Association of intraocular pressure with the metabolic syndrome and novel cardiometabolic risk factors

Prevalence of Ocular Hypertension and Other Risk Factors of Open-Angle Glaucoma Among Middle-Aged Adults in Al-Baha City, Saudi Arabia

Background Ocular hypertension (OHT), defined by elevated intraocular pressure (IOP) beyond standard levels, is a predominant risk factor for initiating and exacerbating glaucoma, a collection of progressive optic neuropathies responsible for irreversible vision loss. Given the profound implications for vision care, it is imperative to elucidate the interplay between OHT and glaucoma for effective clinical management. Objective The present study aims to measure IOP levels and identify risk factors associated with glaucoma among middle-aged individuals in Al-Baha City, Saudi Arabia. Methods A cross-sectional study was conducted over a six-month span (January-June 2022) in Al-Baha City. The study cohort comprised adults aged 35 and above attending a glaucoma awareness campaign at King Fahad Hospital, Al-Baha. Parameters such as demographics, socioeconomic status, medical and ocular history, and familial history of eye diseases were collated. Initial ophthalmologic assessments and IOP measurements were performed. Statistical analyses utilized Pearson's Chi-square test for nominal variables. Results The study encompassed 111 participants, 84 (75.7%) of whom were male, and 75 (67.6%) were of Saudi nationality. Notably, 102 (91.9%) reported no family history of glaucoma, 91 (81.1%) indicated no past medical history and 81 (73.0%) were not on any chronic medications. The mean IOP for participants' right and left eyes fluctuated between 18.2-21.5 mmHg and 18.9-22.1 mmHg, respectively. Factors such as age, gender, family history of glaucoma, past medical history, use of chronic medications, and history of ophthalmic surgeries demonstrated a statistically significant correlation with IOP (p<0.05). Conclusion This study highlights a higher prevalence of OHT in females, with several risk factors for OHT and glaucoma identified, such as familial history, vascular diseases, diabetes mellitus, and chronic medication use. Notably, our study did not observe a significant association with age or smoking. These findings emphasize the necessity of regular eye examinations and IOP monitoring, especially in high-risk groups.

Identification of the novel role of sterol regulatory element binding proteins (SREBPs) in mechanotransduction and intraocular pressure regulation

Trabecular meshwork (TM) cells are contractile and mechanosensitive, and they aid in maintaining intraocular pressure (IOP) homeostasis. Lipids are attributed to modulating TM contractility, with poor mechanistic understanding. In this study using human TM cells, we identify the mechanosensing role of the transcription factors sterol regulatory element binding proteins (SREBPs) involved in lipogenesis. By constitutively activating SREBPs and pharmacologically inactivating SREBPs, we have mechanistically deciphered the attributes of SREBPs in regulating the contractile properties of TM. The pharmacological inhibition of SREBPs by fatostatin and molecular inactivation of SREBPs ex vivo and in vivo, respectively, results in significant IOP lowering. As a proof of concept, fatostatin significantly decreased the SREBPs responsive genes and enzymes involved in lipogenic pathways as well as the levels of the phospholipid, cholesterol, and triglyceride. Further, we show that fatostatin mitigated actin polymerization machinery and stabilization, and decreased ECM synthesis and secretion. We thus postulate that lowering lipogenesis in the TM outflow pathway can hold the key to lowering IOP by modifying the TM biomechanics.

Metabolic Health, Obesity, and Intraocular Pressure

Obesity has been associated with increased intraocular pressure (IOP), but the results are inconsistent. Recently, a subgroup of obese individuals with good metabolic profiles were suggested to have better clinical outcomes than normal-weight individuals with metabolic diseases. The relationships between IOP and different combinations of obesity and metabolic health status have not been investigated. Therefore, we investigated the IOP among groups with different combinations of obesity status and metabolic health status. We examined 20,385 adults aged 19 to 85 years at the Health Promotion Center of Seoul St. Mary's Hospital between May 2015 and April 2016. Individuals were categorized into four groups according to obesity (body mass index (BMI) ≥ 25 kg/m²) and metabolic health status (defined based on prior medical history or abdominal obesity, dyslipidemia, low high-density lipoprotein cholesterol, high blood pressure, or high fasting blood glucose levels upon medical examination). ANOVA and ANCOVA were performed to compare the IOP among the subgroups. The IOP of the metabolically unhealthy obese group (14.38 ± 0.06 mmHg) was the highest, followed by that of the metabolically unhealthy normal-weight group (MUNW, 14.22 ± 0.08 mmHg), then, the metabolically healthy groups (p < 0.001; 13.50 ± 0.05 mmHg and 13.06 ± 0.03 mmHg in the metabolically healthy obese (MHO) and metabolically healthy normal-weight groups, respectively). Subjects who were metabolically unhealthy showed higher IOP compared to their counterparts who were metabolically healthy at all BMI levels, and there was a linear increase in IOP as the number of metabolic disease components increased, but no difference between normal-weight vs. obese individuals. While obesity, metabolic health status, and each component of metabolic disease were associated with higher IOP, those who were MUNW showed higher IOP than those who were MHO, which indicates that metabolic status has a greater impact than obesity on IOP.

The Association Between Age and Systemic Variables and the Longitudinal Trend of Intraocular Pressure in a Large-Scale Health Examination Cohort

Purpose

The detailed effects of age and systemic factors on intraocular pressure (IOP) have not been fully understood because of the lack of a large-scale longitudinal investigation. This study aimed to investigate the effect of various systemic factors on the longitudinal change of IOP.

Methods

There were a total of 20,909 eyes of 10,471 subjects from a health checkup cohort that were followed up for systemic factors: (i) age at baseline, (ii) sex, (iii) time series body mass index (BMI), (iv) time series smoking habits, (v) time series systolic and diastolic blood pressures (SBP and DBP), and (vi) time series 19 blood examinations (all of the time series data was acquired at each annual visit), along with IOP annually for at least 8 years. Then the longitudinal effect of the systemic factors on the change of IOP was investigated.

Results

IOP significantly decreased by −0.084 mm Hg/year. BMI, SBP, DBP, smoking habits, total triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and glycosylated hemoglobin A1c were not significantly associated with the change of IOP. Higher values of age, aspartate aminotransferase, hemoglobin, platelet, and calcium were suggested to be significantly associated with the decrease of IOP, whereas higher alanine aminotransferase, guanosine triphosphate, white blood cell count, red blood cell count, and female gender were significantly associated with the increase of IOP.

Conclusions

Age, aspartate aminotransferase, hemoglobin, platelet, calcium, alanine aminotransferase, guanosine triphosphate, white blood cell count, red blood cell count, and gender were the systemic variables significantly associated with the change of IOP.

The Association between Serum Lipids and Intraocular Pressure in 2 Large United Kingdom Cohorts

PURPOSE

Serum lipids are modifiable, routinely collected blood test features associated with cardiovascular health. We examined the association of commonly collected serum lipid measures (total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and triglycerides) with intraocular pressure (IOP).

DESIGN

Cross-sectional study in the UK Biobank and European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk cohorts.

PARTICIPANTS

We included 94 323 participants from the UK Biobank (mean age, 57 years) and 6230 participants from the EPIC-Norfolk (mean age, 68 years) cohorts with data on TC, HDL-C, LDL-C, and triglycerides collected between 2006 and 2009.

METHODS

Multivariate linear regression adjusting for demographic, lifestyle, anthropometric, medical, and ophthalmic covariables was used to examine the associations of serum lipids with corneal-compensated IOP (IOPcc).

MAIN OUTCOME MEASURES

Corneal-compensated IOP.

RESULTS

Higher levels of TC, HDL-C, and LDL-C were associated independently with higher IOPcc in both cohorts after adjustment for key demographic, medical, and lifestyle factors. For each 1-standard deviation increase in TC, HDL-C, and LDL-C, IOPcc was higher by 0.09 mmHg (95% confidence interval [CI], 0.06-0.11 mmHg; P < 0.001), 0.11 mmHg (95% CI, 0.08-0.13 mmHg; P < 0.001), and 0.07 mmHg (95% CI, 0.05-0.09 mmHg; P < 0.001), respectively, in the UK Biobank cohort. In the EPIC-Norfolk cohort, each 1-standard deviation increase in TC, HDL-C, and LDL-C was associated with a higher IOPcc by 0.19 mmHg (95% CI, 0.07-0.31 mmHg; P = 0.001), 0.14 mmHg (95% CI, 0.03-0.25 mmHg; P = 0.016), and 0.17 mmHg (95% CI, 0.06-0.29 mmHg; P = 0.003). An inverse association between triglyceride levels and IOP in the UK Biobank (-0.05 mmHg; 95% CI, -0.08 to -0.03; P < 0.001) was not replicated in the EPIC-Norfolk cohort (P = 0.30).

CONCLUSIONS

Our findings suggest that serum TC, HDL-C, and LDL-C are associated positively with IOP in 2 United Kingdom cohorts and that triglyceride levels may be associated negatively. Future research is required to assess whether these associations are causal in nature.

Association of Metabolic Syndrome With Glaucoma and Ocular Hypertension in a Midwest United States Population

PRCIS

For patients with glaucoma, metabolic syndrome was associated with higher intraocular pressure and greater central corneal thickness. Patients with metabolic syndrome were more likely to have ocular hypertension.

PURPOSE

The purpose of this study was to determine whether glaucomatous optic neuropathy, also known as glaucoma, and ocular hypertension are more likely to occur in patients with metabolic syndrome.

PATIENTS AND METHODS

Patients in Olmsted County, MN, were identified as having metabolic syndrome based on diagnosis codes, laboratory values, and/or medication use to meet 3 or more of the 5 standard criteria for diagnosing metabolic syndrome: systemic hypertension, hyperglycemia, hypertriglyceridemia, reduced high-density lipoprotein cholesterol, and central adiposity defined by increased body mass index. Patients with glaucoma, including primary open angle, low tension, pigment dispersion, and pseudoexfoliation, were identified using diagnostic codes. The charts of patients with glaucoma were individually reviewed to collect visual acuity, intraocular pressure, cup to disc ratio, central corneal thickness, visual field mean deviation, retinal nerve fiber layer thickness, and treatment of intraocular pressure. Patients with ocular hypertension were separately identified and similarly evaluated.

RESULTS

For patients with glaucoma, those with metabolic syndrome had higher intraocular pressure and greater central corneal thickness compared with those without metabolic syndrome. After adjustment for central corneal thickness, there was no longer a significant difference in intraocular pressure between groups. Metabolic syndrome was also associated with the diagnosis of ocular hypertension, and although central corneal thickness trended higher in patients with metabolic syndrome, it did not attain statistical significance.

CONCLUSION

In Olmsted County, though metabolic syndrome was associated with ocular hypertension and higher intraocular pressure in patients with glaucoma, the results were likely related to a thicker central corneal in this patient population.

Ankle-brachial index and ocular diseases in a Russian population

Background

To assess potential associations between the ankle-brachial blood pressure index (ABI) and ocular disorders.

Methods

In the population-based cross-sectional Russian Ural Eye and Medical Study including 5,899 (80.5%) out of 7328 eligible participants aged 40+ years, the participants underwent a series of ocular and medical examinations including measurement of ABI.

Results

Blood pressure measurements of both arms and ankles were available for 3187 (54.0%) individuals. The mean ABI was 1.26 ± 0.19 (median:1.20; range: 0.61, 2.20). In multivariate analysis, a higher ABI was associated with younger age (P < 0.001; non-standardized regression coefficient B: −0.001; 95% confidence interval (CI): −0.002, −0.001), female sex (P < 0.001; B: 0.03; 95% CI: 0.02, 0.04), lower body mass index (P < 0.001; B: −0.004; 95% CI: −0.006, −0.003), lower waist-to-hip ratio (P = 0.01; B: −0.10; 95% CI: −0.17, −0.02), lower glucose serum concentration (P = 0.008; B: −0.005; 95% CI: −0.009, −0.001), lower prevalence of arterial hypertension (P < 0.001; B: −0.14; 95% CI: −0.16, −0.12), higher mean systolic blood pressure (P < 0.001; B: 0.003; 95% CI: 0.002, 0.003), and higher prevalence of any alcohol consumption (P < 0.001; B: 0.03; 95% CI: 0.02, 0.04). In that multivariate model, prevalence of glaucoma (P = 0.67) as a whole, open-angle glaucoma (P = 0.86) and angle-closure glaucoma (P = 0.54), stage of glaucomatous optic neuropathy (P = 0.57), prevalence of age-related macular degeneration (P = 0.88), prevalence and stage of diabetic retinopathy (P = 0.30, and P = 0.29, respectively), nuclear cataract (P = 0.32, and P = 0.41, resp.), cortical cataract (P = 0.33, and P = 0.92, resp.), subcapsular cataract (P = 0.74 and P = 0.60, resp.), and pseudoexfoliation (P = 0.44 and P = 0.47, resp.), intraocular pressure (P = 0.52), axial length (P = 0.20), and peripapillary retinal nerve fibre layer thickness (P = 0.55) were not significantly associated with the ABI.

Conclusions

In this ethnically mixed population from Russia, none of the major ocular diseases was associated with ABI suggesting that subclinical atherosclerosis is not markedly associated with the aetiology of these ocular disorders.

Association of Hypertriglyceridemia and Incident Glaucoma in a Rural Chinese Population: The Handan Eye Study

Purpose

The purpose of this paper was to investigate the association between baseline metabolic risk factors and incident glaucoma over a 5-year period in rural Chinese adults.

Methods

Population-based prospective cohort study. Participants aged 30 years and older without glaucoma at baseline who underwent comprehensive examinations at baseline and after a 5-year interval in the Handan Eye Study were enrolled. Incident glaucoma was defined as people without glaucoma in either eye at baseline that had developed glaucoma in at least one eye in the 5-year follow-up. Five metabolic syndrome components, mean blood pressure, fasting plasma glucose, total cholesterol, triglycerides (TGs), low density lipoprotein cholesterol, high-density lipoprotein cholesterol, and obesity, determined as body mass index ≥30 kg/m2 at baseline were considered as potential metabolic risk factors for incident glaucoma. Univariate and multivariate logistic regression analyses were carried out to determine baseline metabolic risk factors associated with incident glaucoma.

Results

A total of 5184 participants were included in our study. During the 5-year follow-up, incident glaucoma developed in 82 subjects. Age (odds ratio [OR] = 1.060, 95% confidence interval [CI] = 1.034, 1.086, P < 0.001) and TGs level (OR = 1.213, 95% CI = 1.030, 1.429, P = 0.021) were independently and positively associated with incident glaucoma.

Conclusions

Our study revealed that increased age and high TGs level, one of the baseline metabolic features, were independent risk factors for incident glaucoma. The data implied that the metabolic features be involved in the pathogenesis of glaucoma.

Translational Relevance

This study shed the light on that the TGs level was involved in the pathogenesis of glaucoma.

Metabolic syndrome and the aging retina

PURPOSE OF REVIEW

This review explores metabolic syndrome (MetS) as a risk factor that accelerates aging in retinal neurons and may contribute to the neurodegeneration seen in glaucomatous optic neuropathy (GON) and age-related macular degeneration (AMD).

RECENT FINDINGS

Both animal model experiments and epidemiologic studies suggest that metabolic stress may lead to aberrant regulation of a number of cellular pathways that ultimately lead to premature aging of the cell, including those of a neuronal lineage.

SUMMARY

GON and AMD are each leading causes of irreversible blindness worldwide. Aging is a significant risk factor in the specific retinal neuron loss that is seen with each condition. Though aging at a cellular level is difficult to define, there are many mechanistic modifiers of aging. Metabolic-related stresses induce inflammation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, alterations to the unfolded protein response, defects in autophagy, alterations to the microbiome, and deposition of advanced glycation end products that can all hasten the aging process. Due to the number of variables related to metabolic health, defining criteria to enable the study of risk factors at a population level is challenging. MetS is a definable constellation of related metabolic risk factors that includes enlarged waist circumference, dyslipidemia, systemic hypertension, and hyperglycemia. MetS has been associated with both GON and AMD and may contribute to disease onset and/or progression in each disease.

Relationship between anthropometric and biochemical changes of metabolic syndrome with retinal nerve fiber layer and macular thickness

Objective

To evaluate the retinal nerve fiber layer (RNFL) and macular thicknesses and identify systemic risk factors for thinning of these layers in patients with metabolic syndrome (MetS).

Methodology

A cross-sectional observational study was performed on patients diagnosed with MetS and compared to normal controls. All patients underwent ophthalmic and anthropometric examination, serological and biochemical blood investigations; and ocular imaging using spectral-domain optical coherence tomography. Patients with ocular pathology were excluded. Unpaired t-test was used to compare mean thickness between the two groups. One-way ANOVA with Bonferroni correction for multiple comparisons was used to compare mean thickness between different tertiles of MetS parameters, and a generalized estimating equation was used to correct for inter-eye correlation and to assess association between mean thickness and covariates.

Results

Two hundred and forty-eight eyes from 124 participants (1:1 ratio of MetS patients to controls) were included. Age ranged between 30 to 50 years old, and mean age was 40 ± 6.6 years. RNFL thickness was lower globally (93.6 ± 9.9 μm vs 99.0 ± 9.3, p<0.001) and in the inferior (124.5 ± 17.5 μm vs 131.0 ± 16.4 μm, p = 0.002), superior (117.2 ± 16.0 μm vs 126.3 ± 14.4 μm, p<0.001) and temporal (65.5 ± 10.2 μm vs 69.5 ± 9.8, p = 0.002) sectors in MetS patients compared to controls. Only the central (237.0 ± 14.0 μm vs 243.6 ± 18.0 μm, p = 0.002) and inferior parafoveal (307.8 ± 20.9 vs 314.6 ± 14.6, p = 0.004) area of the macula was significantly thinner. The inferior RNFL sector had the most difference (mean difference = 9.1 μm). The Generalized Estimating Equation found that, after adjusting for age, diastolic blood pressure, BMI, HDL and obesity; the number of MetS components and elevated triglyceride levels were independent risk factors for reduced thickness in global RNFL (β = -4.4, 95% CI = -7.29 to -1.5, p = 0.003) and inferior parafovea (β = -6.85, 95% CI = -11.58 to -2.13, p = 0.004) thickness respectively.

Conclusion

RNFL thinning was seen more than macula thinning in MetS patients, suggesting RNFL susceptibility to neurodegeneration than the macula. A higher number of metabolic components and elevated triglyceride levels were independent risk factors for retinal thinning in this group of patients.

Predicting intraocular pressure using systemic variables or fundus photography with deep learning in a health examination cohort

The purpose of the current study was to predict intraocular pressure (IOP) using color fundus photography with a deep learning (DL) model, or, systemic variables with a multivariate linear regression model (MLM), along with least absolute shrinkage and selection operator regression (LASSO), support vector machine (SVM), and Random Forest: (RF). Training dataset included 3883 examinations from 3883 eyes of 1945 subjects and testing dataset 289 examinations from 289 eyes from 146 subjects. With the training dataset, MLM was constructed to predict IOP using 35 systemic variables and 25 blood measurements. A DL model was developed to predict IOP from color fundus photographs. The prediction accuracy of each model was evaluated through the absolute error and the marginal R-squared (mR2), using the testing dataset. The mean absolute error with MLM was 2.29 mmHg, which was significantly smaller than that with DL (2.70 dB). The mR2 with MLM was 0.15, whereas that with DL was 0.0066. The mean absolute error (between 2.24 and 2.30 mmHg) and mR2 (between 0.11 and 0.15) with LASSO, SVM and RF were similar to or poorer than MLM. A DL model to predict IOP using color fundus photography proved far less accurate than MLM using systemic variables.

Metabolic Syndrome Is Associated With Ocular Hypertension and Glaucoma

Glaucoma remains the world's leading cause of irreversible blindness and though intraocular pressure (IOP) is the most prevalent risk factor and only reliable therapeutic target, a number of systemic disease associations have been reported. Metabolic syndrome (MetS) is a constellation of findings that includes systemic hypertension, abdominal obesity, glucose intolerance, and dyslipidemia. MetS is becoming increasingly common worldwide, with prevalence up to 40% in some countries. Not only is MetS a significant cause of morbidity, but it is also associated with an increase in all-cause mortality. Reports have been conflicting regarding the association of individual components of MetS, including systemic hypertension and diabetes, with elevated IOP or glaucoma. However, though limitations in the existing literature are present, current evidence suggests that MetS is associated with IOP as well as glaucoma. Additional studies are needed to clarify this association by incorporating additional metrics including assessment of central corneal thickness as well as optic nerve structure and function. Future studies are also needed to determine whether lifestyle modification or systemic treatment of MetS could reduce the incidence or progression of glaucoma.

The Association of Intraocular Pressure With Obesity and Cardiometabolic Risk in a Young Farmworker Population

PRCIS

Intraocular pressure (IOP) was found to be significantly correlated with body mass index (BMI), waist circumference, and diastolic blood pressure (DBP) in a farmworker population located in the southeast Georgia, USA. BMI was correlated with IOP, independent of systemic blood pressures.

PURPOSE

Elevated IOP is a known risk factor for glaucomatous optic neuropathy and is believed to be associated with obesity and cardiometabolic diseases. The high prevalence of these conditions in the United States necessitates an evaluation of the relationship among obesity, cardiometabolic risks, and IOP among understudied younger populations.

MATERIALS AND METHODS

Farmworker data were collected from the annual Costa-Layman Health Fair between 2013 and 2017. Correlations of IOP with demographic factors, obesity, and cardiometabolic risks were analyzed using analysis of covariance, partial Pearson correlations, and linear regressions.

RESULTS

In the farmworker population (n=346), the mean IOP was 15.5 mm Hg and the prevalence of ocular hypertension (IOP>21 mm Hg) was 5.5%. BMI, waist circumference, and DBP were significantly correlated (r=0.192, P=0.001; r=0.128, P=0.017; r=0.142, P=0.007, respectively) with IOP when adjusted for age, sex, and ethnicity. Each 10 mm Hg increase in DBP corresponded with a 0.51 mm Hg increase in IOP. With adjustment for age, sex, ethnicity, systolic blood pressure, and DBP, BMI remained significantly correlated with IOP (r=0.166, P=0.002).

CONCLUSIONS

Higher IOP is associated with obesity measures including BMI and waist circumference and is correlated with DBP. These findings suggest that BMI is an independent risk factor for elevated IOP.

Ocular findings in metabolic syndrome: a review

Metabolic syndrome (MetS) has emerged as a worldwide health hazard of the modern lifestyle, representing a cluster of metabolic abnormalities and a risk factor for cardiovascular disease. Eye diseases, such as diabetic retinopathy, central retinal artery occlusion, cataract, age-related macular degeneration, glaucoma, and dry eye syndrome have been linked with many of MetS components. Their relationship with MetS itself is, however, a recent topic of investigation. This review aims to gather published evidence supporting associations between ocular findings and MetS and to explore the related physiopathological processes that congregate in this syndrome and lead to these diseases. Despite compiling interesting and compelling evidence, it raises awareness to the need of further studies in this field to keep solidifying these associations and unveiling the pathological processes that support them. It ultimately targets MetS patients as a population of individuals who are at increased risk of developing age-related eye diseases and vision loss.

Effects of French maritime pine bark/bilberry fruit extracts on intraocular pressure for primary open-angle glaucoma

We tested oral French maritime pine bark (40 mg)/bilberry fruit extract (90 mg) supplements for intraocular pressure-lowering effects in Japanese subjects with primary open-angle glaucoma. Eighteen subjects (29 eyes) were recruited with intraocular pressure of ≥15 mmHg who used one to three bottles of antiglaucoma medications. After a 2-week observation (period 1), subjects ingested a tablet/day of Sante^® Glagenox for 4 weeks (period 2). The mean intraocular pressure (17.2 ± 2.3 mmHg) decreased significantly to 15.7 ± 1.9 mmHg (8.7% reduction) at week 4 (p = 0.0046). The mean morning intraocular pressure (14.1 ± 3.1 mmHg) self-measured using the iCare HOME tonometer during period 1 decreased significantly to 13.3 ± 2.9 mmHg (5.7% reduction) during period 2 (p = 0.0291). Blood redox parameters, diacron reactive oxygen metabolites, biologic antioxidant potential, and sulfhydryl tests were unchanged after 4-week supplementation. Intra-subject comparisons, compared to period 1, showed pooled, self-measured, period-2 intraocular pressures was significantly lower in nine subjects (50%), unchanged in six subjects (33%), and elevated in three subjects (17%), suggesting some non-responders. Four-week supplementation with French maritime pine bark/bilberry fruit extracts can further reduce intraocular pressure even in Japanese patients with controlled primary open-angle glaucoma. Further study should confirm the intraocular pressure-lowering effects and mechanisms of this supplement in glaucoma management. The study was registered in UMIN (ID: UMIN000033200).

Systemic factors associated with intraocular pressure among subjects in a health examination program in Japan

Background

To elucidate the possible effect of various systemic factors on intraocular pressure (IOP) using a dataset from a health examination program database in Japan.

Methods

This cross-sectional study included 1569 subjects selected from the 2287 subjects who comprised the database. Various systemic parameters including age, sex, height, body weight, waist circumference, percent body fat, blood pressure (BP), pulse rate, body mass index, 28 blood examination values, intimal medial thicknesses of both carotid arteries, and intraocular pressure (IOP) values measured by non-contact tonometry in both eyes were collected. The possible correlation between the IOP and other parameters was assessed initially by univariate analyses followed by multivariate analyses.

Results

Stepwise multivariate analyses, which included all parameters extracted by the univariate analyses (p<0.1) and sex, identified the same six parameters as indicators of the IOP values for each right and left IOP model. Among the parameters, age (r = -0.05 and -0.04/year for right and left IOPs, respectively) was associated negatively and the percent body fat (r = 0.06 and 0.05/%), systolic BP (r = 0.02 and 0.03/mmHg), pulse rate (r = 0.03 and 0.03/counts/minutes), albumin (r = 1.12 and 1.00/g/dL), and hemoglobin A1c (r = 0.38 and 0.44/%) were associated positively with the IOP in each eye.

Conclusions

Older age was associated with low IOP, while factors reflecting the metabolic syndrome were associated with high IOP in our study population.

Examining the associations among intraocular pressure, hepatic steatosis, and anthropometric parameters

Emerging evidences had reported the positive relationship between obesity and intraocular pressure (IOP). The aim of the present study was to investigate the association between hepatic steatosis and IOP in an adult Taiwanese population.Seven thousand seven hundred twelve males and 6325 females who received a health examination at the Tri-Service General Hospital during the period from 2010 to 2016 were included in this study.IOP was measured by noncontact tonometry. Hepatic steatosis was diagnosed by abdominal ultrasound examination. Multivariate regression analyses were used to assess the associations among various anthropometric parameters and IOP.After adjusting for pertinent covariables, hepatic steatosis had a closer association with increased IOP than percentage body fat, body mass index, or waist circumference (β = 0.017, 95% confidence interval [CI] = 0.006, 0.028). This relationship remained significant among males in the study population (β = 0.015, 95% CI = 0.001, 0.029). Furthermore, hepatic steatosis was significantly correlated with increased risk of high IOP (odd ratios = 1.235, 95% CI = 1.041-1.465).Our study highlights that hepatic steatosis is a better index for assessing the relationship with increased IOP than other anthropometric parameters. Underlying pathophysiological mechanisms regulating the association between hepatic steatosis and increasing IOP and even the risk of glaucoma should be examined in further studies.

Gender Difference in Intraocular Pressure and Incidence of Metabolic Syndrome: A Community-Based Cohort Study in Matsu, Taiwan

Background: We aimed to assess the effect of intraocular pressure (IOP) on incident metabolic syndrome (MetS) using a longitudinal follow-up of screening cohort in contrast to most of previous studies addressing the association between both. Methods: The empirical data were derived from a community-based integrated screening program in Matsu during the period 2003 to 2010. A total of 1347 participants older than 30 years were enrolled in this study. With the enrollment of 1056 participants with MetS free at baseline, the cohort with IOP measurement in 2003 were followed up over time to identify incident MetS to elucidate the temporal sequence of both. Results: The statistically significant effect noted was that elevated IOP (≥15 mmHg vs. <15 mmHg) had 1.46-fold risk for developing incident MetS (adjusted relative ratio [aRR]: 1.46; 95% confidence interval [CI]: 1.08-1.99) for both sex combined, particularly in men (aRR: 1.66; 95% CI: 1.13-2.45) but not in women. The finding that elevated IOP occurred before the presence of high blood pressure was noted in both men and women, whereas men with elevated IOP may be concomitant with more individual components (severity) of MetS earlier than women with elevated IOP. Conclusions: Elevated IOP leading to the risk for incident or severe MetS was noted in men but not in women. Evidence on this temporal sequence revealed the possibility of showing signs of elevated IOP before the development of MetS, which indicates the necessity of monitoring IOP in routine health check-up for prevention of MetS-related chronic diseases.

Heterogeneity in arterial hypertension and ocular perfusion pressure definitions: Towards a consensus on blood pressure-related parameters for glaucoma studies

PURPOSE

Glaucoma studies have long taken into account the blood pressure (BP) status of patients. This study summarizes and evaluates the impact of the different criteria that have been used for BP-related variables in glaucoma research.

METHODS

Studies included in two meta-analyses that reviewed the role of BP in glaucoma were analyzed. Additional studies published after the search periods of the meta-analyses were also included. Criteria for the definition of arterial hypertension and other BP-related variables, such as mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP), were retrieved.

RESULTS

Sixty-four studies were evaluated. One-third used 140 mmHg as a systolic BP cut-off to define hypertension, 20% used 160 mmHg and the remaining half used various other criteria. Less than 20% of studies reported MAP and/or MOPP. While eight of the ten studies reporting MAP used a correct formula that only happened for five of the eleven studies reporting MOPP. Using as an example average blood pressure values, incorrectly used formulas could have led to an overestimation of more than 100% of the expected values.

CONCLUSION

Considerable heterogeneity exists in BP-related variables in glaucoma research and different definitions can lead to large disparities. Glaucoma research would benefit from a consensus regarding blood pressure parameters.

The association of intraocular pressure with metabolic syndrome and its components: a Meta-analysis and systematic review

AIM

To perform a Meta-analysis to explore the correlation between metabolic syndrome and intraocular pressure (IOP).

METHODS

We searched PubMed and Embase in November 2017 for studies discussing the relationship between metabolic syndrome components and IOP in patients. Pearson correlation coefficients, odds ratios and standardized betas were extracted from inclusive studies. Heterogeneity and publication bias were checked.

RESULTS

Of 295 articles, 10 met inclusion criteria and provided sufficient data for Meta-analysis. Results showed a significant positive relation between metabolic syndrome and IOP (Z=0.47, 95%CI: 0.15-0.79, P=0.005). The five components [waist circumference, hypertriglyceridemia, high blood pressure, high fasting glucose and low high density lipoprotein (HDL)-cholesterol] of metabolic syndrome all showed positive correlation with IOP except the low HDL-cholesterol which had no statistical significance. The pooled Z was 0.08 (95%CI: 0.04-0.12), 0.16 (95%CI: 0.11-0.21), 0.16 (95%CI: 0.10-0.22), 0.30 (95%CI: 0.20-0.40) and 0.12 (95%CI: 0.08-0.16), respectively. Begg's test and Egger's test showed no evidence of significant publication bias of this Meta-analysis.

CONCLUSION

Our findings suggest that metabolic syndrome and its components are significantly associated with IOP, besides the HDL-cholesterol. This association may be used to control IOP by intervening the occurrence of metabolic syndrome.

Metabolic syndrome as a risk factor for high intraocular pressure: the Korea National Health and Nutrition Examination Survey 2008-2010

BACKGROUND

High intraocular pressure (IOP) is well established as the most significant risk factor for both the development and progression of primary open-angle glaucoma. Elevated IOP is more frequently seen in the presence of metabolic disturbances that are associated with the components of metabolic syndrome (MetS). The aim of this study was to investigate the association between ocular hypertension and MetS.

PATIENTS AND METHODS

We examined the relationship between ocular hypertension and MetS in 17,160 Korean adults without glaucoma aged >19 years (7,368 men and 9,792 women) who participated in the 2008-2010 Korea National Health and Nutrition Examination Survey. Multivariate logistic regression analysis was used to assess the relationship between MetS and ocular hypertension, after adjusting for age, body mass index, smoking, alcohol consumption, and regular exercise.

RESULTS

The prevalence of MetS was 35.1% among males and 30.1% among females. The prevalence of ocular hypertension was 1.3% among males with MetS and 0.7% among females with MetS. Participants with MetS had a significantly higher IOP than those without MetS (P≤0.001), and each component of MetS had a different effect on the IOP. Hypertension was the strongest predictor of an elevated IOP. In multivariate regression analysis, ocular hypertension was significantly associated with MetS (P=0.027 for men; P=0.015 for women).

CONCLUSION

There is a statistically significant relationship between MetS and ocular hypertension.

Systemic Disease and Long-term Intraocular Pressure Mean, Peak, and Variability in Nonglaucomatous Eyes

PURPOSE

Elevated intraocular pressure (IOP) is a well-known risk factor in glaucoma development and progression. As most glaucoma risk factors are not modifiable, IOP remains the sole focus of medical and surgical therapy. Identifying modifiable factors and their effects on IOP, such as systemic diseases, is therefore of interest. The objective is to assess the long-term, longitudinal relationship between systemic diseases and IOP mean, peak, and variability, including diabetes, hypertension, body mass index (BMI), and smoking status.

DESIGN

Secondary analysis of randomized clinical trial data.

METHODS

Longitudinal IOP and systemic disease data from the Age-Related Eye Disease Study (AREDS), a randomized clinical trial of high-dose antioxidants, was analyzed.

STUDY POPULATION

A total of 3909 older participants without a reported diagnosis of glaucoma or glaucoma treatment during AREDS with up to 12 years of annual IOP and systemic disease data.

MAIN OUTCOME MEASURES

Independent systemic disease risk factors associated with IOP.

RESULTS

Univariate analysis identified numerous systemic disease factors associated with IOP mean, peak, and variability. Longitudinal adjusted models identified diabetes, obesity, and systolic hypertension as significantly associated with increased IOP, while systemic beta-blocker use was inversely associated.

CONCLUSIONS

Results demonstrate a relationship between multiple systemic diseases and IOP; moreover, they demonstrate that systemic diseases influence additional parameters beyond mean IOP, such as IOP peak and variability. Although only to be taken within the context of IOP, these population-level trends reveal potentially modifiable factors in IOP control, and are particularly important in the context of increasing obesity and diabetes prevalence rates in American adults.

Association Between Nonalcoholic Fatty Liver Disease and Intraocular Pressure in Korean Adults

PURPOSE

Elevated intraocular pressure (IOP) is an important modifiable risk factor predicting glaucoma progression. Recent studies have demonstrated that metabolic risk factors influence IOP. Nonalcoholic fatty liver (NAFLD) is an emerging chronic liver disease that is closely associated with metabolic syndrome, obesity, and type 2 diabetes. Therefore, we investigated the relationship between NAFLD and intraocular pressure in Korean adults.

PATIENTS AND METHODS

This retrospective cross-sectional study analyzed a total of 7681 participants who visited a local health promotion center. NAFLD was defined via ultrasonography and patients were classified into 3 groups based on severity: normal, mild, and moderate to severe. We conducted multiple logistic regression analysis to examine the relationship between NAFLD and high IOP. We additionally performed multiple linear regression analysis to investigate the independent association between NAFLD and mean IOP.

RESULTS

Mean IOP levels significantly and linearly increased with increasing NAFLD grades. Compared with normal, the odds ratio and 95% confidence intervals for high IOP were 1.09 (0.96-1.24) for mild NAFLD and 1.28 (1.12-1.48) for moderate to severe NAFLD after adjusting for confounding factors. NAFLD severity was noticed as an independent factor associated with mean IOP levels using stepwise and enter methods for multiple linear regression analyses.

CONCLUSIONS

NAFLD severity was associated with high IOP (>15 mm Hg) in Korean adults in a dose-dependent manner.

The synergistic effect of inflammation and metabolic syndrome on intraocular pressure: A cross-sectional study

Intraocular pressure is associated with metabolic syndrome. C-reactive protein (CRP) is associated with cardiovascular disease, irrespective of the presence of metabolic syndrome. In this study, we examined the synergistic effect of CRP and metabolic syndrome on intraocular pressure.A total of 1041 subjects were included for data analyses in this cross-sectional study. Intraocular pressure was measured using a noncontact tonometer, and serum CRP levels were measured using a commercially available kit.The intraocular pressure was significantly higher in the subjects with metabolic syndrome than in those without (14.1 ± 3.0 vs 13.4 ± 3.0 mm Hg, P = .002). Furthermore, intraocular pressures significantly increased according to CRP tertiles (13.1 ± 3.0, 13.7 ± 3.0, and 13.8 ± 3.0 mm Hg from the lowest to highest tertile of CRP, respectively; P = .002). The highest intraocular pressure was observed in subjects with metabolic syndrome in the highest CRP tertile (P value for trend < .001). Multivariate linear regression analysis revealed that the influence of CRP was independent of metabolic syndrome and that high CRP levels were significantly associated with high intraocular pressure (95% confidence interval: 0.080-1.297, P = .027).In conclusion, systemic inflammation, reflected by serum CRP levels, is associated with high intraocular pressure in subjects with and without metabolic syndrome.

Relationship between homocysteine and intraocular pressure in men and women: A population-based study

The relationship between homocysteine levels and glaucoma has been questioned in previous studies without conclusive results. In the current study, we assessed the relationship between homocysteine levels and intraocular pressure which is one of the main factors in the development of glaucoma in men and women.A retrospective cross-sectional analysis of a database from a screening center in Israel which assessed 11,850 subjects, within an age range 20 to 80 years. The relationship between homocysteine and intraocular pressure has been investigated by comparing intraocular pressure in subjects with elevated and normal homocysteine and by comparing homocysteine levels in subjects with elevated and normal intraocular pressure. In addition, we compared the levels of homocysteine in subjects with and without a confirmed diagnosis of glaucoma.The mean IOP (±SD) in subjects with normal homocysteine levels(≤15 μmol/L) was 13.2 ± 2.3 mm Hg and 13.4 ± 2.4 mm Hg in those with high homocysteine levels (>15 μmol/L) (P < 0.008, 95% confidence interval [CI] 0.3-0.09).Nonetheless, after multivariate adjustment for age, gender, vitamin B12, and folic acid statistical significance was no longer demonstrated (P = 0.37). Mean homocysteine levels (±SD) in subjects with normal intraocular pressure of ≤ 21 mm Hg was 11.7 ± 5.5 μmol/L and 12.09 ± 3.43 μmol/L in those with elevated intraocular pressure (P = 0.4, 95%CI 1.1-1.8). Mean homocysteine levels (±SD) in subjects with glaucoma were 11.2 ± 3.5 μmol/L compared to 11.7 ± 5.5 μmol/L in subjects without glaucoma and normal intraocular pressure ≤ 21 mm Hg (P = 0.4, 95% CI 1.2-2.1).The current study displays no clinical correlation between the homocysteine level and the intraocular pressure. Homocysteine may not be used as a predictive parameter to recognize those subjects prone to develop elevated intraocular pressure.

The association between intraocular pressure and different combination of metabolic syndrome components

BACKGROUND

Although the association between metabolic syndrome and intraocular pressure is well known, the relationship between the intraocular pressure and different combination of the components of metabolic syndrome has not been actively researched yet. The study aimed to investigate the relationship between the intraocular pressure and metabolic syndrome components with their different combinations.

METHODS

Thirty-one thousand two hundred seventy one healthy people aged 19-79 who attended a community hospital for a health check-up between January 2011 and December 2013 were enrolled in the study. Subjects with a history of intraocular disease, at least in one eye and those receiving medical treatment for glaucoma were excluded. Metabolic syndrome was diagnosed following the criteria defined in Circulation 2009.

RESULTS

Subjects with combination of three metabolic syndrome components of triglycerides, abdominal obesity, and fasting glucose had the highest intraocular pressure. And subjects with the combination of four components of blood pressure, high-density lipoproteins, triglycerides, fasting glucose had a significantly higher intraocular pressure than ones with the combination of all five metabolic syndrome components.

CONCLUSIONS

The difference in the risk of high intraocular pressure according to the different combination of the metabolic syndrome components could be confirmed. If additional follow-up studies are conducted, the findings can be used as an indicator for predicting intraocular pressure increases in patients with metabolic syndrome.

Evaluation of the associations between changes in intraocular pressure and metabolic syndrome parameters: a retrospective cohort study in Japan

OBJECTIVE

The contributions of highly correlated cardiovascular risk factors to intraocular pressure (IOP) are not clear due to underlying confounding problems. The present study aimed to determine which metabolic syndrome parameters contribute to elevating IOP and to what extent.

DESIGN

Retrospective cohort study.

SETTING

A private healthcare centre in Japan.

PARTICIPANTS

Individuals who visited a private healthcare centre and underwent comprehensive medical check-ups between April 1999 and March 2009 were included (20,007 in the cross-sectional study and 15,747 in the longitudinal study).

PRIMARY AND SECONDARY OUTCOME MEASURES

Changes in IOP were evaluated in terms of ageing and changes in metabolic syndrome parameters. Pearson's correlation coefficients and mixed-effects models were used to examine the relationship of changes in IOP with ageing and changes in metabolic syndrome parameters in cross-sectional and longitudinal studies, respectively.

RESULTS

In the cross-sectional study, IOP was negatively correlated with age and positively correlated with waist circumference, high-density lipoprotein cholesterol (HDL-C) levels, triglyceride levels, systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting plasma glucose (FPG) levels. In the longitudinal multivariate analysis, the associated IOP changes were -0.12 (p<0.0001) mm Hg with male sex; -0.59 (p<0.0001) mm Hg with 10 years of ageing; +0.42 (p<0.0001) mm Hg with 1 mmol/L increase in HDL-C levels; +0.092 (p<0.0001) mm Hg with 1 mmol/L increase in triglyceride levels; +0.090 (p<0.0001) mm Hg with 10 mm Hg increase in SBP; +0.085 (p<0.0001) mm Hg with 10 mm Hg increase in DBP; and+0.091 (p<0.0001) mm Hg with 1 mmol/L increase in FPG levels.

CONCLUSIONS

Elevation of IOP was related to longitudinal worsening of serum triglyceride levels, blood pressure and FPG and improvement in serum HDL-C levels.

A Longitudinal Study of Association between Adiposity Markers and Intraocular Pressure: The Kangbuk Samsung Health Study

Importance

Intraocular pressure (IOP) reduction or stabilization is the only proven method for glaucoma management. Identifying risk factors for IOP is crucial to understand the pathophysiology of glaucoma.

Objective

To examine the associations of change in body mass index (BMI), waist circumference, and percent fat mass with change in intraocular pressure (IOP) in a large sample of Korean adults.

Design, setting and participants

Cohort study of 274,064 young and middle age Korean adults with normal fundoscopic findings who attended annual or biennial health exams from January 1, 2002 to Feb 28, 2010 (577,981 screening visits).

Exposures

BMI, waist circumference, and percent fat mass.

Main Outcome Measure(s)

At each visit, IOP was measured in both eyes with automated noncontact tonometers.

Results

In multivariable-adjusted models, the average increase in IOP (95% confidence intervals) over time per interquartile increase in BMI (1.26 kg/m²), waist circumference (6.20 cm), and percent fat mass (3.40%) were 0.18 mmHg (0.17 to 0.19), 0.27 mmHg (0.26 to 0.29), and 0.10 mmHg (0.09 to 0.11), respectively (all P < 0.001). The association was stronger in men compared to women (P < 0.001) and it was only slightly attenuated after including diabetes and hypertension as potential mediators in the model.

Conclusions and Relevance

Increases in adiposity were significantly associated with an increase in IOP in a large cohort of Korean adults attending health screening visits, an association that was stronger for central obesity. Further research is needed to understand better the underlying mechanisms of this association, and to establish the role of weight gain in increasing IOP and the risk of glaucoma and its complications.

The Association between Primary Open-Angle Glaucoma and Blood Pressure: Two Aspects of Hypertension and Hypotension

Glaucoma is the second leading cause of blindness worldwide. Although the mechanism of the development of primary open-angle glaucoma (POAG) is not fully understood, elevated intraocular pressure (IOP) is considered the most important risk factor. Several vascular factors have also been identified as risk factors and can lead to hypoperfusion of the optic nerve head and thus may play an important role in the pathogenesis and progression of POAG. The results of the present study suggest that both high and low blood pressure (BP) are associated with an increased risk of POAG based on a comprehensive literature review. Elevated BP is associated with elevated IOP, leading to increased risk of glaucoma, but excessive BP lowering in glaucoma patients may cause a drop in ocular perfusion pressure (OPP) and subsequent ischemic injury. The relationship between IOP, OPP, and BP suggests that the relationship between BP and glaucoma progression is U-shaped.

Metabolic syndrome: a risk factor for high intraocular pressure in the Israeli population

AIM

To evaluate the association among elevated intraocular pressure (IOP), the metabolic syndrome (MetS), body mass index (BMI), and some of their components in the Israeli population.

METHODS

We retrospectively reviewed the charts of 12 747 soldiers of the Israeli Defense Forces, aged 35y or older, who underwent a routine periodical medical examination between 1991 and 2004. None of the subjects received medical treatment for either glaucoma or ocular hypertension. High IOP (>21 mm Hg) was correlated with age, sex, arterial blood pressure, total blood cholesterol levels, triglyceride levels, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, smoking, BMI and MetS.

RESULTS

A statistically significant difference was found between the IOP of subjects with a low risk and higher risk for the development of MetS (P<0.0001 for males, P=0.0026 for females). A statistically significant positive correlation was found in male subjects between high BMI and elevated IOP (r=0.11677, P<0.0001).

CONCLUSION

MetS and BMI were significantly more prevalent in subjects with increased IOP levels. We suggest that both should be taken into consideration in the assessment of glaucoma suspects.

Apolipoprotein B: novel indicator of elevated intraocular pressure

PURPOSE

Many studies have reported associations between elevated intraocular pressure (IOP) and systemic health parameters, which suggest a common mechanism links IOP elevation and various related cardiometabolic risk factors. Furthermore, according to a recent study, serum apolipoprotein B (APO B) level is a predictor of coronary artery disease. This study was undertaken to analyse the relationship between serum apolipoprotein levels and IOP.

METHODS

Healthy people (28,852) who attended a community hospital for a health checkup between January 2011 and December 2013 were enroled in the study. We measured age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein A1 (APO A1) and APO B, APO B/APO A1 ratios, and IOP.

RESULTS

Univariate regression analysis showed IOP was positively correlated with BMI, SBP, DBP, TC, LDL-C, TG, APO B, and APO B/APO A1 (P<0.001), and negatively correlated with HDL-C (P<0.001). On the other hand, multivariate regression analysis adjusted for age, BMI, SBP, and DBP, revealed IOP was positive correlated with TC, TG, LDL-C, APO B, and APO B/APO A1, and negatively correlated with HDL-C (all <0.05).

CONCLUSIONS

Among the various lipid profiles investigated, APO B was found to be most strongly correlated with IOP, regardless of sex. Additional studies are required to confirm the validity of apolipoprotein level as an index for predicting IOP.

Exercise training prevents increased intraocular pressure and sympathetic vascular modulation in an experimental model of metabolic syndrome

The present study aimed to study the effects of exercise training (ET) performed by rats on a 10-week high-fructose diet on metabolic, hemodynamic, and autonomic changes, as well as intraocular pressure (IOP). Male Wistar rats receiving fructose overload in drinking water (100 g/L) were concomitantly trained on a treadmill for 10 weeks (FT group) or kept sedentary (F group), and a control group (C) was kept in normal laboratory conditions. The metabolic evaluation comprised the Lee index, glycemia, and insulin tolerance test (KITT). Arterial pressure (AP) was measured directly, and systolic AP variability was performed to determine peripheral autonomic modulation. ET attenuated impaired metabolic parameters, AP, IOP, and ocular perfusion pressure (OPP) induced by fructose overload (FT vs F). The increase in peripheral sympathetic modulation in F rats, demonstrated by systolic AP variance and low frequency (LF) band (F: 37±2, 6.6±0.3 vs C: 26±3, 3.6±0.5 mmHg²), was prevented by ET (FT: 29±3, 3.4±0.7 mmHg²). Positive correlations were found between the LF band and right IOP (r=0.57, P=0.01) and left IOP (r=0.64, P=0.003). Negative correlations were noted between KITT values and right IOP (r=-0.55, P=0.01) and left IOP (r=-0.62, P=0.005). ET in rats effectively prevented metabolic abnormalities and AP and IOP increases promoted by a high-fructose diet. In addition, ocular benefits triggered by exercise training were associated with peripheral autonomic improvement.

Insulin resistance is associated with intraocular pressure elevation in a non-obese Korean population

Based on reports of an association between elevated intraocular pressure (IOP) and metabolic syndrome (MetS), and the major role of insulin resistance (IR) in MetS pathogenesis, a positive association between IOP and IR has been hypothesized. Although Asian populations tend to have lower body mass indices (BMIs) than Western populations, they tend to have a higher risk of developing MetS. This study examined the hypothesis that the association between IOP and IR differs by obesity status in an Asian population, by examining a nationally representative sample of South Korean adults. Data collected from 4,621 South Korean adults regarding demographic, lifestyle, and laboratory parameters by the 2010 Korea National Health and Nutrition Examination Survey were subjected to linear regression analysis to evaluate the relationship between IOP and metabolic profiles. After adjusting for confounding factors, the data were subjected to multiple linear regression analysis to examine the association between IR, as measured by the homeostasis model assessment of insulin resistance (HOMA-IR), and IOP. Obesity was defined as BMI≥27.5 kg/m2, and the subjects were divided into obese vs. non-obese groups for investigation of the association between IR and IOP according to obesity status. IOP was found to correlate with fasting blood sugar, total cholesterol, insulin, and HOMA-IR values in non-obese men; and with BMI, waist circumference, triglycerides, total cholesterol, HOMA-IR, and low-density lipoprotein cholesterol values in non-obese women, whereas no association between IOP and IR was found in obese men or women. IOP was significantly associated with IR in non-obese men and women after adjusting for age, and in non-obese men after adjusting for age, BMI, and lifestyle and demographic factors. These findings indicate that a positive and independent relationship exists between IOP and IR in non-obese individuals only, suggesting that other factors likely contribute to IOP elevation in obese individuals.

Diabetes, glucose metabolism, and glaucoma: the 2005-2008 National Health and Nutrition Examination Survey

Background

Diabetes may affect vascular autoregulation of the retina and optic nerve and may be associated with an increased risk of glaucoma,but the association of prediabetes, insulin resistance, markers of glucose metabolismwith glaucoma has not beenevaluated in general population samples.

Objective

To examine the relation between diabetes, pre-diabetes, metabolic syndrome and its components and the levels of fasting glucose, HbA1c and HOMA-IR with the prevalence of glaucoma in the general U.S. population.

Methods

Cross-sectional study of 3,299 adult men and women from the 2005–2008 National Health and NutritionExamination Survey (NHANES). The presence of diabetes, prediabetes, the metabolic syndrome and its individual components and biomarkers of glucose metabolisms were based on standardized questionnaire and physical exam data and laboratory tests. The history of glaucoma was assessed through questionnaire during the home interview.

Results

Diabetes was strongly associated with prevalent glaucoma.In fully adjusted models, the odds ratiofor glaucoma comparing participants with diabetes with participants in the reference group with neither pre-diabetes nor diabetes was 2.12 (95% CI: 1.23, 3.67). The corresponding odd ratio comparing participants with pre-diabetes to those in the reference group was 1.01 (95% CI: 0.57, 1.82). Patients with 5 or more years of diabetes duration hadan OR for glaucoma of 3.90 (95% CI: 1.63, 9.32) compared with patients with <5 years of diabetes duration. We also found a hockey-stick shaped associations between biomarkers of glucose metabolisms and the prevalence of glaucoma.

Conclusions

Diabetes was associated with higher risk of glaucoma. Participants without diabetes but at the higher levels of fasting glucose, fasting insulin, HbA1c and HOMA-IR spectrum may also be at greater risk of glaucoma.

Age-related association of refractive error with intraocular pressure in the Korea National Health and Nutrition Examination Survey

Background

To investigate the distribution of intraocular pressure (IOP) and refractive errors according to age group in a representative sample of non-glaucomatous Korean adults.

Methods

A total of 7,277 adults (≥19 years) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2011 underwent ophthalmic examination were divided into three groups according to age: the young- (19–39 years), middle- (40–59 years), and old- (≥60 years) age groups. Simple and multiple regression analyses between IOP and various parameters (including the refractive error) were conducted.

Results

The mean IOP of the total population was 14.0±0.1 mmHg [young: 13.9±0.1 mmHg; middle: 14.1±0.1 mmHg; old: 13.8±0.2 mmHg (P for trend = 0.085)]. Myopia and high myopia were more prevalent in the young- (70.8% and 16.1%, respectively), compared to the middle- (44.6% and 10.9%) and old- (8.9% and 2.2%) age groups. Univariate analysis in the total population showed that higher IOP was associated with myopic refractive error, the female gender, higher body mass index (BMI), diabetes, hypertension, and hypercholesterolemia (all P<0.05). In the young- and middle-age groups, higher IOP was associated with myopic refractive error, the female gender, higher BMI, hypercholesterolemia and diabetes (all P<0.05). In the old-age group, the association between IOP and refractive error was not significant (P = 0.828). In multiple linear regression analysis, similar significant relationships between the refractive error and IOP were found in the young- and middle-age groups (beta = −0.08 and −0.12; P = 0.002 and <0.001 for young- and middle-age group, respectively), but not in the old-age group (beta = 0.03; P = 0.728), after adjusting for age, gender, BMI, region of habitation, diabetes, hypertension, and hypercholesterolemia.

Conclusions

Myopic refractive error was an independent predictor of higher IOP in non- glaucomatous eyes, and the association between refractive error and IOP differed according to age.

The association of blood pressure and primary open-angle glaucoma: a meta-analysis

PURPOSE

To conduct a systematic review and meta-analysis of the association between blood pressure levels and hypertension with primary open-angle glaucoma and intraocular pressure endpoints.

DESIGN

Systematic review with quantitative meta-analysis.

METHODS

Studies were identified by searching the PubMed and EMBASE databases. Inverse-variance weighted random-effects models were used to summarize relative risks. Subgroup analyses and meta-regression were used to explore potential sources of heterogeneity across studies.

RESULTS

Sixty observational studies were included. The pooled relative risk for primary open-angle glaucoma comparing patients with hypertension to those without hypertension was 1.16 (95% CI = 1.05-1.28), with modest heterogeneity across studies (I(2) 34.5%). Virtually all studies reported a positive association between blood pressure and intraocular pressure (IOP). The pooled average increase in IOP associated with a 10 mm Hg increase in systolic blood pressure was 0.26 mm Hg (95% CI 0.23-0.28, I(2) 30.7%), and the average increase associated with a 5 mm Hg increase in diastolic blood pressure was 0.17 mm Hg (95% CI 0.11-0.23, I(2) 90.5%).

CONCLUSIONS

In this meta-analysis, hypertension was associated with increased intraocular pressure. The association between hypertension and primary open-angle glaucoma was stronger in cross-sectional compared with case-control and longitudinal studies. Our findings support a role of increased blood pressure in elevated intraocular pressure and possibly in the development of glaucoma.

Association between urinary albumin excretion and intraocular pressure in type 2 diabetic patients without renal impairment

Background

To assess the relationship between urinary albumin excretion and intraocular pressure (IOP) in type 2 diabetes patients without renal impairment.

Methods

We explored the effects of albuminuria on high IOP in 402 non-glaucomatous type 2 diabetes without renal impairment who participated in the 2011 Korean National Health and Nutrition Examination Survey (KNHANES). Multiple logistic regression analysis was used to assess the relationship between log-transformed albumin/creatinine ratio (ACR) tertiles and an IOP of ≥18 mmHg after adjusting for age, gender, hypertension, body mass index, triglycerides, area of residence, and education level.

Results

Subjects with a high IOP ≥18 mmHg were more likely to be current smokers (P = 0.038), heavy drinkers (P = 0.006), and to have high systolic blood pressure (P = 0.016), triglycerides (P = 0.008), and a higher log-transformed ACR (P = 0.022).In multivariate regression analysis, ACR tertile was associated with the prevalence of high IOP significantly (P = 0.022). The associations between ACR tertiles and high IOP were significant in overweight patients and those with abdominal obesity (P = 0.003 and 0.003, respectively). In contrast, there were no associations in the subgroup of patients who were not overweight and those without abdominal obesity (P = 0.291 and 0.561, respectively).

Conclusions

Urinary albumin excretion is associated with high IOP in the type 2 diabetes population without renal insufficiency. The effect of the albuminuria on IOP was evident in a subgroup of patients with components of metabolic syndrome.

Higher intraocular pressure is associated with leukoaraiosis among middle-aged and elderly Koreans without glaucoma or dementia

AIM

Leukoaraiosis and high intraocular pressure are strongly associated with cardiovascular disease, vascular angiopathy, and geriatric syndrome. Until now, little is known about the relationship between intraocular pressure and leukoaraiosis in its preclinical stage. The aim of this study was to evaluate the association between intraocular pressure and leukoaraiosis among middle-aged and elderly Koreans without glaucoma or dementia.

METHODS

We examined the relationship of intraocular pressure with leukoaraiosis at a preclinical stage in 753 Korean adults (474 men, 279 women; mean age 57.8 ± 6.6 years). A multiple logistic regression analysis was performed in order to determine whether intraocular pressure is an independent determinant for leukoaraiosis.

RESULTS

The overall prevalence of leukoaraiosis was 7.3%. Mean ocular pressure (±SD) was significantly higher in the leukoaraiosis group than the control group (14.3 ± 2.9 and 13.5 ± 2.9, respectively; P=0.028). In multiple logistic regression analysis, the odds ratio for leukoaraiosis was 1.18 (95% confidence interval: 1.06-1.31) for each 1 mm Hg increase in intraocular pressure.

CONCLUSION

Intraocular pressure was found to be independently and positively associated with leukoaraiosis. This finding indicates that higher intraocular pressure may be a useful additional measure in assessing the risk of leukoaraiosis in the clinical setting.

High intraocular pressure is associated with cardiometabolic risk factors in South Korean men: Korean National Health and Nutrition Examination Survey, 2008-2010

OBJECTIVE

Elevated intraocular pressure (IOP) contributes to the progression of visual defects such as glaucoma. This study determined whether metabolic syndrome (MetS) and cardiovascular risk factors are associated with IOP in South Korean men.

METHODS

We analyzed data on 4875 men who participated in the Korean National Health and Nutrition Examination Survey 2008-2010. We recorded the values for age, weight, height, body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBG), insulin, homeostasis model assessment of estimated insulin resistance (HOMA-IR), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), non-HDL-C (NHDL-C), and TG/HDL-C, as well as sociodemographic factors. IOP was measured using Goldmann applanation tonometry.

RESULTS

Weight, BMI, WC, SBP, DBP, FBG, insulin, HOMA-IR, TC, LDL-C, TG, NHDL-C, TG/HDL-C, and the prevalence of MetS differed significantly among the three groups with IOP (P<0.05). Mean IOP was higher in subjects who were obese and had hypertension, diabetes mellitus, MetS, abdominal obesity, high TG, high FBG, or high BP compared with normal subjects (P<0.005). Analysis using Pearson's correlation coefficient showed that all cardiometabolic risk factors were significantly associated with IOP (P<0.005), with the exception of WC and HDL-C. A multivariate linear regression analysis showed that IOP was positively correlated with BMI, SBP, DBP, FBG, HOMA-IR, TC, LDL-C, TG, NHDL-C, and TG/HDL-C after adjusting for all covariates (all P<0.05).

CONCLUSIONS

Cardiometabolic risk factors, including the components of MetS, are associated with increased IOP.

Ocular associations of metabolic syndrome

Metabolic syndrome is a cluster of diseases including central obesity, dyslipidemia, hyperglycemia, and high blood pressure. People with metabolic syndrome have been shown to be at an increased risk of developing cardiovascular disease, beyond the risk associated with individual components of the syndrome. The association of diabetes and hypertension with retinopathy, cataract, and raised intraocular pressure is well known. This review highlights the association of metabolic syndrome, including all its components, with various ocular conditions such as retinopathy, central retinal artery occlusion, cataracts, and raised intraocular pressure.

Epidemiologic characteristics of intraocular pressure in the Korean and Mongolian populations: the Healthy Twin and the GENDISCAN study

PURPOSE

The purpose of this study was to demonstrate a negative association between intraocular pressure (IOP) and age in 2 Asian populations. In addition, we evaluated genetic and nongenetic factors associated with IOP.

DESIGN

Family-based cohort study.

PARTICIPANTS

Study subjects >10 years of age from one Korean (The Healthy Twin; n = 1431) and 2 Mongolian populations (The GENDISCAN; n = 859 and 806) with IOP values.

METHODS

The IOP values were measured with a noncontact tonometer. Each participant received a standard health examination and received questionnaires, which include candidate risk factors on IOP. Mixed models were used to identify risk factors for IOP. Variance-component methods were applied to estimate the heritability of IOP.

MAIN OUTCOME MEASURES

The negative trend of IOP with aging and evaluation of impact of genetic and nongenetic components on IOP.

RESULTS

The mean ages were 43.6, 34.1, and 36.3 years for the Korean, Orhontuul, and Dashbalbar populations, respectively. The mean IOPs were 14.4 mmHg (95% confidence interval [CI], 14.3-14.6) in the Koreans and 14.1 mmHg (95% CI, 13.9-14.3) and 12.6 mmHg (95% CI, 12.4-12.9) in the Orhontuul and Dashbalbar populations, respectively. In the 3 populations, the IOP decreased as age increased. We replicated an association of systolic blood pressure (SBP) with IOP. In addition, components of the metabolic syndrome (MS), such as plasma glucose, lipid level, and body mass index, showed positive associations with IOP, after adjusting for age and SBP. The IOP also had strong genetic contributions in all populations (heritability, 0.47-0.51).

CONCLUSIONS

Negative associations between age and IOP were observed in all 3 populations, which cannot be explained by the increasing prevalence of myopia in the younger generation. The different age trend in IOP may in part be responsible for differences in the prevalence of glaucoma subtypes. Our findings suggest that associations between IOP and MS components were independent of established risk factors such as SBP or age. In addition, the importance of inherited risks requires further genetic dissection of IOP determinants for biological understandings of underlying pathophysiology.

Age- and gender-specific association between intraocular pressure and metabolic variables in a Taiwanese population

BACKGROUND

To analyze the relationship between intraocular pressure, metabolic variables, and components of metabolic syndrome in different age and gender groups.

METHODS

We examined 10,491 Taiwanese adults aged 21 to 79 years and categorized according to gender and age. All participants underwent examinations, including body mass index (BMI), waist circumference, blood pressure, intraocular pressure, and blood chemistry. Multiple linear regression analyses were performed to evaluate the relationships between intraocular pressure and these variables as well as to determine the relative influence of each component of metabolic syndrome.

RESULTS

Intraocular pressure showed a significant reduction with aging in men but not in women. BMI had a positive association with intraocular pressure in young adults and middle-aged men. Systolic blood pressure was positively associated with intraocular pressure in most groups, whereas diastolic blood pressure was positively associated with intraocular pressure only in middle-aged and elderly men. Fasting blood sugar levels showed a significant association with high intraocular pressure in middle-aged and elderly adults. All participants with metabolic syndrome had higher intraocular pressure levels, and each component of metabolic syndrome had a distinct effect on the intraocular pressure, with blood pressure being the strongest predictor.

CONCLUSION

Elevated intraocular pressure is associated with a number of metabolic variables, and each component of metabolic syndrome has a distinct impact on the intraocular pressure in individual age- and gender-specific groups. The present results may allow internal medicine specialists to manage metabolic risk factors while considering possible ocular involvement and potential treatment interactions.