in partial fulfil]ment of the - MSpace - University of Manitoba

test, howeverr mây not be practical for use lcith children, especially
young children, since it requires cognitive ski11s and subjects have to
be attentive and cooperative throughout the testing procedure. That is,
subjects need to deveLop a criteria that enables them to distinguish
different test objects (blue discs from red discs) and remember the
criteria when performing the test. Subjects should also concentrate on
lest objects without a break and continue sorting test objects according
to specific color groups.
67
8"3 USE OF DARK ÀDAPTÀTION TESTS FOR ADUTTS
The relationship between Vitamin À status and dark adaptation ability
of adults was denonstrated by Vinton and Russel (1981). The subjects
included in this study were 32 normal controls, 1'1 patients hospitalized
with a variety of diseases not resulting in Vitamin À deficiency and 19
Vitamin À deficient patients. Vitarnin À deficíency was defined as the
presence of an abnormal dark adaptation curve (i.e., a final dark
adapted threshold more than 2 standard deviation greater than the agespecific
mean) and a fasting serum vitamin A level less than 40 ug/d]
(carney and Russell, 1980). All subjects were screened for evidence of
eye disease. À11 had nornal ophthalnoscopic exam (no evidence of eye
disease). Subjects were test,ed by both the Classical and Rapid Dark
.{daptaLion Test. In the Classical Dark Adaptation Test, a
Goldman-Weekers Adaptometer lvas used. Each subject was initially light
adapted to a diffuse white light of 3.13 millilamberts luminance for'10
minutes, afLer which threshold measurements were started immediately.
The subject fixated on a 2 mm red light located above the center of the