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Article
June 1988

Selection of Controls for Clinical Research Studies in Ophthalmology

Author Affiliations

From The Wilmer Ophthalmological Institute, Clinical Trials and Biometry, The Johns Hopkins Medical Institutions, Baltimore.

Arch Ophthalmol. 1988;106(6):835-840. doi:10.1001/archopht.1988.01060130905050
Abstract

• Ophthalmologists are becoming increasingly aware of the need for welldesigned, controlled studies to investigate etiology and treatment of ocular conditions. While patients with the conditions of interest, or with characteristics that place them at high risk of eventual development of such conditions, may be readily identified in the ophthalmology clinic, identification of appropriate controls to be used for comparison may be quite difficult. In this article, epidemiologic principles for selection of controls for retrospective (case-control) and prospective (cohort) studies are reviewed. Two related studies, a case-control study in which multiple control groups were employed and a 15-year cohort study of all cases and controls, provided an opportunity to compare controls selected at random from an ophthalmology practice with controls selected at random from the general population. Participation rates were higher among office patients selected for study, both in the case-control study and in the cohort study. In the cohort study, office controls were more likely to lose visual acuity and to develop new degenerative eye conditions. These differences between control groups selected from two different sources emphasize the need for careful evaluation of potential groups of controls with respect to biases that each may bring to interpretation of clinical research findings.

References
1.
Goldstein H, Henderson M, Goldberg ID, et al:  Perinatal factors associated with strabismus in Negro children . Am J Public Health 1967;57:217-228.Article
2.
Ganley JP:  Epidemiologic characteristics of presumed ocular histoplasmosis . Acta Ophthalmol 1973;( (suppl 119) ):1-63.
3.
Maltzman BA, Mulvihill MN, Greenbaum A:  Senile macular degeneration and risk factors: A case-control study . Ann Ophthalmol 1979;11:1197-1201.
4.
Albert DM, Robinson NL, Fulton AB, et al:  Epidemiological investigation of increased incidence of choroidal melanoma in a single population of chemical workers . Int Ophthalmol Clin 1980;20:71-92.
5.
Seddon JM, Schwartz B, Flowerdew G:  Case-control study of ocular hypertension . Arch Ophthalmol 1983;101:891-894.Article
6.
Hyman LG, Lilienfeld AM, Ferris FL, et al:  Senile macular degeneration: A case-control study . Am J Epidemiol 1983;118:213-227.
7.
Rand LI, Krolewski AS, Aiello LM, et al:  Multiple factors in the prediction of risk of proliferative diabetic retinopathy . N Engl J Med 1985;313:1433-1438.Article
8.
Seddon JM, Gragoudas ES, Albert DM, et al:  Comparison of survival rates for patients with uveal melanoma after treatment with proton beam irradiation or enucleation . Am J Ophthalmol 1985;99:282-290.
9.
Ferris FL:  Epidemiologic approach to clinical research: Design strategies , in Duane TD, Jaeger EA, Sommer A (eds): Clinical Ophthalmology . New York, Harper & Row Publishers, 1986, vol 5, chap 66.
10.
Blumenkranz MS, Russell SR, Robey MG, et al:  Risk factors in age-related maculopathy complicated by choroidal neovascularization . Ophthalmology 1986;93:552-557.Article
11.
Ferris FL, in discussion, Blumenkranz MS, Russell SR, Robey MG, et al:  Risk factors in age-related maculopathy complicated by choroidal neovascularization . Ophthalmology 1986;93:552-557.Article
12.
Diener-West M:  Letter to the editor . Ophthalmology 1987;94:92-93.Article
13.
Kennedy RH, Brubaker RF, O'Fallon WM, et al:  Impact of referral bias on evaluation of cataract surgery . Am J Ophthalmol 1985;99:149-153.
14.
Seigel D:  Designs for clinical research . Arch Ophthalmol 1987;105:1647-1649.Article
15.
Stolley PD,  Schlesselman JJ: Planning and conducting a study , Case-Control Studies: Design, Conduct, Analysis . New York, Oxford University Press Inc, 1982, chap 3, pp 76, 85.
16.
Mausner JS, Bahn AK: Epidemiology: An Introductory Text . Philadelphia, WB Saunders Co, 1974, p 315.
17.
Liang K-Y, Stewart WF:  Polychotomous logistic regression methods for matched casecontrol studies with multiple case or control groups . Am J Epidemiol 1987;125:720-730.
18.
Fairweather WR:  Comparing proportions exposed in case-control studies using several control groups . Am J Epidemiol 1987;126:170-178.Article
19.
Comstock GW, Abbey H, Lundin FE:  The nonofficial census as a basic tool for epidemiologic observations in Washington County, Maryland , in Kessler II, Levin ML (eds): The Community as an Epidemiologic Laboratory: A Casebook of Community Studies . Baltimore, The Johns Hopkins University Press, 1970, pp 73-99.
20.
Bailey IL, Lovie JE:  New design principles for visual acuity letter charts . Am J Optom Physiol Opt 1976;53:740-745.Article
21.
Snedecor GW, Cochran WG: Statistical Methods . Ames, Iowa, Iowa State University Press, 1980, pp 206-208.
22.
Fisher RA: Statistical Methods for Research Workers . New York, Hafner Press, 1970, pp 96-97.
23.
Silverman DT, Hoover RN, Swanson GM:  Artificial sweeteners and lower urinary tract cancer: Hospital vs population controls . Am J Epidemiol 1983;117:326-334.
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