Canaloplasty in the Treatment of Open-Angle Glaucoma: A Review of Patient Selection and Outcomes.

Canaloplasty is a relatively new non-penetrating surgery for the reduction of intraocular pressure in patients affected by glaucoma. The technique uses a microcatheter to perform a 360 º cannulation of Schlemm's canal and leaves in place a tension suture providing an inward distension. It aims to restore the physiological outflow pathways of the aqueous humour and is independent of external wound healing. Several studies have shown that canaloplasty is effective in reducing intraocular pressure and has a low rate of complications, especially compared with trabeculectomy, the gold standard for glaucoma surgery. Currently, canaloplasty is indicated in patients with open-angle glaucoma, having a mild to moderate disease, and the combination with cataract phacoemulsification may provide further intraocular pressure reduction. This article reviews canaloplasty indications, results and complications and analyses its outcomes compared with traditional penetrating and non-penetrating techniques

Intraocular Pressure in Pregnant and Non-Pregnant Nigerian Women

A number of hormones are known to affect intraocular pressure. Of these, the female sex hormones are the predominant ones to cause variations in intraocular pressure. The aim of this study was to determine if variation in sex hormones in pregnancy affects intraocular pressure. This study was a longitudinal one. 117 pregnant women aged 20 to 35 years in their first trimester of pregnancy were followed longitudinally throughout the course of pregnancy, and six weeks post partum. One hundred non pregnant women with a regular menstrual cycle of 26-29 days were also recruited and examined for changes in intraocular pressure. Intraocular pressure was measured with the handheld Kowa applanation tonometer. Mean Intraocular Pressure (MIOP) was 14.7 ± 2.2 mmHg, 13.2 ± 2.0 mmHg and 11.0 ± 1.3 mmHg in the three trimesters respectively. There was thus a fall in Intraocular Pressure during pregnancy and this was highly statistically significant (P<0.0001). At 6 weeks postpartum MIOP increased to 14.2 ± 1.8 mmHg. The difference between the mean values of Intraocular Pressure in the third trimester and 6 weeks postpartum was also statistically significant P<0.0001. Intraocular pressure decreased as pregnancy advanced. Postpartum, there was increase in intraocular pressure to near pre pregnant level. The difference in mean IOP between the pregnant and non pregnant women was statistically significant (P<0.05)

Influence of gross saponins from tribulus terrestris L on SOD activity and MDA content for chronic high intraocular pressure in rabbit

AIM:To observe influence of gross saponins from tribulus terrestris L(GSTT)on SOD activity and MDA content for chronic high intraocular pressure in rabbit, and discusses the retina oxidative damage inhibition on chronic high intraocular pressure model of rabbit. METHODS:Totally 24 healthy New Zealand rabbits were randomly divided into 4 groups: normal control group(A group); high intraocular pressure model blank group(B group); high intraocular pressure model with GSTT treated group(C group); high intraocular pressure model with Erigeron brevicapas hand mass(EBHM)treated group(D group). High intraocular pressure model was induced by 20g/L methylcellulose injection into the anterior chamber in B group, C group and D group. D group was injected 5 mg/kg GSTT and C group was injected 4.5mg/kg EBHM and measured intraocular pressure with Schiotz tonometer every day for 4 weeks. The retina tissue superoxide dismutase(SOD)and maleic dialdehyde(MDA)content were detected 28 days later. RESULTS: After glaucoma model of rabbit eyes were established, the intraocular pressure during observation period was maintained in 32-39mmHg; High intraocular pressure model blank group and normal control group, EBHM treatment group, GSTT treatment group were compared, the differences of retina MDA, SOD content had statistical significance(P<0.05); numerical difference between EBHM treatment group and GSTT group was not statistically significant(P>0.05); EBHM treatment group, GSTT treatment group and normal control group were compared, the content of MDA in the retina was still slightly higher(P<0.05), the content of SOD slightly lower(P<0.05) CONCLUSION: GSTT can effectively improve the retina SOD activity of chronic high intraocular pressure in rabbit and reduce the content of MDA, which has a protective effect of persistent high intraocular retinal oxidative stress

Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility

Glaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, which binds to CACNA2D1 protein and lowers intraocular pressure significantly. Because our study utilizes a genetically diverse population of mice with kno

A cohort study of duplex Doppler examinations of the carotid artery in primary open angle glaucoma

Objectives To explore the possibility of pathological change in the common carotid artery at the bifurcation and in the internal carotid artery beyond the bifurcation which could contribute to a reduced diastolic pressure as observed in primary open angle glaucoma. Design Duplex ultrasonic examinations of carotid bifurcations were conducted on 80 patients. Carotid artery defects were allocated into three types: no demonstrable flow defects, internal carotid artery abnormalities and disease in the carotid bulb. Setting Bristol Royal Infirmary Vascular Laboratory. Participants Eighty patients (mean age 69.6 years) providing a total of 160 sides to the analysis. Main outcome measures An estimated central retinal artery pressure, intraocular pressure and field loss were recorded for each side measured. Results Doppler investigations revealed significant levels of pathological change in the internal carotid distinct from changes at the carotid bulb. The disease revealed in the internal carotid artery was significantly associated with intraocular pressure (p = 0.032), with an effect small to medium in magnitude. The Q2 measure, derived from mean arterial pressure and intraocular pressure, was also substantively associated with disease in the internal carotid artery. Both intraocular pressure and the Q2 measure effectively discriminated between groups, with field loss providing rather less discriminating capability. There was a strong trend towards a higher intraocular pressures and a greater visual field loss with internal carotid artery disease. Conclusions Pathological changes in the extra cranial carotid artery in primary open angle glaucoma exceed those in the arteries classified as normal. The presence of disease specifically in the internal carotid artery emphasised the need for a mechanism for the evaluation of the internal carotid apart from the carotid bulb. A basis for clarifying the presence of an ischaemic zone is proposed

System, Device, and Method for Determination of Intraocular Pressure

A system for determination of intraocular pressure includes: an intraocular pressure sensor; a light source illuminating the sensor with one or more wavelengths of light; and a detector that measures emitted light from the sensor. The sensor includes a substrate member, a spacer member, and a flexible membrane, which define a sealed cavity. The flexible membrane moves in response to intraocular pressure changes. A device for measuring intraocular pressure includes: the sensor; an anchoring member attached to the sensor for immobilizing the sensor in an eye; and a protective member attached to the anchoring member and covering the sensor to prevent contact between the flexible membrane and the eye. A method for determination of intraocular pressure includes: placing the sensor in an eye; illuminating, with a light source, the sensor with one or more wavelengths of light; and detecting, with a detector, a resultant light that contains information about intraocular pressure

Intraocular pressure in a clinical population: a retrospective study

A retrospective study was carried out to determine the distribution of intraocular pressure in normal patients who came for vision problems at the Optometry Clinic, Universiti Kebangsaan Malaysia (UKM) Kuala Lumpur Campus, and to determine the differences in intraocular pressure with respect to age, gender and race. The cohort consisted of 148 subjects divided into five groups with age ranged from 10 to 59 years. The inclusion criteria were, subjects had no sistemic or ocular disease, subjects were not taking any medication, visual acuity was 6/6 or better, refractive errors < ±6.00D, astigmatism < 2.00D, anisometropia <2.00D, and mean intraocular pressure measured using the X-PERT tonometer and taken between 9 am to 2 pm. Statistical analysis (ANOVA) showed the mean intraocular pressure without consideration for age, race or gender was 12.6 mmHg (SD ±2.5). There was no significant differences in intraocular pressure between right and left eyes, between different age groups and between different genders. However, the intraocular pressuse for the Chinese was found to be significantly higher than the Malays. It was found that the intraocular pressure of patients who came for vision problems at the Optometry Clinic UKM follows a normal distribution and there was no significant diference found between right and left eyes, between different age groups and genders. Race seemed to contribute to the differences in intraocular pressure

The influence of retrobulbar adipose tissue volume upon intraocular pressure in obesity

Background/Aim. It is known that glaucoma is associated with elevated intraocular pressure and obesity, yet the precise etiology remains unclear. The aim of this study was to determine whether there is a potential causality between the volume of retrobulbar adipose tissue and the level of intraocular pressure in obese subjects compared with non-obese. Methods. A total of 100 subjects were divided according to the body mass index (BMI), into two groups: normal weight (n = 50, BMI = 18-24.9 kg/m2) and obese (n = 50, BMI ≥ 30 kg/m2) subjects. Anthropometric measurements, body composition analysis, measurement of intraocular pressure, as well as magnetic resonance imaging (MRI) of the head at the level of the optic nerve, and the derived retrobulbar adipose tissue volume, were undertaken in all subjects. Results. The obese subjects, as compared with normal weight ones, had a significantly higher mean retrobulbar adipose tissue volume (6.23 cm3 vs 4.85 cm3, p < 0.01) and intraocular pressure (15.96 mmHg vs 12.99 mmHg, p < 0.01). Furthermore, intraocular pressure correlated positively with retrobulbar adipose tissue volume. Conclusion. In obese people, elevated intraocular pressure may be caused by changes in ocular blood flow, affected by the physical pressure exerted by higher retrobulbar adiposity, and/or by internal vascular changes secondary to complications of obesity. These findings indicate the need for more frequent measurement of intraocular pressure in obese individuals to earlier detect glaucoma, and in so doing prevent irreversible blindness

The intraocular pressure response to dehydration: a pilot study

This study was designed to determine the Intraocular Pressure (IOP) response to differing levels of dehydration. Seven males participated in a 90 minute treadmill walk (5 km/h and 1 % grade) in both a cool (22 °C) and hot (43 °C) climate. At Baseline and at 30 minute intervals measurements of IOP, by tonometery, and indicators of hydration status (nude weight and plasma osmolality (Posm)) were taken. Body temperature and heart rate were also measured at these time points. Statistically significant interactions (time point (4) by trial (2)) were observed for IOP (F = 10.747, p = 0.009) and body weight loss (F = 50.083, p < 0.001) to decrease, and Posm (F = 34.867, p < 0.001) to increase, by a significantly greater amount during the hot trial compared to the cool. A univariate general linear model showed a significant relationship between IOP and body weight loss (F = 37.63, p < 0.001) and Posm (F = 38.53, p < 0.001). A significant interaction was observed for body temperature (F = 20.908, p < 0.001) and heart rate (F = 25.487, p < 0.001) between the trials and time points, but there was negligible association between these variables and IOP (Pearson correlation coefficient < ±0.5). The present study provides evidence to suggest that IOP is influenced by hydration status