Binocular vision

BSV BINOCULAR VISION
BINOCULAR SINGLE VISION

1. SIVA TEJA CHALLA BINOCULAR VISION

2. DEFINITION NORMAL BINOCULAR VISION DEVELOPMENT OF BINOCULAR VISION THEORIES OF BINOCULAR VISION MECHANISM OF BINOCULAR VISION GRADES OF BINOCULAR VISION ABNORMALITIES OF BSV INVESTIGATIONS

3. DEFINITION State of simultaneous vision which is achieved by coordinated use of both eyes so that separate and slight dissimar images arising in each eye appreciated as single image by process of fusion

4. NORMAL BINOCULAR VISION REQUISITES ADVANTAGES

5. DEVELOPMENT OF BSV BEGINS AT 4 MONTHS OF AGE PEAKS 2 YRS WELL DEVELOPED 4 YRS SLOW DECLINE BY 9 YRS

6. THEORIES OF BINOCULAR VISION Theory of correspondence and disparity Neurophsiological theory Older theories Alternation theory Projection theory Motor theory Isomorphism theory

7. MECHANISM OF BINOCULAR VISION Visual axis Retinal correspondence Egocentric localisation Horopter Pannums fusional area

8. VISUAL AXIS

9. RETINAL CORRESPONDENCE Normal retinal correspondence Abnormal retinal correspondence(ARC) Harmonius arc Un harmonius arc HARMONIUS  angle of anamoly = angle of strabismus UNHARMONIUS angle of anamoly < angle of strabismus

10. EGOCENTRIC LOCALISATION

11. HOROPTER

12. PANNUMS FUSIONAL AREA

13. GRADES OF BINOCULAR VISION SIMULTANEOUS PERCEPTION FUSION STEREOPSIS

14. RETINAL RIVALRY

15. ABNORMALITIES IN BSV Confusion Diplopia Supression  central vs peripheral monocular vs alternate facultative vs obligatory

16. INVESTIGATIONS For retinal correspondence For supression 1.Red filter test 2.Worth FDT 3.Bagolinis striate glass test 4.After image testing

17. Red glass test

18. WFDT MONOFIXATION SYNDROME

19. BAGOLINIS GLASS TEST

20. BAGOLINIS GLASS TEST

21. AFTER IMAGE TESTING

22. Stereopsis testing Stereo acuity is a quantitative measure of stereopsis, it represents the smallest horizontal retinal image disparity that give rise to a sensation of depth. Stereopsis is measured in seconds of arc. 1degree=60minutes of arc, 1minute=60seconds of arc. Normal stereoacuity = <60seconds of arc.

23. Tests for stereopsis Qualitative Random dot stereograms Synaptophore Quantitative Titmus fly test TNO test Lang test

24. MACULAR EXTRAMACULAR BEGINS AT 2-3 MONTHS MATURE AT BIRTH IF DEPRIVED NEVER DEVELOPS WILL NOT DEPRIVE POOR VN AND NYSTAGMUS -- SEVERES FIXATION --- ONCE DEVELOPED REINFORCEMENT REQUIRE TILL 9 YRS AGE --- OTHERWISE AMBLYOPIA DEVELOPS --- CONES AND PARVOCELLULAR GANGLION CELLS RODS AND MAGNOCELLULAR ANGLION CELLS 14’ OF ARC OF STEREOPSIS 200’ ARC OF STEREOPSIS

25. BV MACULAR EXTRAMACULAR SIMULTANEOUS PERCEPTION NONE EXCELLENT FUSION EXCELLENT LIMITED STEREOPSIS EXCELLENT LIMITED SO THERE ARE NO ADAPTATIONS IF MACULAR BINOCULAR VISION IS IMPAIRED AND THERE WILL BE LIMITED FUSION AND STEREOPSIS IF EXTRAMACULAR BV IS IMPAIRED SUPPRESSION AND ARC TAKES PLACE

26. SUMMARY BSV is not inborn,but develops in the first decade of life Abnormal visual experience results in poor or no BSV Reversible only if intervened in the plastic period of development A good understanding of mechanism of BSV is fundamental in successive treatment of its anamolies

27. THANK YOU