A comparison of white-to-white measurements obtained by Anterion AS-OCT versus three optical devices in refractive surgery candidates.

BACKGROUND AND OBJECTIVES: To assess the agreement between Anterion AS-OCT and three optical devices in measuring the white-to-white (WTW) diameter in candidates for refractive surgery. METHODS: In this cross-sectional prospective study, 129 right eyes of 129 normal individuals underwent consecutive scans with the Anterion, the Pentacam AXL, the IOLMaster 700, and the Orbscan IIz. Mean difference (MD), 95% limits of agreement (LoA), and concordance correlation coefficient (CCC) were calculated to assess agreement and interchangeability. RESULTS: The mean age of participants was 30.4 ± 5.9 (range: 21-47) years. The mean WTW distance measured by the different instruments was as follows: 12.00 ± 0.42 mm (range, 10.57 to 13.05) using the Anterion, 11.87 ± 0.34 (11.10 to 12.80) using the Pentacam, 12.12 ± 0.44 (11.00 to 13.30) using the IOLMaster, and 11.73 ± 0.37 (11.00 to 13.10) using the Orbscan. The MD and 95% LoA for Anterion vs. Pentacam, IOLMaster, or Orbscan were [0.11; -0.31 to 0.54 mm], [-0.13; -0.93 to 0.66], and [0.25; -0.28 to 0.78], respectively. The corresponding CCCs were 0.803, 0.514, and 0.631. CONCLUSIONS: This study found weak agreement between Anterion and Pentacam AXL, IOLMaster 700, and Orbscan IIz devices regarding WTW distance measurements in refractive surgery candidates. Therefore, it is not recommended to use Anterion's WTW measurements interchangeably with the other three devices, particularly for phakic intraocular lens sizing.

Lipid accumulation product and type 2 diabetes risk: a population-based study.

BACKGROUND: The Lipid Accumulation Product (LAP) is a measure that indicates excessive fat accumulation in the body. LAP has been the focus of research in epidemiological studies aimed at forecasting chronic and metabolic diseases. This study aimed to evaluate the association between LAP and type 2 diabetes mellitus (T2DM) among adults in western Iran. METHODS: The study involved 9,065 adults who participated in the initial phase of the Ravansar non-communicable diseases study (RaNCD) cohort. To investigate the association between LAP and T2DM, multiple logistic regressions were employed. Additionally, the receiver operating characteristic (ROC) curve was used to evaluate LAP's predictive ability concerning T2DM. RESULTS: The participants had an average age of 47.24 ± 8.27 years, comprising 49.30% men and 50.70% women. The mean LAP was 53.10 ± 36.60 for the healthy group and 75.51 ± 51.34 for the diabetic group (P < 0.001). The multiple regression analysis revealed that the odds of T2DM in the second quartile of LAP were 1.69 (95% CI: 1.25, 2.29) times greater than in the first quartile. Furthermore, the odds in the third and fourth quartiles were 2.67 (95% CI: 2.01, 3.55) and 3.73 (95% CI: 2.83, 4.92) times higher, respectively. The ROC analysis for predicting T2DM showed that the LAP index had an area under the curve (AUC) of 0.66 (95% CI: 0.64, 0.68). CONCLUSION: A strong association was identified between elevated LAP levels and T2DM in the adult population of western Iran. LAP is recommended as a potential tool for screening diabetes susceptibility.

Thoracolumbar fracture and spinal cord injury in blunt trauma: a systematic review, meta-analysis, and meta-regression.

Thoracolumbar (TL) fractures are among the most common vertebral fractures. These patients have high morbidity and mortality due to injury mechanisms and associated injuries. Spinal cord injury (SCI) is a prevalent complication of spinal fractures of the thoracolumbar region. AIM: To determine the pooled rate of thoracolumbar fractures and SCI in blunt trauma patients. METHODS: A systematic review and meta-analysis of observational studies were performed. The search was conducted in the PubMed, Scopus, Web of Science, and Embase databases. The authors screened and selected studies based on predefined inclusion and exclusion criteria. Studies were then evaluated for risk of bias using the JBI checklist. The pooled event rate and 95% confidence intervals (CI) were calculated using random effects models. Subgroup and meta-regression analyses were performed to explore sources of heterogeneity. RESULTS: Twenty-one studies fulfilled the selection criteria. The pooled rate of TL fractures was 8.08% (CI = 6.18-10.50%), with high heterogeneity (I2 = 99.98%, P < 0.001). Thoracic and lumbar fractures accounted for 45.23% and 59.01% of the TL fractures, respectively. Meta-regression revealed that the midpoint of the study period was a significant moderator. The pooled event rate of SCI among TL fracture patients was 15.81% (CI = 11.11 to 22.01%) with high heterogeneity (I2 = 98.31%, P < 0.001). The country of study was identified as a source of heterogeneity through subgroup analysis, and studies from the United States reported higher rates of SCI. Meta-regression revealed that the critical appraisal score was negatively associated with event rate. CONCLUSION: Our study evaluated the rate of TL fractures in multiple countries at different time points. We observed an increase in the rate of TL fractures over time. SCI results also seemed to vary based on the country of the original study.

Standardized immunological assays for assessing COVID-19 vaccines by the CEPI-Centralized Laboratory Network.

The CEPI Centralized Laboratory Network implemented key steps in the transfer and monitoring of the developed immunological SARS-CoV-2 assays to ensure standardization across all the facilities of the network. This comprehensive evaluation reinforces the reliability of the generated data and establishes a solid foundation for a standardized approach, enabling precise inter-laboratory comparisons and contributing to the overall integrity of our network's clinical results. Herein, we will provide a brief elaboration on the specific measures and procedures implemented to standardize the transfer of assays across our network.

Quality of life and activities of daily living one year after Coronary Artery Bypass Graft (CABG) surgery: a cross-sectional study.

BACKGROUND: Daily activities have been recommended to minimize the long-term complications of coronary artery bypass as one of the strategies to return to the normal activity level, the effectiveness of which needs further investigation. This study aims to determine the quality of life and activities of daily living one year after CABG. METHODS: This cross-sectional study was performed on 206 patients who had undergone CABG for more than one year in 2018 in the north of Iran. The research instrument was a questionnaire including five sections, Data were analyzed using descriptive statistics and Chi2, Mann-Whitney U, Kruskal-Wallis tests, and a Logistic regression model. RESULT: The mean score of quality of life was 31.7 ± 2.04 of 12 to 48 possible scores. About Activities of Daily Living results showed 99.5% and 84.7% of the samples needed help with many of these activities respectively. The mean score of quality of life was significantly different based on sex (p < 0.018) and instrumental activity of daily living (p < 0.0001). A logistic regression model was used to determine the factors related to quality of life. The final model showed cross-clamp duration (OR = 0.33,p = 0.014), length of stay(LOS)in the intensive care unit(OR = 0.42,p = 0.05), and instrumental activities of daily living (OR = 0.08,p = 0.001) predicted patients' quality of life one year after coronary artery bypass grafting. CONCLUSION: Although more than half of the samples had a good average quality of life score, due to the lack of definitive treatment for coronary artery disease, it is suggested to consider predictive variables to help plan to improve the quality of life of these patients.

The quality of life (QoL) of patients after CABG depends on many variables, one of the effective variables is the daily activity of these patients, which can significantly affect their quality of life, so it seems that by creating low-cost programs to improve the activity level of these people, it is possible to help increase their quality of life. The results of this research showed that about half of the research samples had an average quality of life and the majority of them still needed help to perform daily life activities. Maybe the design of special tools to determine the quality of life of these patients after coronary artery bypass surgery can show a clearer picture of the quality of life of these patients after surgery.

Driving consistency: CEPI-Centralized Laboratory Network's conversion factor initiative for SARS-CoV-2 clinical assays used for efficacy assessment of COVID vaccines.

To date, thousands of SARS-CoV-2 samples from many vaccine developers have been tested within the CEPI-Centralized Laboratory Network. To convert data from each clinical assay to international standard units, the WHO international standard and the CEPI standard generated by the Medicines and Healthcare products Regulatory Agency were run in multiple facilities to determine the conversion factor for each assay. Reporting results in international units advances global understanding of SARS-CoV-2 immunity and vaccine efficacy, enhancing the quality, reliability, and utility of clinical assay data.

Risk factors for gastroesophageal reflux disease: a population-based study.

BACKGROUND: Gastroesophageal reflux disease (GERD) in the long term reduces the quality of life, leading to digestive diseases. The present study aims to determine the risk factors for GERD. METHOD: This study was conducted on 9,631 adults aged 35-65 years. The demographic characteristics, behavioral habits, nutritional intake, physical activity, anthropometric indices, and GERD data were extracted from the databank related to the Ravansar non-communicable diseases (RaNCD). Statistical analysis was performed using logistic regression models. RESULTS: The prevalence of GERD was 10.99% (n = 1,058). The GERD was higher among older age and women. After adjusting for age and sex, the odds of GERD among current smokers was 23% higher than non-smokers. Drinking increased odds of GERD (OR: 1.51; 95% CI: 1.13, 1.99). The odds of GERD among depressed individuals were 46% higher than non-depressed. In addition, a significant relationship was observed between the high intake of sweets and desserts with increased GERD (OR: 1.02, 95% CI: 1.01, 1.03). Further, high intake of fiber (OR: 0.98, 95% CI: 0.97, 0.99) and dairy (OR: 0.99, 95% CI: 0.98, 0.99) was related to reducing the odds of GERD. Furthermore, a significant relationship was reported between the waist hip ratio (WHR) and visceral fat area (VFA) with increased odds of GERD. Finally, the physical activity level was inversely related to GERD. CONCLUSION: Based on the results, smoking, alcohol, inactivity, high intake of sweets and desserts, low intake of fiber, depression, visceral fat, and obesity are considered as risk factors for GERD. Modifying lifestyle and behavioral habits prevent GERD.

Association between healthy beverage index and nonalcoholic fatty liver disease in the Ravansar noncommunicable disease cohort study.

The quality of drinks affects the functioning of the liver. In recent decades, the variety of high-calorie and sweet drinks has increased. The objective of this study was to explore the association between Healthy Beverage Index (HBI) and the risk of nonalcoholic fatty liver disease (NAFLD) among adults. We included 6,276 participants aged 35 to 65 from the Ravansar Non-Communicable Disease (RaNCD) cohort study at baseline. NAFLD is defined based on the fatty liver index (FLI), calculated using anthropometric measurements and non-invasive markers. The HBI was developed using a combination of water, low-fat milk, 100% fruit juice, sugar-sweetened beverages, met fluid requirement and % energy from beverages. Logistic and linear regression models were employed to investigate the associations of the HBI and high FLI. The average FLI was significantly lower in the first tertile of HBI compared to the third tertile (47.83 vs. 45.77; P = 0.001). After adjusting for confounding variables, the odds of high FLI decreased by 28% (OR 0.72, 95% CI 0.63, 0.82) in the second tertile of HBI and by 21% in the third tertile (OR 0.79, 95% CI 0.70, 0.91). There was no correlation between gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate transaminase (AST) levels with HBI. The study findings indicate an inverse association between high FLI and HBI. Therefore, it is recommended to consume healthy beverages and without added sugar. However, additional longitudinal studies are required to examine the association between beverage consumption and the development of NAFLD.

Standardised quantitative assays for anti-SARS-CoV-2 immune response used in vaccine clinical trials by the CEPI Centralized Laboratory Network: a qualification analysis.

BACKGROUND: Accurate quantitation of immune markers is crucial for ensuring reliable assessment of vaccine efficacy against infectious diseases. This study was designed to confirm standardised performance of SARS-CoV-2 assays used to evaluate COVID-19 vaccine candidates at the initial seven laboratories (in North America, Europe, and Asia) of the Coalition for Epidemic Preparedness Innovations (CEPI) Centralized Laboratory Network (CLN). METHODS: Three ELISAs (pre-spike protein, receptor binding domain, and nucleocapsid), a microneutralisation assay (MNA), a pseudotyped virus-based neutralisation assay (PNA), and an IFN-γ T-cell ELISpot assay were developed, validated or qualified, and transferred to participating laboratories. Immune responses were measured in ELISA laboratory units (ELU) for ELISA, 50% neuralisation dilution (ND50) for MNA, 50% neutralisation titre (NT50) for PNA, and spot-forming units for the ELISpot assay. Replicate assay results of well characterised panels and controls of blood samples from individuals with or without SARS-CoV-2 infection were evaluated by geometric mean ratios, standard deviation, linear regression, and Spearman correlation analysis for consistency, accuracy, and linearity of quantitative measurements across all laboratories. FINDINGS: High reproducibility of results across all laboratories was demonstrated, with interlaboratory precision of 4·1-7·7% coefficient of variation for all three ELISAs, 3·8-19·5% for PNA, and 17·1-24·1% for MNA, over a linear range of 11-30 760 ELU per mL for the three ELISAs, 14-7876 NT50 per mL for PNA, and 21-25 587 ND50 per mL for MNA. The MNA was also adapted for detection of neutralising antibodies against the major SARS-CoV-2 variants of concern. The results of PNA and MNA (r=0·864) and of ELISA and PNA (r=0·928) were highly correlated. The IFN-γ ELISpot interlaboratory variability was 15·9-49·9% coefficient of variation. Sensitivity and specificity were close to 100% for all assays. INTERPRETATION: The CEPI CLN provides accurate quantitation of anti-SARS-CoV-2 immune response across laboratories to allow direct comparisons of different vaccine formulations in different geographical areas. Lessons learned from this programme will serve as a model for faster responses to future pandemic threats and roll-out of effective vaccines. FUNDING: CEPI.

Analysis of Interleukin-6 Gene Variants (rs1800795, rs1800796, rs1554606, rs1800797, rs2069840, rs12700386, and rs2069861) as Prognostic Markers in Breast Cancer: A Systematic Review, Meta-Analysis, and Network Analysis.

Interleukin-6 (IL-6) has obviously tumor-promoting and tumor-inhibitory effects and can induce an epithelial-mesenchymal transition phenotype in human breast cancer (BC) cells and implicate its potential to promote BC metastasis. Herein, we aimed to evaluate the association of IL-6 variants (rs1800795, rs1800796, rs1554606, rs1800797, rs2069840, rs12700386, and rs2069861) with the susceptibility to BC. The databases of PubMed/Medline, Web of Science, Scopus, and Cochrane Library were searched until December 19, 2022, without any restrictions. The quality assessment of each study was performed based on the Newcastle-Ottawa Scale tool. The Review Manager 5.3 software presented the effect sizes including odds ratio (OR) along with a 95% confidence interval (CI). Both publication bias and sensitivity analyses were carried out by the Comprehensive Meta-Analysis version 2.0 software. A total of 2,508 records were identified among databases and at last, 27 articles were entered into the meta-analysis. Seven polymorphisms of IL-6 were entered into the analyses. Just rs1800797 polymorphism in the dominant model (OR = 1.51; 95% CI = 1.15-2.00; P = 0.003) and rs2069840 polymorphism in heterozygous (OR = 0.89; 95% CI = 0.81-0.97; P = 0.008) and dominant (OR = 0.91; 95% CI = 0.84-0.99; P = 0.02) models had a significant association with the BC risk. In conclusion, among 7 polymorphisms and despite a few included cases, the present meta-analysis recommended that the AA+GA genotype of rs1800797 polymorphism had a significantly elevated risk and the GC and the CC+GC genotypes of rs2069840 polymorphism had a protective role in the BC patients.

Interaction of Rosmarinus officinalis L. with UV-A radiation by preserving its morphological traits and modifying its phenolic composition.

This study investigated the effects of supplemental ultraviolet-A (UV-A) radiation on phenolic compounds, antioxidant properties, and agro-morphological characteristics of Rosmarinus officinalis L. Greenhouse plants were exposed to UV-A for 1, 2, and 4 h daily, 40 days. Based on the results, UV-A radiation had no significant effect on agro-morphological traits, while it remarkably altered chlorophyll content, total phenolic and flavonoid contents, as well as radical scavenging activity. Plants exposed to UV-A (4h) had the highest total phenolic and flavonoid contents, antioxidant activity, as well as the content of rosmarinic, carnosic, vanillic, and caffeic acids, and naringin. Conversely, carnosol, cirsimaritin, and hispulin levels decreased in treated plants. Overall, UV-A radiation had a positive effect on the medicinal aspects of R. officinalis L., which is important in the pharmaceutical industry. Therefore, it is suggested application of UV-A emitting LEDs for commercial purposes, with a lower risk level than UV-B and UV-C.

Investigating the outcomes of cardiopulmonary resuscitation and factors affecting it: A cross-sectional study at Dr. Moaven Hospital, Sahneh City from 2014 to 2021.

Background and Aims: Cardiopulmonary resuscitation (CPR) is referred to an attempt to maintain the respiratory system and blood circulation active to oxygenate the body's important organs until the heart and blood circulation system return to normal. CPR results are influenced by a variety of circumstances and factors. The purpose of this study was to look into the outcomes of CPR and the factors that influence them at the Dr. Moaven Hospital in Sahneh. Methods: This cross-sectional descriptive study was carried out retrospectively from the start of 2014 to the start of 2021. Kermanshah University of Medical Sciences provides hospitals with a two-page form for data collection. After entering the data into SPSS24, descriptive and inferential statistical tests were applied to analyze the results. Results: Out of 497 patients who referred to Dr. Moaven Hospital in Sahne City, 280 were men and 217 were women, with a resuscitation success rate of 22.5% in men and 23.5% in women. CPR was conducted on 63.2% of patients in the emergency department, with 22.2% of them having successful CPR. The existence of the underlying disease had a statistically significant link with the outcomes of CPR (p = 0.007). The most prevalent cause for visit was cardiorespiratory arrest (30.6%), and there was no statistically significant difference between the diagnostic and reason for visit and the outcome of resuscitation, according to the χ 2 test. Conclusion: According to the findings of this study, increasing age and duration of CPR, the existence of underlying diseases, and the absence of shockable rhythms all reduce the likelihood of success in CPR.

Multiple sclerosis and ulcerative colitis: A systematic review and meta-analysis.

Background: Comorbidity is a current area of interest in multiple sclerosis (MS) and is essential for multidisciplinary management. Although recent studies suggest that patients with MS have an elevated risk of developing inflammatory bowel diseases (IBD), this systematic review and meta-analysis aimed to estimate the overall risk of developing ulcerative colitis (UC), specifically in patients with MS. Methods: In 2021, a comprehensive literature search was performed on PubMed, Scopus, Embase, and Web of Science to identify studies investigating the association between UC and MS. The selected papers were utilized to estimate the associations, risk ratios (RRs), and a 95% confidence interval (CI). Results: The analysis revealed a slightly elevated risk of UC incidence in patients with MS compared to controls, but this finding was not statistically significant (RR: 1.27 [95% CI: 0.96-1.67]). In contrast, the study found that patients with UC have a significantly higher risk of developing MS than controls (RR: 1.66 [95% CI: 1.15-2.40]). Conclusion: Our findings highlight that the presence of UC increases the risk of developing MS by more than 50%, whereas the presence of MS does not increase the risk of UC occurrence. These results underscore the importance of considering the potential development of UC in the clinical management and early diagnosis of patients with MS, as it may contribute to better therapeutic outcomes.

Application of Functionalized Fe3O4 Magnetic Nanoparticles Using CTAB and SDS for Oil Separation from Oil-in-Water Nanoemulsions.

Using magnetic nanoparticles (MNPs) for emulsified oil separation from wastewater is becoming increasingly widespread. This study aims to synthesize MNPs using amphiphilic coatings to stabilize the MNPs and prevent their agglomeration for efficiently breaking oil-in-water nanoemulsions. We coat two different sizes of Fe3O4 nanoparticles (15-20 and 50-100 nm) using cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) with surfactant-to-MNP mass ratios of 0.4 and 0.8. We study the effect of various variables on the demulsification performance, including the MNP size and concentration, coating materials, and MNP loading. Based on the oil-water separation analysis, the smaller size MNPs (MNP-S) show a better demulsification performance than the larger ones (MNP-L ) for a 1000 ppm dodecane-in-water emulsion containing nanosized oil droplets (250-300 nm). For smaller MNPs (MNP-S) and at low dosage level of 0.5 g/L, functionalizing with surfactant-to-MNP mass ratio of 0.4, the functionalization increases the separation efficiency (SE) from 57.5% for bare MNP-S to 86.1% and 99.8 for the SDS and CTAB coatings, respectively. The highest SE for MNP-S@CTAB and the zeta potential measurements imply that electrostatic attraction between negatively charged oil droplets (-55.9 ± 2.44 mV) and positively charged MNP-S@CTAB (+35.8 ± 0.34 mV) is the major contributor to a high SE. Furthermore, the reusability tests for MNP-S@CTAB reveal that after 10 cycles, the amount of oil adsorption capacity decreases slightly, from 20 to 19 mg/g, indicating an excellent stability of synthesized nanoparticles. In conclusion, functionalized MNPs with tailored functional groups feature a high oil SE that could be effectively used for oil separation from emulsified oily wastewater streams.

Ginger as an anticolorectal cancer spice: A systematic review of in vitro to clinical evidence.

Ginger and its derivatives have been shown to be effective in the prevention and treatment of cancer. We undertook a systematic review to answer the question of whether ginger has a role in modifying the biomarkers of cancer in cell culture conditions and on colorectal cancer in randomized clinical trials. We performed a comprehensive search of the literature from Scopus, Embase, Web of Science, PubMed, Cochrane central register of controlled trials, and Cochrane database of systematic reviews. At first, all 12 papers studied the effect of ginger or its derivatives on cell culture conditions. The results of cell culture studies show that ginger has a powerful role in inducing apoptosis. In the second part, five studies of clinical trials were analyzed. By analyzing antitumor markers of clinical trials, ginger increased some anticancer markers but performed poorly in inducing some anticancer markers. This systematic review showed that the consumption of ginger extract has the potential to prevent and treat colorectal cancer but this ability is weak.

Changes in liver enzymes and association with prognosis in patients with COVID-19: a retrospective case-control study.

OBJECTIVE: COVID-19 has recently emerged as a serious threat to global health. This study examined the laboratory investigations of patients with COVID-19, with an emphasis on liver enzymes. METHODS: This retrospective, single-center study was performed on patients with COVID-19 who were admitted to Imam Reza Hospital, Iran from March 2020 to February 2021. Laboratory tests included a complete blood cell count, white blood cell (WBC) count, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), lymphocyte/monocyte ratio, and levels of aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase. Patient survival was among the outcome measures investigated in association with laboratory findings. RESULTS: We enrolled 77 patients with COVID-19 and 63 healthy controls. In comparison with the control group, patients with COVID-19 showed COVID-19 increased ALT, WBC, neutrophils, NLR, and PLR, and decreased platelet counts and lymphocytes. CONCLUSION: Although elevated levels of AST, NLR, PLR, and LMR were found in patients with COVID-19, they were not linked to mortality. Given the presence of AST in other tissues, the influence of SARS-CoV-2 on the liver should be interpreted with caution.

Single-use porous polymer thin-film device: A reliable sampler for analysis of drugs in small volumes of biofluids.

The response to the demand for biomedical testing on small volumes of biofluids has led to a range of new microsampling devices and related techniques. Simple cost-effective sampling devices are available, but most do not incorporate sample clean-up and necessitate extensive sample processing by the analyst. To address both cleanup and analyte stability, a porous polymeric thin film made of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) coated (5 × 18 mm2) on a stainless steel substrate was used for the extraction of seven tricyclic antidepressants (TCAs) from plasma spots, with analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Essential factors such as sample volume, extraction time, matrix effects, and the desorption process were investigated. The optimized method is comprised of a quick 3-min extraction from 10 µL of plasma, a wash (10 s in 1 mL of 1% aqueous triethylamine (TEA) to remove plasma matrix interferences, and 2-min desorption (200 µL of ACN with 0.1% formic acid (FA)). For the purpose of sample archiving, thin film devices containing extracted TCAs were stored for 30 days at room temperature and showed a consistent analyte recovery. Inter-device reproducibility was evaluated without internal standard (%RSD 8.2-19.3%), and using two methods of introducing a single deuterated internal standard (imipramine-D3) either prior to (%RSDs 5.6-13.9%) or after (%RSDs 4.9-10.2%) sample loading to the device. Although the intention of this study was to introduce a single use device for rapid and easy analysis, reusability showed the feasibility of 15 consecutive extractions using same device without any performance loss. The optimized method revealed excellent linearity (R2 > 0.99) in the range of 1-1000 ng mL-1, with good intra- and inter-day accuracy (81.4-118%) and precision (≤12%) in human plasma.

Angle κ and its effect on the corneal elevation maps in refractive surgery candidates.

PURPOSE: To assess the associations of angle κ and Pentacam decentration indices with elevation maps in normal refractive surgery candidates. SETTING: Salouti Cornea Research Center, Salouti Eye Clinic, Shiraz, Iran. DESIGN: Retrospective observational study. METHODS: In this research, the right eyes of 173 refractive surgery candidates were assessed. Data of front and back corneal elevation maps, keratometric data, decentration indices, and corneal astigmatism obtained by Pentacam HR system and angle κ obtained by Orbscan IIz were extracted. Maximum elevation (or depression) for each of the 4 quadrants was recorded. Correlations of elevation values with angle κ, Pentacam decentration indices, keratometry, and astigmatism were examined by Pearson correlation coefficient. 148 age- and sex-matched cases with keratoconus grade 1 were selected as a positive control group, and Pentacam variables were compared between the groups. RESULTS: Overall, data from 173 eyes of 173 normal refractive surgery candidates and 148 eyes of 148 patients with keratoconus were recorded and analyzed. In normal refractive surgery candidates, the mean of angle κ was 5.32 ± 1.36 (SD) degrees. Angle κ had a positive correlation with front and back temporal elevations based on a best-fit sphere (BFS) ( r = 0.339, P = .001; r = 0.300, P < .001, respectively). Front and back keratometric astigmatisms were positively correlated with front and back nasal and temporal elevations ( r ≥ 0.543, P < .001) and negatively correlated with superior and inferior elevations ( r ≤ -0.547, P < .001). These associations no longer existed when using best-fit toric ellipse (BFTE) for calculating elevation data. The thinnest point to vertex decentration was significantly associated with the back temporal elevation (based on the BFTE) in both normal ( r = 0.311, P < .001) and keratoconus ( r = 0.190, P = .021) eyes. CONCLUSIONS: This study showed that elevation maps obtained by the Pentacam system using BFS might be affected by both the large angle κ and corneal astigmatism, confounding the preoperative assessment of refractive surgery candidates. Using BFTE as a reference for calculating elevation data should eliminate most diagnostic issues and thus is encouraged in this context.