VISUALACUITY CHARTS

VISUAL ACUITY CHART

1. VISUAL ACUITY CHARTS PRESENTED BY HARSHALI MESTRI 2nd YEAR B-OPTOMETRY ITM-IHS

2. What is visual acuity??? Visual acuity is the ability or power of the eye by which object are distinguished one from the other It is also measure the smallest retinal image formed at the foveal region such can be appreciated reguarding shape & size.

3. Visual acuity charts There are two types of visual acuity charts Distance vision chart Near vision chart

4. Visual acuity tests Different types are: Snellen test . Random E’s/Tumbling E chart. Landolt’s Broken ring chart. Optokinetic drum. Landolt c chart . Log MAR chart.

5. Snellen chart Construction Each individual subtends an angle of 5’min of arc . Each component subtends an of 1’min of arc at the nodal point of the eye. In snellen a series of black capital letter on white background arranged in progressively & diminishing the size.

6. Snellen chart

7. Measurement of visual acuity for distance To measure the visual acuity the chart and patient distance should be 6meteror 20feets. This distance can be applicable with 3m or 10feets with the help of mirror.

8. Contd….. All visual acuity measurement can maintain the distance of 6m because ll rays of light coming from infinity will start at 6m distance . Visual acuity always has standard notation which starts from 6/6 to 6/60 METER: 6/6, 6/9, 6/12, 6/18, 6/24, 6/30, 6/ 36, 6/ 60 . FOOTS: 20/20, 20/30, 20/ 40, 20/60, 20/80, 20/ 120 , 20/200.

9. Landolt’s broken ring chart This is similar construction to the snellen . Instead of letter the broken circle are used. Each ring subtends an angle of 5’min of arc. This chart commonly used for illeterate people by asking the gap of broken ring

10. Tumbling E chart

11. Log MAR chart

12. Near vision chart Jaeger’s chart Notation chart Snellen visual acuity chart

13. Measurement of visual acuity for near The test distance commonly used for near distance is25 to 30cm from the eye All near charts are printer type arranged in decrease order The commonly used charts are jaeger’s chart In jaeger’s chart the printer font size decreases from 1st to 7th line The order is below N36, N18 ,N12, N10, N8, N6

14. Age group Infants (birth-14month) Toddlers(14month-2years) Pre-schoolers(2year-5year) School going children(5year-15year)

15. PEDIATRIC TEST OF VISUAL ACUITY

16. Catford drum test

17. Hundred and thousand sweet test

18. Visually Evoked Potential(VEP)

19. The cardiff card test

20. Isolated hand figure test

21. Lea symbol chart

22. Preferential looking test for vision

23. Dot visual acuity testing

24. Sheridan-gardiner HOTV test

25. THANK YOU