). The mean value for IOP in Emmetropes was16.665 mm Hg for Schiotz , 15.027 Hg for GAT and 15.081 mm Hg for I –Care .Whereas Hypermetropes revealed mean value of 15.055 mm Hg for Schiotz , 14.323 mm Hg for GAT and 14.065 mm Hg for I –Care . The mean value for IOP in Myopic eyes was 16.875 mm Hg for Schiotz , 14.375 mm Hg for GAT and 14.688 mm Hg for I –Care . Conclusion : The study had revealed higher mean value of IOP in Myopic eyes as compare to Emetropic and Hypermetropic subjects. IOP measurements by the Schiotz tonometer were signicantly higher as compare to GAT and I-Care tonometer. Whereas recordings by GAT and I Care tonometers were almost in agreement .Denitive correlation could not be established between pachymetry readings and adjusted IOP following GAT and I –Care tonometry .

A comparison of goldmann applanation tonometry and rebound tonometry measurements among patients attending a glaucoma clinic in Southwest Nigeria.

The accurate measurement of intraocular pressure (IOP) is a fundamental basic examination in daily ophthalmic practice and is important in managing many ophthalmic diseases and conditions such as glaucoma, uveitis, and following trauma. Accurate measurement of IOP is particularly important in glaucoma because the intraocular pressure is the most important modifiable risk factor in its management. To compare intraocular pressure (IOP) measurements obtained with the Goldmann applanation (GAT) tonometer to intraocular pressure measurements obtained with the iCare rebound tonometer (RBT) and evaluate the suitability of the iCare tonometer for routine clinical use among adult patients attending a glaucoma clinic in Southwest, Nigeria. The study was a comparative cross-sectional study. A total of 132 eyes of 132 patients were recruited for the study. Three consecutive IOP measurements were obtained with each of the instruments by the same observer. A difference in IOP of ± 3 mmHg between the two instruments was considered clinically significant in this study. The mean IOP measurement from GAT was 15.18 mmHg (±4.26 mmHg) and 16.32 mmHg (±4.48 mmHg) from RBT. The mean central cornea thickness was 520.66 μm (±33.34). Pearson's correlation (r = 0.84) revealed a strong statistically significant correlation between GAT and RBT measurements and paired student t-test revealed a statistically significant difference in the means of IOP obtained by the GAT and RBT. There was a tendency for RBT to yield higher IOP measurements. The intraocular pressure measurements obtained with iCare RBT and GAT though strongly correlated, showed statistically significant differences in the means. The impact of central cornea thickness on measurements obtained by GAT and RBT was statistically insignificant. The iCare rebound tonometer, cannot replace GAT for routine use in the glaucoma clinic.

The short-term effects of intravitreal bevacizumab injection on intraocular pressure, cornea, iridocorneal angle, and anterior chamber.

Transient increase in intraocular pressure (IOP), changes in anterior chamber parameters, and changes in aqueous humor dynamics may occur after intravitreal injections because of intravitreal volume changes. In this observational study, we investigated the early effects of intravitreal bevacizumab (IVB) injection on IOP, central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), and iridocorneal angle (ICA). The patients who had one single-dose IVB (2.5 mg/0.1 mL) injection were included in the study. The patients underwent IOP, CCT, CV, ACD, and ICA measurements before and 1 h and 1 day after the injection. Pre-injection and post-injection values were compared. Forty-two eyes of 42 patients were included in the study, and the mean age of patients was 60.1 ± 7.4 years. The mean IOP measurements before and after injection at 1 h and day 1 were 15 ± 2.4, 17.4 ± 2.4, and 14.7 ± 2.3, respectively. The mean IOP, CCT, and CV values 1 h after injection were significantly higher than pre-injection values (p < 0.05, p < 0.05, and p = 0.02, respectively). Conversely, mean ACD and ICA values 1 h after injection were significantly lower than pre-injection values (p = 0.01 for both). There were no statistically significant differences on the first day after injection for all parameters. IVB (2.5 mg/0.1 mL) injection causes transient increases in IOP and transient decreases in ACD and ICA at the first hour after injection. Related to elevation in IOP, CCT and CV may increase transiently. These changes return to baseline values on the first day after injection.

The outcome of cataract surgery in eyes with end–stage glaucoma

Purpose: To evaluate the outcome of phacoemulsification and intraocular lens implantation (PHACO IOL) in eyes with end–stage glaucoma.&#x0D; Methods: Eighteen eyes of 18 patients with end–stage glaucoma in which PHACO IOL was performed were included in this prospective clinical study. Intraocular pressure (IOP) was measured before and 1 week, and 1, 3, 6, and 12 months after PHACO IOL. The best corrected visual acuity (BCVA), the number of antiglaucoma medications and the visual field (VF) test results before PHACO IOL and at the end of follow–up were evaluated.&#x0D; Results: The follow–up period after PHACO IOL was 12 months for all eyes. The mean IOP before surgery was 13.5 mmHg (SD 2.6). There were no differences between the mean IOP measurements before and after surgery during the entire follow– up period (P&gt;0.05). The mean preoperative BCVA was 0.65 (SD 0.3) logMAR, improving to a mean of 0.19 (SD 0.1) logMAR postoperatively (P&lt;0.0001). The mean number of antiglaucoma medications before surgery was 1.8 (SD 1.4), and it was 2.0 (SD 1.3) postoperatively (P=0.104). The mean value of the mean deviation in 7 eyes on automated perimetry was –23.57 dB (SD 3.9) preoperatively and –22.87 dB (SD 4.1) postoperatively (P=0.105). The mean VF island in 11 eyes on Goldmann perimetry was 17.0° (SD 7.2) preoperatively, improving to 20.4° (SD 9.0) postoperatively (P=0.033).&#x0D; Conclusion: PHACO IOL in eyes with end–stage glaucoma resulted in a stable IOP and a significantly improved BCVA without worsening of the VF.

Safety of intravitreal triamcinolone and its impact on optic nerve morphology in patients treated for diabetic macular edema.

To assess the impact of one intravitreal injection (IVT) of Triamcinolone Acetonide (TA) on intraocular pressure (IOP) and optic nerve structural parameters in patients treated for Diabetic Macular Edema (DME). This retrospective study included patients with DME that were naïve to intraocular steroids and underwent one IVT of TA of 4 mg/0.1 mL and age-matched controls with DME without criteria for IVT. Patients records were reviewed for IOP (at baseline and a month after IVT) and optic nerve parameters measured by optical coherence tomography (up to 6 months before and 6 months after IVT). Exclusion criteria included glaucoma and treatment with hypotensive agents. Twenty-six eyes were included in the Control Group and 29 in the IVT Group, with a mean age of 65.10 ± 10.08 and 67.30 ± 4.71 years, respectively (p = 0.06). At baseline, IOP and optic nerve measurements were equivalent between groups (p > 0.05). One month after IVT, mean IOP measurements in IVT Group were higher than those of controls (17.84 ± 4.50 vs 11.59 ± 3.09 mmHg, p < 0.001). Ocular hypertension (OHT) developed in 17.24% of cases and reversed with topical medication. After one IVT, vertical cup/disc ratio was higher (0.57 ± 0.25 vs 0.60 ± 0.14, p = 0.04) and retinal nerve fiber layer thickness was globally lower (mean: 91.03 ± 4.25 vs 81.33 ± 19.10 µm, p = 0.001) in the IVT Group. Our results confirmed that intravitreal TA results in IOP increase. This seems to negatively affect optic nerve morphology, even in patients without OHT or adequately treated with hypotensive agents.

Intraocular Pressure Reduction Effect of 0.005% Latanoprost Eye Drops in a Hyaluronic Acid-Chitosan Nanoparticle Drug Delivery System in Albino Rabbits.

PurposeThe purpose of this study was to evaluate the intraocular pressure (IOP) reduction efficiency of hyaluronic acid-chitosan-latanoprost link nanoparticle (HA-CS-latanoprost link NP) formulated eye drops.MethodsThe IOP reduction study was performed in 24 normotensive albino rabbits. The test animals were randomized and grouped accordingly to treatment namely, HA-CS-latanoprost link NP, plain latanoprost, and the commercially available Xalatan eye drop, all were formulated with 0.005% latanoprost. The 9 days of the experiment were divided into baseline period (days 1–2), treatment period (days 3–6), and recovery period (days 7–9). A wireless noncontact tonometer was used to measure IOP at a time interval of 2 hours for 12 hours per day with 5 readings each.ResultsThe highest mean daily IOP reduction during the treatment period was 24% for plain latanoprost, 23% for Xalatan, and 29% for HA-CS-latanoprost link NP. The maximum reduction in IOP for plain latanoprost and Xalatan all occurred at the sixth hour with the peak effects of 4.85 mm Hg (37%) and 4.8 mm Hg (36%), respectively. Although HA-CS-latanoprost link NP had peak effects of 5.75 mm Hg (43%) at the sixth hour and 5.22 mm Hg (39%) at the eighth hour. Daily mean IOP measurements of each treatment group showed that HA-CS-latanoprost link NP has a greater IOP reduction effect compared with the other two treatments (P < 0.001).ConclusionsThe results showed that the formulation of latanoprost with CS and HA is more effective in reducing the IOP than by drug alone.Translational RelevanceThe results provide evidence from animal experiment that HA-CS-latanoprost link NP formulation could improve and sustain drug concentration in the anterior segment of the eye. The improved reduction in IOP with that HA-CS-latanoprost link NP formulation can serve as a basis that latanoprost eye drops can be formulated with decreased concentration of benzalkonium HCl, an irritant preservative and penetration enhancer.

Comparison of the iCare, Tono-Pen, non-contact airpuff, and Goldmann applanation tonometers in eyes with corneal edema after penetrating keratoplasty.

To compare the utility of the iCare, Tono-Pen, and non-contact airpuff (NCT) tonometers with the Goldmann applanation tonometer (GAT) for measuring intraocular pressure (IOP) in patients with corneal edema after penetrating keratoplasty (PKP) and to assess the effects of central corneal thickness (CCT) and corneal curvature (CC) on IOP measurements. Thirty-two eyes of 27 patients with corneal edema after PKP due to corneal abnormalities and 43 control eyes of 30 patients with normal corneas were recruited. Before IOP measurements, all patients underwent a baseline examination, including auto-refraction, keratometry, slit lamp biomicroscopy, and CCT measurement. IOP was measured using the devices in the same order: first the NCT, followed by the iCare, Tono-Pen, and GAT. The differences between the iCare, Tono-Pen, NCT, and GAT were calculated with repeated-measures analysis of variance. The Bland-Altman method was used to assess the agreement between the iCare, Tono-Pen, and NCT versus the GAT. The influences of CCT and CC on IOP measurement were evaluated by correlation analysis using Pearson's correlation coefficient. Mean IOP measurements were significantly higher with the NCT and Tono-Pen than with the GAT in the PKP and control groups. When compared with GAT, iCare showed significantly higher IOP readings in the control group, but the IOP readings did not differ between the iCare and GAT in the PKP group. Poor agreement was noted between the NCT and GAT in both groups. The Tono-Pen showed clinically acceptable agreement with GAT in control eyes and poor agreement in PKP eyes. The agreement between the iCare and GAT appeared to be clinically acceptable in both groups. Correlation analysis of the results from control eyes showed that the IOP measurements with the GAT and NCT were weakly related to CCT and moderately correlated with CC. The iCare IOP readings were weakly correlated with CCT and CC. In the PKP group, the NCT and Tono-Pen significantly overestimated IOP, whereas the iCare IOP readings were similar to those obtained using the GAT. Poor agreement was noted between the NCT and GAT as well as between the Tono-Pen and GAT, but the iCare showed clinically acceptable agreement with GAT. In normal corneas, the GAT, NCT, and iCare were affected by CCT and CC. The iCare tonometer was less affected by corneal edema than were the NCT and the Tono-Pen. The iCare appears to be a useful device for IOP measurement in eyes with corneal edema after PKP.

Comparison of central corneal thickness and intraocular pressure measured with two different tono/pachymeter devices in non-glaucomatouse children.

The goal of this research is to compare the intraocular pressure (IOP) and the mean central corneal thickness (CCT) values obtained from the measurements with Nidek NT-530P and Canon TX-20P devices with the values obtained by ultrasound pachymetry (UP) and Goldmann applanation tonometry (GAT) in children. This prospective study was conducted with 119 healthy children. The measurements were repeated three times for each eye. The intraclass correlation coefficient (ICC) was used to assess the correlation between the measurements obtained from different devices. The Bland-Altman plot was used to analyze the agreement between two different devices graphically. The measurements were taken in the same order in all subjects: TX-20P, NT-530P, UP, and GAT. The mean age of the children was 10.1 ± 3.2 (6-17) years. The mean CCT values for the eyes were 568.90 and 569.68 (TX-20P), 571.44 and 566.37 (NT-530P), 564.77 and 564.67 μm UP, (right and left, respectively). The highest correspondence observed for CCT was between UP and NT-530P devices (ICC, 0.982, the left eye). The mean IOP measurements for Canon TX-20P, NT-530P, and GAT were 16.5 ± 3.2, 16.3 ± 3.2, and 16.8 ± 3.6 mmHg for the right eyes, respectively, while those for the left eyes were 16.6 ± 3.1, 16.2 ± 3.3, and 16.8 ± 3.7 mmHg. The highest correspondence was noted between measurements obtained using GAT and Nidek NT-530P devices (ICC, 0.945, in the left eye). Tono/pachymetry devices in the healthy children are provides significant agreements with the gold standard methods for IOP and CCT measurements.Clinical Trial Registration number: 2016-94.

Circadian rhythm of intraocular pressure in clinically normal donkeys (Equus asinus)

ABSTRACT The present study aimed to report the circadian rhythm of intraocular pressure (IOP) in clinically normal donkeys. A prospective study was conducted on 30 adult donkeys. Measurement of the IOP was made at 2-hr interval starting at 6:00 hr till the next day at 4:00 using applanation tonometry. Measurements were recorded for both eyes and compared for male and female differences. The overall mean (± SEM) IOP measurement was 24.99 ± 0.14 mmHg. The mean (± SEM) IOP of the right and left eyes was 25.59 ± 0.19 and 24.27 ± 0.19 mmHg, respectively. The IOP values of the right and left eyes as well as of male and female values did not change significantly (P > 0.05) at all times. IOP measurements demonstrated diurnal fluctuation during the light phase of the day. The IOP significantly (P < 0.001) increased (27.07 ± 0.42) in the early morning (peak daytime at 8:00 hr) and was significantly (P < 0.001) lower (20.68 ± 0.34) at the mid-light phase (12:00 hr) compared to all evaluation times. The study documented the daily rhythm of IOP in donkeys. The 24-hr variation of IOP measurement should be considered when evaluating IOP in donkeys.

Oral consumption of Garcinia kola(Bitter kola) lowers intraocular pressure.

Garcinia kola (bitter kola) is locally ingested across the West African subregion. It has ocular hypotensive effects similar to some commonly used glaucoma medications when administered topically. The study assessed the effect of oral ingestion of G.kola on intraocular pressure (IOP). A randomized, single-blind, placebo-controlled, cross-over design was used in this study. Forty-six healthy subjects, aged between 19 and 27years were recruited and randomized into two groups (A and B). Subjects in group A ingested 100mg/kg body weight bitter kola in a 200ml solution on their first visit and group B ingested 200ml of water. On the second visit, the order of treatment was reversed, IOP was measured at baseline and every 45min interval for 135min. The mean difference between the baseline and post-treatment IOP measurements were tested for statistical significance using repeated-measures analysis of variance (95% confidence intervals [CIs]). Mean IOP measurements decreased by 7.9, 18.2 and 20.6% at 45, 90 and 135min, respectively, after G.kola treatment. The reduction, though variable across subjects, was statistically significant (F [2.13, 95.62]=90.35, p<0.0001) across the respective time points. Repetition of an identical protocol without G. kola caused clinically negligible changes in IOP. There was no statistically significant influence of gender or age in G.kola effect on IOP reading. Oral ingestion of G.kola lowered the intraocular pressure of healthy young adults by 21%. Such an effect may be of therapeutic benefit to patients with POAG or ocular hypertension in low-income settings.

Changes in intraocular pressure after intraocular eye surgery-the influence of measuring technique.

To investigate the changes in intraocular pressure (IOP) before and after intraocular surgery measured with Goldmann applanation tonometry (GAT) and pascal dynamic contour tonometry (PDCT), and assessed their agreement. Patients who underwent trans pars plana vitrectomy (TPPV) with or without cataract extraction (CE) were included. The IOP was measured in both eyes with GAT and PDCT pre- and postoperatively, where the non-operated eyes functioned as control. Preoperatively, mean IOP measurements were 16.3±6.0 mm Hg for GAT and 12.0±2.8 mm Hg for PDCT for the operated eyes. Postoperatively, the mean IOP dropped to 14.3±5.6 mm Hg for GAT (P=0.011) and rose up to 12.7±2.6 mm Hg for PDCT (P=0.257). Bland-Altman analysis showed a poor agreement between GAT and PDCT with a mean difference of 2.9 mm Hg preoperatively and 95% limits of agreement ranging from -3.2 to 9.0 mm Hg. Postoperatively, the mean difference was 1.2 mm Hg with 95% limits of agreement ranging from -8.3 to 10.7 mm Hg. There were no significant differences between the TPPV and TPPV+CE group, except when measured with PDCT postoperatively (P=0.012). The IOP is reduced after surgery when measured with GAT and remained stable when measured with PDCT. However, the agreement between GAT and PDCT is poor. Although PDCT may be a more accurate predictor of the true IOP, it seems less suitable for daily use in the clinical practice.

Multifunctional biophotonic nanostructures inspired by the longtail glasswing butterfly for medical devices.

Numerous living organisms possess biophotonic nanostructures that provide coloration and other diverse functions for survival. While such structures have been actively studied and replicated in the laboratory, it remains unclear whether they can be used for biomedical applications. Here we show a transparent photonic nanostructure inspired by the longtail glasswing (Chorinea faunus) butterfly and demonstrate its use in intraocular pressure (IOP) sensors in vivo. We exploit the phase separation between two immiscible polymers (poly(methyl methacrylate) and polystyrene) to form nanostructured features on top of a Si3N4 substrate. The membrane thus formed shows good angle-independent white light transmission, strong hydrophilicity and anti-biofouling properties that prevent adhesion of proteins, bacteria, and eukaryotic cells. We then developed a microscale implantable IOP sensor using our photonic membrane as an optomechanical sensing element. Finally, we performed in vivo testing on New Zealand white rabbits and show that our device reduces the mean IOP measurement variation compared to conventional rebound tonometry without signs of inflammation.

Formulation of a Peribulbar Block for Prolonged Postoperative Pain Management in Vitreoretinal Surgery: A Randomized Clinical Trial

To evaluate postoperative pain level using a supplemental peribulbar injection at the conclusion of retinal surgery. Prospective, parallel-assigned, single-masked, randomized clinical trial. Fifty-eight patients undergoing scleral buckle, vitrectomy, or combined surgery. In a single academic institutional practice, 58 patients undergoing scleral buckle, vitrectomy, or combined surgery were enrolled. Exclusion criteria included those with a risk for glaucoma, a pre-existing chronic pain disorder, among others. Patients were assigned randomly to receive a postoperative peribulbar formulation of either bupivacaine, triamcinolone acetonide, and cefazolin (group A) or bupivacaine, balanced salt solution, and cefazolin (group B). The postoperative pain score and ocular motility were assessed by a masked observer on the first postoperative day. The primary outcome measure was the postoperative pain score. Secondary outcome measures included oral analgesic use, ocular motility, and intraocular pressure (IOP). The mean pain scores were 2.8±2.9 for group A and 3.8±2.6 for group B (P= 0.095). Pain was absent in 28% of group A patients versus 14% of group B patients (P= 0.11). Group A required less narcotic pain medication (hydroxycodone: group A, 0.7±3 mg vs. group B, 3±6 mg; P= 0.05; oxycodone: group A, 7±7 mg vs. 9±13 mg; P= 0.2) than group B. Motility was full in group B and limited in group A (P ≤ 0.001), with no differences in mean IOP measurements at any point after surgery. We did not demonstrate a statistically significant reduction in mean postoperative pain scores. However, patients in group A required less hydroxycodone use and had greater akinesia, suggesting prolonged neural blockade.