Retinal nerve fibre layer thickness is reduced in metabolic syndrome

Obesity, body fat distribution and eye diseases

BACKGROUND

The prevalence of obesity, a chronic disease, is increasing, and obesity is now considered a global epidemic. Eye diseases are also increasing worldwide and have serious repercussions on quality of life as well as increasingly high costs for the community. The relationships between obesity and ocular pathologies are not yet well clarified and are not pathologically homogeneous: they seem to be somehow linked to excess body fat, especially to the distribution of adipose tissue and its ectopic deposits.

PURPOSE

Our objective was to examine the associations between obesity and anthropometric indices, including body mass index (BMI), waist circumference (WC), and the waist/hip ratio (WHR), and the risk of most widespread eye diseases, with particular attention given to the most significant metabolic mechanisms.

METHODS

This article provides a narrative overview of the effect of obesity and anthropometric measurements of body fat on prevalent eye diseases. We used the MEDLINE/PubMed, CINAHL, EMBASE, and Cochrane Library databases from 1984 to 2024. In addition, we hand-searched references from the retrieved articles and explored a number of related websites. A total of 153 publications were considered.

RESULTS

There is significant evidence that obesity is associated with several eye diseases. Waist circumference (WC) and the waist/hip ratio (WHR) have been observed to have stronger positive associations with eye diseases than BMI.

CONCLUSIONS

Obesity must be considered a significant risk factor for eye diseases; hence, a multidisciplinary and multidimensional approach to treating obesity, which also affects ocular health, is important. In the prevention and treatment of eye diseases related to obesity, lifestyle factors, especially diet and physical activity, as well as weight changes, both weight loss and weight gain, should not be overlooked.

LEVEL OF EVIDENCE

Level V narrative review.

Retinal thickness changes in preobese and obese patients without hyperglycemia: Optical coherence tomography study

PURPOSE

To evaluate retinal thickness changes by optical coherence tomography in preobese and obese patients without hyperglycemia.

METHODS

This comparative cross-sectional study was conducted on 55 normal (18.5-24.9 kg/m2), 42 preobese (25-29.9 kg/m2), 34 obese (>30 kg/m2), a total of 131, according to body mass index (BMI) value at the time of examination. All participants were examined in the internal medicine department and fasting serological biochemical and lipid tests were performed, and those with hyperglycemia were excluded from the study. All participants underwent a full ophthalmological examination and sectoral examination of the retina with optical coherence tomography.

RESULTS

The study included 55 right eyes of 55 normal, 42 of 42 preobese, and 34 of 34 obese, age- and sex-matched participants, without hyperglycemia. The mean BMI of the normal group was 22.3 ± 1.3, 26.8 ± 1.3 in the preobese group, and 33.2 ± 4.2 in the obese group. Central foveal thickness (normal 229.8 ± 20.1 µm, preobese 234.7 ± 18.8 µm and obese 222.0 ± 23.4 µm, P:0.031) and mean inferior (normal 280.7 ± 55.8 µm, preobese 296.7 ± 11.1 µm and obese 285.3 ± 9.9 µm) thickness in the 3 mm The Early Treatment Diabetic Retinopathy Study (ETDRS) circle was significantly higher in the preobese group and significantly lower in the obese group. Mean nasal, temporal, and superior thickness in the 3 mm ETDRS circle and peripapillary retinal nerve fiber layer was higher in the preobese group and lower in the obese group but this difference was statistically not significant.

CONCLUSION

The fact that preobesity, which is not accompanied by hyperglycemia, causes an increase in the thickness of the central macular regions and obesity causes thinning of the retina, supports that lipid metabolism in the body alone can affect retinal thickness changes and retinal neurodegeneration.

Association of Metabolic Syndrome with Macular Thickness and Volume in Older Adults: A Population-Based Optical Coherence Tomography Study

Background: To explore the associations of the metabolic syndrome (MetS) and individual components with macular thickness and volume among rural-dwelling Chinese older adults. Methods: This population-based cross-sectional study included 705 participants (age ≥60 years) derived from the MIND-China study. In 2018-2019, we collected data through face-to-face interview, clinical examination, optical coherence tomography (OCT) examination, and blood test. We measured macular thickness and volume using spectral-domain OCT. MetS was defined following the International Diabetes Federation (IDF) criteria, the IDF/American Heart Association (AHA) criteria, the National Cholesterol Education Program-Adult Treatment Panel III criteria, and the Chinese Diabetes Society (CDS) criteria. Data were analyzed with multivariable general linear models. Results: MetS was significantly associated with thinner macula in central (multivariable-adjusted β = -5.29; 95% confidence interval: -9.31 to -1.26), parafoveal (-2.85; -5.73 to 0.04) and perifoveal regions (-4.37; -6.79 to -1.95) when using the IDF criteria, in the perifoveal regions (-3.82; -6.18 to -1.47) when using the IDF/AHA criteria, and in the central region (-5.63; -10.25 to -1.02) when using the CDS criteria, and with reduced macular volume when using the IDF (-0.16; -0.26 to -0.07) and IDF/AHA (-0.13; -0.22 to -0.04) criteria. In the parafoveal region, the IDF-defined MetS was significantly associated with thinner retina in men (β = -6.25; -10.94 to -1.56) but not in women. Abdominal obesity (-2.83; -5.41 to -0.25) and elevated fasting blood glucose (-2.65; -5.08 to -0.21) were associated with thinner macular thickness in the perifoveal region. Conclusion: MetS is associated with macular thinning and reduced macular volume among rural-dwelling older adults, and the associations vary by the defining criteria of MetS.

The role of Keap1-Nrf2 signaling pathway during the progress and therapy of diabetic retinopathy

Diabetic retinopathy is a complex and progressive ocular complication of diabetes mellitus and is a leading cause of blindness in people of working age worldwide. The pathophysiology of diabetic retinopathy involves multifactorial processes, including oxidative stress, inflammation and vascular abnormalities. Understanding the underlying molecular mechanisms involved in its pathogenesis is essential for the development of effective therapeutic interventions. One of the pathways receiving increasing attention is the Keap1-Nrf2 signaling pathway, which regulates the cellular response to oxidative stress by activating Nrf2. In this review, we analyze the current evidence linking Keap1-Nrf2 signaling pathway dysregulation to diabetic retinopathy. In addition, we explore the potential therapeutic implications and the challenges of targeting this pathway for disease management. A comprehensive understanding of the molecular mechanisms of diabetic retinopathy and the therapeutic potential of the Keap1-Nrf2 pathway may pave the way for innovative and effective interventions to combat this vision-threatening disease.

Quantitatively Evaluating the Relationships between Insulin Resistance and Retinal Neurodegeneration with Optical Coherence Tomography in Early Type 2 Diabetes Mellitus

INTRODUCTION

The aim of this study was to quantitatively assess retinal neurodegenerative changes with optical coherence tomography (Cirrus HD-OCT) in type 2 diabetes mellitus (T2DM) patients without diabetic retinopathy (DR) and evaluate their relationships with insulin resistance (IR) and associated systemic indicators.

METHODS

102 T2DM patients without DR and 48 healthy controls were included in this observational cross-sectional study. The OCT parameters of macular retinal thickness (MRT) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were evaluated between diabetic and normal eyes. The receiver operating characteristics (ROC) curve was generated to evaluate the discrimination power of early diabetes. Correlation and multiple regression analysis were performed between ophthalmological parameters and T2DM-related demographic and anthropometric variables, and serum biomarkers and homeostasis model assessment of insulin resistance (HOMA-IR) scores.

RESULTS

MRT and GCIPL thicknesses showed significant thinning in patients, especially in inferotemporal area. High body mass index (BMI) correlated with decreased GCIPL thicknesses and elevated intraocular pressure (IOP). A negative correlation between waist-to-hip circumference ratio (WHR) and GCIPL thicknesses was also found. High-density lipoprotein (HDL) and fasting C-peptide (CP0) were associated with GCIPL thickness but only in inferotemporal region (r = 0.20, p = 0.04; r = -0.20, p = 0.05, respectively). Multiple regression analysis showed that increased HOMA-IR scores independently predicted both average (β = -0.30, p = 0.05) and inferotemporal (β = -0.34, p = 0.03) GCIPL thinning.

CONCLUSION

Retinal thinning in early T2DM was associated with obesity-related metabolic disorders. IR as an independent risk factor for retinal neurodegeneration may increase the risk of developing glaucoma.

The Association of Retinal age gap with metabolic syndrome and inflammation

BACKGROUND

Metabolic syndrome (MetS) is a clustering of cardiometabolic components, posing tremendous burdens in the aging society. Retinal age gap has been proposed as a robust biomarker associated with mortality and Parkinson's disease. Although MetS and chronic inflammation could accelerate the aging process and increase the risk of mortality, the association of the retinal age gap with MetS and inflammation has not been examined yet.

METHODS

Retinal age gap (retina-predicted age minus chronological age) was calculated using a deep learning model. MetS was defined as the presence of three or more of the following: central obesity, hypertension, dyslipidemia, hypertriglyceridemia, and hyperglycemia. Inflammation index was defined as a high-sensitivity C-reactive protein level above 3.0 mg/L. Logistic regression models were used to examine the associations of retinal age gaps with MetS and inflammation.

RESULTS

We found that retinal age gap was significantly associated with MetS and inflammation. Specifically, compared to participants with retinal age gaps in the lowest quartile, the risk of MetS was significantly increased by 10% and 14% for participants with retinal age gaps in the third and fourth quartile (odds ratio [OR]:1.10; 95% confidence interval [CI], 1.01,1.21;, p = .030; OR: 1.14, 95% CI, 1.03,1.26; p = .012, respectively). Similar trends were identified for the risk of inflammation and combined MetS and inflammation.

CONCLUSION

We found that retinal age gaps were significantly associated with MetS as well as inflammation. Given the noninvasive and cost-effective nature and the efficacy of the retinal age gap, it has great potential to be used as a screening tool for MetS in large populations.

Ocular manifestations of central insulin resistance

Central insulin resistance, the diminished cellular sensitivity to insulin in the brain, has been implicated in diabetes mellitus, Alzheimer's disease and other neurological disorders. However, whether and how central insulin resistance plays a role in the eye remains unclear. Here, we performed intracerebroventricular injection of S961, a potent and specific blocker of insulin receptor in adult Wistar rats to test if central insulin resistance leads to pathological changes in ocular structures. 80 mg of S961 was stereotaxically injected into the lateral ventricle of the experimental group twice at 7 days apart, whereas buffer solution was injected to the sham control group. Blood samples, intraocular pressure, trabecular meshwork morphology, ciliary body markers, retinal and optic nerve integrity, and whole genome expression patterns were then evaluated. While neither blood glucose nor serum insulin level was significantly altered in the experimental or control group, we found that injection of S961 but not buffer solution significantly increased intraocular pressure at 14 and 24 days after first injection, along with reduced porosity and aquaporin 4 expression in the trabecular meshwork, and increased tumor necrosis factor α and aquaporin 4 expression in the ciliary body. In the retina, cell density and insulin receptor expression decreased in the retinal ganglion cell layer upon S961 injection. Fundus photography revealed peripapillary atrophy with vascular dysregulation in the experimental group. These retinal changes were accompanied by upregulation of pro-inflammatory and pro-apoptotic genes, downregulation of anti-inflammatory, anti-apoptotic, and neurotrophic genes, as well as dysregulation of genes involved in insulin signaling. Optic nerve histology indicated microglial activation and changes in the expression of glial fibrillary acidic protein, tumor necrosis factor α, and aquaporin 4. Molecular pathway architecture of the retina revealed the three most significant pathways involved being inflammation/cell stress, insulin signaling, and extracellular matrix regulation relevant to neurodegeneration. There was also a multimodal crosstalk between insulin signaling derangement and inflammation-related genes. Taken together, our results indicate that blocking insulin receptor signaling in the central nervous system can lead to trabecular meshwork and ciliary body dysfunction, intraocular pressure elevation, as well as inflammation, glial activation, and apoptosis in the retina and optic nerve. Given that central insulin resistance may lead to neurodegenerative phenotype in the visual system, targeting insulin signaling may hold promise for vision disorders involving the retina and optic nerve.

Retinal layers and associated clinical factors in schizophrenia spectrum disorders: a systematic review and meta-analysis

INTRODUCTION

The retina shares structural and functional similarities with the brain. Furthermore, structural changes in the retina have been observed in patients with schizophrenia spectrum disorders (SSDs). This systematic review and meta-analysis investigated retinal abnormalities and their association with clinical factors for SSD.

METHODS

Studies related to retinal layers in SSD patients were retrieved from PubMed, Scopus, Web of Science, Cochrane Controlled Register of Trials, International Clinical Trials Registry Platform, and PSYNDEX databases from inception to March 31, 2021. We screened and assessed the eligibility of the identified studies. EZR ver.1.54 and the metafor package in R were used for the meta-analysis and a random-effects or fixed-effects model was used to report standardized mean differences (SMDs).

RESULTS

Twenty-three studies (2079 eyes of patients and 1571 eyes of controls) were included in the systematic review and meta-analysis. The average peripapillary retinal nerve fiber layer (pRNFL) thickness, average macular thickness (MT), and macular ganglion cell layer-inner plexiform layer (GCL-IPL) thickness were significantly lower in patients than in controls (n = 14, 6, and 3, respectively; SMD = -0.33, -0.49, and -0.43, respectively). Patients also had significantly reduced macular volume (MV) compared to controls (n = 7; SMD = -0.53). The optic cup volume (OCV) was significantly larger in patients than in controls (n = 3; SMD = 0.28). The meta-regression analysis indicated an association between several clinical factors, such as duration of illness and the effect size of the pRNFL, macular GCL-IPL, MT, and MV.

CONCLUSION

Thinning of the pRNFL, macular GCL-IPL, MT, and MV and enlargement of the OCV in SSD were observed. Retinal abnormalities may be applicable as state/trait markers in SSDs. The accumulated evidence was mainly cross-sectional and requires verification by longitudinal studies to characterize the relationship between OCT findings and clinical factors.

Long-term cost-effectiveness of quality of diabetes care; experiences from private and public diabetes centers in Iran

BACKGROUND

The quality of health care has a significant impact on both patients and the health system in terms of long-term costs and health consequences. This study focuses on determining the long-term cost-effectiveness in quality of diabetes care in two different settings (private/public) using longitudinal patient-level data in Iran.

METHODS

By extracting patients intermediate biomedical markers in under-treatment type 2 diabetes patients(T2DP) in a longitudinal retrospective study and by applying the localized UKPDS diabetes model, lifetime health outcomes including life expectancy, quality-adjusted Life expectancy (QALE) and direct medical costs of managing disease and related complications from a healthcare system perspective was predicted. Costs and utility decrements had derived on under-treatment T2DP from 7 private and 8 Public diabetes centers. We applied two steps sampling mehods to recruit the needed sample size (cluster and random sampling). To cope with first and second-order uncertainty, we used Monte-Carlo simulation and bootstrapping techniques. Both cost and utility variables were discounted by 3% in the base model.

RESULTS

In a 20-year time horizon, according to over 5 years of quality of care data, outcomes-driven in the private sector will be more effective and more costly (5.17 vs. 4.95 QALE and 15,385 vs. 8092). The incremental cost-effectiveness ratio (ICER) was $33,148.02 per QALE gained, which was higher than the national threshold.

CONCLUSION

Although quality of care in private diabetes centers resulted in a slight increase in the life expectancy in T2DM patients, it is associated with unfavorable costs, too. Private-sector in management of T2DM patients, compared with public (governmental) diabetic Centers, is unlikely to be cost-effective in Iran.

Degeneration of retina-brain components and connections in glaucoma: Disease causation and treatment options for eyesight preservation

Eyesight is the most important of our sensory systems for optimal daily activities and overall survival. Patients who experience visual impairment due to elevated intraocular pressure (IOP) are often those afflicted with primary open-angle glaucoma (POAG) which slowly robs them of their vision unless treatment is administered soon after diagnosis. The hallmark features of POAG and other forms of glaucoma are damaged optic nerve, retinal ganglion cell (RGC) loss and atrophied RGC axons connecting to various brain regions associated with receipt of visual input from the eyes and eventual decoding and perception of images in the visual cortex. Even though increased IOP is the major risk factor for POAG, the disease is caused by many injurious chemicals and events that progress slowly within all components of the eye-brain visual axis. Lowering of IOP mitigates the damage to some extent with existing drugs, surgical and device implantation therapeutic interventions. However, since multifactorial degenerative processes occur during aging and with glaucomatous optic neuropathy, different forms of neuroprotective, nutraceutical and electroceutical regenerative and revitalizing agents and processes are being considered to combat these eye-brain disorders. These aspects form the basis of this short review article.

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.

The Causal Association Between Obesity and Primary Open-Angle Glaucoma: A Two-Sample Mendelian Randomization Study

The correlation between obesity and primary open-angle glaucoma (POAG) has not yet been fully established. The aim of this study was to investigate the causal relationship between obesity and POAG by a two-sample Mendelian randomization (MR) study. In this study, body mass index (BMI), an index to evaluate general obesity, and waist and hip circumference, indices to evaluate abdominal obesity, were selected as exposures in MR analysis. Single-nucleotide polymorphisms (SNPs) were chosen as instrumental variables (IVs). Summary data from genome-wide association studies (GWASs) based on a European ancestry by Locke et al., with regard to BMI, and Shungin et al., with regard to waist and hip circumference, were used. Genetic predictors of POAG were obtained from public GWAS summary data. To assess the causal effect of obesity on POAG, the inverse variance-weighted (IVW) method was used as the primary method, and other methods, such as MR-Egger, weighted median, simple mode, and weighted mode, were also used as complementary analyses. Finally, we performed Cochran's Q statistic to assess heterogeneity, and sensitivity analysis was performed to evaluate the reliability and stability of the MR results. MR analysis showed that BMI has a positive effect on the risk of POAG, with 1 standard deviation (SD) increase in BMI; the risk of POAG increases by approximately 90.9% [OR = 1.909; 95% CI= (1.225, 2.975); p = 0.0042)] (analyzed by IVW); there were no heterogeneity and pleiotropy in the result; and waist circumference also had a positive effect on the risk of POAG [OR = 2.319; 95% CI= (1.071, 5.018); p = 0.033)] analyzed by weighted median. As hip circumference increases, with 1 SD increase in hip circumference, the risk of POAG increases by approximately 119% [OR = 2.199; 95% CI= (1.306, 3.703); p = 0.00305)] estimated by IVW, there were not heterogeneity and pleiotropy as for the result. Our study for the first time confirms that obesity might increase the risk of POAG using two-sample MR analysis. These results might provide guidance on the prevention and treatment of POAG.

Spectral-domain OCT measurements in obesity: A systematic review and meta-analysis

Background

Previous studies proposed possible applications of spectral-domain optical coherence tomography (SD-OCT) measurements in prognosticating pathologies observed in overweight/obesity, including ocular, vascular, and neurologic consequences. Therefore, we conducted a systematic review and meta-analysis to investigate the changes in the in SD-OCT measurements of the patients with higher body mass index (BMI) compared to normal weight individuals.

Materials and methods

We conducted a systematic search on PubMed, Scopus, and Embase. The search results underwent two-phase title/abstract and full-text screenings. We then analyzed SD-OCT measurements differences in patients with high BMI and controls, and performed meta-regression, sub-group analysis, quality assessment, and publication bias assessment. The measurements included macular thickness, cup to disc ratio, ganglion cell-inner plexiform layer (GC-IPL) and its sub-sectors, RNFL and peripapillary RNFL (pRNFL) and their sub-layers, and choroidal thickness and its sub-sectors.

Results

19 studies were included in this meta-analysis accounting for 1813 individuals, 989 cases and 824 controls. There was an overall trend towards decreased thickness in high BMI patients, but only two measurements reached statistical significance: temporal retinal nerve fiber layer (RNFL) (Standardized mean difference (SMD): -0.33, 95% confidence interval (CI): -0.53 to -0.14, p<0.01) and the choroidal region 1.0 mm nasal to fovea (SMD: -0.38, 95% CI: -0.60 to -0.16, p<0.01).

Conclusion

Some ocular layers are thinner in patients with higher BMI than the controls. These SD-OCT measurements might correlate with adverse events related to increased body weight and have prognostic abilities. As SD-OCT is a robust, rapid and non-invasive tool, future guidelines and studies are needed to evaluate the possibility of their integration into care of the patients with obesity.

Combining Optical Coherence Tomography and Fundus Photography to Improve Glaucoma Screening

We aimed to evaluate the accuracy of glaucoma screening using fundus photography combined with optical coherence tomography and determine the agreement between ophthalmologists and ophthalmology residents. We used a comprehensive ophthalmologic examination dataset obtained from 503 cases (1006 eyes). Of the 1006 eyes, 132 had a confirmed glaucoma diagnosis. Overall, 24 doctors, comprising two groups (ophthalmologists and ophthalmology residents, 12 individuals/group), analyzed the data presented in three screening strategies as follows: (1) fundus photography alone, (2) fundus photography + optical coherence tomography, and (3) fundus photography + optical coherence tomography + comprehensive examination. We investigated the diagnostic accuracy (sensitivity and specificity). The respective sensitivity and specificity values for the diagnostic accuracy obtained by 24 doctors, 12 ophthalmologists, and 12 ophthalmology residents were as follows: (1) fundus photography: sensitivity, 55.4%, 55.4%, and 55.4%; specificity, 91.8%, 94.0%, and 89.6%; (2) fundus photography + OCT: sensitivity, 80.0%, 82.3%, and 77.8%; specificity, 91.7%, 92.9%, and 90.6%; and (3) fundus photography + OCT + comprehensive examination: sensitivity 78.4%, 79.8%, and 77.1%; specificity, 92.7%, 94.0%, and 91.3%. The diagnostic accuracy of glaucoma screening significantly increased with optical coherence tomography. Following its addition, ophthalmologists could more effectively improve the diagnostic accuracy than ophthalmology residents. Screening accuracy is improved when optical coherence tomography is added to fundus photography.

Factors related to retinal nerve fiber layer thickness in bipolar disorder patients and major depression patients

BACKGROUND

We analyzed the correlation of the clinical data with retinal nerve fiber layer (RNFL) thickness and macular thickness in bipolar disorder patients and major depression patients. The aim of this study is to explore factors that affect RNFL thickness in bipolar disorder patients and major depression patients, with a view to providing a new diagnostic strategy.

METHODS

Eighty-two bipolar disorder patients, 35 major depression patients and 274 people who were age and gender matched with the patients were enrolled. Demographic information and metabolic profile of all participants were collected. Best-corrected visual acuity of each eye, intraocular pressure (IOP), fundus examination was performed. RNFL and macular thickness were measured by optical coherence tomography (OCT). Correlations between RNFL and macular thickness and other data were analyzed.

RESULTS

RNFL and macula lutea in bipolar dipolar patients and major depression patients are thinner than normal people. Triglyceride and UA levels are the highest in the bipolar disorder group, while alanine aminotransferase (ALT) and glutamic oxalacetic transaminase (AST) levels in the depression group are the highest. Age onset and ALT are positively while uric acid (UA) is negatively correlated with RNFL thickness in bipolar dipolar patients. Cholesterol level is positively correlated with RNFL thickness while the duration of illness is correlated with RNFL thickness of left eye in major depression patients.

CONCLUSIONS

RNFL and macula lutea in bipolar dipolar patients and major depression patients are thinner than normal people. In bipolar disorder patients, age-onset and ALT are potential protective factors in the progress of RNFL thinning, while UA is the pathological factor.

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.

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.

Metabolic Syndrome Triggered by Fructose Diet Impairs Neuronal Function and Vascular Integrity in ApoE-KO Mouse Retinas: Implications of Autophagy Deficient Activation

Metabolic syndrome is a disorder characterized by a constellation of clinical findings such as elevated blood glucose, hyperinsulinemia, dyslipidemia, hypertension, and obesity. A positive correlation has been found between metabolic syndrome or its components and retinopathy, mainly at microvascular level, in patients without a history of diabetes. Here, we extend the investigations beyond the vascular component analyzing functional changes as well as neuronal and glial response in retinas of Apolipoprotein E knockout (ApoE-KO) mice fed with 10% w/v fructose diet. Given that autophagy dysfunction is implicated in retinal diseases related to hyperglycemia and dyslipidemia, the activation of this pathway was also analyzed. Two months of fructose intake triggered metabolic derangements in ApoE-KO mice characterized by dyslipidemia, hyperglycemia and hyperinsulinemia. An increased number of TUNEL positive cells, in addition to the ganglion cell layer, was observed in the inner nuclear layer in retina. Vascular permeability, evidenced by albumin–Evans blue leakage and extravasation of albumin was also detected. Furthermore, a significant decrease of the glial fibrillary acidic protein expression was confirmed by Western blot analysis. Absence of both Müller cell gliosis and pro-angiogenic response was also demonstrated. Finally, retinas of ApoE-KO FD mice showed defective autophagy activation as judged by LC3B mRNA and p62 protein levels correlating with the increased cell death. These results demonstrated that FD induced in ApoE-KO mice biochemical alterations compatible with metabolic syndrome associated with neuronal impairment and mild vascular alterations in the retina.

Metabolic Health, Obesity, and the Risk of Developing Open-Angle Glaucoma: Metabolically Healthy Obese Patients versus Metabolically Unhealthy but Normal Weight Patients

BACKGROUND

This study sought to investigate the associations between metabolic health status, obesity, and incidence of primary open-angle glaucoma (POAG).

METHODS

In this nationwide, population-based, longitudinal prospective cohort study conducted using the Korean National Health Insurance System, we categorized all subjects based on presence and severity of metabolic syndrome and obesity. Insurance claims data were used to identify POAG development. Then, Cox regression was applied to calculate the hazard of developing POAG in people with various components of metabolic syndrome, obesity, or their combination.

RESULTS

Of the total 287,553 subjects, 4,970 (1.3%) developed POAG. High fasting glucose, blood pressure, and total cholesterol levels were all associated with increased risk of developing POAG. Regarding obesity level, people with body mass index (BMI) greater than 30 kg/m² were more likely to develop POAG than those with normal BMI. Also, people with greater number of metabolic syndrome components showed a greater POAG incidence. People who are metabolically unhealthy and obese (adjusted hazard ratio [HR], 1.574; 95% confidence interval [CI], 1.449 to 1.711) and those who are metabolically unhealthy nonobese (MUNO: adjusted HR, 1.521; 95% CI, 1.405 to 1.645) but not those who are metabolically healthy obese (MHO: adjusted HR, 1.019; 95% CI, 0.907 to 1.144) had an increased hazard of developing POAG compared with metabolically healthy nonobese (MHNO) subjects.

CONCLUSION

Metabolic health status and obesity were significantly associated with increased risk of POAG incidence. MUNO subjects but not MHO subjects showed a higher risk of POAG development than did MHNO subjects, suggesting that metabolic status is more important than obesity in POAG.

Retinal layer abnormalities and their association with clinical and brain measures in psychotic disorders: A preliminary study

Studies utilizing optical coherence tomography (OCT) in psychosis have identified abnormalities in retinal cytoarchitecture. We aim to analyze retinal layer topography in psychosis and its correlation with clinical and imaging parameters. Macular retinal images were obtained via OCT in psychosis probands (n = 25) and healthy controls (HC, n = 15). Clinical, cognitive and structural MRI data were collected from participants. No thinning was noted for the retinal nerve fiber, ganglion cell or inner plexiform layers. We found significant thinning in the right inner temporal, right central, and left inner superior quadrants of the outer nuclear layer (ONL) in probands compared to HC. Thickening of the outer plexiform layer (OPL) was observed in the right inner temporal, left inner superior, and left inner temporal quadrants. The right inner temporal and left inner superior quadrants of both the OPL and ONL showed significant inverse correlations. Retinal pigment epithelium thinning correlated with worse mania symptoms, and thinning in the ONL was associated with worse cognitive function. ONL thinning was also associated with smaller total brain and white matter volume. Our findings suggest that outer retinal layers may provide additional insights into the pathophysiology of psychosis, possibly reflecting synaptic or inflammatory aberrations that lead to retinal pathologies.

Retinal Nerve Fiber Layer Thickness Decrease in Obesity as a Marker of Neurodegeneration

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a serious condition that is frequently associated with irreversibly vision loss, having a higher incidence among obese women. Our aims were to screen subclinical IIH in obese patients scheduled to bariatric surgery using peripapillary retinal nerve fiber layer (RNFL) thickness and to evaluate if the findings demand the possible need of a preoperative evaluation in this population.

METHODS

This study included 111 eyes from 36 obese patients (86% female, body mass index > 35 kg/m²) scheduled to bariatric surgery and 20 non-obese (body mass index < 25 kg/m²) age-matched controls. We measured sectorial and mean RNFL thickness in a 3.5-mm-diameter circular scan centered on the optic nerve head, using optical coherence tomography (Heidelberg Spectralis SD-OCT) in all participants. Multivariate linear regression was used for adjustments.

RESULTS

No patient had subclinical IIH corresponding to increased RNFL thickness. However, in obese individuals, global peripapillary RNFL was thinner than in controls (104 ± 6 μm versus 99 ± 12 μm, p = 0.005). Overall, RNFL thickness was superior in the control group for all sectors. The differences reached significance for the nasal, temporal, superior temporal, and inferior temporal sectors. These differences remained even after adjusting for possible confounders (hypertension, dyslipidemia, diabetes, age, sleep apnea syndrome, and sex).

CONCLUSIONS

Routine screening asymptomatic obese patients undergoing bariatric surgery for IIH using RNFL thickness was not clinically relevant in our study. However, we found that severe obesity is associated with neurodegeneration independently of the other components of the metabolic syndrome, what may justify future investigation on the need of monitoring these patients.

An investigation of retinal layer thicknesses in unaffected first-degree relatives of schizophrenia patients

INTRODUCTION

A large number of studies using different neuroimaging methods showed various structural changes both in patients and their unaffected first-degree relatives (FDRs) over the past years. Optical coherence tomography (OCT) is a relatively new, non-invasive imaging method used to obtain high-resolution cross-sectional images of the retina. A growing body of evidence reports thinning of retinal layers in patients with schizophrenia which is considered as a proxy for CNS alterations. We hypothesized that retinal layer changes would be observed in FDRs, in parallel with those seen in patients, as a potential endophenotype candidate.

METHODS

Thirty-eight schizophrenia patients, 38 FDRs of schizophrenia and 38 age and gender-matched healthy subjects with no family history (HCs) were recruited to this study. OCT measurements were performed and peripapillary retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL) and macular thicknesses were measured.

RESULTS

The groups did not differ on RNFL, macular or GCL thickness. However, IPL thickness was significantly lower in both patients and FDRs than HCs (p = .025 and p = .041, respectively). The difference between groups remained significant after controlling for confounders such as age, gender, smoking status, comorbid medical diseases and BMI (p = .016 patients vs HCs and p = .014 FDRs vs HCs).

CONCLUSION

Our findings suggest that IPL thinning may hold promise as a useful endophenotype for genetic and early detection studies. The evaluation of this area could provide an important avenue for elucidating some of the neurodevelopmental aberrations in the disorder.

A Meta-analysis of Retinal Cytoarchitectural Abnormalities in Schizophrenia and Bipolar Disorder

BACKGROUND

Schizophrenia (SZ) and bipolar disorder (BD) are characterized by reductions in gray matter and white matter. Limitations in brain imaging have led researchers to use optical coherence tomography (OCT) to explore retinal imaging biomarkers of brain pathology. We examine the retinal layers that may be associated with SZ or BD.

METHODS

Articles identified using PubMed, Web of Science, Cochrane Database. Twelve studies met inclusion for acutely/chronically ill patients. We used fixed or random effects meta-analysis for probands (SZ and BD), SZ or BD eyes vs healthy control (HC) eyes. We adjusted for sources of bias, cross-validated results, and report standardized mean differences (SMD). Statistical analysis performed using meta package in R.

RESULTS

Data from 820 proband eyes (SZ = 541, BD = 279) and 904 HC eyes were suitable for meta-analysis. The peripapillary retinal nerve fiber layer (RNFL) showed significant thinning in SZ and BD eyes compared to HC eyes (n = 12, SMD = -0.74, -0.51, -1.06, respectively). RNFL thinning was greatest in the nasal, temporal, and superior regions. The combined peripapillary ganglion cell layer and inner plexiform layer (GCL-IPL) showed significant thinning in SZ and BD eyes compared to HC eyes (n = 4, SMD = -0.39, -0.44, -0.28, respectively). No statistically significant differences were identified in other retinal or choroidal regions. Clinical variables were unrelated to the RNFL or GCL-IPL thickness by meta-regression.

CONCLUSION

The observed retinal layer thinning is consistent with the classic gray- and white-matter atrophy observed on neuroimaging in SZ and BD patients. OCT may be a useful biomarker tool in studying the neurobiology of psychosis.

Diabetes in Iran: Prospective Analysis from First Nationwide Diabetes Report of National Program for Prevention and Control of Diabetes (NPPCD-2016)

We estimated proportions of different types of diabetes, comorbidities, treatment (the use of oral glucose-lowering agents and insulin), control (hyperglycemia, dyslipidemia and hypertension) and chronic microvascular and macrovascular complications among people with diabetes presenting to the tertiary-care academic diabetes outpatient clinics in Iran. This study is the prospective analysis of data (n = 30,202) from the registry of university-affiliated adult outpatient diabetes clinics in the country during 2015-2016. The proportions of type 1 diabetes, types 2 diabetes, and other types of diabetes were 11.4%, 85.5%, and 1.3%, respectively. The frequencies of drug-naivety, use of oral agents, insulin monotherapy and insulin combination therapy were 2.9%, 60.5%, 11.5%, and 25.1%, respectively. Around 13.2%, 11.9% and 43.3% of patients with diabetes had controlled hyperglycemia, hyperlipidemia and hypertension, respectively. The proportions of retinopathy, nephropathy, peripheral neuropathy, diabetic foot, and ischemic heart disease were 21.9%, 17.6%, 28.0%, 6.2%, and 23.9%, respectively. Despite the wide availability of medications and insulin coverage in Iran, the estimated national control of hyperglycemia, hyperlipidemia and hypertension (especially for young men and old women) remains subpar. The present study further suggests that the frequencies of chronic vascular complications among patients with diabetes are relatively high in Iran.