Page 163 - July-August 2020

WORTH’S FOUR DOT TEST
This test is also known as Worth’s
Four Light Test. This instrument
consists of an illuminated box with
four apertures. Coloured glasses are
put before each aperture - one red,
two green and one white, yellow
or ground glass. This test assesses
the patient’s flat fusion ability at a
When the Maddox Rod is placed distance and a nearer point. This
horizontally over the right eye, the hand-held test is also used to detect
patient sees a vertical red line and a a small unilateral central scotoma.
white light. If the eyes are aligned, The instrument is also used in the
the red line will go through the white SYNOPTOPHORE differential diagnosis of unilateral
light. If the eyes are not aligned, the decreased visual acuity.
red light will deviate in the opposite This is an instrument which is
direction of the eye which will be utilised for the measurement of HESS SCREEN
relative to the white light. subjective and objective angles of The Hess Screen test was
a squint. It stands on a heavy cast designed by Walter Rudolf in 190.
MADDOX WING
iron base with one movable foot This test uses a black screen on
This is a handheld clinical adjustable by a screw. Gun metal which a square-meter tangent
orthoptic instrument which makes columns are attached to this base scale is marked. The tangent nature
use of mechanical dissociation of the which carries the illuminating of the coordinate lines converts
fields of the two eyes. It is used to system, slide holders and reflecting equidistant points, seen in a virtual
detect the amount of phoria for the mirrors and lenses. The arrangement sphere like a perimeter, into a two-
nearer distance. Maddox Wing has of the Synoptophore results in
a face piece, a diaphragm, a handle, the rapid flashing of the light to
and a chart. The fields of the two eyes stimulate the under-functioning
are separated by the diaphragm. This macula. Synoptophore is an excellent
is an effective method of detecting instrument as it is adjustable for
the presence of, and measuring the several measurements. Horizontal,
degree of, heterophoria. In this test, vertical and rotator movements are
one eye sees a double tangent scale controlled and measured in scales.
that is calibrated to read in prism
dioptres while the other eye sees a ANY DISTURBANCE
white arrow pointing upward, and IN MUSCLE BALANCE
a red arrow pointing horizontally to CAN CAUSE PHORIA
the left. As the two retinal images (LATENT SQUINT) OR
are quite different, there is no TROPIA (MANIFEST
attempt of a fusion point and the SQUINT) WHICH
eyes stay in the passive position. The CAUSES COSMETIC
arrows that are seen by the left eye DISFIGUREMENT OF
point to the numbers seen by the THE FACE AS WELL
right eye. The numbers represent the AS SIGNIFICANT
vertical and horizontal components DISTURBANCES IN THE
of the phoria, which can be read VISUAL PATHWAY
directly by the observer.

JULY-AUG 2020 | 159 Muscle Balance