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R.J. Adams, J.R. Drover, M.L. Courage, E.S. White, A.E. Earle; Advances in the Production of a Clinically–Oriented Psychophysical Test of Spatial Contrast Sensitivity for Young Pediatric Patients . Invest. Ophthalmol. Vis. Sci. 2005;46(13):5649.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:. Over the past decade, our laboratory (e.g., ARVO 1992, 1993, 1998, 2001) has reported on advances in the production of a card–based psychophysical test for measuring spatial contrast sensitivity(CS) in non–verbal subjects, namely infants and young children. The goal is to develop a CS test which is simple, time–efficient, portable, accurate, and reliable, all of which are essential requirements of a clinical test. Although our last version of the CS cards had accomplished most of these goals, the contrast levels within the sine–wave gratings were very difficult to reproduce and the test was very susceptible to light damage and chemical leaching which altered the characteristics of the gratings, even after a short period of time. Using new printing technology and higher quality materials, we have developed a newer version of the test designed to overcome these shortcomings. Methods: Using new custom software and an advanced photo quality printer, 17 cm diameter "test" sine wave gratings of given spatial frequency (SF) were printed on high resolution photograph paper. To produce a stimulus "card", each test grating (16 deg at 60 cm) was mounted on acid–free thin foam core, adjacent to a second "control" grating that contained 0% contrast and was invisible to adults. There were 5 sets of 56 x 28 cm cards based on the spatial frequency of the test grating (0.75, 1.5, 3, 6, & 12 c/deg). In each set, there were 5 cards with test grating contrast ranging from 57% to 3.6%. Using a Teller card FPL technique, thresholds at each SF for 30 infants (M = 12 mo) and preschoolers (M = 3.5 yr) were obtained by using a descending method of limits. Results: All preschoolers and most infants completed the test in less than 10 min, and all generated a CSF with the typical inverted U–shape. Mean CSFs for both groups were well within the range of previous FPL studies. Moreover, we produced two other new sets of cards which continue to replicate contrast levels to exact specifications. There has been no evidence of light damage or chemical leaching in any set to date. Conclusions: We have been able to develop a new set of CS cards with sine–wave gratings that can be reproduced with greater reliability and durability. Moreover, these cards appear to yield interpretable data from young children in a relatively short period of time. These are important steps in the goal of developing a universal, time–efficient tool for the clinical assessment of this critical aspect of vision in young pediatric and other non–verbal patients.
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