Association between Renal Function and Open-Angle Glaucoma

Looking into the Eyes to See the Heart of Chronic Kidney Disease Patients

In patients with chronic kidney disease (CKD), the main cause of morbidity and mortality is cardiovascular disease (CVD). Both coronary artery calcium scoring by computed tomography (CT) and optical coherence tomography (OCT) are used to identify patients at increased risk for ischemic heart disease, thereby indicating a higher cardiovascular risk profile. Our study aimed to investigate the utility of these techniques in the CKD population. In patients with CKD, OCT was used to measure the choroidal thickness (CHT) and the thickness of the peripapillary retinal nerve fiber layer (pRNFL). A total of 127 patients were included, including 70 men (55%) with an estimated glomerular filtration rate (eGFR) of 39 ± 30 mL/min/1.73 m2. Lower pRNFL thickness was found to be related to high-sensitivity troponin I (r = -0.362, p < 0.001) and total coronary calcification (r = -0.194, p = 0.032). In a multivariate analysis, pRNFL measurements remained associated with age (β = -0.189; -0.739--0.027; p = 0.035) and high-sensitivity troponin I (β = -0.301; -0.259--0.071; p < 0.001). Severe coronary calcification (Agatston score ≥ 400 HU) was related to a worse eGFR (p = 0.008), a higher grade of CKD (p = 0.036), and a thinner pRNFL (p = 0.011). The ROC curve confirmed that the pRNFL measurement could determine the patients with an Agatston score of ≥400 HU (AUC 0.638; 95% CI 0.525-0.750; p = 0.015). Our study concludes that measurement of pRNFL thickness using OCT is related to the markers associated with ischemic heart disease, such as coronary calcification and high-sensitivity troponin I, in the CKD population.

Trends in the Prevalence of Blindness and Correlation With Health Status in Korean Adults: A 10-Year Nationwide Population-Based Study

BACKGROUND

Contemporary data on vision impairment form an important basis for public health policies. However, most data on the clinical epidemiology of blindness are limited by small sample sizes and focused not on systemic conditions but ophthalmic diseases only. In this study, we examined the ten-year trends of blindness prevalence and its correlation with systemic health status in Korean adults.

METHODS

This study investigated 10,000,000 participants randomly extracted from the entire Korean population (aged ≥ 20 years) who underwent a National Health Insurance Service health checkup between 2009 and 2018. Participants with blindness, defined as visual acuity in the better-seeing eye of ≤ 20/200, were identified. The prevalence of blindness was assessed, and the systemic health status was compared between participants with blindness and without blindness.

RESULTS

The mean prevalence of blindness was 0.473% (47,115 blindness cases) and tended to decrease over ten years (0.586% in 2009 and 0.348% in 2018; P < 0.001). The following factors were significantly associated with blindness: female sex, underweight (body mass index < 18.5), high serum creatinine (> 1.5 mg/dL), and bilateral hearing loss. In addition, except for those aged 30-39 and 40-49 years, high fasting glucose (≥ 126 mg/dL) and low hemoglobin (male: < 12 g/dL, female: < 10 g/dL) were significantly correlated with prevalent blindness.

CONCLUSION

Our ten-year Korean nationwide population-based study suggested a gradual decrease in the prevalence of blindness and its association with specific systemic health status. These conditions might be the cause or consequence of blindness and can be used as a reference for the prevention and/or rehabilitation of blindness to establish public health policies.

Association between atrial fibrillation and the risk of glaucoma development: a 12-year Nationwide cohort study

OBJECTIVE

To investigate the risk of glaucoma development in patients with atrial fibrillation (A-fib) using Korean National Health Insurance Service data.

METHODS

The present study used a National Sample Cohort consisting of approximately one million random subjects who were tracked from 2002 to 2013 (12 years). Newly diagnosed glaucoma and A-fib were included based on the Korean Classification of Disease codes. The A-fib group consisted of patients who received an initial A-fib diagnosis between January 2003 and December 2007 as an index period (n = 8765). The control group (n = 43,352) was selected using a 1:5 propensity-score matching for social and demographic factors. Each subject was followed up until 2013. Multivariate Cox proportional hazard regression analysis was performed to compare the risk of glaucoma development between the A-fib group and the control group.

RESULTS

The rate of glaucoma development was 3.54% in the A-fib group and 2.96% in the control group (P < 0.0001). A-fib increased the risk of glaucoma development [hazard ratio = 1.31; 95% confidence interval (CI): 1.15 to 1.48] after adjusting for age, sex, comorbidities, residence, household income, and year of enrollment. In multivariable Cox regression analysis, patients with comorbidity of diabetes mellitus and chronic renal failure and those aged ≥50 years showed significantly higher risk of glaucoma development (all P < 0.001).

CONCLUSIONS

A-fib was significantly associated with the development of glaucoma after adjusting for potential confounding factors. Physicians may need to monitor patients with A-fib carefully for possible glaucoma development.

Co-occurrence of chronic kidney disease and glaucoma: Epidemiology and etiological mechanisms

As the histology, physiology, and pathophysiology of eyes and kidneys show substantial overlap, it has been suggested that eye and kidney diseases, such as glaucoma and chronic kidney disease (CKD), may be closely interlinked. We review the relationship between CKD and various subtypes of glaucoma, including primary open-angle glaucoma, primary angle- closure glaucoma, normal tension glaucoma, pseudoexfoliation syndrome, and several glaucoma endophenotypes. We also discuss the underlying pathogenic mechanisms and common risk factors for CKD and glaucoma, including atherosclerosis, the renin-angiotensin system, genes and genetic polymorphisms, vitamin D deficiency, and erythropoietin. The prevalence of glaucoma appears elevated in CKD patients, and vice versa, and the literature points to many intriguing associations; however, the associations are not always confirmed, and sometimes apparently opposite observations are reported. Glaucoma and CKD are complex diseases, and their mutual influence is only partially understood.

Accelerated Peripapillary Retinal Nerve Fiber Layer Degeneration in Patients With Chronic Kidney Disease: A 2-Year Longitudinal Study

Purpose

To evaluate the longitudinal changes in the peripapillary retinal nerve fiber layer (pRNFL) in patients with chronic kidney disease (CKD).

Methods

In this prospective cohort study, the CKD group consisted of patients with CKD stage ≥ 3. Age-matched healthy controls were enrolled at a 1:4 ratio. Spectral-domain optical coherence tomography was used to measure the pRNFL at baseline, 1 year, and 2 years. Within-group longitudinal changes and between-group comparisons were performed using linear mixed models.

Results

Overall, 152 patients with CKD and 40 controls were included (mean ages, 62.8 ± 9.1 years vs. 63.0 ± 9.3 years; P = 0.931). The CKD group showed faster loss of pRNFL than the control group (-0.87 µm/y vs. -0.26 µm/y; P = 0.004). Subgroup analysis found that the rate of pRNFL change was -0.41 µm/y in stage 3a CKD, -0.74 µm/y in stage 3b, -0.98 µm/y in stage 4/5, and -1.38 µm/y in end-stage renal disease. Multiple linear regression analysis revealed that CKD stage (coefficient = -0.549; 95% confidence interval [CI], -0.966 to -0.131; P = 0.010), hypertension (coefficient = -1.557; 95% CI -3.013 to -0.101; P = 0.036), and rim area (coefficient = -1.505; 95% CI, -2.940 to -0.070; P = 0.040) were factors associated with the pRNFL change over 2 years.

Conclusions

Patients with CKD experienced faster pRNFL loss than healthy controls did. Severity of CKD, hypertension, and rim area were independent factors associated with the loss of pRNFL.

Translational Relevance

This study contributes to our understanding of retinal neurodegeneration in normal aging and in patients with chronic kidney diseases.

Prevalence of Glaucoma and Its Systemic Risk Factors in a General Japanese Population: The Hisayama Study

Purpose

To estimate the prevalence of glaucoma and its risk factors in a Japanese community.

Methods

This study included 3405 Japanese community dwellers who were ≥40 years of age and enrolled in the Hisayama Study. This population-based, cross-sectional study was conducted from 2017 to 2018. A glaucoma screening test was performed using stereo fundus images and swept-source optical coherence tomography. Glaucoma was defined based on the International Society of Geographical and Epidemiological Ophthalmology criteria.

Results

The prevalence of glaucoma was 7.6% (95% confidence interval [CI], 6.7–8.6) overall. The prevalence of primary open-angle glaucoma (POAG) was 5.8% (95% CI, 5.0–6.6); that of primary angle-closure glaucoma (PACG) was 0.7% (95% CI, 0.5–1.1); and that of exfoliation glaucoma was 1.1% (95% CI, 0.7–1.4). In addition to aging, lower estimated glomerular filtration rate (eGFR) (odds ratio [OR] = 1.15; 95% CI, 1.02–1.33), higher intraocular pressure (OR = 1.06; 95% CI, 1.01–1.12), longer axial length (OR = 1.44; 95% CI, 1.31–1.59), and thinner central corneal thickness (CCT) (OR = 1.09; 95% CI, 1.04–1.15) were significant risk factors for POAG. Diabetes (OR = 2.81; 95% CI, 1.19–6.62) was a significant risk factor for PACG, and diabetes (OR = 2.15; 95% CI, 1.03–4.47) and thinner CCT (OR = 1.14; 95% CI, 1.02–1.28) were significant risk factors for exfoliation glaucoma.

Conclusions

The prevalence of glaucoma was approximately 8%, probably due to the increase in the Japanese aging population. Not only ocular factors but also lower eGFR for POAG and diabetes for PACG and exfoliation glaucoma were risk factors in a general Japanese population.

Translational Relevance

Systemic factors such as eGFR and diabetes must also be considered when implementing preventive measures against glaucoma.

Bidirectional association between glaucoma and chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

Glaucoma and chronic kidney disease (CKD) are prevalent and debilitating conditions, with common pathogenic pathways like oxidative stress and fluid dysregulation. We evaluated if there is a bidirectional association between them, as previous studies have yielded conflicting results.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase and Cochrane Library from inception until 15 June 2021, including full-length English articles published in peer-reviewed journals reporting on glaucoma and CKD as either exposure or outcome, among participants aged ≥18 years. We pooled overall summary estimates of odds ratios using random-effect meta-analysis and conducted subgroup meta-analyses and univariate meta regression. We assessed risk of bias using the Newcastle-Ottawa Scale (NOS) and quality of evidence using the GRADE framework. Our article is PROSPERO-registered and adherent to both PRISMA and MOOSE guidelines. This review is registered with PROSPERO (CRD42021262846).

FINDINGS

We identified 14 articles comprising of 3 retrospective cohort studies and 12 cross-sectional studies from 2,428 records, including 1,978,254 participants. Risk of bias was low to moderate. Participants with CKD at baseline had higher pooled odds of glaucoma (odds ratio[OR]=1.18, 95% confidence interval[CI]=1.04-1.33, I²=66%, N=12) compared to participants without CKD. The association remained significant in subgroups of longitudinal studies, participants with diabetes, East Asian studies and primary open-angle glaucoma. In the reverse direction, participants with glaucoma at baseline had over three-fold higher odds of incident CKD compared to participants without glaucoma after 10-15 years of follow-up in longitudinal studies (OR=3.67, 95% CI=2.16-6.24, I²=75%, N=2). All studies adjusted for age and sex, while most studies adjusted for comorbidities such as diabetes and hypertension. Meta-regression identified ethnicity (East Asians vs Non-East Asians) as a significant effect moderator. Associations were robust to trim-and-fill adjustment for publication bias, single-study influence and cumulative meta-analyses.

INTERPRETATION

Our meta-analysis suggests a bidirectional relationship between glaucoma and CKD, particularly among East Asians. Further studies are required to elucidate underlying mechanisms and account for differential association by ethnicity.

FUNDING

Ching-Yu Cheng is supported by Clinician Scientist Award (NMRC/CSA-SI/0012/2017) of the Singapore Ministry of Health's National Medical Research Council.

Comparison of peripapillary retinal nerve fiber layer and macular thickness in non-diabetic chronic kidney disease and controls

Objective

This study aimed to compare the peripapillary retinal nerve fiber layer (pRNFL) thickness and macular thickness (MT) between patients with non-diabetic chronic kidney disease (NDCKD) and controls, as well as between different stages of NDCKD. We also evaluated the correlation between pRNFL thickness and MT with duration of NDCKD.

Methods

This was a comparative cross-sectional study. Subjects were divided into NDCKD and control groups. Both pRNFL thickness and MT, including center subfield thickness (CST), average MT as well as average ganglion cell-inner plexiform layer (GC-IPL) were measured using spectral-domain optical coherence tomography. One-way ANCOVA test was used to compare the differences in pRNFL and MT between NDCKD and controls, as well as between the different stages of NDCKD. Spearman rank-order correlation coefficients were employed to determine the effects of NDCKD duration on pRNFL thickness and MT.

Results

A total of 132 subjects were recruited, 66 with NDCKD and 66 controls. There was a statistically significant difference in superior (110.74 ± 23.35 vs 117.36 ± 16.17 μm, p = 0.022), nasal (65.97 ± 12.90 vs 69.35 ± 10.17 μm, p = 0.006), inferior quadrant (117.44 ± 23.98 vs 126.15 ± 14.75 μm, p = 0.006), average pRNFL (90.36 ± 14.93 vs 95.42 ± 9.87 μm, p = 0.005), CST (231.89 ± 26.72 vs 243.30 ± 21.05 μm, p = 0.006), average MT (268.88 ± 20.21 vs 274.92 ± 12.79 μm, p = 0.020) and average GC-IPL (75.48 ± 12.44 vs 81.56 ± 6.48, p = 0.001) values between the NDCKD group and controls. The superior quadrant (p = 0.007), nasal quadrant (p = 0.030), inferior quadrant (p = 0.047), average pRNFL (p = 0.006), average MT (p = 0.001) and average GC-IPL (p = 0.001) differed significantly between different stages of NDCKD. There was no correlation between pRNFL thickness and MT with duration of NDCKD.

Conclusion

CST, average MT, average GC-IPL thickness, average pRNFL and all quadrants of pRNFL except the temporal quadrant were significantly thinner in NDCKD patients compared to controls. These changes were associated with the severity of CKD, but not its duration.

GUNN's DOTS AS INDICATORS OF RENAL FUNCTION, FINDINGS FROM THE TONGREN HEALTH CARE STUDY

PURPOSE

To investigate the prevalence of Gunn's dots (GDs) and associated systemic factors in adult Chinese.

METHODS

A cross-sectional study enrolling participants older than 45 years from a community-based study. Gunn's dots were evaluated using fundus photography, and associated systemic factors were analyzed. Patients with any retinal or optic neuropathy were excluded.

RESULTS

The study included 4,118 participants (mean age: 58.3 ± 9.9 years; male: 1,699/41.3%). Gunn's dots were found in 931 participants, with a prevalence of 22.6 ± 0.8% (95% confidence interval [CI]: 21.3-23.9). Systemic factors associated with a higher GD prevalence were younger age (odds ratio [OR]: 0.92; 95% CI: 0.91-0.93; P < 0.001), higher estimated glomerular filtration rate (eGFR) (OR: 1.01; 95% CI: 1.001-1.02; P = 0.022), and higher serum concentration of triglycerides (OR: 1.08; 95% CI: 1.004-1.16; P = 0.040). The GD prevalence was 3.5 (OR = 3.46; 95% CI: 1.06-11.35) and 4.4 (OR = 4.37; 95% CI: 1.27-15.09) times greater for participants with an eGFR of ≥90 mL/minute/1.73 m2 and an eGFR of ≥100 mL/minute/1.73 m2, respectively, as compared with participants with an eGFR of <60 mL/minute/1.73 m2.

CONCLUSION

The GD prevalence (mean: 22.6%) was associated with younger age, higher eGFR, and higher serum triglyceride concentrations. The presence of GDs may serve as indicators of healthy renal function.

Association between chronic kidney disease and open-angle glaucoma in South Korea: a 12-year nationwide retrospective cohort study

Various non-intraocular pressure factors have been identified as possible risk factors for open-angle glaucoma (OAG). However, there is still controversy around the association between OAG and chronic kidney disease (CKD). In this study, we used a nationwide cohort to investigate the risk of OAG in the 12 years following a diagnosis of CKD. This retrospective cohort study included 1,103,302 subjects from the Korean National Health Insurance Service National Sample Cohort database. The CKD group (n = 1318) included patients who were initially diagnosed with CKD between 2003 and 2008. The subjects in the comparison group were matched at a 1:5 ratio using propensity scores. In multivariate Cox regression analysis, a diagnosis of CKD was significantly associated with an increased incidence of OAG (hazard ratio [HR] = 1.546, 95% confidence interval [CI] 1.363–1.754, p < 0.001). Further analysis revealed that the risk of OAG increased with the severity of CKD (mild to moderate CKD [CKD stage 1–3]: HR = 1.280, 95% CI 1.077–1.521, p = 0.005; advanced CKD [CKD stage 4–5]: HR = 1.861, 95% CI 1.589–2.180, p < 0.001). In subgroup analysis, female CKD patients had a greater risk of developing OAG than males, and subjects with CKD aged ≥ 40 years were more likely to develop OAG compared with those aged < 40 years. Our study demonstrates that CKD is a significant risk factor for OAG and that severe CKD is associated with an increased risk of developing OAG.

Effect of Hemodialysis on Peripapillary Choroidal Thickness Measured by Swept-Source Optical Coherence Tomography

PURPOSE

The aim was to investigate the effects of hemodialysis (HD) on peripapillary choroidal thickness (PCT) by swept-source optical coherence tomography and on other ophthalmologic parameters in patients with end-stage kidney disease.

MATERIALS AND METHODS

This was a prospective observational study. The authors evaluated 29 patients who underwent HD for end-stage kidney disease. Detailed ophthalmologic examinations and swept-source optical coherence tomography were performed immediately before and after HD. PCT was measured using the modification tool in the built-in OCT image viewer program. Changes in PCT before and after HD were statistically analyzed.

RESULTS

The average PCT significantly decreased from 127.3±49.2 μm before HD to 117.1±50.9 μm after HD (P<0.001). A significant correlation was found between changes in PCT and macular choroidal thickness (ρ=0.547, P=0.002). Changes in mean ocular perfusion pressure did not significantly correlate with changes in PCT (ρ=-0.049, P=0.803).

CONCLUSIONS

PCT significantly decreased after HD. HD could influence the optic nerve head and its surrounding structures.

Association Between Chronic Renal Disease and the Risk of Glaucoma Development: A 12-year Nationwide Cohort Study

Purpose

The purpose of this study was to present the results of our investigation into the risk of glaucoma development in patients with chronic renal disease (CRD).

Methods

The present retrospective cohort study used the Korean National Health Insurance Service data, which consisted of 1,025,340 random subjects who were tracked from 2002 to 2013. Newly diagnosed glaucoma and CRD were included on the basis of the Korean Classification of Disease codes. The CRD group consisted of patients who received an initial CRD diagnosis between January 2003 and December 2007 as an index period (n = 3640). The control group (n = 17,971) was selected using 1:5 propensity-score matching using social and demographic factors, along with the year of enrollment. Each group subject was followed until 2013. We used multivariate Cox proportional hazard regression analysis to compare the risk of glaucoma development between the two groups.

Results

Glaucoma consecutively developed in 4.3% in the CRD group and 2.8% in the control group (P < 0.0001). CRD increased the risk of glaucoma development (hazard ratio [HR] = 1.63, 95% confidence interval [CI] = 1.34–1.98] after adjusting for age, sex, comorbidities, residence, household income, and the year of enrollment. In multivariate Cox regression analysis, patients with comorbidity of hypertension, diabetes mellitus, or aged ≥ 50 years showed a significantly higher risk of glaucoma development (all P < 0.008).

Conclusions

A significant association between CRD and following development of glaucoma was revealed after adjusting the potential confounding factors.

Association Between the Asymmetric Dimethylarginine Levels and Glaucoma Severity: A Cross-Sectional Analysis of the LIGHT Study

Purpose

Asymmetric dimethylarginine (ADMA), a potent endogenous inhibitor of nitric oxide synthase, may be involved in the pathophysiology of glaucoma by dysfunctioning nitric oxide and oxidative stress. The purpose of this study was to determine whether the serum ADMA level is associated with the severity of glaucoma.

Methods

One hundred twenty-five patients with glaucoma (mean age 69.4 years) were analyzed in this cross-sectional study. The severity of glaucoma was determined by the visual field mean deviation in the worse eye; severe, a mean deviation ≤ -12 dB; and mild, a mean deviation > -12 dB. The serum ADMA levels were classified into three groups according to tertiles; low (T1), intermediate (T2), and high group (T3).

Results

The mean serum ADMA levels in the severe glaucoma group was significantly higher than that in the mild glaucoma group (0.41 vs. 0.39 µmol/L; P = 0.031). A significantly higher prevalence of patients with severe glaucoma was found in the T3 group than that in the T1 group (T1, 44.7% and T3, 68.2%; P = 0.018). In the multivariable logistic regression analysis adjusted for the potential confounders, e.g., age, sex, obesity, smoking, hypertension, diabetes, and renal function, the odds ratio for severe glaucoma in the T3 group was significantly higher than that in the T1 group (odds ratio 3.02; 95% confidence interval 1.04 to 8.79; P = 0.043).

Conclusions

A significant association between higher serum ADMA levels and severe glaucoma was found, and this association remained significant after adjusting for the potential confounders.

Nationwide Glaucoma incidence in end stage renal disease patients and kidney transplant recipients

Glaucoma shares common risk factors with chronic kidney disease (CKD) but previous cross-sectional studies have demonstrated discrepancies in the risk of glaucoma in CKD patients. This study enrolled kidney transplantation recipients (KTRs) (n = 10,955), end stage renal disease (ESRD) patients (n = 10,955) and healthy controls (n = 10,955) from National Health Insurance Service database of the Republic of Korea. A Cox proportional hazard regression model was used to calculate the hazard ratios (HR) for primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) incidences. The incidence of POAG was higher in ESRD patients (3.36/1,000 person-years, P < 0.0001) and KTRs (3.22 /1,000 person-years, P < 0.0001), than in healthy controls (1.20/1,000 person-years). However, POAG risk showed no significant increase in either ESRD patients (P = 0.07) or KTRs (P = 0.08) when adjusted for the confounding factors. The incidence of PACG was significantly higher in ESRD patients (0.41/1,000 person-years) than in healthy controls (0.14/1,000 person-years, P = 0.008). The PACG incidence was significantly lower in KTRs than in ESRD patients (HR = 0.35, P = 0.015). In conclusion, this nationwide cohort study demonstrated that kidney transplantation can reduce the risk of PACG but not POAG in ESRD patients.

Retinal neurovascular changes in chronic kidney disease

PURPOSE

To examine retinal neurovascular changes in patients with chronic kidney disease (CKD).

METHODS

Case-control study. A total of 171 CKD cases and 40 controls were recruited (mean age 62.9 ± 10.3 versus 60.8 ± 9.2, p = 0.257). Retinal neural parameters, including parafoveal retinal thickness (PfRT), macular ganglion cell complex thickness (GCCt), global loss volume (GLV), focal loss volume (FLV) and peripapillary retinal nerve fibre layer thickness (RNFLt), were measured using optical coherence tomography (OCT). Microvascular parameters, including foveal avascular zone size, vessel density over the parafoveal superficial vascular plexus (SVP-VD), parafoveal deep vascular plexus (DVP-VD) and radial peripapillary capillary (RPC-VD), were measured using OCT angiography.

RESULTS

Chronic kidney disease (CKD) patients showed reduced PfRT, GCCt and RNFLt and increased GLV and FLV compared with the controls (all p < 0.005). Among patients with CKD, estimated glomerular filtration rate was an independent factor associated with PfRT (coefficient 0.19, p = 0.015), GCCt (coefficient 0.10, p = 0.006), GLV (coefficient - 0.08, p = 0.001), FLV (coefficient - 0.02, p = 0.006) and RNFLt (coefficient 0.15, p = 0.002). Parafoveal retinal thickness (PfRT), GCCt, GLV, FLV and RNFLt were correlated with SVP-VD (all p < 0.001) but not with DVP-VD (all p > 0.1).

CONCLUSIONS

Chronic kidney disease (CKD) patients demonstrated a significant reduction in macular thickness and changes in retinal neural parameters. These changes were associated with the severity of CKD and correlated with the microvascular rarefaction in the parafoveal SVP.

Glaucoma patients have an increased level of trimethylamine, a toxic product of gut bacteria, in the aqueous humor: a pilot study

Purpose

Animal studies suggest that gut bacteria metabolites are involved in regulation of intraocular pressure or development of glaucoma. However, clinical data are lacking. Here, we wanted to compare level of trimethylamine (TMA), an uremic toxin produced by gut bacteria, along with betaine and trimethylamine N-oxide (TMAO), a substrate and a product of its metabolism, in the aqueous humor and in plasma of patients with glaucoma and their controls.

Methods

Twenty patients were selected for cataract phacoemulsification, and 20 patients selected for phacotrabeculectomy were enrolled in the study. Patients were matched with controls on systemic diseases and estimated glomerular filtration rate. Blood samples were collected in the preoperative suite, whereas aqueous humor samples were collected as the first step of both procedures. Subsequently, level of betaine, TMA and TMAO was analyzed by means of chromatography.

Results

In the aqueous humor, level of TMA, but not betaine or TMAO, was significantly higher in the phacotrabeculectomy group than in the phacoemulsification group. Plasma level of betaine, TMA and TMAO was similar between groups. In both groups, level of betaine and TMA, but not TMAO, was significantly higher in plasma than in the aqueous humor.

Conclusion

TMA, but not TMAO or betaine level, is increased in the aqueous humor of patients with glaucoma. TMA might play a role in pathogenesis of glaucoma; however, prospective studies are needed to confirm our findings.

Primary Open-angle Glaucoma and Increased Risk of Chronic Kidney Disease

PRECIS

The association between primary open-angle glaucoma (POAG) and subsequent development of chronic kidney disease (CKD) was investigated using a nationwide, population-based, retrospective cohort in South Korea. POAG increases the risk of subsequent CKD development.

PURPOSE

The purpose of this study was to investigate the risk of subsequent CKD development in patients with POAG.

METHODS

In this nationwide, population-based longitudinal cohort, 1,025,340 beneficiaries in the 2002-2013 Korean National Health Insurance database were included. We identified patients with incident POAG and evaluated the risk of subsequent CKD development using diagnostic codes from the database after 2-year wash-out periods. We applied time-varying covariate Cox regression analyses to determine the effect of POAG on the development of CKD: Model 1 included only POAG as a time-varying covariate; Model 2 included Model 1 and demographic information; and Model 3 included Model 2, comorbidity, comedication, and the Charlson Comorbidity Index score.

RESULTS

The fixed cohort included 478,303 eligible subjects, and of these subjects, 1749 suffered incident POAG, and 3157 developed CKD. POAG was associated with an increased risk of CKD development [hazard ratio (HR)=7.63; 95% confidence interval (CI), 5.89-9.87] in Model 1; HR=3.54 (95% CI, 2.73-4.58) in Model 2; and HR=2.90 (95% CI, 2.24-3.76) in Model 3].

CONCLUSION

POAG increased the risk of subsequent CKD in the general population, suggesting that POAG and CKD might share a common pathogenic mechanism.

Dyslipidemia, Dyslipidemia Treatment, and Open-angle Glaucoma in the Korean National Health and Nutrition Examination Survey

PURPOSE

The purpose of this study was to investigate the association between dyslipidemia treatment and open-angle glaucoma (OAG).

PATIENTS AND METHODS

We included 16,939 participants aged ≥40 years from the Korea National Health and Nutrition Examination Survey (2008 to 2012) and classified them into 2 groups based on current dyslipidemia treatment. The prevalence of OAG was determined using the modified International Society of Geographical and Epidemiological Ophthalmology criteria. The association between dyslipidemia treatment and OAG was evaluated using logistic mixed-effects model and propensity-score-weighted odds ratios.

RESULTS

Analyses using the 2 abovementioned models revealed that dyslipidemia treatment was not associated with OAG (odds ratio, 1.08; 95% confidence interval, 0.75-1.56; P=0.838 and 1.03; 0.71-1.48; P=0.882, respectively), presence of optic disc hemorrhage (0.64; 0.15-2.73; P=0.648 and 1.10; 0.39-3.11; P=0.855), high vertical cup-to-disc ratio or asymmetry (1.02; 0.81-1.28; P=0.736 and 0.95; 0.75-1.20; P=0.650), presence of retinal nerve fiber layer defects (0.97; 0.67-1.42; P=0.857 and 1.03; 0.75-1.42; P=0.857), and presence of visual field defects (0.93; 0.55-1.54; P=0.931 and 0.97; 0.81-1.52; P=0.528). Total cholesterol and high-density lipoprotein cholesterol were also not associated with OAG. However, higher serum triglyceride levels were associated with OAG in the treated patients (1.31; 1.02-1.68; P=0.027) but not in the untreated patients (1.03; 0.93-1.14; P=0.079).

CONCLUSIONS

In the Korean population, dyslipidemia treatment was not significantly associated with open-angle glaucoma. However, hypertriglyceridemia was associated with OAG in treated patients.

Relationships between Obesity, Nutrient Supply and Primary Open Angle Glaucoma in Koreans

To investigate the association between nutrient intake and primary open angle glaucoma (POAG) in Koreans, a population-based, cross-sectional survey, the Korean National Health and Nutrition Examination Survey, was analyzed. Glaucoma diagnosis was based on criteria established by the International Society of Geographic and Epidemiologic Ophthalmology. Multivariate regression analysis was used to assess the correlation between dietary intake and the prevalence of POAG in all enrolled subjects. In the low Body mass index(BMI) group (BMI <18.5), females with POAG had significantly lower intakes of energy, protein, fat, carbohydrate, ash, calcium, phosphorus, sodium, potassium, vitamin A, B-carotene, thiamin, riboflavin, and vitamin C than their non-glaucoma counterparts, based on a multivariate logistic regression analysis (all p < 0.05). In females with a medium BMI (18.5 ≤ BMI < 23), POAG showed a significant association with lower food intake, energy, protein, calcium, phosphorus, potassium, thiamin and niacin. (all p < 0.05). Lower protein thiamine intake in medium BMI males was related to POAG. Low dietary intake of several nutrients showed an association with glaucoma in low BMI female subjects. An insufficient intake of certain nutrients may be associated with an increased risk of glaucoma in Koreans. Further large-scale cohort studies are needed to determine how specific nutrients alter the risk of glaucoma.

Associations Among Pregnancy, Parturition, and Open-angle Glaucoma: Korea National Health and Nutrition Examination Survey 2010 to 2011

PURPOSE

The purpose of this study was to investigate the association between factors associated with parturition and open-angle glaucoma (OAG) in Korean females.

METHODS

A population-based, cross-sectional survey was performed from the Korean National Health and Nutrition Examination Survey from 2010 to 2011 and enrolled postmenopausal female participants (n=1798). We obtained information on demographics, comorbidities, and health-related behaviors and performed comprehensive ophthalmic examinations. Multivariate regression analysis was used to assess the correlation between pregnancy and delivery and the prevalence of OAG in all enrolled subjects.

RESULTS

The prevalence of OAG among study participants was 6.42%. There was a significant difference in the number of deliveries and age at first delivery between the OAG group and the nonglaucoma group. In multiple linear regression models adjusted for age, hypertension, and intraocular pressure only pregnancy 1 was associated with higher risk of OAG compared with pregnancy 2 (P=0.023). Subjects who had 3 or 4 deliveries were at higher risk of OAG compared with subjects with 2 deliveries (P=0.027). An age at first delivery of 16 to 20 years or 21 to 23 years was associated with increased OAG risk compared with the reference group (P<0.05).

CONCLUSIONS

A history of three or more deliveries and an age at first delivery younger than 23 years were associated with increased risk of OAG. These results suggest that changes or events during the period from pregnancy to delivery affect the development of glaucoma.

Association of serum uric acid levels with primary open-angle glaucoma: a 5-year case-control study

PURPOSE

It has been hypothesised that uric acid (UA) has a protective effect against oxidative damage in the central nervous system. Therefore, we investigated serum UA concentrations in patients with primary open-angle glaucoma (POAG) and explored the relationship between serum UA concentration and glaucoma severity.

METHODS

This prospective, cross-sectional, case-control study was conducted in 163 POAG patients and 103 normal controls. Clinical and demographic information was obtained from the medical data platform of the Eye & ENT Hospital of Fudan University, Shanghai, China. The POAG patients were categorised into mild [median deviation (MD) ≤ 6.00 dB], moderate (MD > 6 Db-≥12 dB) and severe (MD > 12 dB) subgroups, based on their visual field MD results.

RESULTS

The level of serum UA in the POAG group (0.321 ± 0.084 mmol/l) was approximately 12.77% lower (p < 0.001) than that of the control group (0.362 ± 0.053 mmol/l). The UA/creatinine (Cr) ratio was approximately 14.99% lower (p < 0.001) in patients with POAG (4.47 ± 1.15), compared with the control group (5.14 ± 1.05). The mean level of UA was lowest in the severe POAG group, followed by the moderate POAG group, and the mild POAG group (p < 0.001). A similar trend was observed when UA levels were compared between the POAG and control groups in males. Multivariate regression analyses showed a significant negative correlation between UA and vertical cup-disc ratio (B = -0.320, p = 0.034), and UA and MD (B = -0.441, p = 0.031) in males.

CONCLUSION

Primary open-angle glaucoma patients have lower UA levels; however, a negative association between UA levels and disease severity was evident in male patients.

Vision Impairment in CKD Patients: Epidemiology, Mechanisms, Differential Diagnoses, and Prevention

Eyes and kidneys have numerous structural, developmental, physiologic, and pathogenic pathways in common, suggesting that many kidney and eye diseases may be interlinked. Studies suggest that the prevalence of eye diseases and vision impairment are higher among persons with end-stage kidney disease and earlier stages of chronic kidney disease (CKD) than in those without. Ocular morbidity in persons with CKD and end-stage kidney disease may be due to the following risk factors: (1) underlying conditions and risk factors for CKD such as diabetes or hypertension, (2) metabolic disorders associated with CKD, (3) uremia and anemia, and (4) CKD treatment. Among the chief eye diseases, diabetic retinopathy and age-related macular degeneration are most consistently associated with CKD. Further research for eye diseases such as glaucoma and cataract is needed to determine their relationships with CKD. Despite the high prevalence and burden of vision impairment among persons with CKD, eye screening in patients with CKD is not currently recommended as standard practice. This review suggests that patients with CKD should be encouraged to undergo a complete eye examination. Furthermore, physicians should be aware that patients undergoing dialysis may develop acute eye problems such as acute glaucoma, and appropriate referral to ophthalmologists should be considered in those with a history of glaucoma or recent ocular surgery. Interdisciplinary collaboration between nephrologists and ophthalmologists will ensure enhanced and appropriate management of patients with CKD.

Association between Pretreatment Serum Uric Acid Levels and Progression of Newly Diagnosed Primary Angle-Closure Glaucoma: A Prospective Cohort Study

Purpose

Increased evidence reveals that uric acid (UA) may have an important neuroprotective effect through its antioxidant properties. The aim of the present study was to investigate the relationship between pretreatment serum UA levels and the progression of newly diagnosed primary angle-closure glaucoma (PACG).

Methods

This prospective observational cohort study included 64 patients with newly diagnosed PACG who were followed up for a mean period of 12.77 months (range: 3–28 months). All subjects underwent a complete ophthalmological examination during the baseline and final follow-up visits, together with the acquisition of blood samples for UA measurements. During the follow-up period, the progression of PACG was defined as a clinical diagnosis of medically uncontrolled intraocular pressure and a loss of visual field with a mean deviation of >1 dB/year. Univariable and multivariable Cox regression models were used to investigate the association between baseline serum UA levels and the progression of PACG. The cumulative probability of progression of glaucoma was analyzed using the Kaplan-Meier method.

Results

During follow-up, 32 subjects were defined as progressive PACG, among whom baseline UA values were significantly higher in nonprogressing subjects than in progressing subjects (0.314 ± 0.069 mmol/l versus [vs.] 0.258 ± 0.069 mmol/l, respectively; P = 0.002). Similar results were also observed in male and female subgroups (P < 0.05). In a multivariable model, a decreased baseline serum UA level was associated with an increased risk for progressing PACG: both in male (hazard ratio [HR] 6.088 [95% confidence interval (CI) 1.163–31.8638]; P = 0.032) and female subjects (HR 3.565 [95% CI 1.131–11.236]; P = 0.030). Subjects with high UA levels demonstrated higher cumulative probabilities of nonprogressing PACG than those with low UA levels (male [16.67% vs. 80.00%; P = 0.0084] and female [29.41% vs. 68.00%; P = 0.0182]).

Conclusion

An association between high baseline serum UA levels and a decreased risk for progressing PACG was found. This primary finding suggests that high serum UA levels may have a protective role against PACG and could slow disease progression.

Association Between Optic Disc Hemorrhage and Renal Function in South Korea

PURPOSE

The purpose of this article is to investigate the relationship between renal function and disc hemorrhage (DH).

MATERIALS AND METHODS

This retrospective cross-sectional survey was conducted at Kangbuk Samsung Hospital Health Screening Center between August 2012 and July 2013, and a total of 168,044 participants at least 20 years of age who voluntarily visited the health screening center for systemic and ophthalmologic examinations, including fundus photography, were enrolled. All subjects underwent a physical examination and provided samples for laboratory analysis. Digital fundus photographs of both eyes were taken and reviewed. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine concentration using the Modification of Diet in Renal Disease (MDRD) formula and Cockcroft-Gault (CG) formula. Subjects were stratified by eGFR into quartiles.

RESULTS

Among participants, 220 (0.1%) showed DH, and 2376 (1.6%) showed glaucomatous retinal nerve fiber layer defects. The DH group showed higher creatinine and lower eGFR than the non-DH group. A significant trend was observed among higher creatinine, decreased eGFR as obtained by the MDRD and CG formulas, and the prevalence of DH (P for trend ≤0.003, logistic regression analysis). A multiple logistic regression model adjusted for age, sex, hypertension, diabetes, and hyperlipidemia showed that the lowest eGFR quartiles estimated by MDRD and CG were significantly associated with DH compared with the highest eGFR quartile (adjusted odds ratio, 1.96; 95% confidence interval, 1.22-3.14 by CG, 1.86; 95% confidence interval, 1.17-2.96 by MDRD).

CONCLUSION

Renal function impairment was independently associated with a higher prevalence of DH in a South Korean population.

Impact of age at first childbirth on primary open-angle glaucoma

OBJECTIVE

No studies have addressed the relationship between the timing of first childbirth and primary open-angle glaucoma (POAG). The aim of the study was to identify the relationship between age at first childbirth and POAG and to examine the contribution of parity to the age at first childbirth-POAG relationship in postmenopausal women.

METHODS

The study population comprised postmenopausal women aged 50 or above in the cross-sectional Korea National Health and Nutrition Examination Survey from 2010 to 2012. Participants were grouped into quintiles by age at first childbirth for analysis. This study used logistic regression and mediation analyses with accommodations for the complex sampling structure of the survey.

RESULTS

Of the 4,057 women in the study population, the mean age at first childbirth was 23.7 years, and POAG prevalence was 3.4%. Prevalence of POAG was lowest in women whose first childbirth was between the ages of 27 and 44 (1.8%). Their risk for POAG (odds ratio [OR], 0.25; 95% CI, 0.10-0.65) was significantly lower than in those whose first childbirth was between the ages of 13 and 20, after adjustments for covariates. Late first delivery (≥27 y) was directly (OR, 0.57) and totally (OR, 0.85) associated with the decreased risk of POAG; decreased parity in women who delivered their first child at an older age attenuated the age at first childbirth-POAG relationship (OR of indirect effect, 1.50).

CONCLUSIONS

First childbirth at the age of 27 years or above decreases the risk of POAG in postmenopausal women. Decreased parity, caused by late first childbirth, attenuated the magnitude of the total effects of age at first childbirth on POAG.