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LANG-STEREOTEST p. LANG STEREOTEST Fähnlibrunnenstr. 5 CH-8700 Küsnacht Switzerland

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Presentation on theme: "LANG-STEREOTEST p. LANG STEREOTEST Fähnlibrunnenstr. 5 CH-8700 Küsnacht Switzerland"— Presentation transcript:

1 LANG-STEREOTEST p

2 LANG STEREOTEST Fähnlibrunnenstr. 5 CH-8700 Küsnacht Switzerland

3 Hi Doc! Help to prevent blindness! Screen your patients with the LANG STEREOTEST and rule out lazy eyes and strabismus! Peter,6 yrs

4 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

5 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

6 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

7 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

8 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

9 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, LANG- STEREOTEST 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

10 LANG-STEREOTEST I (monocular vision)

11 LANG-STEREOTEST I (simulated stereoscopic vision)

12 LANG-STEREOTEST I Disparities: Car: 550 Star: 600 Cat: 1200

13 LANG-STEREOTEST II (monocular vision)

14 LANG-STEREOTEST II (simulated stereoscopic vision) Disparities: Moon: 200 Truck: 400 Elephant: 600 Star: always visible!

15 getting childs attention with the LANG FIXATION CUBE

16 testing stereopsis with LANG STEREOTEST

17 eye observing while using LANG STEREOTEST

18 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

19 Test properties: Sensitivity and Specificity: LANG-STEREOTESTS have similar overall sensitivities like other stereotests, ranging from 17 to 47%. They are highly 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)

20 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

21 LANG FIXATION STICK front: Fixation Test back: Examination of accomodations and convergence visus: Distance of 30cm LANG FIXATION CUBE to be used for the cover test, the motility test as well as for holding the childs attention for the examination with the LANG- STEREOTEST I & II Fixation auxiliaries which compliment LANG-STEREOTEST I & II :

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