Distinct microbial communities enriched in water-saturated and unsaturated reactors influence performance of integrated hydroponics-microbial electrochemical technology.

This study aimed to understand the wastewater treatment and electricity generation performance besides the microbial communities of the integrated Hydroponics-Microbial Electrochemical Technology (iHydroMET) systems operated with water-saturated and water-unsaturated reactors. The organics removal was slightly higher in the water-unsaturated system (93 ± 4 %) than in the water-saturated system (87 ± 2 %). The total nitrogen removal and electric voltage were considerably higher in the water-saturated system (42 ± 5 %; 111 ± 8 V per reactor) than in the water-unsaturated system (18 ± 3 %; 95 ± 9 V per reactor). The enhanced organics and nitrogen removal and high voltage output in respective conditions were due to the dominance of polysaccharide-degrading aerobes (e.g., Pirellula), anammox bacteria (e.g., Anammoximicrobium), denitrifiers (e.g., Thauera and Rheinheimera), and electroactive microorganisms (e.g., Geobacter). The differential performance governed by distinct microbial communities under the tested conditions indicates that an appropriate balancing of water saturation and unsaturation in reactors is crucial to achieving optimum iHydroMET performance.

Fungal Community Composition and Function Associated with Loose Smokeless Tobacco Products.

Smokeless tobacco products (STPs) contain several microbial communities which are responsible for the formation of carcinogens, like tobacco-specific nitrosamine (TSNAs). A majority of STPs are sold in loose/unpackaged form which can be loaded with a diverse microbial population. Here, the fungal population and mycotoxins level of three popular Indian loose STPs, Dohra, Mainpuri Kapoori (MK), and loose leaf-chewing tobacco (LCT) was examined using metagenomic sequencing of ITS1 DNA segment of the fungal genome and LC-MS/MS, respectively. We observed that Ascomycota was the most abundant phylum and Sterigmatomyces and Pichia were the predominant fungal genera in loose STPs. MK displayed the highest α-diversity being enriched with pathogenic fungi Apiotrichum, Aspergillus, Candida, Fusarium, Trichosporon, and Wallemia. Further, FUNGuild analysis revealed an abundance of saprotrophs in MK, while pathogen-saprotroph-symbiotroph were abundant in Dohra and LCT. The level of a fungal toxin (ochratoxins A) was high in the MK product. This study caution that loose STPs harbor various harmful fungi that can infect their users and deliver fungal toxins or disrupt the oral microbiome of SLT users which can contribute to several oral pathologies.

Are integrated bioelectrochemical technologies feasible for wastewater management?

The need for sustainable technological solutions for wastewater management at different scales has led to the emergence of several promising integrated bioelectrochemical technologies in the past decade. A thorough assessment of these technologies is imperative to understand their practical implementation feasibility and to identify the key challenges to prioritise the research and development work. Our multicriteria-based assessment reveals that the integrated technologies are efficient for wastewater treatment in terms of normalised land footprint [(0.31-1.39 m2/population equivalent (PE))] - and energy consumption (0.18-1.49 kWH/m3) as compared to the conventional biotechnologies, and suggests that they have potential for real-world application. Specifying the boundaries according to their treatment capabilities and scale-up potential besides niche application sites or geographical locations is required to expedite their transition to the real-world wastewater management sector.

Performance evaluation of the integrated hydroponics-microbial electrochemical technology (iHydroMET) for decentralized domestic wastewater treatment.

Here we report on the performance of the integrated drip hydroponics-microbial electrochemical technology (iHydroMET) for decentralized management of domestic wastewater at the household level. The study focused on optimizing the iHydroMET reactor components, followed by its performance evaluation for domestic wastewater treatment at different feed volumes. Based on the reactor components optimization work, granular activated charcoal:cocopeat (20:80) combination for bed matrix, 75% immersed cathode in effluent configuration, and Catharanthus roseus plant were selected for further experiments. The iHydroMET system with the optimized reactor components achieved efficient removal of organic matter (up to 93%) and turbidity (up to 98%) but minimal total nitrogen (<24%) and total phosphorous (<8%) removal after 24 h with 10 L of feed volume. It also removed the contaminants of emerging concern, such as sterols, at >95% efficiency. The UV-treated effluent (<2 MPN/100 mL) with considerable concentrations of N (∼34 mg/L) and P (∼5 mg/L) nutrients qualifies the standards for agricultural use and landscape irrigation purposes and contribute to lowering the burden on freshwater usage. The system also produced a power density of 30.3 mW/m2. Cultivation of evergreen C. roseus, a high aesthetic value ornamental and medicinal plant, further adds to ecological and environmental benefits of the iHydroMET technology. Further modifications in system operation like creating a saturation zone in the reactor units might improve the electric output and result in sufficient removal of nutrients, making the use of effluent for flushing and other purposes possible in households.

High-altitude meteorology of Indian Himalayan Region: complexities, effects, and resolutions.

The Himalaya, by virtue of its location and stupendous height, acts as a great climatic divide and regulates meteorological conditions in the subcontinent regions of South Asia. However, the associated complexities and their effects are yet to be resolved to understand the meteorology of the Indian Himalayan Region (IHR). In this review volume, we synthesize the results and inferences of several studies carried out in the IHR using in situ data, remotely sensed data, and model-based meteorological observations. Results provide insights into climate change, scientific gaps, and their causes in deciphering meteorological observations from the last century to recent decades and envisage impacts of climate change on water reservoirs in the future. Warming trend of air temperature, in contrast to global temperature, has been projected in recent decades (after 1990) with a greater warming rate in the maximum temperature than the minimum temperature. This drifting of air temperature from the beginning of last century accelerates the diurnal temperature range of the Himalayas. An elevation-dependent warming trend is mostly perceived in the northwest Himalayan region, implicating an increased warming rate in the Greater Himalaya as compared to the lower and Karakoram Himalaya. No definite trends of precipitation have been observed over different regions of the IHR, suggesting heterogeneous cryosphere-climate interaction between western and central Himalaya. In this review, we have tried to emphasize to the scientific community and policy-makers for enhancing the knowledge of physical and dynamical processes associated with meteorological parameters in the Himalayan terrain.

Recent Advancements in the Synthesis and Chemistry of Benzo-fused Nitrogen- and Oxygen-based Bioactive Heterocycles.

Since a variety of benzo-fused nitrogen- and oxygen-based bioactive heterocyclic moieties are present in the form of benzoxazinones, spirooxindole-based heterocyclic compounds, coumarinfused heterocyclic compounds, and 2H-indazoles, this review article briefly describes some of the major advancements and developments in the area of 1,4-benzoxazine-3-ones, 1,4-benzoxazin-2- ones, spiropyrrolidine and spiropyrrolizine-based ring compounds, coumarin-fused compounds, benzopyran- fused coumarins and a 2H-indazoles class of bioheterocycles. Thus, keeping in view the medicinal importance of these bioactive benzo-fused heterocycles, special attention has been given to their synthesis as well as medicinal/pharmaceutical properties in detail.

Diagnostic Abilities of Variable and Enhanced Corneal Compensation Algorithms of GDx in Different Severities of Glaucoma.

PURPOSE: To compare the abilities of retinal nerve fiber layer (RNFL) parameters of variable corneal compensation (VCC) and enhanced corneal compensation (ECC) algorithms of scanning laser polarimetry (GDx) in detecting various severities of glaucoma. METHODS: Two hundred and eighty-five eyes of 194 subjects from the Longitudinal Glaucoma Evaluation Study who underwent GDx VCC and ECC imaging were evaluated. Abilities of RNFL parameters of GDx VCC and ECC to diagnose glaucoma were compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities, and likelihood ratios. RESULTS: After excluding 5 eyes that failed to satisfy manufacturer-recommended quality parameters with ECC and 68 with VCC, 56 eyes of 41 normal subjects and 161 eyes of 121 glaucoma patients [36 eyes with preperimetric glaucoma, 52 eyes with early (MD>-6 dB), 34 with moderate (MD between -6 and -12 dB), and 39 with severe glaucoma (MD<-12 dB)] were included for the analysis. Inferior RNFL, average RNFL, and nerve fiber indicator parameters showed the best AUCs and sensitivities both with GDx VCC and ECC in diagnosing all severities of glaucoma. AUCs and sensitivities of all RNFL parameters were comparable between the VCC and ECC algorithms (P>0.20 for all comparisons). Likelihood ratios associated with the diagnostic categorization of RNFL parameters were comparable between the VCC and ECC algorithms. CONCLUSION: In scans satisfying the manufacturer-recommended quality parameters, which were significantly greater with ECC than VCC algorithm, diagnostic abilities of GDx ECC and VCC in glaucoma were similar.

The ISNT rule in glaucoma: revisiting with spectral domain optical coherence tomography.

PURPOSE: To evaluate the ability of the neuroretinal rim (NRR) rules determined using spectral domain optical coherence tomography (SDOCT) in diagnosing glaucoma and to study the effect of optic disc size and disease severity on the diagnostic ability of these rules. METHODS: In a cross-sectional study, 125 eyes of 96 glaucoma patients and 96 eyes of 72 control subjects underwent optic nerve head (ONH) imaging with SDOCT. Inferior (I), superior (S), nasal (N) and temporal (T) NRR areas were automatically determined by the sdoct software. Diagnostic abilities of ISNT (I > S > N > T), IT (I > T) and ST (S > T) rules in glaucoma were evaluated using sensitivity, specificity and likelihood ratios (LR). Effect of optic disc size and disease severity [based on mean deviation (MD) on visual fields] on the diagnostic ability of the NRR rules was evaluated using regression models. RESULTS: Sensitivities of ISNT, IT and ST rules were 80.8%, 60.0% and 29.6%, respectively, and the specificities were 32.3%, 84.4% and 93.8%, respectively. Positive LRs of ISNT, IT and ST rules were 1.19, 3.84 and 4.74, respectively, and negative LRs were 0.60, 0.47 and 0.75, respectively. Sensitivities of ISNT (coefficient: -1.06, p = 0.02) and IT (-0.71, 0.05) rules decreased with increasing disc size. Positive LR of IT rule increased significantly (-0.01, 0.04) with decreasing MD, and negative LR of IT rule decreased (got better) significantly (0.26, 0.05) with decreasing disc size. CONCLUSIONS: Neuroretinal rim rules, as determined by SDOCT, do not allow robust differentiation of glaucomatous from non-glaucomatous discs.

Atypical birefringence pattern and the diagnostic ability of scanning laser polarimetry with enhanced corneal compensation in glaucoma.

PURPOSE: To evaluate the effect of typical scan score (TSS), when within the acceptable limits, on the diagnostic performance of retinal nerve fibre layer (RNFL) parameters with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in glaucoma. METHODS: In a cross-sectional study, 203 eyes of 160 glaucoma patients and 140 eyes of 104 control subjects underwent RNFL imaging with the ECC protocol of SLP. TSS was used to quantify atypical birefringence pattern (ABP) images. Influence of TSS on the diagnostic ability of SLP parameters was evaluated by receiver operating characteristic (ROC) regression models after adjusting for the effect of disease severity [based on mean deviation (MD)] on standard automated perimetry). RESULTS: Diagnostic abilities of all RNFL parameters of SLP increased when the TSS values were higher. This effect was statistically significant for TSNIT (coefficient: 0.08, p<0.001) and inferior average parameters (coefficient: 0.06, p=0.002) but not for nerve fibre indicator (NFI, coefficient: 0.03, p=0.21). In early glaucoma (MD of -5 dB), predicted area under ROC curve (AUC) for TSNIT average parameter improved from 0.642 at a TSS of 90 to 0.845 at a TSS of 100. In advanced glaucoma (MD of -15 dB), AUC for TSNIT average improved from 0.832 at a TSS of 90 to 0.947 at 100. CONCLUSION: Diagnostic performances of TSNIT and inferior average RNFL parameters with ECC protocol of SLP were significantly influenced by TSS even when the TSS values were within the acceptable limits. Diagnostic ability of NFI was unaffected by TSS values.

Comparing spectral-domain optical coherence tomography and standard automated perimetry to diagnose glaucomatous optic neuropathy.

PURPOSE: To compare the abilities of standard automated perimetry (SAP) and spectral-domain optical coherence tomography (SDOCT) in diagnosing eyes with glaucomatous optic neuropathy (GON). METHODS: In a cross-sectional study, 280 eyes of 175 subjects referred to tertiary eye care center by general ophthalmologists for a glaucoma evaluation underwent retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) imaging with SDOCT. All subjects had at least 2 reliable and repeatable SAP. Two glaucoma experts masked to clinical and SAP results classified the optic nerves into GON and nonglaucomatous groups based on digital optic disc photographs. Ability of SDOCT parameters and SAP to discriminate GON eyes from nonglaucomatous eyes was evaluated using sensitivity, specificity, and likelihood ratios (LR). RESULTS: Experts classified 179 eyes into GON and 101 eyes into nonglaucomatous group. Sensitivity of SAP (69.8%) was significantly lower (P<0.05) than that of inferior quadrant RNFL thickness (83.8%), average RNFL thickness (77.2%), GCC focal loss volume (FLV, 81.5%), and global loss volume (GLV, 82.6%). Specificity and positive LR of SAP (95% and14.1, respectively) were significantly greater than those of all RNFL parameters, FLV (84.2% and 5.1) and GLV (82.2% and 4.6). Negative LR of SAP (0.32) was significantly inferior to that of inferior quadrant RNFL thickness (0.22), FLV (0.22), and GLV (0.21). CONCLUSIONS: Most of the RNFL and GCC parameters of SDOCT had better sensitivities and negative LRs to diagnose GON compared with SAP. The specificities and positive LRs of most SDOCT parameters were inferior to that of SAP.

Role of visual field reliability indices in ruling out glaucoma.

IMPORTANCE: Standard automated perimetry is the current criterion standard for assessment of visual field (VF) loss in glaucoma. The 3 commonly used reliability indices to judge the quality of standard automated perimetry results are fixation losses (FLs) and false-positive (FP) and false-negative (FN) response rates. However, the influence of reliability indices, when within the manufacturer-recommended limits, on VF classification has been sparsely studied. OBJECTIVE: To evaluate the role of VF reliability indices in ruling out glaucoma. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study of 291 eyes of 291 participants referred to a tertiary eye care facility by general ophthalmologists. The participants were suspected to have glaucoma based on optic disc appearance, but the eyes were judged to be normal with physiological cupping by glaucoma experts on masked evaluation of optic disc photographs. All participants underwent VF testing with the Swedish interactive threshold algorithm standard 24-2 program. MAIN OUTCOMES AND MEASURES: Logistic regression models were used to evaluate the associations between reliability indices and FP classifications on VF testing (glaucoma hemifield test as outside normal limits and pattern standard deviation with P < .05). RESULTS: Median FL, FP, and FN response rates were 7%, 1%, and 2%, respectively. Among the 241 participants with reliable VF results (FL <20% and FP response rate <15%), the VF classification was normal in 188 (78.0%) and glaucoma (FP) in 53 (22.0%). Probability of FP VF classification was associated with FN response rates (odds ratio [OR], 1.36; 95% CI, 1.25-1.48, P < .001) but did not appear to be associated with FLs (OR, 0.96; 95% CI, 0.90-1.03, P = .30) or FP response rates (OR, 0.96; 95% CI, 0.83-1.12, P = .64). Predicted probability of FP VF classification was 9% (95% CI, 6%-14%), 40% (32%-49%), and 82% (68%-91%) at FN response rates of 0%, 8%, and 16%, respectively. CONCLUSIONS AND RELEVANCE: This study suggests that FN response rates have an effect on the ability of automated VF assessments to rule out glaucoma. Since FN response rates are ignored by the manufacturer while flagging a test as unreliable, clinicians and researchers may benefit by realizing that FN response rates can lead to FP VF classification, even when their frequencies are small.

Reference Standard Test and the Diagnostic Ability of Spectral Domain Optical Coherence Tomography in Glaucoma.

PURPOSE: To evaluate the relationship between the reference standard used to diagnose glaucoma and the diagnostic ability of spectral domain optical coherence tomograph (SDOCT). METHODS: In a cross-sectional study, 280 eyes of 175 consecutive subjects, referred to a tertiary eye care center for glaucoma evaluation, underwent optic disc photography, visual field (VF) examination, and SDOCT examination. The cohort was divided into glaucoma and control groups based on 3 reference standards for glaucoma diagnosis: first based on the optic disc classification (179 glaucoma and 101 control eyes), second on VF classification (glaucoma hemifield test outside normal limits and pattern SD with P-value of <5%, 130 glaucoma and 150 control eyes), and third on the presence of both glaucomatous optic disc and glaucomatous VF (125 glaucoma and 155 control eyes). Relationship between the reference standards and the diagnostic parameters of SDOCT were evaluated using areas under the receiver operating characteristic curve, sensitivity, and specificity. RESULTS: Areas under the receiver operating characteristic curve and sensitivities of most of the SDOCT parameters obtained with the 3 reference standards (ranging from 0.74 to 0.88 and 72% to 88%, respectively) were comparable (P>0.05). However, specificities of SDOCT parameters were significantly greater (P<0.05) with optic disc classification as reference standard (74% to 88%) compared with VF classification as reference standard (57% to 74%). CONCLUSIONS: Diagnostic parameters of SDOCT that was significantly affected by reference standard was the specificity, which was greater with optic disc classification as the reference standard. This has to be considered when comparing the diagnostic ability of SDOCT across studies.

Factors affecting the ability of the spectral domain optical coherence tomograph to detect photographic retinal nerve fiber layer defects.

PURPOSE: To evaluate the ability of normative database classification (color-coded maps) of spectral domain optical coherence tomograph (SDOCT) in detecting wedge shaped retinal nerve fiber layer (RNFL) defects identified on photographs and the factors affecting the ability of SDOCT in detecting these RNFL defects. METHODS: In a cross-sectional study, 238 eyes (476 RNFL quadrants) of 172 normal subjects and 85 eyes (103 RNFL quadrants with wedge shaped RNFL defects) of 66 glaucoma patients underwent RNFL imaging with SDOCT. Logistic regression models were used to evaluate the factors associated with false positive and false negative RNFL classifications of the color-coded maps of SDOCT. RESULTS: False positive classification at a p value of <5% was seen in 108 of 476 quadrants (22.8%). False negative classification at a p value of <5% was seen in 16 of 103 quadrants (15.5%). Of the 103 quadrants with RNFL defects, 64 showed a corresponding VF defect in the opposite hemisphere and 39 were preperimetric. Higher signal strength index (SSI) of the scan was less likely to have a false positive classification (odds ratio: 0.97, p = 0.01). Presence of an associated visual field defect (odds ratio: 0.17, p = 0.01) and inferior quadrant RNFL defects as compared to superior (odds ratio: 0.24, p = 0.04) were less likely to show false negative classifications. CONCLUSIONS: Scans with lower signal strengths were more likely to show false positive RNFL classifications, and preperimetric and superior quadrant RNFL defects were more likely to show false negative classifications on color-coded maps of SDOCT.

Peripapillary retinal nerve fiber layer assessment of spectral domain optical coherence tomography and scanning laser polarimetry to diagnose preperimetric glaucoma.

PURPOSE: To compare the abilities of peripapillary retinal nerve fiber layer (RNFL) parameters of spectral domain optical coherence tomograph (SDOCT) and scanning laser polarimeter (GDx enhanced corneal compensation; ECC) in detecting preperimetric glaucoma. METHODS: In a cross-sectional study, 35 preperimetric glaucoma eyes (32 subjects) and 94 control eyes (74 subjects) underwent digital optic disc photography and RNFL imaging with SDOCT and GDx ECC. Ability of RNFL parameters of SDOCT and GDx ECC to discriminate preperimetric glaucoma eyes from control eyes was compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities and likelihood ratios (LR). RESULTS: AUC of the global average RNFL thickness of SDOCT (0.786) was significantly greater (p<0.001) than that of GDx ECC (0.627). Sensitivities at 95% specificity of the corresponding parameters were 20% and 8.6% respectively. AUCs of the inferior, superior and temporal quadrant RNFL thickness parameters of SDOCT were also significantly (p<0.05) greater than the respective RNFL parameters of GDx ECC. LRs of outside normal limits category of SDOCT parameters ranged between 3.3 and 4.0 while the same of GDx ECC parameters ranged between 1.2 and 2.1. LRs of within normal limits category of SDOCT parameters ranged between 0.4 and 0.7 while the same of GDx ECC parameters ranged between 0.7 and 1.0. CONCLUSIONS: Abilities of the RNFL parameters of SDOCT and GDx ECC to diagnose preperimetric glaucoma were only moderate. Diagnostic abilities of the RNFL parameters of SDOCT were significantly better than that of GDx ECC in preperimetric glaucoma.

Ganglion cell-inner plexiform layer thickness of high definition optical coherence tomography in perimetric and preperimetric glaucoma.

PURPOSE: We determined the diagnostic performance of ganglion cell-inner plexiform layer (GCIPL) parameters of high definition optical coherence tomography (HD-OCT) in perimetric and preperimetric glaucoma, and compared it to optic nerve head (ONH) and peripapillary retinal nerve fiber layer (RNFL) parameters. METHODS: In a cross-sectional study, 53 eyes of normal subjects and 83 eyes of glaucoma patients (62 perimetric and 21 preperimetric) from the Longitudinal Glaucoma Evaluation Study (LOGES) underwent HD-OCT imaging with Optic Disc and Macular Cube protocols. Diagnostic abilities of GCIPL, ONH, and RNFL parameters were determined using area under receiver operating characteristic curves (AUC) and likelihood ratios (LR). RESULTS: The AUCs of GCIPL parameters to diagnose perimetric glaucoma ranged from 0.84 to 0.90. The same of ONH and RNFL parameters ranged from 0.88 to 0.97 and 0.56 to 0.94, respectively. The AUCs of GCIPL, ONH, and RNFL parameters to diagnose preperimetric glaucoma ranged from 0.55 to 0.63, 0.77 to 0.92, and 0.39 to 0.80, respectively. For diagnosing preperimetric glaucoma, AUCs of all GCIPL parameters were significantly lower (P < 0.05) than those of the global ONH (vertical cup-to-disc ratio [CDR]; AUC, 0.92) and RNFL (average RNFL; AUC, 0.79) parameters. Outside normal limits category of GCIPL parameters also were associated with significantly smaller effects on the posttest probability of perimetric and preperimetric glaucoma. CONCLUSIONS: The diagnostic ability of GCIPL parameters was similar to that of ONH and peripapillary RNFL parameters in perimetric glaucoma. However, in preperimetric glaucoma, the diagnostic ability of GCIPL parameters was significantly lower than that of ONH and RNFL parameters.

Scanning the macula for detecting glaucoma.

BACKGROUND: With the advent of spectral domain optical coherence tomography (SDOCT), there has been a renewed interest in macular region for detection of glaucoma. However, most macular SDOCT parameters currently are thickness parameters which evaluate thinning of the macular layers but do not quantify the extent of area over which the thinning has occurred. We therefore calculated a new macular parameter, "ganglion cell complex surface abnormality ratio (GCC SAR)" that represented the surface area over which the macular thickness was decreased. PURPOSE: To evaluate the ability of SAR in detecting perimetric and preperimetric glaucoma. DESIGN: Retrospective image analysis. MATERIALS AND METHODS: 68 eyes with perimetric glaucoma, 62 eyes with preperimetric glaucoma and 165 control eyes underwent GCC imaging with SDOCT. SAR was calculated as the ratio of the abnormal to total area on the GCC significance map. STATISTICAL ANALYSIS: Diagnostic ability of SAR in glaucoma was compared against that of the standard parameters generated by the SDOCT software using area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities. RESULTS: AUC of SAR (0.91) was statistically significantly better than that of GCC average thickness (0.86, P = 0.001) and GCC global loss volume (GLV; 0.88, P = 0.01) in differentiating perimetric glaucoma from control eyes. In differentiating preperimetric glaucoma from control eyes, AUC of SAR (0.72) was comparable to that of GCC average thickness (0.70, P > 0.05) and GLV (0.72, P > 0.05). Sensitivities at specificities of 80% and 95% of SAR were comparable (P > 0.05 for all comparisons) to that of GCC average thickness and GLV in diagnosing perimetric and preperimetric glaucoma. CONCLUSION: GCC SAR had a better ability to diagnose perimetric glaucoma compared to the SDOCT software provided global GCC parameters. However, in diagnosing preperimetric glaucoma, the ability of SAR was similar to that of software provided global GCC parameters.

Retinal nerve fiber layer measurements by scanning laser polarimetry with enhanced corneal compensation in healthy subjects.

PURPOSE: To evaluate the (i) effects of biological (age and axial length) and instrument-related [typical scan score (TSS) and corneal birefringence] parameters on the retinal nerve fiber layer (RNFL) measurements and (ii) repeatability of RNFL measurements with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in healthy subjects. METHODS: In a cross-sectional study, 140 eyes of 73 healthy subjects underwent RNFL imaging with the ECC protocol of SLP. Linear mixed modeling methods were used to evaluate the effects of age, axial length, TSS, and corneal birefringence on RNFL measurements. One randomly selected eye of 48 subjects from the cohort underwent 3 serial scans during the same session to determine the repeatability. RESULTS: Age significantly influenced all RNFL measurements. RNFL measurements decreased by 1 µm for every decade increase in age. TSS affected the overall average RNFL measurement (ß=-0.62, P=0.003), whereas residual anterior segment retardance affected the superior quadrant measurement (ß=1.14, P=0.01). Axial length and corneal birefringence measurements did not influence RNFL measurements. Repeatability, as assessed by the coefficient of variation, ranged between 1.7% for the overall average RNFL measurement and 11.4% for th nerve fiber indicator. CONCLUSIONS: Age significantly affected all RNFL measurements with the ECC protocol of SLP, whereas TSS and residual anterior segment retardance affected the overall average and the superior average RNFL measurements, respectively. Axial length and corneal birefringence measurements did not influence any RNFL measurements. RNFL measurements had good intrasession repeatability. These results are important while evaluating the change in structural measurements over time in glaucoma patients.

Effect of scan quality on diagnostic accuracy of spectral-domain optical coherence tomography in glaucoma.

PURPOSE: To evaluate the effect of scan quality on the diagnostic accuracies of optic nerve head (ONH), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) parameters of spectral-domain optical coherence tomography (SD OCT) in glaucoma. DESIGN: Cross-sectional study. METHODS: Two hundred fifty-two eyes of 183 control subjects (mean deviation [MD]: -1.84 dB) and 207 eyes of 159 glaucoma patients (MD: -7.31 dB) underwent ONH, RNFL, and GCC scanning with SD OCT. Scan quality of SD OCT images was based on signal strength index (SSI) values. Influence of SSI on diagnostic accuracy of SD OCT was evaluated by receiver operating characteristic (ROC) regression. RESULTS: Diagnostic accuracies of all SD OCT parameters were better when the SSI values were higher. This effect was statistically significant (P < .05) for ONH and RNFL but not for GCC parameters. In mild glaucoma (MD of -5 dB), area under ROC curve (AUC) for rim area, average RNFL thickness, and average GCC thickness parameters improved from 0.651, 0.678, and 0.726, respectively, at an SSI value of 30 to 0.873, 0.962, and 0.886, respectively, at an SSI of 70. AUCs of the same parameters in advanced glaucoma (MD of -15 dB) improved from 0.747, 0.890, and 0.873, respectively, at an SSI value of 30 to 0.922, 0.994, and 0.959, respectively, at an SSI of 70. CONCLUSION: Diagnostic accuracies of SD OCT parameters in glaucoma were significantly influenced by the scan quality even when the SSI values were within the manufacturer-recommended limits. These results should be considered while interpreting the SD OCT scans for glaucoma.

Risk factors for dementia in patients over 65 with diabetes.

OBJECTIVE: This study identified factors in patients with diabetes associated with risk of developing dementia. RESEARCH DESIGN AND METHODS: This retrospective, longitudinal study used a national cohort of US Veterans with diabetes 65 years or older to examine incidence of dementia over 2 years. A multivariable Cox regression model was used to estimate risk of developing dementia associated with sociodemographic factors, use of diabetes medications, and duration of diabetes. RESULTS: In all, 377,838 patients (average age, 75.53 ± 6.07 years) were studied. Over the 2 year follow-up, 14,580 (3.85%) were diagnosed with dementia. Major risk factors for dementia were age >75 years (75-85 years, hazard ratio [HR] 2.092, 95% confidence interval [CI] 2.017-2.169; ≥85 years, HR 3.468, CI 3.274-3.672), race black versus white, HR 1.218, CI 1.164-1.274), Southern residence (HR = 1.181, CI 1.133-1.232), and diabetes duration (HR for 5 years or more, 1.428, CI 1.357-1.504). There was a reduced HR for dementia with use of an oral hypoglycemic agent (HR 0.940, CI 0.909-0.972) and HMG-CoA reductase inhibitors (HR, 0.875, CI 0.846-0.906). There was no change in HR with insulin use (HR 1.024, CI 0.983-1.067). CONCLUSIONS: Several important factors were identified that are associated with increased dementia risk, and two factors were identified that are associated with reduced risk. It will be important to ascertain whether risk-factor modification reduces the HR for dementia in persons with diabetes, and to further examine effects of medication use for comorbid conditions.