A total of 5000 pts of glaucoma are identified and surveyed by pts. inteviews regarding family history of glaucoma. Such a study design is called ?
**Core Concept**
The question is testing the understanding of epidemiological study designs, specifically the one used to investigate the association between family history and the occurrence of glaucoma. This concept is crucial in understanding the methodology behind research studies and identifying potential risk factors for diseases.
**Why the Correct Answer is Right**
Case-control studies are a type of observational study design where individuals with a specific outcome (in this case, glaucoma) are compared to those without the outcome. The study design mentioned in the question, where patients with glaucoma are surveyed about their family history, fits the definition of a case-control study. In this design, the researchers look back in time to identify potential risk factors or associations, such as family history, that may be linked to the development of glaucoma.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a cohort study involves following a group of individuals over time to observe the development of outcomes, whereas a case-control study looks back in time to identify potential risk factors.
**Option B:** This option is incorrect because a cross-sectional study involves assessing a population at a single point in time, but does not involve looking back in time to identify risk factors.
**Option C:** This option is incorrect because a randomized controlled trial (RCT) is an experimental study design where participants are randomly assigned to different groups to test the effectiveness of an intervention, whereas a case-control study is an observational design.
**Clinical Pearl / High-Yield Fact**
When designing a study to investigate the association between a risk factor (such as family history) and a disease (such as glaucoma), researchers should consider the study design carefully to ensure that it can provide valid and reliable results.
**Correct Answer: D. Case-control study. A study in which individuals with a specific disease or condition (cases) are compared with individuals without the disease or condition (controls) to identify potential risk factors or associations.**