Major Epidemiological Studies in Optometry Flashcards
Lecture objectives
1) recall the development process for the modified clinical technique
2) recall the distinguishing characteristics and major findings of key studies
3) identify how key studies have affected the practice of optometry
Prevalence
disease burden of the population
Incidence
how fast the population gets sick
relative risk
which groups are at higher risk for developing a disease
Orinda Vision Screening Study Summary
hybrid study design, prevalence of visual disorders in children, clinical trial: best screening protocol in the hands of an ECP, modified clinical technique: gold standard for vision screenings
What is the gold standard for vision screenings?
modified clinical technique from Orinda Study
Vision in Preschoolers Study Summary
clinical trial phase I: best single screening tests in the hands of an ECP; phase II: best single screening test in the hands of lay people; combining tests and creating a protocol can be much more effective: increases direct cost and time and decreases the adverse outcomes from screening tests
Framingham eye study Summary
prospective cohort, incidence of cataract/ARMD/diabetic ret/POAG
Goal of Orinda vision screen study
to design the least expensive, least technical and most effective screening program for finding essentially all elementary-school children with vision problems
What was the Orinda hybrid study design?
descriptive epidemiology and retrospective clinical trial
What is the modified clinical technique?
snellen acuity, retinoscopy with lens rack, distance and near cover test, ophthalmoscopy
Where is orinda?
near Berkeley, CA
What was the first interdisciplinary effort to establish the validity of a vision screening protocol?
Orinda vision screening study 1954 to 1956
Who was involved in the Orinda study?
OD, OMD, biostatisticians, school psychologists, parents and teachers
T/F Orinda is an example of evaluating diagnostic and therapeutic modalities as well as the delivery of health care services
true
What made Orinda retroscpective?
worked backwards from the comprehensive examinations; distilled information to minimum set of distinguishing visual characteristics, compared distilled information to screening programs for best fit
What is a critique of the Orinda study?
criteria determined by committee, not strict data analysis
What was the sensitivity and specificity of the Orinda vision screening program?
96% and 98% respectively
What were ancillary findings of the Orinda study?
> 50% of children with previous eye care still failed the screening, the incidence of vision problems increases with age (1.6%/yr), direct cost of $0.45 per student
What are weaknesses of Orinda?
not applicable to all populations, must be performed by clinicians, not lay people, does not include visual skills testing; many alternatives have been proposed (like NYSOA)
Goal of Vision in Preschoolers Study
developing evidence-based guidelines for preschool vision screening test
What disorders did the Vision in Preschoolers Study find?
amblyopia, strabismus, significant refractive error, unexplained reduced visual acuity
What study design was VIP?
experimental
Phase I VIP
set target sensitivity and specificity, used a mobile test center for screening and full exam; best tests for detecting vision disorders by ECP, tested 2588 3-5 year old Head Start students
VIP test specificity
set at 90%; the best tests detected approximately thirds of children with >/= 1 targeted conditions and nearly 90% of children with the most important/severe levels of each conditions
What are the best tests for detecting vision disorders by ECP (VIP Phase I)?
non-cycloplegic retinoscopy, retinomax, sure sight, crowded linear lea symbols at 10 feet