Transcript Folie 1 - Lang Stereotest

LANG-STEREOTEST
p
LANG STEREOTEST
Fähnlibrunnenstr. 5
CH-8700 Küsnacht
Switzerland
[email protected]
Hi Doc!
Peter,6 yrs
Help to prevent blindness!
Screen your patients
with the
LANG STEREOTEST
and rule out lazy eyes
and strabismus!
What YOU know, but PARENTS do not know:
 1 in 20 preschoolers has a vision
problem
 children are often unaware of their
vision problem
 85% of amblyopia cases are not detected
until after the preschool years
 if amblyopia is untreated by the age of
6 - 9, permanent vision loss is likely
Most common vision problems in children:
 Strabismus - affecting about 4% of children.
Microtropia is prevalent in 1% of the population.
 Amblyopia - which can be secondary to
strabismus, anisometropia, congenital cataracts,
etc.
 Refractive errors - such as myopia and
hypermetropia, and corneal disorders
Testing for stereopsis is an essential
part of vision screening
 the child who fails the stereopsis screening
is at greater risk for amblyopia or loss of
vision, in one eye
 when the brain is able to blend the separate
images from each eye into one image, the child
perceives three-dimensional space and is said to
have good stereopsis
 the LANG-STEREOTEST is an easy-to-use
screening-test designed for early detection of
problems with stereoscopic vision in children
From idea …
 the LANG-STEREOTEST was created in 1983 by
Joseph Lang, to simplify stereopsis screening in
small children
 it is based on the combination of two
principles:
random dots and cylinder gratings
 the images of two eyes are separated by a
system of fine parallel semi-cylindrical
strips. Beneath each cylinder there are two
fine strips of pictures, one seen by the right,
the other seen by the left eye
 this has two advantages:
no polarized glasses are necessary
the eye movements of the examenee
can easily be observed
From idea
……………………
……to reality!
 upon monocular viewing, the test plate appears
as a grey random dot surface. Stereoscopic test
objects are perfectly hidden.
 the two versions of the test, LANGSTEREOTEST I and II, only differ in the type of
stereoscopic objects to be recognized
 the LANG-STEREOTEST II additionally contains
a star that can be recognized with only one eye
LANG-STEREOTEST I
(monocular vision)
LANG-STEREOTEST I
(simulated stereoscopic vision)
LANG-STEREOTEST I
Disparities:
 Car: 550“
 Star: 600“
 Cat: 1200“
LANG-STEREOTEST II
(monocular vision)
LANG-STEREOTEST II
(simulated stereoscopic vision)
Disparities:
 Moon: 200“
 Truck: 400“
 Elephant: 600“
 Star: always visible!
getting childs attention with
the LANG FIXATION CUBE
testing stereopsis with LANG STEREOTEST
eye observing while using LANG STEREOTEST
Screening results:
1. Positive:
Correct localization and naming of all hidden objects
and/or typically jumping eye movements from one object
to the next. -> Fine stereopsis is proven
NO FURTHER EXAMINATION OF STEREOSCOPIC VISION
IS NEEDED
Retesting at further age is recommended
2. Negative/Doubtful:
No object or only one object can be detected, and eye
movements also do not indicate the recognition of the
3D objects. Eyes are scanning the test plate and then
shift away from it -> Fine stereopsis remains unproven
REFER TO OPHTHALMOLGIST FOR FURTHER EXAMINATION
Test properties:
Sensitivity and
similar overall
ranging from 17
They are highly
Specificity: LANG-STEREOTESTS have
sensitivities like other stereotests,
to 47%.
sensitive for strabimus.
Patients with microtropia very rarely show a positive
result on the LANG-STEREOTEST, because it is a test
for global stereopsis for which binocular vision is
necessary. In contrast, tests for local stereopsis
(like Titmus) can be positive also in cases with
microtropia.
LANG-STEREOTEST II has demonstrated testability of
94.4% in children aged 6 months.(Sydney Paediatric Eye
Disease Study JAAPOS 2012 April; 16/2);185-92)
What YOU know of course:
(a disclaimer for those who might not know)
the LANG-STEREOTEST does not measure visual
acuity and does not substitute for an
ophthalmologic examination. A negative test
result indicates only a lack of stereoscopic
vision at the time of examination
the LANG-STEREOTEST must always be held
quietly and the examinee must not move his
head.
the LANG-STEREOTEST must be combined with
other visual tests for correct vision screening
Fixation auxiliaries
which compliment LANG-STEREOTEST I & II:
LANG FIXATION STICK
front: Fixation Test
back: Examination of accomodations
and convergence
visus: Distance of 30cm
0.2-0.5
LANG FIXATION CUBE
to be used for the cover test, the motility
test as well as for holding the child‘s
attention for the examination with the LANGSTEREOTEST I & II