Abstract
Purpose: :
Over the past decade, our laboratory has been attempting to develop a more efficient test of spatial contrast sensitivity (CS), especially for use in clinical settings with pediatric patients. To date, our CS card test (ARVO 2004) satisfies most of these requirements, except that they provide only rough estimates of CS threshold due to large step size and limited contrast range. They are also susceptible to damage. Here we report on a new version in which the sine–wave gratings are printed into a smaller, better protected, user–friendly, hand–held booklet format. The gratings also span a larger contrast range and have a smaller step size, both of which now make it suitable for testing adults as well as children. Here we evaluate the success of the CS booklet within a large–scale pediatric vision screening program, and with adults.
Methods: :
The new test consists of regular page–size (22 x 28 cm) sheets mounted in a spiral flip–binder. One half of each sheet contains a sine–wave grating with a given spatial frequency (1.5, 3, 6, 12, or 24 cy/deg at 60 cm). For each SF set, contrast ranges from 3 to 160 CS units in 11 0.21 log CS steps. The other half of the page contains a "control" (blank) grating of the same SF and 0% contrast. For each SF set, testing is forced–choice and proceeds in modified staircase fashion. To date, 150 2–6–year–olds and 85 young adults (Mage = 20.3 y) have been tested with the CS Booklet. All participants were refracted and all adults were tested with and without correction. For validation purposes, adults were also tested with the commercial Vistech CS chart.
Results: :
85% of the preschoolers and all adults completed the procedure. All subjects showed interpretable CS functions (CSF), i.e., those with the expected inverted–U shape. Adult CSFs obtained with the CS booklet matched closely those obtained with the commercial CS test, both for corrected and uncorrected vision. Among children, those showing abnormal booklet CSFs also showed optical or ocular dysfunction on other tests in the screening battery (visual acuity, ocular alignment/motility, autorefraction, and/or stereopsis).
Conclusions: :
The CS booklet appears to be a significant improvement over previous pediatric CS tests developed in our lab. It is very compact and easily portable, is tester and child–friendly, is relatively quick (about 4 min/eye), and appears sensitive to optical and visual pathology. Moreover, an additional clinical advantage is that it is a full–spectrum test, i.e., one capable of estimating precise CS thresholds in both young children and adults with and without ocular pathology.
Keywords: contrast sensitivity • visual development • clinical (human) or epidemiologic studies: systems/equipment/techniques