18. Case-Control Study Patients with CRVO Patients w/o CRVO Present (Outcome) Past (Exposure) Hypertensive Hypertensive Non hypertensive Non hypertensive Cases Controls Comparison
19.
20. Case-Control Study Patients w POAG Patients w/o PAOG Present (Outcome) Past (Exposure) RNFL thickness by OCT RNFL thickness by OCT Cases Controls
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23. Measures of association Sensitivity = A/A+C Specificity = D/B+D Odds ratio: AD/BC 1= no diff. case & control >1 = risk more < 1 = risk less No Yes Disease D C B A Risk factors No Yes
24.
25. Prospective Cohort Study Exposed to risk factors Not exposed to risk factors Do not develop disease Develop disease Develop disease Do not develop disease Present Future comparison Study population wo disease
26.
27. Cohort study: Tobacco smoking and lung cancer, England & Wales, 1951 32.4 19.8 8.1 Ref. 2.27 1.39 0.57 0.07 57 54 22 03 25,100 38,900 38,600 42,800 ≥ 25 15 – 24 1-14 none Rate ratio Rate per 1000 p-y Cases Person-years at risk Cigarettes smoked/d
28.
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31.
32.
33.
34. Clinical Trial Study Population Treatment Group Control Group Outcomes Outcomes R a n d om i z e Comparison
35. Clinical Trial Patients w Ocular lymphoma Randomi ze Ivt Rutiximab Ivt methotrexate Comparison Outcome Outcome