Contrast Acuity Meter
logMAR version
AMA Optics, Inc. is offering the
Contrast Acuity Meter™ as an experimental tool for those wishing to
study contrast sensitivity using this hand-held and easy-to-use
instrument. The internally controlled lighting sets it apart from
other near contrast sensitivity tests.
Contrast Sensitivity
The EYE Chart:
Twelve lines of letters are presented from -0.1 to 1.0 logMAR.
Snellen conversion is listed in parenthesis on the back label and
on the index wheel. Three lines
of letters are tested at 8 inches (marked in red on the index wheel) and
nine lines of letters are tested at 16 inches (marked in black on the
CAM™
chart wheel). By halving the
distance the visual angle is doubled.
For focusing, an add of +2.5 diopters is used at the16 inches and
an add of +5.0 diopters is used at the 8 inches testing distance.
Contrast
Parameters
%
Contrast
Contrast Sensitivity
4%
25
11%
9
25%
4
50%
2
The filter attenuates the
luminance to 85 cd/m2 average
across window brightness.
Contrast sensitivity testing
is performed at near with near correction and without a pinhole.
