Abstract
Purpose: :
To determine the course of development of infant contrast sensitivity (CS) using a new card test, the Stripe Card Contrast Sensitivity Test (SCCS). It uses a low-spatial-frequency square wave of variable contrast to measure the maximum of the CSF in a single measurement. Our methodology is based on the Card Procedure used with the Teller Acuity Cards (TAC). Here, we evaluate this test in a laboratory setting.
Methods: :
The 81 presumptively normal subjects were 16 2-mo-olds, 45 4-mo-olds, and 20 9-mo-olds. Each subject was tested twice, OU, by two different testers; test orders were counterbalanced across subjects.
Results: :
Contrast sensitivity increased with age. Ninety-one percent of infants had CS numerically better than their ages in months, and 52% of infants had CS better than 3 times their ages in months, suggesting these as atheoretic rules of thumb. The 95% "range of normal" CS covered ±0.46 to ±0.55 log10 units (l.u.).·····In a study of community-dwelling elderly adults, Haegerstrom-Portnoy et al. (Optom & Vis Sci 2000) obtained a 95% range of Pelli-Robson CS (±0.37 l.u.) that was about 0.68 times as wide as what we obtained on infants. For comparison, the 95% range of high-contrast logMAR acuity (VA) of those adults (±0.16 l.u.) was about 0.60 times as wide as Mayer et al. (IOVS, 1995) obtained on infants aged 2.5, 4, and 9 mos. Thus, the range of normal infant CS, compared to that of elderly adults, is similar to the range of normal infant VA, compared to that of elderly adults.·····Test-retest CS values differed by ±0.038 l.u. on average; the 95% range was ±0.45 l.u. Seventy-two percent of second tests were within 0.15 l.u. of the first, and 88% were within 0.3 l.u. of the first. This is within the range of test-retest reliability of VA found by others (Mayer et al, 1995; Salomao & Ventura, IOVS 1995).
Conclusions: :
These data indicate that the Stripe Card Contrast Sensitivity test can be used successfully on infants aged 2–9 months. The "range of normal" for infants tested using the card procedure was similarly related to that of adults tested with letters, for both CS and VA. Furthermore, the test-retest repeatability for infant Stripe Card CS was comparable to that for infant Teller Acuity Card VA.
Keywords: infant vision • contrast sensitivity • visual development: infancy and childhood