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

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

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)

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

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)

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)

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

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. 2010 Apr;51(4):2019-23. Epub 2009 Nov 20.

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

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

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

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