Higher Intraocular Pressure Values Research Articles

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

Statistical Investigations on Relationship of Intraocular Pressure with Environmental Factors

Clinical relevance: Intraocular pressure (IOP) has a significant role in glaucoma pathophysiology. There are factors that influence in the IOP value, such as central corneal thickness or the biomechanical properties of the cornea. However, other less studied factors may influence the IOP, such as environmental pollution.
 Background: The increase in air pollution is related to acute respiratory pathologies. Regarding the eyes, is related to conjunctivitis or dry eye disease. The purpose was to analyse the correlation of environmental factors (atmospheric pressure, temperature, O3, NO2, PM10 and PM2.5 concentrations) with intraocular pressure in young healthy patients.
 Methods: A cross-sectional study was carried out on patients treated at General Optica centres in Spain and Portugal in collaboration with the University of Valladolid. This study included healthy patients (between 18 and 40 years old). IOP measurements were taken with different air tonometers (CT-80, CT-800, NCT-200, NT-510 and NT-530) for one week and correlated with environmental factors (atmospheric pressure, temperature, O3, NO2, PM10 and PM2.5 concentrations). Correlation (Spearman’s Rho) analyses were performed between IOP and the different environmental parameters. Moreover, groupings were performed as a function of the values for healthy exposure levels recommended by the WHO. Different comparisons were performed using the Mann‒Whitney U test.
 Results: Statistically significant correlations were found (p < .04) between IOP and temperature (r = 0.37), atmospheric pressure (r = 0.20), NO2 (r = 0.14), PM10 (r = 0.21), O3 (r = 0.16) and PM2.5 concentrations (r = 0.16). Regarding the IOP values of people who were exposed to unhealthy concentrations (AQI > 20) versus those who were not, higher IOP values were only found in people exposed to PM2.5.
 Conclusion: Slight correlations were found between higher temperature, atmospheric pressure and concentrations of pollutant gases and increased IOP. More clinical studies are needed to understand the role that these environmental factors play in the aqueous humour flow and the value of IOP to know if and to what extent these factors may be risk of glaucoma.

Exploring the Potential of Wild Olive (Acebuche) Oil as a Pharm-Food to Prevent Ocular Hypertension and Fibrotic Events in the Retina of Hypertensive Mice.

Our laboratoryhas previously described the antioxidant and anti-inflammatory potential of a wild olive (acebuche, ACE) oil against hypertension-associated vascular retinopathies. The current study aims to analyze the antifibrotic effect of ACE oil on the retina of hypertensive mice. Mice are rendered hypertensive by administration of NG-nitro-L-arginine-methyl-ester (L-NAME) and simultaneously subjected to dietary supplementation with ACE oil or a reference extra virgin olive oil (EVOO). Intraocular pressure (IOP) is measured by rebound tonometry, and retinal vasculature/layers are analyzed by fundus fluorescein angiography and optical coherence tomography. Different fibrosis-related parameters are analyzed in the retina and choroid of normotensive and hypertensive mice with or without oil supplementation. Besides preventing the alterations found in hypertensive animals, including increased IOP, reduced fluorescein signal, and altered retinal layer thickness, the ACE oil-enriched diet improves collagen metabolism by regulating the expression of major fibrotic process modulators (matrix metalloproteinases, tissue inhibitors of metalloproteinases, connective tissue growth factor, and transforming growth factor beta family). Regular consumption of EVOO and ACE oil (with better outcomes in the latter) might help reduce abnormally high IOP values in the context of hypertension-related retinal damage, with significant reduction in the surrounding fibrotic process.

Klinik olarak Tek Taraflı Psödoeksfoliasyon Sendromu Olanların Ön Segment Parametrelerinin Schempflug Görüntüleme Tekniği ile değerlendirilmesi

Objective: We aimed to compare the intraocular pressure (IOP), keratometry values (K), and anterior segment parameters of patients with clinically unilateral pseudoexfoliation syndrome (PEX) with the other eyes without PEX and the control group. Material and Method: Fifty four patients with unilateral PEX findings and 40 participants without PEX findings in both eyes were included in the study as a control group. IOP was measured by Goldmann applanation tonometry. K values and anterior segment parameters [central corneal thickness (CCT), anterior chamber depth (ACD), iridocorneal angle (ICA), and anterior chamber volume (ACV)] were measured using Scheimpflug imaging technique. Results: The mean age of PEX patients was 67.9±9.2 years, while the mean age of the control group was 58.9±5.7 years. The IOP values of the eyes with PEX were significantly higher than the other eyes (p=0.02), and there was no significant difference between them and the control group (p=0.59). In terms of K values and anterior segment parameters, the measurements of eyes with PEX and the other eyes, and eyes with PEX and control group were similar (p>0.05). Conclusion: In our study, eyes with PEX had higher IOP values than the fellow eyes and control group. In addition, thinner CCT, narrower ACD, and ICA values were found in eyes with PEX than in the other eyes. However, these values were not statistically significant.

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.

Obesity-induced ocular changes in children and adolescents: A review.

Childhood obesity has reached epidemic levels worldwide. Overweight and obesity is associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation responsible for macro- and microvascular dysfunction. While the impact of obesity on overall health is well-described, less is known about its ocular manifestations. Still, there are few studies in children and adolescents in this regard and they are inconsistent. However, some evidence suggests a significant role of overnutrition in the development of changes in retinal microvasculature parameters (wider venules, narrower arterioles, lower arteriovenous ratio). Higher values of intraocular pressure were found to be positively correlated with high body mass index (BMI) as well as obesity. In addition, the retinal nerve fiber layer (RNFL) values seem to be lower in obese children, and there is a significant negative correlation between RNFL values and anthropometric and/or metabolic parameters. Changes also could be present in macular retinal thickness and choroidal thickness as well as in the retinal vessel density in children with obesity. However, these associations were not consistently documented. The purpose of this review is to present the most current issues on child obesity and the related potential ocular effects through an overview of international publications from the years 1992-2022.

Novel drug delivery systems for the treatment of glaucoma

AbstractGlaucoma is a group of chronic irreversible neuropathies in which a progressive death of retinal ganglion cells (RGC) and a glaucomatous optic disc neuropathy occurs leading to an irreversible visual field alteration. Intraocular pressure (IOP) increase is a major risk factor strongly associated with the onset and progression of the disease although a non IOP‐dependent neurodegeneration also occurs. Taking all this into account, the glaucoma therapy is based on two different targets: lowering the IOP and neuroprotection.The treatment of choice in patients with high IOP values is topical administration of hypotensive active agents on the ocular surface. The chronicity of the pathology, together with the low bioavailability of the antiglaucomatous drugs applied topically, make it necessary daily instillations, which are associated, in many cases, with the appearance of surface eye alterations and dry eye disease (DED). For these reasons, the development of therapeutic platforms able to increase the bioavailability of the drug while being soft with the ocular surface is getting special attention. Novel formulations involve pharmaceutical systems such as liposomes, nanoemulsions and microemulsions including also compounds with protective activity on the corneal surface (osmoprotective, antioxidants and/or bioadhesive polymers)(1–3).It is well known that therapies lowering IOP does not address neurodegeneration. Moreover, pathophysiological studies of glaucoma have shown that even in patients presenting IOP values within the normal limits, neuronal degeneration occurs. For this reason, the use of neuroprotective therapy in the treatment of glaucoma alone or simultaneously with the therapy based on the control of IOP results of great interest. Treatments destined to lower IOP, in which the target is the anterior segment of the eye are administered topically. By the contrary, neuroprotective therapies require the administration of the drugs near to the retinal target as well as their maintenance during long term Due to the multifactorial nature of the disease there is special interest in the design of novel drug delivery systems able to include a combination of active agents in the same formulation and provide long term effects with a single administration(4).Acknowledgements: Acknowledgements‐ Grant: Fondo Europeo de Desarrollo Regional (FEDER‐CICYT), grant: FIS‐PI17/00079 and PI17/00466, Research Group UCM 920415 ‘Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal)’ and the ISCII‐FEDER RETICS (OFTARED) (RD16/0008/0004 and RD16/0008/0009)PID2020‐113281RB‐C21 funded by MCIN/AEI/ 10.13039/501100011033.References.1. López‐Cano J.J, González‐Cela‐Casamayor M.A., Andrés‐Guerrero V.,Herrero‐Vanrell R. Molina‐Martínez I.T. “Liposomes as vehicles for topical ophthalmic drug delivery and ocular surface protection”. Expert Opinion on Drug Delivery. 2021. 18(7):819–847. DOI: 10.1080/17425247.2021.1872542.2. M. Gómez‐Ballesteros; J. López‐Cano; I. Bravo‐Osuna; R. Herrero‐Vanrell; I.T. Molina‐Martínez. “Osmoprotectants in Hybrid Liposome/HPMC Systems as Potential Glaucoma Treatment”. Polymers. 2019; 11(6): 929. DOI: 10.3390/polym110609293. I Bravo‐Osuna; V Andrés‐Guerrero; P Pastoriza Abel; IT Molina‐Martínez; R Herrero‐Vanrell. Pharmaceutical microscale and nanoscale approaches for efficient treatment of ocular diseases. Drug Deliv Translational Research.2016. 6(6):686–707.DOI: 10.1007/s13346‐016‐0336‐5.4. R Herrero‐Vanrell; I. Bravo‐Osuna; V. Andrés‐Guerrero; M. Vicario‐de‐la‐Torre; I.T. Molina‐Martínez. The potential of using biodegradable microspheres in retinal diseases and other intraocular pathologies. Progress in Retinal and Eye Research. 2014. 42; 27–43. DOI: 10.1016/j.preteyeres.2014.04.002.

Evaluation of eye health in children with type 1 diabetes mellitus and celiac disease.

Pediatric celiac disease (CeD) and type 1 diabetes mellitus (T1DM) have well established effects on eye health but comorbid effect is not known. To evaluate the eye health of children with T1DM and CeD to predict microvascular retinal pathologies by diagnosis of probable intraocular pressure increase which is an important glaucoma trigger. In this case-controlled study, 28 eyes of 14 children both T1DM and CeD, with a mean age of 12.6 ± 3.9 years, and 28 eyes of gender-matched 14 healthy children as a control group were included. In both groups, detailed ocular examinations and measurement of intraocular pressure (IOP), ocular pulse amplitude (OPA), thicknesses of ganglion cell layer (GCL), inner plexiform layer (IPL), retinal nerve fiber layer (RNFL), and choroid thicknesses (CT) were done. All the patients with T1DM and CeD were newly diagnosed. The evaluations of IOP and OPA were made using a Pascal dynamic tonometer and thicknesses measured by optical coherence tomography. The IOP and OPA values of the patient group were found to be statistically significantly higher than those of the control group (17.1 and 1.86 vs 14.78 and 1.57 mmHg, P <.0001, P <.001, respectively). IOP values of all patients were higher than IOP cut off levels for diagnosis of hypertension. CT was significantly thinner in the patient group than in the control group (385.4 μm vs 331.71 μm, respectively, P < 0.03). No significant difference was found between the groups in respect of GCL, IPL, and RNFL values. The higher IOP and OPA values of the children with T1DM and CeD were considered to be the result of the microvascular pathologies in T1DM and increased inflammation associated with CeD. High IOP and OPA values can lead to damage in the eye as intraocular blood flow and choroidal perfusion are affected. In order to prevent these eye problems, measurement of IOP and OPA should be done in children with diagnosis of T1DM and CeD and also follow up studies needed.

A Study on the Association Between Myopia and Elevated Intraocular Pressure Conducted at a Tertiary Care Teaching Hospital in Gujarat, India.

IntroductionGlaucoma is characterized by the loss of retinal nerve fiber tissues and the loss of the neuroretinal rim of the optic nerve head is termed glaucomatous optic neuropathy (GON). The early diagnosis of glaucoma requires measurement of intraocular pressure (IOP) by tonometry. The gold standard method widely used in clinical settings to measure IOP is Goldmann applanation tonometry (GAT). Myopia is also considered a risk factor for glaucoma. Population-based and hospital-based evidence suggests that the prevalence of GON is higher in high myopic eyes than in emmetropic eyes. The present study aims to document the association between myopia and elevated IOP.Materials and methodsA total of 400 medium and high myopic patients attending the ophthalmology outpatient department, in a tertiary care hospital, were measured for IOP using GAT and underwent a detailed clinical evaluation. All the patients also underwent slit lamp biomicroscopic examination and fundus examination. Other data included details on demographic, socio-economic, and occupational history.ResultsA detailed refractive error examination revealed that amongst 400 right eyes, 67.5% had medium myopia, while 66.75% of the left eye were medium myopic. Amongst the medium myopic eyes, the average IOP was 15.51±3.68 mm of Hg, while in high myopic, the average IOP was 16.19±3.33 mm of Hg. A difference of 0.68 mm of Hg with high myopic eyes having higher IOP values than medium myopic eyes was observed, and it was significant statistically with a p-value <0.05.ConclusionThere is a statistically significant association between elevated IOP and the high myopic group. In comparison to IOP measured in medium myopic and high myopic patients, elevated IOP was observed in the high myopic group than in the medium myopic group.

PSEUDOEXFOLIATIVE SYNDROME AS A TRIGGER FOR PSEUDOEXFOLIATIVE GLAUCOMA

Glaucoma is one of the leading causes of blindness and disability worldwide. Pseudoexfoliative glaucoma is known to be the most aggressive and difficult-to-treat form of secondary glaucoma. According to the literature, pseudoexfoliative glaucoma occurs in 25-30% of cases among all open-angle glaucoma. The recent studies have established that a quarter of patients with pseudoexfoliative glaucoma are blind in one eye, and 7% are blind in both eyes. Risk factors for glaucoma include systemic and ophthalmic factors, one of which is the development of pseudoexfoliative syndrome. In patients with pseudoexfoliative syndrome, glaucoma occurs 20 times more often than in the general population of the same age. The purpose of this research is to study the informativeness of individual phenomena of pseudoexfoliative syndrome (PES) in order to improve early diagnosis and prevention of pseudoexfoliative glaucoma. The study included 114 patients diagnosed as having PES. Exclusion criteria were as follows: age up to 45 years, surgery on the eyeball, a history of disease (iridocyclitis, uveitis, corneal pathology, and traumatic eye disease), pigment dispersion syndrome. Along with the standard set of diagnostic measures, patients underwent biomicroscopy in the conditions of maximum drug-induced mydriasis, gonioscopic examination; the proportion of patients was examined by optical coherence tomography (SD-OCT Topson 3D oct-2000FA Plus (version 7/21/003/0)). The study revealed signs of pseudoexfoliative syndrome (deposition of pseudoexfoliative material on various structures of the anterior segment of the eye) in 100% of cases. Higher values of intraocular pressure (from 29 to 34 mm Hg) were found in the patients with elements of blocking the angle of the anterior chamber (narrowing or closing the angle, increased pigmentation and the presence of draining exfoliative conglomerates). The optical coherence tomography study revealed a thinning of the retinal nerve fibres (33.60 ± 0.43 μm), a significant thinning of retinal nerve fibre layer in patients with pseudoexfoliative syndrome and even more significant thinning in 29 patients diagnosed with pseudoexfoliative glaucoma. Thus, we can conclude knowing the microsymptoms of the disease, mandatory investigating the conditions of the maximum drug-induced mydriasis can contribute to detect pseudoexfoliative syndrome even in the initial stages and thus to prevent the development of pseudoexfoliative glaucoma.

Evaluation of Retinal Neurodegeneration and Choroidal Thickness in Patients with Inactive Graves' Ophthalmopathy.

The study was conducted for the assessment of the retinal nerve fiber layer, ganglion cell layer, and subfoveal choroidal thickness changes in patients with inactive Graves' ophthalmopathy (GO) using swept-source optical coherence tomography (SS-OCT) before the development of active GO findings. The cross-sectional designed study consisted of patients with inactive Graves' ophthalmopathy (study group) and healthy subjects (control group). The thicknesses of the retinal ganglion cell layer, retinal nerve fiber layer, and subfoveal choroid (SFCT) were measured using SS-OCT with deep range imaging technology to compare these parameters between the study and control groups. Patients with inactive Graves' ophthalmopathy had higher values of intraocular pressure but similar best-corrected visual acuity (p = 0.001, p = 0.232, respectively). The retinal nerve fiber layer was thinner only in the superior zone of the study group (p = 0.039), whereas similar values were noted in the temporal, nasal, and inferior areas as well as the average thickness. We did not observe any statistically significant difference in any sector of the ganglion cell layer between the study and control groups. A thicker mean subfoveal choroidal thickness value was measured in patients with inactive Graves' ophthalmopathy than in healthy subjects (p = 0.013) in correlation with a clinical activity score (p = 0.046). SS-OCT showed minimal retinal neurodegenerative alteration and significant choroidal thickening in inactive GO. Thus, SS-OCT might be a beneficial technique to detect retinal neurodegenerative and choroidal changes earlier in the stage of inactive GO before the development of active GO signs, which may affect the time and type of treatment modalities to prevent further ocular or systemic complications. Additionally, SFCT may be a good indicator for assessment of the severity of Graves' disease.

Intraocular pressure predicts premature coronary atherosclerosis.

The aim of this study was to investigate the association between intraocular pressure (IOP) and premature atherosclerotic coronary artery disease (PACAD) by comparing central corneal thicknesses (CCTs) measurements. One hundred-eighty-six subjects were enrolled in this cross-sectional study, 100 in the PACAD group and 86 in the control group. All participants underwent a physical examination and routine biochemical tests. Ophthalmological examinations, including IOP and CCTs measurements, were performed for each subject. Additionally, pulse wave velocity measurements were obtained and recorded. Participants with PACAD showed significantly higher IOP values than those without atherosclerosis (p = 0.001), and there was no statistically significant difference between the groups in terms of CCT (p = 0.343). Also, pulse wave velocity (PWV) values were statistically significantly higher in the PACAD group (p = 0.001). High IOP was not significantly associated with metabolic syndrome parameters (p > 0.05). A relationship was found between PACAD and IOP, but CCTs were not associated with PACAD. The IOP measurement is affected by CCT; therefore, CCT is used to correct IOP values. To our knowledge, this is the first study to report a positive relationship between PACAD and IOP based on CCTs measurements.

Analysis of Foveal and Parafoveal Microvascular Density and Retinal Vessel Caliber Alteration in Inactive Graves' Ophthalmopathy.

Purpose We aimed to evaluate foveal and parafoveal density using optical coherence tomography angiography and the alteration on the retinal vessel diameter in patients with inactive Graves' ophthalmopathy compared to age-matched normal population. Materials and Methods. Patients with inactive Graves' ophthalmopathy (study group) and healthy individuals (control group) were enrolled in the cross sectionally designed study. The optical coherence tomography angiography parameters and retinal vessel diameter measurements were assessed between the study and control groups. Foveal and parafoveal microvascular density in the retina was measured using optical coherence tomography angiography. Retinal artery and vein diameter and artery/vein ratio were assessed for retinal vessel caliber changes. Results Patients with inactive Graves' ophthalmopathy had higher values of intraocular pressure, proptosis, and axial length (P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, P=0.001, Conclusion Optical coherence tomography angiography could be a novel and promising noninvasive diagnostic technique in patients with inactive Graves' ophthalmopathy to detect foveal and parafoveal vessel density changes compared to healthy subjects. The decrease of retinal vessel diameter might be observed in patients with inactive graves ophthalmopathy.

Central Retinal Vessel Trunk Caliber Changes After Short-term Intraocular Pressure Elevation.

After a short-term intraocular pressure (IOP) elevation, the central retinal vein caliber may be widened at lower IOP rise levels, while be compressed at higher IOP rise values. The purpose of this study was to investigate changes in the calibers of the central retinal vein trunk (CRVT) and central retinal artery trunk (CRAT) trunk during a short-term elevation of IOP. A prospective observational study. Acute primary angle-closure suspects underwent a dark room prone provocative test (DRPPT) for 2 hours. Before and at the end of the test, tonometry, swept-source optical coherence tomography, and nonmydriatic fundus photography were performed. The calibers of the CRVT and CRAT were measured on the fundus photos taken at baseline and at the end of the DRPPT. The study included 101 eyes (61 individuals; mean age: 54.8±9.3 y; range: 30 to 70 y) which showed an increase in IOP by 9.6±9.0 mm Hg (range: 2.3 to 46.7 mm Hg). From baseline to the end of the DRPPT, the mean CRVT caliber increased from 101.8±25.9 to 107.7±26.6 μm (P<0.001), while the CRAT caliber did not differ significantly (110.3±24.2 vs. 109.7±21.5 μm; P=0.54) during the test. The CRVT widening was larger in the subgroup with IOP rise of <6 mm Hg than in the subgroup with an IOP rise of 6 to 15 mm Hg, while in the subgroup with an IOP rise of >15 mm Hg the CRVT caliber did not change significantly (P=0.20) during the test. A physiological short-term IOP rise at lower levels of IOP elevation led to a widening of the CRVT, while at higher IOP values, the further IOP-rise may have compressed the retinal vein. Because of higher intraluminal pressure values, the retinal artery diameters were not affected by the IOP-rise.

GLAUCOMA PROGRESSION. IMPACT OF RISK FACTORS ON THE DISEASE

The aim of the study is to assess the effect of systemic and local risk factors on the rate of glaucoma progression, the specificity and informative nature of ophthalmological studies for assessment of the rate of glaucoma progression. Material and methods . A retrospective analysis of the medical case histories and outpatient charts of 217 patients (268 eyes) for the period from 2014 to 2017 was conducted. The patients with primary open-angle glaucoma having at least 5 Humphrey field-of-view (24-2) studies and optic coherence tomography of the optic nerve disk and retina with a guided progression analysis (GPA) function (SD-OCT) were included in the study. The patients were divided into 2 groups: with rapid progression (more than 1 dB per year, 144 eyes (103 patients)) and slow progression (less than 1 dB per year, 124 eyes (114 patients)). The data of standard ophthalmological methods of investigation (visometry, ophthalmoscopy, biomicroscopy, measurement of intraocular pressure (IOP) according to Maklakov) were additionally analyzed. Demographic and clinical data were assessed: gender, age, cornea central thickness, refraction, IOP, glucocorticosteroid intake, cardiovascular diseases presence, arterial hypertension, arterial hypotension, local hypotensive therapy. Results and discussion. The analysis revealed the main risk factors in glaucoma progression, which include age, cardiovascular diseases presence, high initial IOP values, pronounced functional changes in the visual fields (lower mean deviation), pseudoexfoliation syndrome.

Analysis of reproducibility, evaluation, and preference of the new iC100 rebound tonometer versus iCare PRO and Perkins portable applanation tonometry.

To analyze the reproducibility of the new iC100 rebound tonometer, to compare its results with the applanation tonometry and iCare PRO and to evaluate the preference between them. For the study of reproducibility, 15 eyes of 15 healthy Caucasian subjects were included. Three measurements were taken each day in three separate sessions. For the comparative study, 150 eyes of 150 Caucasian subjects were included (75 normal subjects and 75 patients with glaucoma). Three consecutive measurements were collected with each tonometer, randomizing the order of use. The discomfort caused by each tonometer was evaluated using the visual analogue scale. No statistically significant differences were detected between sessions. In the comparison between tonometers, the measurements with iC100 were statistically lower than those of Perkins (-1.35 ± 0.417, p = 0.004) and that iCare PRO (-1.41 ± 0.417, p = 0.002). The difference between PRO and Perkins was not statistically significant (p = 0.990). The mean time of measurement (in seconds) with iC100 was significantly lower than with Perkins (6.74 ± 1.46 vs 15.53 ± 2.01, p < 0.001) and that PRO (6.74 ± 1.46 vs 11.53 ± 1.85, p < 0.001). Visual analogue scale score with iC100 was lower than Perkins (1.33 ± 0.99 vs 1.73 ± 1.10, p < 0.05). In total, 61.7% preferred iC100 against Perkins. The reproducibility of this instrument has been proven good. iC100 underestimates intraocular pressure compared to applanation tonometry at normal values and tends to overestimate it in high intraocular pressure values. Most of the subjects preferred iC100 tonometer.

Intraocular Pressure-dependent Corneal Elasticity Measurement Using High-frequency Ultrasound.

Measurement of corneal biomechanical properties can aid in predicting corneal responses to diseases and surgeries. For delineation of spatially resolved distribution of corneal elasticity, high-resolution elastography system is required. In this study, we demonstrate a high-resolution elastography system using high-frequency ultrasound for ex-vivo measurement of intraocular pressure (IOP)-dependent corneal wave speed. Tone bursts of 500 Hz vibrations were generated on the corneal surface using an electromagnetic shaker. A 35-MHz single-element transducer was used to track the resulting anti-symmetrical Lamb wave in the cornea. We acquired spatially resolved wave speed images of the cornea at IOPs of 7, 11, 15, 18, 22, and 29 mmHg. The IOP dependence of corneal wave speed is apparent from these images. Statistical analysis of measured wave speed as a function of IOP revealed a linear relation between wave speed and IOP cs = 0.37 + 0.22 × IOP, with the coefficient of determination R2 = 0.86. We also observed depth-dependent variations of wave speed in the cornea, decreasing from anterior toward posterior. This depth dependence is more pronounced at higher IOP values. This study demonstrates the potential of high-frequency ultrasound elastography in the characterization of spatially resolved corneal biomechanical properties.

Influence of the breathing pattern during resistance training on intraocular pressure

This study aimed to assess the effect of the breathing pattern during resistance training on intraocular pressure (IOP). Twenty physically active collegiate students (7 women and 13 men) performed sets of 10 repetitions against the 10-RM (repetition maximum) load during the back-squat and biceps-curl exercises following 3 different breathing patterns: (I) Valsalva: holding the breath during the entire repetition; (II) normal breathing: holding the breath and exhaling during the first and second phases of the repetition, respectively; and (III) modified breathing: inhaling and holding the breath during the first and second phases of the repetition, respectively. Rebound tonometry was used to measure IOP before exercise, after each of the 10 repetitions, and after 1 min of recovery. The breathing pattern significantly affected the changes in IOP values (p < 0.001, = 0.509) with the normal breathing pattern providing lower increases in IOP values compared to the Valsalva (p < 0.001, d = 1.47) and modified breathing (p < 0.001, d = 0.96). Higher IOP values were observed for the back-squat compared to the biceps-curl exercise (p = 0.003, = 0.384). A normal breathing pattern should be recommended to avoid abrupt increments in IOP during resistance training. These findings may be especially important for individuals at high risk for glaucoma onset or progression due to the necessity of maintaining stable IOP levels to avoid the progression of this disease. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings.

INTRAOCULAR PRESSURE CHANGES AFTER UNEVENTFUL PHACOEMULSIFICATION IN EARLY POSTOPERATIVE PERIOD IN HEALTHY EYES.

SUMMARYThe aim was to determine early changes in intraocular pressure (IOP) following uneventful phacoemulsification and intraocular lens (IOL) implantation in healthy eyes. This prospective interventional case series study was conducted at Ophthalmology Department, Kragujevac Clinical Centre, Kragujevac, Serbia. The study included 123 eyes of 123 cataract patients, 66 women and 57 men, age range 50-88 (mean 70.73±7.94) years having undergone phacoemulsification and in-the-bag implantation of a foldable IOL. The patients were treated at Kragujevac Clinical Centre between June 2015 and May 2016. IOP was measured by Goldmann applanation tonometry preoperatively, then 4-6 hours, 18-24 hours and 7 days postoperatively by the same examiner. The mean IOP preoperatively was 15.10±2.68 mm Hg. In three patients, maximum measured IOP was 22 mm Hg. At 4-6 hours postoperatively, the mean IOP was 24.29±7.56 mm Hg (p<0.001), at 18-24 hours it was 18.37±4.80 mm Hg (p<0.001), and 7 days after the surgery the mean IOP was 16.24±2.90 mm Hg (p<0.05). The measured IOP values were statistically significant in all measured times. However, at 4-6 hours and 18-24 hours, the mean IOP value was highly statistically significant (p<0.001). Although 7 days after the surgery IOP normalized, the mean IOP value was statistically significant (p<0.05). In conclusion, our research showed that even eyes with normal preoperative values and uncomplicated phacoemulsification course can show very high IOP values postoperatively, which can cause pain, blurred vision and, rarely, compromise visual function.

Effect of the level of effort during resistance training on intraocular pressure

Background: We aimed to evaluate the influence of the level of effort during four basic resistance exercises leading to muscular failure on intraocular pressure (IOP) and ocular perfusion (OPP), as well as the role of exercise type and sex. Methods: Twenty-five young adults (12 women) performed 10 repetitions against their 10-RM (repetition maximum) load in the squat, military press, biceps curl and calf raise exercises. IOP was measured before, during and after exercise, whereas OPP was indirectly assessed before and after each exercise. Results: There was a progressive IOP rise during exercise (p < 0.001, η² = 0.531), which was dependent on exercise type (p = 0.020, η² = 0.125). The squat exercise induced higher IOP increments in comparison to the other exercises (corrected p-values < 0.001), and higher IOP values were found for the military press and biceps curl than for the calf raise exercise (corrected p-values = 0.012 and 0.002). OPP exhibited a significant reduction when leading to muscular failure (p = 0.001, η² = 0.364), being statistically significant for the squat and military press exercises (corrected p-values = 0.037 and 0.047). No effect of sex was found for IOP and OPP (p > 0.05). Conclusions: A single set of resistance training leading to muscular failure causes an instantaneous and progressive IOP rise in healthy young individuals. These IOP rises depend on exercise type (squat > military press = biceps curl > calf raise), but not on participant´s sex. OPP diminished as a consequence of performing resistance training exercise, being statistically significant for the squat and military press exercises. Future studies should include glaucoma patients aiming to corroborate the generalizability of our findings.