Background: The aim of the study was to introduce a new test to detect
small areas of suppression in the binocular visual field and to tower
the minimum age at which a suppression test could be identified corre
ctly. Two tests were compared: the Binocular Polaroid Test (poltest),
introduced in clinical practice a few years ago and used in screening
programs for vision impairment; and the Second Generation Binocular Po
laroid Test (polstar), more recently designed to have simpler answers
than the poltest. Methods: One hundred and eighty-two children were ex
amined consecutively. To assess the validity of the two tests, sensiti
vity, specificity, predictive value, and phi coefficient were calculat
ed. The applicability of the two tests and the speed of the responses
was assessed by means of the test of probability of binomial distribut
ion. Results: The polstar has appeared to be simpler and easier in you
nger patients (age range 20 to 36 months, P=0.078), and has shown 100%
of specificity with a sensitivity of 84% for the polstar 1 and of 100
% for the polstar 2. Conclusion: The results appear to demonstrate tha
t the poltest has been improved, and that the polstar may be considere
d an interesting investigation device for early detection of monocular
visual impairment.