Genetic Correlations Among Corneal Biophysical Parameters and Anthropometric Traits.

Purpose: The genetic architecture of corneal dysfunction remains poorly understood. Epidemiological and clinical evidence suggests a relationship between corneal structural features and anthropometric measures. We used global and local genetic similarity analysis to identify genomic features that may underlie structural corneal dysfunction. Methods: We assembled genome-wide association study summary statistics for corneal features (central corneal thickness, corneal hysteresis [CH], corneal resistance factor [CRF], and the 3 mm index of keratometry) and anthropometric traits (body mass index, weight, and height) in Europeans. We calculated global genetic correlations (rg) between traits using linkage disequilibrium (LD) score regression and local genetic covariance using ρ-HESS, which partitions the genome and performs regression with LD regions. Finally, we identified genes located within regions of significant genetic covariance and analyzed patterns of tissue expression and pathway enrichment. Results: Global LD score regression revealed significant negative correlations between height and both CH (rg = -0.12; P = 2.0 × 10-7) and CRF (rg = -0.11; P = 6.9 × 10-7). Local analysis revealed 68 genomic regions exhibiting significant local genetic covariance between CRF and height, containing 2874 unique genes. Pathway analysis of genes in regions with significant local rg revealed enrichment among signaling pathways with known keratoconus associations, including cadherin and Wnt signaling, as well as enrichment of genes modulated by copper and zinc ions. Conclusions: Corneal biophysical parameters and height share a common genomic architecture, which may facilitate identification of disease-associated genes and therapies for corneal ectasias. Translational Relevance: Local genetic covariance analysis enables the identification of associated genes and therapeutic targets for corneal ectatic disease.

Genetic Associations Between Smoking- and Glaucoma-Related Traits.

Purpose: The purpose of this study was to describe the genetic relationship between smoking and glaucoma. Methods: We used summary-level genetic data for smoking initiation, smoking intensity (cigarettes per day [CPD]), intraocular pressure (IOP), vertical cup-disc ratio, and open-angle glaucoma (OAG) to estimate global genetic correlations (rg) and perform two-sample Mendelian randomization (MR) experiments that explored relations between traits. Finally, we examined associations between smoking genetic risk scores (GRS) and smoking traits with measured IOP and OAG in Rotterdam Study participants. Results: We identified weak inverse rg between smoking- and glaucoma-related traits that were insignificant after Bonferroni correction. However, MR analysis revealed that genetically predicted smoking initiation was associated with lower IOP (-0.18 mm Hg per SD, 95% confidence interval [CI] = -0.30 to -0.06, P = 0.003). Furthermore, genetically predicted smoking intensity was associated with decreased OAG risk (odds ratio [OR] = 0.74 per SD, 95% CI = 0.61 to 0.90, P = 0.002). In the Rotterdam Study, the smoking initiation GRS was associated with lower IOP (-0.09 mm Hg per SD, 95% CI = -0.17 to -0.01, P = 0.04) and lower odds of OAG (OR = 0.84 per SD, 95% CI = 0.73 to 0.98, P = 0.02) in multivariable-adjusted analyses. In contrast, neither smoking history nor CPD was associated with IOP (P ≥ 0.38) or OAG (P ≥ 0.54). Associations between the smoking intensity GRS and glaucoma traits were null (P ≥ 0.13). Conclusions: MR experiments and GRS generated from Rotterdam Study participants support an inverse relationship between smoking and glaucoma. Translational Relevance: Understanding the genetic drivers of the inverse relationship between smoking and glaucoma could yield new insights into glaucoma pathophysiology.

Paired Optic Nerve Microvasculature and Nailfold Capillary Measurements in Primary Open-Angle Glaucoma.

Purpose: To assess microvascular beds in the optic nerve head (ONH), peripapillary tissue, and the nailfold in patients with primary open-angle glaucoma (POAG) versus controls. Methods: Patients with POAG (n = 22) and controls (n = 12) underwent swept-source optical coherence tomography angiography of ophthalmic microvasculature and nailfold video capillaroscopy of the hand. The main outcomes were vessel density (VD) and blood flow of the ONH, the peripapillary and the nailfold microvasculatures. Results: Patients with POAG were younger than controls (63.5 ± 9.4 vs. 69.9 ± 6.5 years, P = 0.03). Deep ONH VD and blood flow were lower in patients with POAG than controls (39.1% ± 3.5% vs. 43.8% ± 5.7%; 37.8% ± 5.3% vs. 46.0% ± 7.8%, respectively, P < 0.02 for both); similar results were observed with peripapillary VD (37.9 ± 2.6%, 43.4 ± 7.6%, respectively, P = 0.03). Nailfold capillary density and blood flow were lower in patients with POAG than controls (8.8 ± 1.0 vs. 9.8 ± 0.9 capillaries/mm; 19.9 ± 9.4 vs. 33.7 ± 9.8 pL/s, respectively; P < 0.009 for both). After adjusting for age and gender, deep ONH VD and blood flow, peripapillary VD, and nailfold capillary blood flow were lower in POAG than controls (ß = -0.04, -0.07, -0.05, -13.19, respectively, P ≤ 0.046 for all). Among all participants, there were positive correlations between deep ONH and nailfold capillary blood flow (Pearson's correlation coefficient r = 0.42, P = 0.02), peripapillary and nailfold capillary density (r = 0.43, P = 0.03), and peripapillary and nailfold capillary blood flow (r = 0.49, P = 0.01). Conclusions: Patients with POAG demonstrated morphologic and hemodynamic alterations in both ophthalmic and nailfold microvascular beds compared to controls. Translational Relevance: The concomitant abnormalities in nailfold capillaries and relevant ocular vascular beds in POAG suggest that the microvasculature may be a target for POAG treatment.

Regional Infoveillance of COVID-19 Case Rates: Analysis of Search-Engine Query Patterns.

BACKGROUND: Timely allocation of medical resources for coronavirus disease (COVID-19) requires early detection of regional outbreaks. Internet browsing data may predict case outbreaks in local populations that are yet to be confirmed. OBJECTIVE: We investigated whether search-engine query patterns can help to predict COVID-19 case rates at the state and metropolitan area levels in the United States. METHODS: We used regional confirmed case data from the New York Times and Google Trends results from 50 states and 166 county-based designated market areas (DMA). We identified search terms whose activity precedes and correlates with confirmed case rates at the national level. We used univariate regression to construct a composite explanatory variable based on best-fitting search queries offset by temporal lags. We measured the raw and z-transformed Pearson correlation and root-mean-square error (RMSE) of the explanatory variable with out-of-sample case rate data at the state and DMA levels. RESULTS: Predictions were highly correlated with confirmed case rates at the state (mean r=0.69, 95% CI 0.51-0.81; median RMSE 1.27, IQR 1.48) and DMA levels (mean r=0.51, 95% CI 0.39-0.61; median RMSE 4.38, IQR 1.80), using search data available up to 10 days prior to confirmed case rates. They fit case-rate activity in 49 of 50 states and in 103 of 166 DMA at a significance level of .05. CONCLUSIONS: Identifiable patterns in search query activity may help to predict emerging regional outbreaks of COVID-19, although they remain vulnerable to stochastic changes in search intensity.

Densitometric Profiles of Optic Disc Hemorrhages in the Ocular Hypertension Treatment Study.

PURPOSE: The origin of blood in glaucoma-related disc hemorrhages (DH) remains unknown. A prior clinic-based study of primary open-angle glaucoma (POAG)-related DH showed that they had grayscale pixel intensities more similar to blood from retinal macroaneurysms and adjacent retinal arterioles than to blood from retinal vein occlusions or adjacent retinal venules, suggesting an arterial source. Here we assessed the densitometric profile of DH from fundus photographs in the Ocular Hypertension Treatment Study (OHTS). DESIGN: Retrospective cross-sectional study of prospectively collected images. METHODS: Stereo disc photographs of 161 DH events from 83 OHTS participants (mean age [standard deviation (SD)]: 65.6 [9.2] years; 46.6% female; 13.0% black race) were imported into ImageJ to measure densitometry differences (adjacent arterioles minus DH [ΔA] or venules minus DH [ΔV]). Their size as percentage of disc area, ratio of length to midpoint width, and location relative to the disc margin were also analyzed. We performed t tests to compare ΔA and ΔV, analysis of variance to compare ΔA and ΔV across DH recurrent events, and multivariable linear regression to identify determinants of ΔA and ΔV. RESULTS: Mean (SD) ΔA and ΔV were -2.2 (8.7) and -11.4 (9.7) pixel intensity units, respectively (P < .001). ΔA and ΔV each did not differ significantly across recurrence of DH (P ≥ .92) or between DH events with and without POAG (P ≥ .26). CONCLUSIONS: OHTS DH had densitometric measurements more similar in magnitude to adjacent arterioles than venules, supporting an arterial origin for DH. Vascular dysregulation may contribute to disc hemorrhage formation in ocular hypertension.

Genetic Correlations Between Diabetes and Glaucoma: An Analysis of Continuous and Dichotomous Phenotypes.

PURPOSE: A genetic correlation is the proportion of phenotypic variance between traits that is shared on a genetic basis. Here we explore genetic correlations between diabetes- and glaucoma-related traits. DESIGN: Cross-sectional study. METHODS: We assembled genome-wide association study summary statistics from European-derived participants regarding diabetes-related traits like fasting blood sugar (FBS) and type 2 diabetes (T2D) and glaucoma-related traits (intraocular pressure [IOP], central corneal thickness [CCT], corneal hysteresis [CH], corneal resistance factor [CRF], cup-to-disc ratio [CDR], and primary open-angle glaucoma [POAG]). We included data from the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database, the UK Biobank, and the International Glaucoma Genetics Consortium. We calculated genetic correlation (rg) between traits using linkage disequilibrium score regression. We also calculated genetic correlations between IOP, CCT, and select diabetes-related traits based on individual level phenotype data in 2 Northern European population-based samples using pedigree information and Sequential Oligogenic Linkage Analysis Routines. RESULTS: Overall, there was little rg between diabetes- and glaucoma-related traits. Specifically, we found a nonsignificant negative correlation between T2D and POAG (rg = -0.14; P = .16). Using Sequential Oligogenic Linkage Analysis Routines, the genetic correlations between measured IOP, CCT, FBS, fasting insulin, and hemoglobin A1c were null. In contrast, genetic correlations between IOP and POAG (rg ≥ 0.45; P ≤ 3.0 × 10-4) and between CDR and POAG were high (rg = 0.57; P = 2.8 × 10-10). However, genetic correlations between corneal properties (CCT, CRF, and CH) and POAG were low (rg range -0.18 to 0.11) and nonsignificant (P ≥ .07). CONCLUSION: These analyses suggest that there is limited genetic correlation between diabetes- and glaucoma-related traits.

Resting nailfold capillary blood flow in primary open-angle glaucoma.

BACKGROUND/AIMS: An altered haemodynamic profile for various ocular posterior segment capillary beds has been documented in primary open-angle glaucoma (POAG). POAG may also involve abnormal non-ocular blood flow, and the nailfold capillaries, which are not affected by elevated intraocular pressure (IOP), are readily assessable. METHODS: We measured resting nailfold capillary blood flow in 67 POAG and 63 control subjects using video capillaroscopy. Masked readers tracked blood column voids between consecutive, registered image sequence frames, measured vessel diameter and calculated blood flow. We used multiple logistic regression to investigate the relation between nailfold capillary blood flow and POAG. In secondary analyses, we stratified cases by maximum IOP and concurrent topical beta-blocker use. RESULTS: Mean (±SD) blood flow in picolitres per second was 26.8±17.6 for POAG cases and 50.1±24.2 for controls (p<0.0001). After adjustment for demographic and clinical factors including blood pressure and pulse, every picolitre per second increase in resting nailfold blood flow was associated with a 6% (95% CI 0.92 to 0.96) reduced odds of POAG (p<0.0001). Similar relations between nailfold capillary blood flow and POAG were found for cases stratified by maximum known IOP and for cases stratified by concurrent topical beta-blocker use. CONCLUSION: Reduced resting nailfold capillary blood flow is present in POAG independent of covariates such as blood pressure, pulse and IOP.

Nailfold Capillary Morphology in Alzheimer's Disease Dementia.

BACKGROUND: Cerebrovascular disease (CVD) is highly comorbid with Alzheimer's disease (AD), yet its role is not entirely understood. Nailfold video capillaroscopy (NVC) is a noninvasive method of live imaging the capillaries near the fingernail's cuticle and may help to describe further vascular contributions to AD. OBJECTIVE: To examine finger nailfold capillary morphology using NVC in subjects with AD dementia, mild cognitive impairment (MCI), and normal cognition (NC). METHODS: We evaluated nailfold capillary hemorrhages, avascular zones ≥100 microns, and degree of tortuosity in 28 NC, 15 MCI, and 18 AD dementia subjects using NVC. Tortuosity was measured with a semi-quantitative rating scale. To assess the relation between nailfold capillary morphological features and diagnostic grouping, univariate and multivariable logistic regression models were fit to the data. RESULTS: 56% of subjects with AD dementia compared to 14% with NC and 13% with MCI displayed moderate to severe tortuosity. Greater severity of tortuosity was associated with 10.6-fold (95% confidence interval [CI]: 2.4, 46.2; p = 0.0018) and 7.4-fold (95% CI: 1.3, 41.3; p = 0.023) increased odds of AD dementia relative to NC and MCI, respectively, after adjusting for multiple covariates. CONCLUSION: Greater nailfold capillary tortuosity was found in participants with AD dementia compared to those with MCI or NC. These data provide preliminary evidence of a systemic microvasculopathy in AD that may be noninvasively and inexpensively evaluated through NVC.

Fundus Densitometry Findings Suggest Optic Disc Hemorrhages in Primary Open-Angle Glaucoma Have an Arterial Origin.

PURPOSE: To analyze optic disc hemorrhages (DH) associated with primary open-angle glaucoma by quantifying their geometric profile and comparing their densitometry with hemorrhages from retinal vein occlusions (RVO) and retinal macroaneurysms (MA), which have venous and arterial sources of bleeding, respectively. DESIGN: Retrospective cross-sectional study. METHODS: Setting: Massachusetts Eye & Ear. POPULATION: Fundus images of DH (n = 40), MA (n = 14), and RVO (n = 25) were identified. Patient clinical backgrounds and demographics were obtained. MAIN OUTCOME MEASURES: Grayscale pixel intensity units of hemorrhages and adjacent arteriole and venule over the same background tissue were measured. Densitometry differentials (arteriole or venule minus hemorrhage [ΔA and ΔV, respectively]) were calculated. The ratios of length (radial) to midpoint width for DH were calculated. Mean ΔA and ΔV between groups were compared with t tests. Multiple linear regression assessed the relation of retinal hemorrhage diagnosis to ΔA and ΔV and of DH shape to ΔA and ΔV. RESULTS: Mean (± standard deviation) ΔA and ΔV for DH (6.9 ± 7.1 and -4.7 ± 8.0 pixel intensity units, respectively) and MA (5.3 ± 5.9 and -6.0 ± 4.6, respectively) were comparable (P ≥ .43). Mean ΔA (14.6 ± 7.7) and ΔV (6.4 ± 6.3) for RVO were significantly higher compared to DH and MA (P < .0001) and remained significant in multivariable analyses. A unit increase in DH length-to-width ratio was associated with 1.2 (0.5) and 1.3 (0.5) pixel intensity unit (standard error) decrease in ΔA and ΔV, respectively (P ≤ .014). CONCLUSIONS: DH have densitometry profiles comparable to MA and different from RVO, suggesting that DH in glaucoma have an arterial origin.