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Zhang YV, Kumanovics A, Wiencek J, Melanson SEF, Love T, Wu AHB, Zhao Z, Meng QH, Koch DD, Apple FS, Ondracek CR, Christenson RH. Performance of Three Anti-SARS-CoV-2 Anti-S and One Anti-N Immunoassays for the Monitoring of Immune Status and Vaccine Response. Viruses 2024; 16:292. [PMID: 38400067 PMCID: PMC10891747 DOI: 10.3390/v16020292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/06/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
This study aimed to evaluate and compare the performance of three anti-S and one anti-N assays that were available to the project in detecting antibody levels after three commonly used SARS-CoV-2 vaccines (Pfizer, Moderna, and Johnson & Johnson). It also aimed to assess the association of age, sex, race, ethnicity, vaccine timing, and vaccine side effects on antibody levels in a cohort of 827 individuals. In September 2021, 698 vaccinated individuals donated blood samples as part of the Association for Diagnostics & Laboratory Medicine (ADLM) COVID-19 Immunity Study. These individuals also participated in a comprehensive survey covering demographic information, vaccination status, and associated side effects. Additionally, 305 age- and gender-matched samples were obtained from the ADLM 2015 sample bank as pre-COVID-19-negative samples. All these samples underwent antibody level analysis using three anti-S assays, namely Beckman Access SARS-CoV-2 IgG (Beckman assay), Ortho Clinical Diagnostics VITROS Anti-SARS-CoV-2 IgG (Ortho assay), Siemens ADVIA Centaur SARS-CoV-2 IgG (Siemens assay), and one anti-N antibody assay: Bio-Rad Platelia SARS-CoV-2 Total Ab assay (BioRad assay). A total of 827 samples (580 COVID-19 samples and 247 pre-COVID-19 samples) received results for all four assays and underwent further analysis. Beckman, Ortho, and Siemens anti-S assays showed an overall sensitivity of 99.5%, 97.6%, and 96.9%, and specificity of 90%, 100%, and 99.6%, respectively. All three assays indicated 100% sensitivity for individuals who received the Moderna vaccine and boosters, and over 99% sensitivity for the Pfizer vaccine. Sensitivities varied from 70.4% (Siemens), 81.5% (Ortho), and 96.3% (Beckman) for individuals who received the Johnson & Johnson vaccine. BioRad anti-N assays demonstrated 46.2% sensitivity and 99.25% specificity based on results from individuals with self-reported infection. The highest median anti-S antibody levels were measured in individuals who received the Moderna vaccine, followed by Pfizer and then Johnson & Johnson vaccines. Higher anti-S antibody levels were significantly associated with younger age and closer proximity to the last vaccine dose but were not associated with gender, race, or ethnicity. Participants with higher anti-S levels experienced significantly more side effects as well as more severe side effects (e.g., muscle pain, chills, fever, and moderate limitations) (p < 0.05). Anti-N antibody levels only indicated a significant correlation with headache. This study indicated performance variations among different anti-S assays, both among themselves and when analyzing individuals with different SARS-CoV-2 vaccines. Caution should be exercised when conducting large-scale studies to ensure that the same platform and/or assays are used for the most effective interpretation of the data.
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Affiliation(s)
- Y. Victoria Zhang
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Attila Kumanovics
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA;
| | - Joesph Wiencek
- Department of Pathology, Microbiology and Immunology, Vanderbilt School of Medicine, Nashville, TN 37240, USA;
| | - Stacy E. F. Melanson
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA 02115, USA;
- Harvard Medical School, Boston, MA 02115, USA
| | - Tanzy Love
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY 14642, USA;
| | - Alan H. B. Wu
- Department of Laboratory Medicine, University of California, San Francisco, CA 94143, USA;
| | - Zhen Zhao
- Department of Laboratory Medicine and Pathology, Weill Cornell Medicine, New York, NY 10065, USA;
| | - Qing H. Meng
- Department of Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
| | - David D. Koch
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30303, USA;
| | - Fred S. Apple
- Department of Laboratory Medicine and Pathology, Hennepin Healthcare/Hennepin County Medical Center, Minneapolis, MN 55404, USA;
- Hennepin Healthcare Research Institute, Minneapolis, MN 55404, USA
| | - Caitlin R. Ondracek
- Association for Diagnostics & Laboratory Medicine, Washington, DC 22203, USA;
| | - Robert H. Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Zhao Z, Kumanovics A, Love T, Melanson SEF, Meng QH, Wu AHB, Wiencek J, Apple FS, Ondracek CR, Koch DD, Christenson RH, Zhang YV. T Cell Responses Correlate with Self-Reported Disease Severity and Neutralizing Antibody Responses Predict Protection against SARS-CoV-2 Breakthrough Infection. Viruses 2023; 15:v15030709. [PMID: 36992418 PMCID: PMC10058409 DOI: 10.3390/v15030709] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
OBJECTIVES The objective of this prospective study was to investigate the role of adaptive immunity in response to SARS-CoV-2 vaccines. DESIGN AND METHODS A cohort of 677 vaccinated individuals participated in a comprehensive survey of their vaccination status and associated side effects, and donated blood to evaluate their adaptive immune responses by neutralizing antibody (NAb) and T cell responses. The cohort then completed a follow-up survey to investigate the occurrence of breakthrough infections. RESULTS NAb levels were the highest in participants vaccinated with Moderna, followed by Pfizer and Johnson & Johnson. NAb levels decreased with time after vaccination with Pfizer and Johnson & Johnson. T cell responses showed no significant difference among the different vaccines and remained stable up to 10 months after the study period for all vaccine types. In multivariate analyses, NAb responses (<95 U/mL) predicted breakthrough infection, whereas previous infection, the type of vaccine, and T cell responses did not. T cell responses to viral epitopes (<0.120 IU/mL) showed a significant association with the self-reported severity of COVID-19 disease. CONCLUSION This study provides evidence that NAb responses to SARS-CoV-2 vaccination correlate with protection against infection, whereas the T cell memory responses may contribute to protection against severe disease but not against infection.
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Affiliation(s)
- Zhen Zhao
- Department of Laboratory Medicine and Pathology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Attila Kumanovics
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Tanzy Love
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY 14642, USA
| | - Stacy E F Melanson
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Qing H Meng
- Department of Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Alan H B Wu
- Department of Laboratory Medicine, University of California, San Francisco, CA 94143, USA
| | - Joesph Wiencek
- Department of Pathology, Microbiology and Immunology, Vanderbilt School of Medicine, Nashville, TN 37240, USA
| | - Fred S Apple
- Department of Laboratory Medicine and Pathology, Hennepin Healthcare/Hennepin County Medical Center, Minneapolis, MN 55415, USA
- Hennepin Healthcare Research Institute, Minneapolis, MN 55404, USA
| | | | - David D Koch
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30303, USA
| | - Robert H Christenson
- Department of Pathology, University of Maryland School of Medicine, 685 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Yan Victoria Zhang
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 626, Rochester, NY 14642, USA
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Kiernan EA, Carpenter JE, Dunkley CA, Moran TP, Rothstein LS, Silver E, Salehi M, Koch DD, Morgan BW, Murray BP. Elevated methemoglobin levels in patients treated with hydroxocobalamin: a case series and in-vitro analysis. Clin Toxicol (Phila) 2022; 60:1012-1018. [PMID: 35549585 DOI: 10.1080/15563650.2022.2072315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Historically, the first step in treating cyanide (CN-) toxicity utilized antidotes to induce methemoglobinemia. This is concerning in patients who are already hypoxemic or have elevated carboxyhemoglobin. Hydroxocobalamin (OHCbl) is now the first-line antidote for CN- toxicity and is not known to induce methemoglobinemia. We observed elevated methemoglobin (MetHb) levels in several patients treated with OHCbl and sought to investigate the incidence of MetHb formation following administration of OHCbl. METHODS Chart review: A single-center, retrospective case series of patients who received 5 or 10 g of hydroxocobalamin from 01/01/2011 through 04/30/2019. Data was analyzed using descriptive statistics. In-vitro study: Discarded blood was separated into whole blood and plasma samples. OHCbl and normal saline was added to reach 0×, 1×, 2×, and 4× peak therapeutic concentrations and analyzed at times 0, 2, and 4 h after administration. RESULTS Chart review: Twenty-seven cases of OHCbl administration were identified. The median age was 53 years (IQR 38 - 64) and 20 (74.1%) were male. Exposure to a house fire or smoke inhalation was the reason for OHCbl administration in 21 (77.8%) patients. Five (18.5%) patients received 10 g of OHCbl while the rest received 5 g. Six (22.2%) patients developed methemoglobinemia, all after 5 g OHCbl administration; four had been exposed to fire and smoke, two received the medication for severe acidosis of unknown etiology not related to fire or smoke. The median peak level was 7.1% (IQR 2.2 - 16.4%) at a median time of 11.4 h post-administration. Two patients received methylene blue (MB), neither responded. Death occurred in 17 (63%) cases. In-vitro study: We observed a dose dependent elevation in total hemoglobin but did not detect any increase in MetHb. CONCLUSION We observed a noteworthy temporal association between the formation of methemoglobinemia and the administration of hydroxocobalamin. This does not appear to be an artifact of the CO-oximeters. This could have profound implications for patients who are already hypoxemic or have impaired oxygen carrying capacity from carboxyhemoglobin.
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Affiliation(s)
| | | | | | - Tim P Moran
- Emory University School of Medicine, Atlanta, GA, USA
| | | | | | - Maryam Salehi
- Emory University School of Medicine, Atlanta, GA, USA
| | - David D Koch
- Emory University School of Medicine, Atlanta, GA, USA
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Affiliation(s)
- David Alter
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - David D Koch
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia
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Kim E, Murray BP, Salehi M, Moran TP, Carpenter JE, Koch DD, Ritchie JC, Schindler JM, Morgan BW. Does Lidocaine Cause False Positive Results on Cocaine Urine Drug Screen? J Med Toxicol 2019; 15:255-261. [PMID: 31264143 DOI: 10.1007/s13181-019-00720-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Individuals who have tested positive for cocaine have claimed that lidocaine, or its primary metabolite, norlidocaine (monoethylglycinexylidide (MEGX)), have caused false positive results for the cocaine metabolite benzoylecgonine (BE) on urinary immunoassay testing. OBJECTIVE The goal of the study was to determine if lidocaine exposure from routine medical procedures can result in false positives on a commercially available cocaine immunoassay urine drug screen (UDS). METHODS We performed a cross-sectional observational study of patients receiving lidocaine as part of their regular care. Standard immunoassay drug screens and confirmatory liquid chromatography-mass spectrometry (LC-MS) were performed on all urine samples to assess for MEGX and BE. RESULTS In total, 168 subjects were enrolled; 121 samples positive for lidocaine were ultimately included for analysis. One hundred fourteen of the 121 were also positive for MEGX. None of the 121 were positive for cocaine/BE on the UDS (95% CI), 0-3.7% for the full sample and 0-3.9% for the 114 who tested positive for MEGX. CONCLUSION The present study found no evidence that lidocaine or norlidocaine are capable of producing false positive results on standard cocaine urine immunoassays.
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Affiliation(s)
| | - Brian Patrick Murray
- Emory University School of Medicine, 50 Hurt Plaza, Suite 600, Atlanta, GA, 30303, USA.
| | | | - Tim P Moran
- Emory University School of Medicine, 50 Hurt Plaza, Suite 600, Atlanta, GA, 30303, USA
| | - Joseph E Carpenter
- Emory University School of Medicine, 50 Hurt Plaza, Suite 600, Atlanta, GA, 30303, USA
| | | | | | - Joanna M Schindler
- Emory University School of Medicine, 50 Hurt Plaza, Suite 600, Atlanta, GA, 30303, USA
| | - Brent W Morgan
- Emory University School of Medicine, 50 Hurt Plaza, Suite 600, Atlanta, GA, 30303, USA
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Abdulrahman AA, Patel KH, Yang T, Koch DD, Sivers SM, Smith GH, Jaye DL. Is a 500-Cell Count Necessary for Bone Marrow Differentials?: A Proposed Analytical Method for Validating a Lower Cutoff. Am J Clin Pathol 2018; 150:84-91. [PMID: 29757362 DOI: 10.1093/ajcp/aqy034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES By convention, 500 cells are counted for bone marrow aspirate differentials. Evidence supporting such a cutoff is lacking. We hypothesized that 300-cell counts could be sufficient. METHODS Cell count results from 165 cases, for which values were recorded at 300 and 500 cells, were analyzed. We tested for statistical differences and changes in diagnostic classification between the two cutoffs. RESULTS Three hundred cell counts did not produce diagnostically different results, particularly for myeloblasts and plasma cells, where cell percentages are critical for disease classification. Method comparison analysis did not reach statistical significance for any cell type when comparing the two methods. Bias plots showed narrow, even spread about the mean bias. Contingency table analysis yielded no significant diagnostic discrepancies. CONCLUSIONS Performing differential counts on 300 cells would produce clinically and statistically similar results to 500 cells. Reducing the cell number counted has potential cost/labor reductions without affecting quality of care.
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Affiliation(s)
- Ahmed A Abdulrahman
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
| | - Kirtesh H Patel
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
| | - Tong Yang
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
| | - David D Koch
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
| | - Sarah M Sivers
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
| | - Geoffrey H Smith
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
| | - David L Jaye
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA
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Robinson MK, Caudill SP, Koch DD, Ritchie J, Hortin G, Eckfeldt JH, Sandberg S, Williams D, Myers G, Miller WG. Albumin adsorption onto surfaces of urine collection and analysis containers. Clin Chim Acta 2014; 431:40-5. [PMID: 24513540 DOI: 10.1016/j.cca.2014.01.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 01/20/2014] [Accepted: 01/21/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Adsorption of albumin onto urine collection and analysis containers may cause falsely low concentrations. METHODS We added (125)I-labeled human serum albumin to urine and to phosphate buffered solutions, incubated them with 22 plastic container materials and measured adsorption by liquid scintillation counting. RESULTS Adsorption of urine albumin (UA) at 5-6 mg/l was <0.9%; and at 90 mg/l was <0.4%. Adsorption was generally less at pH8 than pH5 but only 3 cases had p<0.05. Adsorption from 11 unaltered urine samples with albumin 5-333 mg/l was <0.8%. Albumin adsorption for the material with greatest binding was extrapolated to the surface areas of 100 ml and 2l collection containers, and to instrument sample cups and showed <1% change in concentration at 5 mg/l and <0.5% change at 20 mg/l or higher concentrations. Adsorption of albumin from phosphate buffered solutions (2-28%) was larger than that from urine. CONCLUSIONS Albumin adsorption differed among urine samples and plastic materials, but the total influence of adsorption was <1% for all materials and urine samples tested. Adsorption of albumin from phosphate buffered solutions was larger than that from urine and could be a limitation for preparations used as calibrators.
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Affiliation(s)
- Mary K Robinson
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control & Prevention, Atlanta, GA, United States
| | - Samuel P Caudill
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control & Prevention, Atlanta, GA, United States
| | - David D Koch
- Grady Memorial Hospital and Emory University, Department of Pathology & Laboratory Medicine, Atlanta, GA, United States
| | - James Ritchie
- Emory University, Department of Pathology & Laboratory Medicine, Atlanta, GA, United States
| | - Glen Hortin
- Quest Diagnostics, Cincinnati, OH, United States
| | - John H Eckfeldt
- University of Minnesota, Department of Laboratory Medicine and Pathology Minneapolis, MN, United States
| | - Sverre Sandberg
- Laboratory of Clinical Biochemistry, Haukeland University Hospital and the Norwegian Quality Improvement of Primary Care Laboratories, Bergen, Norway
| | - Desmond Williams
- Division of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control & Prevention, Atlanta, GA, United States
| | - Gary Myers
- American Association for Clinical Chemistry, Washington, DC, United States
| | - W Greg Miller
- Virginia Commonwealth University, Department of Pathology, Richmond, VA, United States.
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Molinaro RJ, Winkler AM, Kraft CS, Fantz CR, Stowell SR, Ritchie JC, Koch DD, Heron S, Liebzeit J, Santen SA, Guarner J. Teaching laboratory medicine to medical students: implementation and evaluation. Arch Pathol Lab Med 2012; 136:1423-9. [PMID: 23106588 PMCID: PMC3767850 DOI: 10.5858/arpa.2011-0537-ep] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Laboratory medicine is an integral component of patient care. Approximately 60% to 70% of medical decisions are based on laboratory results. Physicians in specialties that order the tests are teaching medical students laboratory medicine and test use with minimal input from laboratory scientists who implement and maintain the quality control for those tests. OBJECTIVE To develop, implement, and evaluate a 1.5-day medical student clinical laboratory experience for fourth-year medical students in their last month of training. DESIGN The experience was devised and directed by laboratory scientists and included a panel discussion, laboratory tours, case studies that focused on the goals and objectives recently published by the Academy of Clinical Laboratory Physicians and Scientists, and medical-student presentations highlighting salient points of the experience. The same knowledge quiz was administered at the beginning and end of the experience and 84 students took both quizzes. RESULTS A score of 7 or more was obtained by 16 students (19%) on the initial quiz, whereas 34 (40%) obtained the same score on the final quiz; the improvement was found to be statistically significant (P = .002; t = 3.215), particularly in 3 out of the 10 questions administered. CONCLUSIONS Although the assessment can only measure a small amount of knowledge recently acquired, the improvement observed by fourth-year medical students devoting a short period to learning laboratory medicine principles was encouraging. This medical student clinical laboratory experience format allowed teaching of a select group of laboratory medicine principles in 1.5 days to an entire medical school class.
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Affiliation(s)
- Ross J Molinaro
- Department of Pathology and Laboratory Medicine, Emory University, 1364 Clifton Rd, Atlanta, GA 30322, USA
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Dell'Aglio DM, Sutter ME, Schwartz MD, Koch DD, Algren DA, Morgan BW. Acute chloroform ingestion successfully treated with intravenously administered N-acetylcysteine. J Med Toxicol 2010; 6:143-6. [PMID: 20552315 PMCID: PMC2919686 DOI: 10.1007/s13181-010-0071-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Chloroform, a halogenated hydrocarbon, causes central nervous system depression, cardiac arrhythmias, and hepatotoxicity. We describe a case of chloroform ingestion with a confirmatory serum level and resultant hepatotoxicity successfully treated with intravenously administered N-acetylcysteine (NAC). A 19-year-old man attempting suicide ingested approximately 75 mL of chloroform. He was unresponsive and intubated upon arrival. Intravenously administered NAC was started after initial stabilization was complete. His vital signs were normal. Admission laboratory values revealed normal serum electrolytes, AST, ALT, PT, BUN, creatinine, and bilirubin. Serum ethanol level was 15 mg/dL, and aspirin and acetaminophen were undetectable. The patient was extubated but developed liver function abnormalities with a peak AST of 224 IU/L, ALT of 583 IU/L, and bilirubin level reaching 16.3 mg/dL. NAC was continued through hospital day 6. Serum chloroform level obtained on admission was 91 μg/mL. The patient was discharged to psychiatry without known sequelae and normal liver function tests. The average serum chloroform level in fatal cases of inhalational chloroform poisoning was 64 μg/mL, significantly lower than our patient. The toxicity is believed to be similar in both inhalation and ingestion routes of exposure, with mortality predominantly resulting from anoxia secondary to central nervous system depression. Hepatocellular toxicity is thought to result from free radical-induced oxidative damage. Previous reports describe survival after treatment with orally administered NAC, we report the first use of intravenously administered NAC for chloroform ingestion. Acute oral ingestion of chloroform is extremely rare. Our case illustrates that with appropriate supportive care, patients can recover from chloroform ingestion, and intravenously administered NAC may be of benefit in such cases.
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Ziemer DC, Kolm P, Weintraub WS, Vaccarino V, Rhee MK, Twombly JG, Narayan KMV, Koch DD, Phillips LS. Glucose-independent, black-white differences in hemoglobin A1c levels: a cross-sectional analysis of 2 studies. Ann Intern Med 2010; 152:770-7. [PMID: 20547905 DOI: 10.7326/0003-4819-152-12-201006150-00004] [Citation(s) in RCA: 249] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND A previous study of participants with prediabetes found that hemoglobin A(1c) (HbA(1c)) levels differed between black and white participants with no differences in glucose concentration. OBJECTIVE To determine whether black-white differences in HbA(1c) level are present in other populations and across the full spectrum of glycemia. DESIGN Cross-sectional, retrospective. SETTING Outpatient. PARTICIPANTS 1581 non-Hispanic black and white participants between 18 and 87 years of age without known diabetes in the SIGT (Screening for Impaired Glucose Tolerance) study and 1967 non-Hispanic black and white participants older than 40 years without known diabetes in the NHANES III (Third National Health and Nutrition Examination Survey). MEASUREMENTS HbA(1c) levels, anthropometry, and plasma glucose levels during oral glucose tolerance testing. RESULTS Hemoglobin A(1c) levels were higher in black than in white participants with normal glucose tolerance (0.13 percentage point [P < 0.001] in the SIGT sample and 0.21 percentage point [P < 0.001] in the NHANES III sample), prediabetes (0.26 percentage point [P < 0.001] and 0.30 percentage point [P < 0.001], respectively), or diabetes (0.47 percentage point [P < 0.020] and 0.47 percentage point [P < 0.013], respectively) after adjustment for plasma glucose levels and other characteristics known to correlate with HbA(1c) levels. LIMITATION The mechanism for the differences is unknown. CONCLUSION Black persons have higher HbA(1c) levels than white persons across the full spectrum of glycemia, and the differences increase as glucose intolerance worsens. These findings could limit the use of HbA(1c) to screen for glucose intolerance, indicate the risk for complications, measure quality of care, and evaluate disparities in health.
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Affiliation(s)
- David C Ziemer
- Division of Endocrinology, Emory University School of Medicine, 49 Jesse Hill Jr. Drive SE, Atlanta, GA 30303, USA
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Phillips LS, Ziemer DC, Kolm P, Weintraub WS, Vaccarino V, Rhee MK, Chatterjee R, Narayan KMV, Koch DD. Glucose challenge test screening for prediabetes and undiagnosed diabetes. Diabetologia 2009; 52:1798-807. [PMID: 19557386 DOI: 10.1007/s00125-009-1407-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 04/11/2009] [Accepted: 05/06/2009] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Diabetes prevention and care are limited by lack of screening. We hypothesised that screening could be done with a strategy similar to that used near-universally for gestational diabetes, i.e. a 50 g oral glucose challenge test (GCT) performed at any time of day, regardless of meal status, with one 1 h sample. METHODS At a first visit, participants had random plasma and capillary glucose measured, followed by the GCT with plasma and capillary glucose (GCTplasma and GCTcap, respectively). At a second visit, participants had HbA(1c) measured and a diagnostic 75 g OGTT. RESULTS The 1,573 participants had mean age of 48 years, BMI 30.3 kg/m(2) and 58% were women and 58% were black. Diabetes (defined by WHO) was present in 4.6% and prediabetes (defined as impaired glucose tolerance [2 h glucose 7.8-11.1 (140-199 mg/dl) with fasting glucose <or=6.9 (125 mg/dl)] and/or impaired fasting glucose with plasma glucose 6.1-6.9 mmol/l [110-125 mg/dl]) in 18.7%. The GCTplasma provided areas under the receiver-operating-characteristic curves of 0.90, 0.82 and 0.79 for detection of diabetes, diabetes or prediabetes, and prediabetes, respectively, all of which were higher than GCTcap, random and capillary glucose, and HbA(1c) (p < 0.02 for all). The performance of GCTplasma was unaffected by time after meals or time of day, and was better in blacks than whites, but otherwise comparable in men and women, and in groups with differing prevalence of glucose intolerance. GCTplasma screening would cost approximately US$84 to identify one person with previously unrecognised diabetes or prediabetes. CONCLUSIONS/INTERPRETATION GCT screening for prediabetes and previously unrecognised diabetes would be accurate, convenient and inexpensive. Widespread use of GCT screening could help improve disease management by permitting early initiation of therapy aimed at preventing or delaying the development of diabetes and its complications.
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Affiliation(s)
- L S Phillips
- Division of Endocrinology and Metabolism, Emory University School of Medicine, 101 Woodruff Circle, WMRB Room 1027, Atlanta, GA 30322, USA.
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El Bassuoni EA, Ziemer DC, Kolm P, Rhee MK, Vaccarino V, Tsui CW, Kaufman JM, Osinski GE, Koch DD, Venkat Narayan KM, Weintraub WS, Phillips LS. The "metabolic syndrome" is less useful than random plasma glucose to screen for glucose intolerance. Prim Care Diabetes 2008; 2:147-53. [PMID: 18779039 PMCID: PMC2638987 DOI: 10.1016/j.pcd.2008.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 03/06/2008] [Accepted: 04/27/2008] [Indexed: 11/15/2022]
Abstract
AIMS To compare the utility of metabolic syndrome (MetS) to random plasma glucose (RPG) in identifying people with diabetes or prediabetes. METHODS RPG was measured and an OGTT was performed in 1155 adults. Test performance was measured by area under the receiver-operating-characteristic curve (AROC). RESULTS Diabetes was found in 5.1% and prediabetes in 20.0%. AROC for MetS with fasting plasma glucose (FPG) was 0.80 to detect diabetes, and 0.76 for diabetes or prediabetes--similar to RPG alone (0.82 and 0.72). However, the AROC for MetS excluding fasting plasma glucose was lower: 0.69 for diabetes (p<0.01 vs. both RPG and MetS with FPG), and 0.69 for diabetes or prediabetes. AROCs for MetS with FPG and RPG were comparable and higher for recognizing diabetes in blacks vs. whites, and females vs. males. MetS with FPG was superior to RPG for identifying diabetes only in subjects with age <40 or BMI <25. CONCLUSIONS MetS features can be used to identify risk of diabetes, but predictive usefulness is driven largely by FPG. Overall, to identify diabetes or prediabetes in blacks and whites with varying age and BMI, MetS is no better than RPG--a more convenient and less expensive test.
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Affiliation(s)
- Eman A. El Bassuoni
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
| | - David C. Ziemer
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
| | - Paul Kolm
- Division of Cardiology, Department of Medicine, Atlanta, GA
| | - Mary K. Rhee
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
| | | | - Circe W. Tsui
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
| | - Jack M. Kaufman
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
| | - G. Eileen Osinski
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
| | - David D. Koch
- Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - K. M. Venkat Narayan
- Hubert Department of Global Health, Rollins School of Public Health, Atlanta, GA
| | | | - Lawrence S. Phillips
- Division of Endocrinology and Metabolism, Department of Medicine, Atlanta, GA
- Veterans Administration Medical Center, Atlanta, GA
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Ziemer DC, Kolm P, Foster JK, Weintraub WS, Vaccarino V, Rhee MK, Varughese RM, Tsui CW, Koch DD, Twombly JG, Narayan KMV, Phillips LS. Random plasma glucose in serendipitous screening for glucose intolerance: screening for impaired glucose tolerance study 2. J Gen Intern Med 2008; 23:528-35. [PMID: 18335280 PMCID: PMC2324161 DOI: 10.1007/s11606-008-0524-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 12/04/2007] [Accepted: 01/04/2008] [Indexed: 01/09/2023]
Abstract
BACKGROUND With positive results from diabetes prevention studies, there is interest in convenient ways to incorporate screening for glucose intolerance into routine care and to limit the need for fasting diagnostic tests. OBJECTIVE The aim of this study is to determine whether random plasma glucose (RPG) could be used to screen for glucose intolerance. DESIGN This is a cross-sectional study. PARTICIPANTS The participants of this study include a voluntary sample of 990 adults not known to have diabetes. MEASUREMENTS RPG was measured, and each subject had a 75-g oral glucose tolerance test several weeks later. Glucose intolerance targets included diabetes, impaired glucose tolerance (IGT), and impaired fasting glucose(110) (IFG(110); fasting glucose, 110-125 mg/dl, and 2 h glucose < 140 mg/dl). Screening performance was measured by area under receiver operating characteristic curves (AROC). RESULTS Mean age was 48 years, and body mass index (BMI) was 30.4 kg/m(2); 66% were women, and 52% were black; 5.1% had previously unrecognized diabetes, and 24.0% had any "high-risk" glucose intolerance (diabetes or IGT or IFG(110)). The AROC was 0.80 (95% CI 0.74-0.86) for RPG to identify diabetes and 0.72 (0.68-0.75) to identify any glucose intolerance, both highly significant (p < 0.001). Screening performance was generally consistent at different times of the day, regardless of meal status, and across a range of risk factors such as age, BMI, high density lipoprotein cholesterol, triglycerides, and blood pressure. CONCLUSIONS RPG values should be considered by health care providers to be an opportunistic initial screening test and used to prompt further evaluation of patients at risk of glucose intolerance. Such "serendipitous screening" could help to identify unrecognized diabetes and prediabetes.
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Affiliation(s)
- David C Ziemer
- Division of Endocrinology and Metabolism, Emory University School of Medicine, Atlanta, GA, USA
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Ziemer DC, Kolm P, Weintraub WS, Vaccarino V, Rhee MK, Caudle JM, Irving JM, Koch DD, Narayan KV, Phillips LS. Age, BMI, and race are less important than random plasma glucose in identifying risk of glucose intolerance: the Screening for Impaired Glucose Tolerance Study (SIGT 5). Diabetes Care 2008; 31:884-6. [PMID: 18310308 PMCID: PMC3685424 DOI: 10.2337/dc07-2282] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Age, BMI, and race/ethnicity are used in National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and American Diabetes Association (ADA) guidelines to prompt screening for pre-diabetes and diabetes, but cutoffs have not been evaluated rigorously. RESEARCH DESIGN AND METHODS Random plasma glucose (RPG) was measured and 75-g oral glucose tolerance tests were performed in 1,139 individuals without known diabetes. Screening performance was assessed by logistic regression and area under the receiver operating characteristic curve (AROC). RESULTS NIDDK/ADA indicators age >45 years and BMI >25 kg/m(2) provided significant detection of both diabetes and dysglycemia (both AROCs 0.63), but screening was better with continuous-variable models of age, BMI, and race and better still with models of age, BMI, race, sex, and family history (AROC 0.78 and 0.72). However, screening was even better with RPG alone (AROCs 0.81 and 0.72). RPG >125 mg/dl could be used to prompt further evaluation with an OGTT. CONCLUSIONS Use of age, BMI, and race/ethnicity in guidelines for screening to detect diabetes and pre-diabetes may be less important than evaluation of RPG. RPG should be investigated further as a convenient, inexpensive screen with good predictive utility.
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Affiliation(s)
- David C. Ziemer
- Division of Endocrinology and Metabolism, Emory University, Atlanta, Georgia
| | - Paul Kolm
- Christiana Care Health System, Newark, Delaware
| | | | - Viola Vaccarino
- Christiana Care Health System, Newark, Delaware
- Division of Cardiology, Emory University, Atlanta, Georgia
| | - Mary K. Rhee
- Division of Endocrinology and Metabolism, Emory University, Atlanta, Georgia
| | - Jane M. Caudle
- Division of Endocrinology and Metabolism, Emory University, Atlanta, Georgia
| | - Jade M. Irving
- Division of Endocrinology and Metabolism, Emory University, Atlanta, Georgia
| | - David D. Koch
- Department of Pathology & Laboratory Medicine, Emory University, Atlanta, Georgia
| | - K.M. Venkat Narayan
- Department of Medicine, Emory University, Atlanta, Georgia
- Hubert Department of Global Health, Emory University, Atlanta, Georgia
| | - Lawrence S. Phillips
- Division of Endocrinology and Metabolism, Emory University, Atlanta, Georgia
- Veterans Administration Medical Center, Atlanta, Georgia
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Lane SS, Kuppermann BD, Fine IH, Hamill MB, Gordon JF, Chuck RS, Hoffman RS, Packer M, Koch DD. A prospective multicenter clinical trial to evaluate the safety and effectiveness of the implantable miniature telescope. Am J Ophthalmol 2004; 137:993-1001. [PMID: 15183782 DOI: 10.1016/j.ajo.2004.01.030] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2004] [Indexed: 11/24/2022]
Abstract
PURPOSE To evaluate the safety and preliminary efficacy of a novel visual prosthetic device, the Implantable Miniature Telescope, IMT (by Dr Isaac Lipshitz) (IMT), in a phase I trial in patients with significant bilateral central vision impairment from late-stage age-related macular degeneration (AMD). The IMT is designed to reduce the relative size of the scotoma by rendering enlarged (threefold) central visual field images over the central and peripheral retina. DESIGN Prospective, multicenter, open-label clinical trial. METHODS In this prospective, multicenter phase I trial, 14 patients aged 60 or older with bilateral geographic atrophy or disciform scar AMD, cataract, and best-corrected visual acuity (BCVA) between 20/80 and 20/400 had an IMT implanted in one eye. Distance and near BCVA, endothelial cell density, and quality of life, measured as activities of daily life (ADL), were evaluated preoperatively and postoperatively. RESULTS At 12 months, 10 (77%) of 13 patients gained 2 more lines of either distance or near BCVA, and eight (62%) of 13 patients gained 3 or more lines in either distance or near BCVA. Mean endothelial cell density decreased by 13%. All adverse events resolved without sequelae. ADL scores improved in the majority of patients. CONCLUSION The results of this phase I trial support further evaluation of the IMT in a larger study population with late-stage AMD. A phase II/III trial is in progress.
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Affiliation(s)
- S S Lane
- Associated Eye Care, Stillwater, Minnesota, USA
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Rapuano CJ, Sugar A, Koch DD, Agapitos PJ, Culbertson WW, de Luise VP, Huang D, Varley GA. Intrastromal corneal ring segments for low myopia: a report by the American Academy of Ophthalmology. Ophthalmology 2001; 108:1922-8. [PMID: 11581075 DOI: 10.1016/s0161-6420(01)00804-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE This document describes intrastromal corneal ring segments (Intacs) inserts technology and examines the evidence to answer the key question about whether the treatment is safe and effective in correcting low myopia. METHODS A literature search that was conducted in September 2000 retrieved 13 relevant citations, and the reference lists of these articles were consulted for additional citations. Panel members reviewed this information and articles were rated according to the strength of evidence. RESULTS Prospective multicenter phase II and III clinical trials (Level II evidence rating) of Intacs inserts for myopia of -1.00 to -3.00 diopters (D), with a maximum of +1.00 D of astigmatism, enrolled a total of 452 subjects, with a total of 454 surgical attempts. The results from phase II and phase III were pooled for much of the analysis. At 1 year, 97% of patients who completed follow-up had 20/40 or better uncorrected visual acuity (UCVA). Seventy-four percent of patients had 20/20 or better UCVA. Ninety-two percent of eyes were within +/-1 D of intended refractive correction, and 69% were within 0.5 D of intended refractive correction. At 3 months, 90% of patients had less than 1.0 D of change from the previous examination performed at 1 month. The ocular complication rate, which was defined as clinically significant events but not resulting in permanent sequelae, was 11% at 12 months. The adverse event rate was 1.1%, defined as a serious event if untreated. Nearly 9% of patients requested to have their inserts removed and a total of 3.8% of patients required a secondary surgical intervention. CONCLUSIONS To date, evidence suggests that low myopia (-1 to -3 D) in a well-defined group of patients who have a stable manifest refraction and less than +1.0 D of astigmatism can be treated with Intacs inserts with a reasonable assurance of safety and effectiveness. Additional clinical research is needed to determine the long-term effectiveness of treatment and the comparative safety, effectiveness, and costs with other treatment modalities, including laser-assisted in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).
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Abstract
PURPOSE To report 4 cases of optic neuropathy following laser in situ keratomileusis (LASIK). SETTING Tertiary Care ophthalmic practices. METHODS In this retrospective observational case series, 4 patients who developed acute visual loss following LASIK are reported. All had clinical evidence of optic neuropathy. Two had optic disc edema and 2 had normal appearing optic discs initially. None of the patients experienced significant visual recovery, and all developed optic atrophy in the affected eye. RESULTS All patients had evaluations for alternative etiologies of their optic neuropathy, with negative results. All patients were therefore presumed to have experienced an ischemic optic neuropathy following LASIK. CONCLUSIONS Patients who have LASIK may experience an acute anterior or retrobulbar optic neuropathy. The etiology is unknown but may be related to the marked increase in intraocular pressure that occurs during a portion of the procedure.
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Affiliation(s)
- A G Lee
- Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
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Abstract
PURPOSE To describe the association between the presence of epithelial defects and the development of diffuse lamellar keratitis (DLK), "Sands of the Sahara" syndrome, following laser in situ keratomileusis (LASIK). SETTING Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA. METHODS In this retrospective study, the postoperative clinical course and surgical outcomes in 735 eyes of 358 consecutive patients who had myopic LASIK between December 1998 and August 1999 were reviewed. Of the 735 procedures, 680 were primary LASIK procedures and 55 were retreatments performed by lifting the existing flaps. The incidence and severity of DLK and the relationship of DLK to epithelial defects were tabulated. RESULTS Diffuse lamellar keratitis developed in 9 of the 16 eyes that had postoperative epithelial defects. Seventeen eyes without epithelial defects also developed DLK. The presence of an epithelial defect increased an individual's risk of developing DLK 24 times (95% confidence interval, 13 to 45). In 8 eyes, the inflammation resolved following treatment with intense topical corticosteroids. One eye had irrigation under the flap because of dense central inflammation; the final outcome was mild inferior corneal steepening. All eyes recovered preoperative best spectacle-corrected visual acuities. CONCLUSION Patients who have epithelial defects of any size following LASIK are at significantly increased risk of developing DLK.
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Affiliation(s)
- M N Shah
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA
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Koch DD. Consultation section. J Cataract Refract Surg 2000; 26:1274. [PMID: 11020605 DOI: 10.1016/s0886-3350(00)00630-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
PURPOSE Photoastigmatic refractive keratectomy (PARK) was studied in a multi-center clinical trial. The Nidek EC-5000 excimer laser was evaluated for its effect on refraction, visual acuity, and safety measures as part of a U.S. Food and Drug Administration (FDA) regulated study. METHODS Eight U.S. centers enrolled adults with eyes having refractive astigmatism up to 4.00 D and a myopic spherical equivalent refraction up to -8.00 D. Results are reported for 749 eyes of 486 patients with at least 6 months follow-up. The rectangular beam scanning Nidek EC-5000 used a 5.5-mm-diameter treatment zone, a 7.0-mm-diameter peripheral blend zone, and a 40 Hz pulse rate for surface treatment of myopic astigmatism. Nomogram corrections to machine settings were required to achieve the desired results. RESULTS Preoperative average spherical equivalent refraction of -4.90+/-1.74 D was reduced to -0.02+/-0.79 D at 6 months. Refractive stability was established at 3 months. Over 62% of eyes were within +/-0.50 D of desired correction at 6 months, with over 86% within +/-1.00 D. Uncorrected visual acuity improved by an average of 10 Snellen lines; over 64% of eyes saw 20/20 or better uncorrected and over 93% saw 20/40 or better uncorrected at 6 and 12 months. PARK treatment effectively reduced astigmatism with little average axis error or magnitude error. Corneal haze and safety concerns were minimal. CONCLUSIONS Photoastigmatic refractive keratectomy using the Nidek EC-5000 excimer laser provided significant reduction of myopia and astigmatism, with minimal complications.
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Affiliation(s)
- S M MacRae
- Casey Eye Institute, Oregon Health Sciences University, Portland 97201-4197, USA.
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Hugger P, Kohnen T, La Rosa FA, Holladay JT, Koch DD. Comparison of changes in manifest refraction and corneal power after photorefractive keratectomy. Am J Ophthalmol 2000; 129:68-75. [PMID: 10653415 DOI: 10.1016/s0002-9394(99)00268-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To determine which corneal curvature values most closely correlate to change in manifest refraction after excimer laser photorefractive keratectomy. METHODS In a prospective study at the Cullen Eye Institute, excimer laser photorefractive keratectomy was performed on 27 eyes of 27 patients (mean age, 38.07+/-6.65 years). Preoperative refractive errors ranged from -2.25 diopters to -8.75 diopters (mean, -5.74+/-2.09 diopters). Preoperatively and 1 month postoperatively, we determined the spherical equivalent of the subjective manifest refraction (corrected for a 12-mm vertex distance) and measured corneal power using standard keratometry (Bausch & Lomb Keratometer; Rochester, New York) and computerized videokeratography (EyeSys Corneal Analysis System; Premier Laser Systems Inc, Houston, Texas). We collected 15 corneal values: standard keratometry and 14 computerized videokeratography values calculated using the axial, instantaneous, and refractive formulas. All calculations were performed with 1.3375 and 1.376 for the refractive index of the cornea. For each of the corneal values, we subtracted the change in corneal power from the change in manifest refraction and calculated for this difference the means, SDs, correlations, and regressions. RESULTS Mean differences between change in refraction and change in corneal power were lower when for a refractive index of 1.376 than for 1.3375, were lowest for the most central measurement points, and displayed a high SD. A value of 1.408 for the refractive index would be required to optimize the correlation between change in manifest refraction and effective refractive power of the central 3 mm of the cornea. CONCLUSIONS For individual patients who have undergone photorefractive keratectomy, changes in corneal values determined by computerized videokeratography or by standard keratometry do not reliably predict change in manifest refraction.
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Affiliation(s)
- P Hugger
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA
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Norton JN, Kohnen T, Hackett RB, Patel A, Koch DD. Ocular biocompatibility testing of intraocular lenses: a 1 year study in pseudophakic rabbit eyes. J Cataract Refract Surg 1999; 25:1467-79. [PMID: 10569161 DOI: 10.1016/s0886-3350(99)00237-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate the appropriate duration for conducting ocular biocompatibility studies with an intraocular lens (IOL) in the pseudophakic rabbit model. SETTING Alcon Laboratories, Inc., Fort Worth, Texas, USA. METHODS A single-piece biconvex poly(methyl methacrylate) (PMMA) IOL was implanted in the capsular bag of 18 eyes of New Zealand white rabbits; 8 eyes received sham surgeries. Rabbits were monitored clinically and then sacrificed 6 or 12 months after surgery for histopathological examination of ocular tissues. RESULTS Biomicroscopic examination revealed mild ocular changes in all surgical eyes during the first 3 months postoperatively. After that, there was a high incidence of posterior synechias, flare, and posterior capsule opacification (PCO) in eyes with PMMA IOLs. Posterior synechias and flare scores remained mild to moderate throughout the study, whereas PCO severity increased over time. Similar findings were observed in sham eyes. In addition, several eyes with PMMA IOLs developed IOL dislocation, hyphema, iris bombe, and a fibrous membrane covering the IOL. No discernible differences in biomicroscopic scores were observed in eyes at 6 or 12 months. Intraocular pressures and morphology of the corneal endothelium were normal in both groups. Results from histopathological analysis of the ocular tissues were consistent with observations from the biomicroscopic examinations. CONCLUSION The results suggest that IOL implantation studies in the pseudophakic rabbit eye should be conducted for 3 or fewer months. Regulatory guidelines requiring longer ocular implantation studies should be revised to reflect the inherently rapid and extensive ocular response in the rabbit model.
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Affiliation(s)
- J N Norton
- Alcon Laboratories, Inc., Texas 76134, USA
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Abstract
PURPOSE To evaluate subjective functional visual improvement after phacoemulsification and intraocular lens (IOL) implantation and identify patient characteristics and treatment features associated with no functional improvement. SETTING Academic referral practice, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA. METHODS A retrospective review was performed of the surgical results in 106 consecutive eyes of 102 patients who completed the American Society of Cataract and Refractive Surgery (ASCRS) Cataract Data Collection Form preoperatively and 1 month postoperatively. One surgeon performed all the surgery. The relationship of patient characteristics and treatment features and reported visual function was analyzed using an analysis of variance and the Wilcoxon rank sum and Fisher exact tests. RESULTS One month postoperatively, all patients demonstrated improved visual acuity. However, 15 patients (14%) reported unimproved or decreased visual function. No statistically significant intergroup difference (P > .05) was detected in mean preoperative, postoperative, and fellow eye best spectacle-corrected visual acuities or refractive errors; reported severity of preoperative symptoms or satisfaction with vision; reported preoperative daily activity functioning or prevalence of hypertension and diabetes; type of anesthesia, lens material, or wound closure used; intraoperative or postoperative complication rates. However, patients reporting unimproved vision tended to be older and less satisfied with their quality of life and medical care than those reporting improved vision (P = .02, .03, .01, respectively). CONCLUSIONS Self-reported visual function generally improved after phacoemulsification and IOL implantation; however, some older patients less satisfied with their quality of life and medical care reported no functional improvement despite improved visual acuity. These patients might benefit from an extended preoperative discussion of postoperative expectations.
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Koch DD. Incorporating new refractive surgical procedures into clinical practice. J Cataract Refract Surg 1999; 25:1029-30. [PMID: 10445178 DOI: 10.1016/s0886-3350(99)00165-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
PURPOSE To evaluate corneal stability, measured by computerized videokeratography (CVK) after discontinuation of contact lens wear in preoperative refractive surgery candidates. SETTING Baylor College of Medicine, Cullen Eye Institute, Houston, Texas, USA. METHODS Topographic differences were analyzed in 136 noncontact lens wearers (NCLW) and 76 contact lens wearers (CLW) (18 rigid gas-permeable contact lenses [RGPCL], 58 soft contact lenses [SCL]) using EyeSys CVK after discontinuation of SCL wear for 2 weeks and RGPCL wear for 5 weeks. RESULTS There were no differences in CVK patterns between the NCLW and the CLW groups. There were no statistically significant differences between the 2 groups in topographic symmetry, asphericity, corneal uniformity index, predicted corneal acuity, and irregular astigmatism. The dioptric range for the axial and the profile difference maps in the CLW group was slightly lower than in the NCLW group. CONCLUSIONS For patients whose manifest refraction and CVK maps were within 0.5 diopters of earlier values, discontinuation of SCL wear for 2 weeks and RGPCL wear for 5 weeks was adequate for the cornea to return to its baseline topographic state.
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Affiliation(s)
- K Budak
- Cullen Eye institute, Baylor College of Medicine, Department of Ophthalmology, Houston, Texas 77030, USA
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Budak K, Hamed AM, Friedman NJ, Koch DD. Corneal topography classification in myopic eyes based on axial, instantaneous, refractive, and profile difference maps. J Cataract Refract Surg 1999; 25:1069-79. [PMID: 10445192 DOI: 10.1016/s0886-3350(99)00130-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To refine and develop systems for classifying the topography of myopic corneas using axial, instantaneous, refractive, and profile difference maps. SETTING Baylor College of Medicine, Cullen Eye Institute Houston, Texas, USA. METHODS Using the EyeSys Corneal Analysis System, computerized videokeratographs of 153 corneas of 78 myopic patients were retrospectively analyzed. Patterns were defined with respect to the mid-dioptric green color. Relationships among pattern types, refractive power, corneal power, corneal uniformity index (CU index), and predicted corneal visual acuity (PC acuity) were calculated. RESULTS Six types of patterns for axial, instantaneous, and refractive maps and 3 types of patterns for the profile difference map were defined. For a given cornea, there was a weak correlation among the patterns in the axial, instantaneous, and profile difference maps. The circular with central irregularity pattern in auto-scale refractive maps and the irregular pattern in profile difference maps and axial maps were correlated with lower CU index and PC acuity values. Clinical classification of instantaneous maps did not contribute substantially to the information provided by axial maps. CONCLUSION Patterns of computerized videokeratographs varied according to the type of topographic map. The classification systems used provide a baseline for analyzing the response of the cornea to various interventions.
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Affiliation(s)
- K Budak
- Cullen Eye Institute, Baylor College of Medicine, Department of Ophthalmology, Houston, Texas 77030, USA
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Zeh WG, Koch DD. Comparison of contact lens overrefraction and standard keratometry for measuring corneal curvature in eyes with lenticular opacity. J Cataract Refract Surg 1999; 25:898-903. [PMID: 10404363 DOI: 10.1016/s0886-3350(99)00088-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE To assess the accuracy of corneal power measurement by contact lens overrefraction in patients with normal corneas and to determine the suitability of this method for use in intraocular lens (IOL) calculations. SETTING General ophthalmology clinic at a public hospital (Ben Taub General Hospital, Houston, Texas, USA). METHODS Using contact lens overrefraction (CLO), and standard keratometry, the corneal power in 33 eyes of 20 normal patients and patients scheduled for cataract extraction was prospectively measured. The eyes were divided into 3 groups based on their best spectacle-corrected visual acuity: (1) 20/20 to 20/40, (2) 20/50 to 20/70, and (3) 20/80 to 20/400. For each group, the means (absolute and arithmetic), standard deviations, and ranges of differences in corneal power as measured by CLO and keratometry were calculated. These values were used to estimate the induced variance in refractive outcome for IOL calculations. RESULTS The mean absolute differences in corneal power by group were 0.35 diopter (D) +/- 0.18 (SD), 0.54 +/- 0.33 D, and 0.77 +/- 0.28 D, respectively. The mean arithmetic differences in corneal power were -0.05 +/- 0.39 D, +0.37 +/- 0.51 D, and +0.17 +/- 0.80 D, respectively. CONCLUSIONS In eyes of patients with good visual acuity (20/20 to 20/40), corneal power measurements by CLO and keratometry were similar. The accuracy of the CLO-derived value decreased with increasing media opacity but was still acceptable with acuity of 20/70. Contact lens overrefraction may be a viable alternative to refractive history and videokeratography for estimating true corneal power in patients with surgically altered or irregular corneas.
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Affiliation(s)
- W G Zeh
- Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
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Abstract
PURPOSE To examine the relationships among several refractive and topographic parameters. SETTING Cullen Eye Institute Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA. METHODS Using computerized videokeratography (EyeSys Corneal Analysis System), 287 corneas of 150 patients were retrospectively analyzed. The Holladay Diagnostic Summary (HDS) refractive maps were used to evaluate relationships among variables of the HDS and refractive error. RESULTS Myopic spherical equivalent refraction (P = .0003) and more negative asphericity (Q-values) (P = .0119) were correlated with steeper corneas. The Q-values were less negative in eyes with moderate myopia (2.0 to 6.0 diopters [D]) than in those with hyperopia (1.0 D or greater). The Q-values below -0.3 were correlated with less favorable values for predicted corneal acuity and corneal uniformity index values. Mean corneal curvature measurements obtained by computerized videokeratography and standard keratometry showed a strong degree of correlation (P = .0001). CONCLUSION As the degree of myopia and negative asphericity increased, the corneal radius of curvature decreased. Corneal Q-values less than -0.3 were associated with reduced optical performance of the cornea.
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Affiliation(s)
- K Budak
- Cullen Eye Institute, Baylor College of Medicine, Department of Ophthalmology, Houston, Texas, USA
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Budak K, Khater TT, Friedman NJ, Koch DD. Corneal topographic changes induced by excision of perilimbal lesions. Ophthalmic Surg Lasers 1999; 30:458-64. [PMID: 10392733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND AND OBJECTIVES To evaluate corneal topographic changes induced by excision of two pterygia and a perilimbal dermoid. MATERIAL AND METHODS Using the EyeSys Corneal Analysis System, we retrospectively analyzed the changes in astigmatism, mean central corneal power, and other topographic parameters of three corneas before and after surgical removal of two pterygia and a perilimbal dermoid. RESULTS Marked corneal steepening occurred along the preoperative flat meridian after the excision of the pterygia and dermoid cyst. For each patient, surgery increased the mean central corneal curvature and decreased total astigmatism. CONCLUSION Surgical excision can ameliorate abnormal corneal topographic changes produced by limbal lesions.
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Affiliation(s)
- K Budak
- Baylor College of Medicine, Cullen Eye Institute, Houston, TX 77030, USA
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Koch DD. Handbook of Interpretation of Diagnostic Tests. Jacques Wallach. Philadelphia, PA: Lippincott-Raven Publishers, 1998, 564 pp., $28.95. ISBN 0-7817-1221-1. Clin Chem 1999. [DOI: 10.1093/clinchem/45.5.722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- David D Koch
- Department of Pathology, and Laboratory Medicine, University of Wisconsin, Madison, WI 53792
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Mader TH, Koch DD, Manuel K, Gibson CR, Effenhauser RK, Musgrave S. Stability of vision during space flight in an astronaut with bilateral intraocular lenses. Am J Ophthalmol 1999; 127:342-3. [PMID: 10088747 DOI: 10.1016/s0002-9394(98)00326-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To report excellent and stable vision in an astronaut during space flight after bilateral cataract surgery with intraocular lenses. METHODS A 60-year-old physician mission specialist astronaut developed cataracts and underwent phacoemulsification with insertion of one-piece polymethylmethacrylate intraocular lenses that had 6-mm optics bilaterally. Several months later, he flew on a space shuttle mission. Ocular examinations were performed before and after the mission, and the patient was questioned about visual changes during flight. RESULTS Ocular examinations demonstrated stable bilateral posterior chamber intraocular lenses. Our subject reported excellent vision during liftoff, 18 days of microgravity, changes in cabin pressure, and reentry. CONCLUSION Results suggest that intraocular lenses are safe, effective, and well tolerated during space flight.
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Affiliation(s)
- T H Mader
- Madigan Army Medical Center, Tacoma, Washington, USA
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Koch DD, Sanan A. Peripheral corneal relaxing incisions for residual astigmatism after photoastigmatic keratectomy and laser in situ keratomileusis. J Refract Surg 1999; 15:S238-9. [PMID: 10202731 DOI: 10.3928/1081-597x-19990302-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Affiliation(s)
- D D Koch
- Cullen Eye Institute, Houston, TX 77030, USA
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Abstract
There have been major changes over the past 5 to 10 years in our understanding of both the chemical basis for and the surgical treatment of cataract in infants and children. Important questions that remain to be answered include the appropriate power and design selection criteria for intraocular lens implantation, as well as management of the posterior capsule and long-term refractive sequelae. In the past 10 years, there have been radical changes in the management of visually significant cataract in the infant and child. Whereas lens removal, subtotal posterior capsulectomy, vitrectomy, and aphakia were once the standard of care, many physicians now feel that small incisions, phacoemulsification technology, and intraocular lenses (IOLs) are best for these patients. Work is continuing to accumulate a significant body of evidence to evaluate results of these changes in technique and to develop optimal IOL designs and selection criteria for these specialized cataract patients.
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Affiliation(s)
- M B Hamill
- Baylor College of Medicine, Cullen Eye Institute, Department of Ophthalmology, Houston, TX 77030, USA
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Valluri S, Minkovitz JB, Budak K, Essary LR, Walker RS, Chansue E, Cabrera GM, Koch DD, Pepose JS. Comparative corneal topography and refractive variables in monozygotic and dizygotic twins. Am J Ophthalmol 1999; 127:158-63. [PMID: 10030557 DOI: 10.1016/s0002-9394(98)00319-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To investigate the role of heredity in determining corneal shape, axial length, and overall refractive error. METHODS Twenty monozygotic and 19 dizygotic twin pairs, age 12 to 73 years, were enrolled in the study. Zygosity was determined by physical similarity and by responses to questions adapted from surveys. Two twin pairs were excluded because of undetermined zygosity and one pair because of keratoconus (both siblings). Refractive error was determined by an automated refractor. Manifest refraction was also recorded, as well as cycloplegic refraction in subjects under age 18 years. Corneal topography data and manual keratometer readings were also obtained. Axial lengths were determined by A-scan ultrasound. Data were analyzed by Student t tests only in the right eye. Left-eye data were comparable for all variables. RESULTS Mean intrapair difference in refractive error (spherical equivalent) was less for monozygotic than for dizygotic twins (RE: 0.41 vs 1.53; P = .001). Mean intrapair difference in axial length was less for monozygotic twins (RE: 0.39 vs 0.76 mm; P = .031). Corneal topography data (power and meridian) in all zones (3, 5, and 7 mm) also showed smaller mean differences among monozygotic pairs than dizygotic, but the difference was statistically significant only for the 5-mm zone. In addition, most Holladay Diagnostic Summary variables that were studied did not show any statistically significant differences. CONCLUSIONS Axial length and overall refractive error have a significant genetic basis. Corneal topography data appear to have other overriding determining factors for several of the variables studied.
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Affiliation(s)
- S Valluri
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Kohnen T, Koch DD. Experimental and clinical evaluation of incision size and shape following forceps and injector implantation of a three-piece high-refractive-index silicone intraocular lens. Graefes Arch Clin Exp Ophthalmol 1998; 236:922-8. [PMID: 9865623 DOI: 10.1007/s004170050181] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Previous studies have demonstrated that incision sizes required for insertion of various foldable intraocular lenses (IOLs) vary according to the IOL/inserter combination. The purpose of this study was to compare incision sizes and wound shape for both forceps and injector implantation of high-refractive-index silicone IOLs. METHODS In fresh human cadaver eyes, limbal corneal tunnel incisions were created, and 12 foldable high-refractive-index silicone (dimethyldiphenylsiloxane) IOLs were inserted in a randomized fashion using either a forceps or an injector. Using incision calipers, internal and external measurements of the tunnel incisions were obtained before and after IOL insertion. Scanning electron microscopy (SEM) was performed on selected corneas following IOL insertion. Additionally, in 12 cataract procedures, the incision sizes following forceps or injector implantation were evaluated intraoperatively. RESULTS In the experimental setting, the external and internal tunnel widths (in mm) before insertion were 3.05 mm (+/-0.07) and 3.02 mm (+/-0.03), respectively, with the forceps and 3.06 mm (+/-0.04) and 3.01 mm (+/-0.04) with the injector. Following IOL implantation, the external and internal incision sizes were 3.33 mm (+/-0.07) and 3.33 mm (+/-0.04) with the forceps and 3.32 mm (+/-0.08) and 3.33 mm (+/-0.07) with the injector. SEM showed tearing of corneal structures after implantation through the smallest possible incisions with both devices. In the clinical study, the incision sizes before and after implantation were 3.23 mm (+/-0.10) and 3.36 mm (+/-0.06) with the forceps and 3.11 mm (+/-0.08) and 3.21 mm (+/-0.10) with the injector. CONCLUSIONS This study confirms that high-refractive-index silicone IOLs provide one of the smallest currently achievable incisions before and after IOL implantation. In clinical use, the new injector reduces the mean incision size required by approximately 0.1 mm.
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Affiliation(s)
- T Kohnen
- Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
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Paulson WD, Roberts WL, Lurie AA, Koch DD, Butch AW, Aguanno JJ. Wide variation in serum anion gap measurements by chemistry analyzers. Am J Clin Pathol 1998; 110:735-42. [PMID: 9844585 DOI: 10.1093/ajcp/110.6.735] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The traditional anion gap [AG = Na-Cl-(total CO2)] mean value of 12 mEq/L was established during the 1970s with analyzer methods that are no longer used widely. No studies have systematically compared mean AG values from analyzers in current use. We used data from healthy subjects obtained from 27 clinical laboratories, 5 manufacturers, and 8 publications to compute mean AG values from 1970s analyzers and 8 current analyzers. We also compared mean AG values by evaluating Na, Cl, and total CO2 data from the College of American Pathologists Chemistry Surveys (1990-1996). Data from healthy subjects showed that overall mean AG values of the 9 analyzers ranged from 5.9 to 12.4 mEq/L. The pooled (i.e., average) AG SD was 2.3 mEq/L. We then used the data of the Surveys and the mean value from 1 analyzer to compute predicted mean values for the other 7 current analyzers. Almost all mean AG values predicted from the Surveys agreed (within 1.5 mEq/L) with mean values from healthy subjects. These results show that mean values of analyzers vary widely, indicating that analytic bias strongly influences the AG. The results should be a useful guide for the AG measurements that can be expected from different analyzers.
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Affiliation(s)
- W D Paulson
- Department of Medicine, Louisiana State University Medical Center, Shreveport, USA
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Budak K, Friedman NJ, Rhodes L, Koch DD. Peripheral radial incisions to treat inferior contact lens edge lift after penetrating keratoplasty for keratoconus. J Cataract Refract Surg 1998; 24:1529-34. [PMID: 9818347 DOI: 10.1016/s0886-3350(98)80179-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A patient with marked corneal astigmatism and inferior contact edge lift after penetrating keratoplasty for keratoconus had corneal relaxing incisions (CRIs) on the donor button and radial incisions on the host cornea. Results were evaluated by computerized videokeratography and by refitting the contact lens. Two pairs of CRIs decreased astigmatism from 11.00 to 4.25 diopters but did not alleviate the contact lens edge lift, which was caused by excessive steepness in the keratoconic host cornea. After 6 radial incisions were made to flatten the inferior host cornea, the peripheral cornea flattened and the patient was successfully refitted with a contact lens.
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Affiliation(s)
- K Budak
- Baylor College of Medicine, Department of Ophthalmology, Houston, Texas 77030, USA
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Abstract
PURPOSE To compare the values for corneal power determined by the axial, instantaneous and refractive formulas when imaging normal human corneas using computerized videokeratography. SETTING Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. METHODS This prospective clinical trial involved 60 corneas of 30 normal volunteers. Computerized videokeratography was performed to determine corneal power at the center and the 1, 3, 5, and 7 mm zones using the 3 formulas. RESULTS Mean central corneal power was 42.86 diopters (D) with each of the formulas. The mean corneal powers for the axial, instantaneous, and refractive formulas were 43.09, 43.21, and 42.98 D at the 1 mm zone; 43.10, 42.92, and 43.46 D at the 3 mm zone; 42.75, 41.63, and 44.02 at the 5 mm zone; 42.21, 40.30, and 44.79 D at the 7 mm zone, respectively. The differences among powers for the 3 formulas at the 3, 5, and 7 mm zones were statistically significant (P < .01). CONCLUSION In normal corneas, clinically significant differences exist in the corneal power values calculated by the axial, instantaneous, and refractive formulas.
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Affiliation(s)
- S Bafna
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA
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Lee AG, Koch DD. The Baylor survey of Ophthalmology Residency graduates: rationale for reform in residency training. Ophthalmic Surg Lasers 1998; 29:649-57. [PMID: 9715490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND OBJECTIVE To survey graduates of an ophthalmology residency training program regarding skills necessary for a well-trained ophthalmologist. METHODS Two survey instruments were mailed to the graduates of the Baylor College of Medicine Department of Ophthalmology Residency Training Program. RESULTS Specific skills were identified that were rated as clinically important and for which training was considered adequate, and, conversely, skills that were rated as less important but for which training was adequate. CONCLUSION This survey instrument may allow ophthalmology residency training programs to identify perceived and real deficiencies in the prioritization of changes in curriculum or the skills transfer process.
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Affiliation(s)
- A G Lee
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
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Koch DD. Finding the perfect match. J Cataract Refract Surg 1998; 24:1013-4. [PMID: 9719954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Abstract
PURPOSE To evaluate the effectiveness of limbal relaxing incisions (LRIs) for correcting corneal astigmatism during cataract surgery. SETTING Cullen Eye Institute, Houston, Texas, USA. METHODS In 12 eyes of 11 patients, cataract surgery was combined with LRIs. The LRIs were made according to a modified Gills nomogram and were based on preoperative corneal astigmatism determined with standard keratometry and computerized videokeratography (EyeSys Corneal Analysis System Version 3.2). RESULTS The mean preoperative keratometric cylinder was 2.46 +/- 0.81 diopters (D). At 1 month postoperatively, mean arithmetic reduction in keratometric cylinder was 1.12 +/- 0.74 D, and the with-the-wound (WTW) change (calculated by Holladay, Cravy, Koch vector analysis formula) was -0.70 +/- 0.44. From 1 day to 1 month postoperatively, there was 0.55 D of WTW regression with minimal change in the mean cylindrical axis. There were no overcorrections. CONCLUSION Limbal relaxing incisions are a practical, simple, and forgiving approach to the correction of astigmatism during cataract surgery.
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Affiliation(s)
- K Budak
- Cullen Eye Institute, Baylor College of Medicine, Department of Ophthalmology, Houston, Texas 77030, USA
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