Test of Visual AcquityDistance vision, Near vision

Nusrat ZerinAssistant Professor

Proyash Institute of Special Education and ResearchBangladesh University of Professionals (BUP)

Dhaka CantonmentDhaka, Bangladesh

• Visual Acuity:It is a number that indicates the sharpness or clarity of vision.

A visual acuity measurement of 20/70 means –

a person with 20/70 vision who is 20 feet from an eye chart sees what a person with unimpaired (or 20/20) vision can see from 70 feet away. (after all possible solution and treatment)

6/60means – can read 60 size font from 6 meters)

Visual Acuity:

Visual Acuity testing:1. Need- E chart, measurement tape, torch2. Select a place or room which has adequate light & less

glare or reflection of light3. Avoid extra lights4. Avoid light from behind of the place where the E chart will

be placed or shown5. Mark the distance with measurement tape (6 meters) (1

meter=39 inches)6. Orient the child with the chart & give instruction to

indicate the open side of E or which side the legs of ‘E’ are open. The child can show it with hand movement.

7. Stand in front of the child & place E chart at the level of the child’s eye at 6 meter distance (child can be seated on a chair or standing)

Visual Acuity testing:…………27. Ask the child to cover left eye with his/her palm8. Show the big E and ask the direction of the open legs of E9. If it is ok then ask him to show direction of the next small E. If it is wrong answer, repeat to show the E in several Direction. If it wrong 3 times and record the distance and the font size of the E for Right eye:

10. If the Child can not see the Big E, reduce the distance to 3 meters. 11. Then show Big E again and ask to indicate the direction. Repeat the

process. And Record the Visual Acuity.

Right Eye: 6/36

Visual Acuity testing:…………37. Ask the child to cover left eye with his/her palm8. Show the big E and ask the direction of the open legs of E9. If it is ok then ask him to show direction of the next small E.

If it is wrong answer, repeat to show the E in several Direction. If it wrong 3 times and record the distance and the font size of the E for Right eye:

10. If the Child can not see the Big E 3 times, reduce the distance to 3 meters.

11. Then show Big E again and ask to indicate the direction. Repeat the process. And Record the Visual Acuity.

Right Eye: 6/60

Right Eye: 3/36

Visual Acuity testing:…………412. If the child can not see the big E from 3 meters 3 times,

reduce the distance to 1 ½ meter and repeat the process and record acuity.

13.If the child can not see the big E 3 times then stand in front of the child at 40 centimeter distance and ask to count your fingers & record the visual acuity :

14. If child can not count fingers 3 times, move your hand in different directions in front of the child’s eye. If he can see record Visual acuity:

Right Eye: Finger counting (FC)

Right Eye: 1 ½ /36

Right Eye: Hand movement (HM)

Visual Acuity testing:…………515. If the child can not see hand movement 3 times put torch light

to the eye from different directions to the eye, ask if he/she can see any light and if he/she can show the direction. If the response is yes, then record acuity:

If 3 times the child can not say rightly, the record will be No light Perception (NLP).

Now complete the process with Left eye, (covering the right eye with palm)record Visual acuity measurement process in left eye: like-

Right Eye:

Light perception (can indicate the direction of the light )

Right Eye: Hand movement Left Eye 1 ½ /60

Right Eye: No Light perception (NLP) / NPL

Visual Acuity testing:…………7

This is primary identification. Please refer the child to an eye ophthalmologist / optometrist/ recreationist if you find any problem with the child for proper treatment/correction or certification.

Near visual acuity:

• Check near visual acuity. Have the examinee read a card held apprx. 14 inches (35.6 cm) away, at a normal reading distance.

• Use bright lighting during this test.

• Decreased near visual acuity may be caused by central cataracts or presbyopia, after age 40

• Visual Field:

Visual field is the total area an individual can see without moving the eyes from side to side (in between 180 degree or 170 degree (on average)

Visual Field testing:1. Stand in front of the child and ask him to see directly 2. Then ask him to expand him hands to one side parallel to thee

body (right hand)3. Ask him to move only fingers and gradually move the fingers

and hand at the front side, he can not move his eye ball of the right eye, he has to see at the front only

4. Ask him to stop moving the hand from where he can not see the fingers

5. Record the visual field: Visual field Right eye= 5 degree less than 90 degree6. Repeat with Left eye and record visual field7. Then calculate the both eyes total field and complete the visual

field calculation.8. If it is less than 10 degree the child will be treated as low vision.

Thanks