1. Authors : Shalaka Paralkar, Mihir Kothari, Khushbu Shah
Comparison of Lang test, Randot test & TNO test in the assessment of stereo-acuity of normal population.
E-Poster No.  FP289
E-Poster Serial No.: 268
Authors : Shalaka Paralkar, Mihir Kothari, Khushbu Shah

2. Disclaimer
We have no Financial interest in any of the products mentioned in this poster
We have not received any financial assistance to carry out this study

3. Introduction
Stereoacuity is reduced in:
Global Prevalence
Uncorrected ametropia
Anisometropia
6%1
Amblyopia
1–5% 2
Strabismus
Monofixation syndrome 1%
Appropriate therapeutic measures can improve the stereoacuity in such patients.
1 - Czepita D, Goslawski W, Mojsa A. Occurrence of anisometropia among students ranging from 6 to 18 years of age. Klin Oczna. 2005;107(4-6):297-9.
2 - Weber, JL; Wood, Joanne : Amblyopia: Prevalence, Natural History, Functional
Effects and Treatment. Clinical and Experimental Optometry 88 (6)

4. Development of normative data for stereoacuity of normal population
Aim
Comparison
of tests
Development of normative data for stereoacuity of normal population

5. Methods and materials Inclusion criteria
Best corrected visual acuity – 6/6
Orthotropic
Normal binocularity
Measured Stereoacuity
Using Lang test(Lang type 1 test),
Randot test and
TNO test:
with appropriate refractive correction
With appropriate environmental lighting
at reading distance ( 40 cm)

6. Results Mean Stereoacuity: Lang test = 550”
46 consecutive patients
aged 19.3 years ± 7.2 (5-36)
26 were females.
All the patients had measurable stereopsis on these tests.
Mean Stereoacuity:
Lang test = 550”
Randot test = 50” ± 36.8” (20-250)
TNO test = 60” ± 63” (15-240)

7. Correlation of Randot and TNO test
The correlation coefficient (Pearson’s r) for Randot test and TNO test = 0.66 – positive correlation

8. Discussion Stereopsis
stereo – solid
opsis – view or sight
Stereopsis
Performance on motor skills of a person is related to stereoacuity*
Various methods have been used to assess stereoacuity in children.
Some tests have made use of global stereopsis (TNO test,Frisby test, Lang test etc.) and some are based on local stereopsis (Titmus test, Randot test)
*O’Connor AR et al : The functional significance of stereopsis.
Invest Ophthalmol Vis Sci Apr;51(4): Epub 2009 Nov 20.

9. LANG TEST OUR EXPERIENCE: Merits: Demerits:
Useful for screening in children.
No glasses necessary
Demerits:
Only gross stereopsis with
Lang 1
Lang 2 required for finer stereopsis
OUR EXPERIENCE:
Easy to perform in children
Gives a general idea about presence of gross stereopsis
More convenient to use in unco-operative children as there is no requirement for glasses

10. RANDOT TEST OUR EXPERIENCE
Merits
Can detect stereoacuity over a range of 20 to 500 seconds of arc
Demerits
Mono-ocular clues are present
OUR EXPERIENCE
Children could easily view the animal figures
Effectively gave an idea of the fine stereopsis

11. TNO TEST OUR EXPERIENCE Demerits Crowding phenomenon may be seen
Can measure stereoacuity over a range of 15 to 480 seconds of arc
No mono-ocular clues
Demerits
Crowding phenomenon may be seen
Dissociation may be present
OUR EXPERIENCE
Easier to perform in children as compared to Randot test

12. THANK YOU FOR YOUR ATTENTION
Conclusion
Lang test, Randot test and TNO test are useful to assess stereopsis in patients.
The Lang test was the easiest test.
Randot and TNO test can assess much finer acuity over a large range of disparities. Both have a good correlation.
THANK YOU FOR YOUR ATTENTION