About The Test
The TS grid is a novel optotype, designed to recognize defects at the central and mid
peripheral visual field. It is designed to be used on a printed form of a typical A4 paper
format presented in horizontal orientation (22.5 cm width and 17.8 cm height).
It consists of 54 squares of a side length of 2.4 cm, 32 squares of side length of 1.2 cm
and 16 squares of side length of 0.6 cm in order to exactly fit in the printable A4 form.
The smaller squares are located in
the center of the optotype, surrounded by the medium-sized squares, which in turn are
surrounded by the larger ones.These squares alternately contain arrows pointing in
horizontal or vertical
directions separated by empty squares in order to facilitate the patient and communication
with the examiner. A small black circle has been posted at the center of the optotype in
order to be utilized as the fixation point.
Therefore, the central area of TS grid subtends 4.8 degrees horizontally and vertically, the
paracentral area 15.4 degrees horizontally and vertically and the entire.
Each eye is examined in two TS grid
tests: Test
1 and Test 2 the first TS grid is complementary
to the second. After correcting for near refractive error and leaning on a desk, each
participant is asked to view the TS grid monocularly
at a distance of 30 cm. The fellow eye is occluded with an eye patch. The examinee is
instructed to fixate on the central black spot. During the first examination the arrows are
presented by the examiner to the patient with
a pen so that the patient is instructed (acquainted) to recognize them. Patients are
instructed to fixate at the central point of the grid at all times and asked to answer if
she/he can see the direction of each arrow that
is pointed by the examiner starting from the central area to the periphery.
Correct and incorrect responses are recorded by circling (indicating a correct response) or
deleting (indicating a false response) on the main reference chart held by the examiner
respectively. If the patient can’t see an arrow, the procedure is repeated
and if she/he is not still able to see the arrow, the arrow is deleted from the chart.
Ideally the TS grid test should be examined at the beginning of the examination in order to
avoid potential fatigue that could affect performance.
A total TS score is summated from correctly answered squares, with 102 the perfect summed
score from all squares.
About Us
We are a non profit company aiming to provide health professionals with an accessible method of screening patients in their everyday practice. We implement a novel, technology free screening test to people with limited access to highly equipped medical facilities. We are passionate about trying to provide a useful tool for the prevention of blindness in developing countries.
