The document provides an overview of visual acuity examinations for adults, including definitions, components, methods of measurement, and clinical procedures used to assess visual acuity. It emphasizes the importance of regular visual acuity assessments in monitoring eye health and identifies common diseases associated with reduced visual acuity. The detailed testing procedures and various acuity charts, such as Snellen and LogMAR, are outlined to ensure accurate measurement in clinical settings.

1. Visual acuity examination
for adult
CHAIRMAN : DR. MD. ASHIQUR RAHMAN AKANDA
Associate Professor
Department of Pediatric ophthalmology, NIO&H
MODERATOR : DR. CHANDAN KUMAR PAUL
Junior Consultant
Department of Pediatric ophthalmology, NIO&H
PRESENTER : DR. SONIA ISLAM
Phase A Resident NIO&H

2. Visual acuity
Definition: Visual acuity is the resolving power of eye by
which objects are distinguished clearly from other.
Visual acuity refers to the spatial limit of visual
discrimination.
Components of vision:
 Visual acuity
 Field of vision
 Colour vision
 Contrast sensitivity
 Light Brightness sensitivity

3. Visual acuity
 Components of visual acuity:
 Minimum visible
 Resolution
 Recognition
 Minimum discriminable or hyperacuity

4. Measurements of VA
Measurements of VA is done to monitor change in vision
with progression of disease and/or treatment plan.
It is the way to measure blurr vision.
VA must be measured on every patient at every visit.
Visual acuity depends on:
 The refractive error of the eye
 The health and integrity of eye
 The test targets used
 The test conditions

5. Clinical measurement of VA
 Criteria:
 Normal testing distance (distance visual acuity ) -6m
 For near -33cm/40cm.
 Illuminated visual acuity chart
 Proper room illumination.
 Steps :
 Unaided VA ( OD,OS,OU)
 Pinhole VA (OD,OS)
 Aided VA(OD,OS,OU)

6. DISTANCE VISUAL ACUITY CHARTS
 Snellen visual acuity chart -6m
 bailey-lovie (logMar) -4m/2m/1m
 Landolt ring chart (C chart)
 Tumbling E chart

7. Procedure
 Patient seated 6 meters from the chart
 Illumination is 20 foot candles
 Each eye is tested separately
 VA is recorded as a fraction (6/60,6/36,6/24,6/12,6/9,6/6)
 Numerator : distance of the patient from the chart
 Denominator : smallest letters accurately read

8. Procedure
 If the patient can not see the top line from 6m, he is
asked to slowly move towards the chart till he can read
the top line (5/60,4/60,3/60,2/60,1/60).
 If the patient is unable to see even from 1 m, he is asked
to count fingers of the examiner.
 When a patient fails to count fingers ,the examiner moves
his hands close to the patient's face & ask whether he
could appreciate the movement or not (HM +/-).
 When the patient cannot appreciate hand movement,
perception to light is noted.(PL+/-)with projection of rays
in four quadrants.

10. Formula

11. Near Acuity Chart
 Reduced snellel chart
 N chart
 M chart
 Jaeger chart

12. Procedure (Near Vision)
 Near vision tested by asking the patient to read a near
vision chart kept at distance of 16 inches (40cm).
 Each eye should be tested separately and respectively .
 Record the binocular acuity achieved.
 The near vision is recorded as the smallest type which the
patient can read comfortably

13. Jaeger’s Chart
 Consists of ordinary printer’s front of
varying sizes
 Prints are marked from 1 to 7 and
accordingly patient’s acuity is labeled
as J1 to J7 depending upon the print he
can read

15. Testing Pinhole Visual Acuity
 Position the patient and occlude the eye not being tested.
 Ask the patient to hold the pin whole occlude in front of eye that is being
tested. That patient’s habitual correction may be worn.
 Instruct the patient to look at the distance chart through the single
pinhole.
 Instruct the patient to use small hand or eye movement to align pinhole
to resolve the sharpest image on the chart .
 Ask the patient to read the line with smallest letters that are legible to
determined on the previous vision test without use of pinhole
 Record the Snellen acuity obtained and precede or follow it with the
abbreviation PH

16. Picture

17. Mechanism of Pinhole

18. LogMar scale
 It stands for logarithm of minimum angle of resolution. The chart
was designed by Bailie & Lovie for the Early Treatment Diabetic
Retinopathy study (ETDRS). Which is designed to be used at a
distance of 4 Meter. Also known as Bailie & lovie Chart.

19. Steps
 Set the patient 4 meters from the chart.
 Cover one eye, if cannot read, then move 1 meter & add 0.6.
 Repeat second eye.
 If still unable to read, then use other option.
 Example: It one read 0.4 line plus 3 letters of 0.3 line, he or she
will have a score of 0.4-(0.2x0.3)=0.34.
19

21. Colour vision
 This is the inability to distinguish certain colour .
 Unexplained reduction in visual acuity e.g. 20/25
 One or more cone type is missing or defective to any
extend.
 Abnormal colour matching and colour confusion .

22. Colour Vision Chart

23. Colour Vision Test
 1. Pseudoisochromatic test
a. Ishihara colour vision chart
b. AOHRR-American Optical Hardy Rand Rittle Plate
 2. Arrangement test
a. Franswoth Munsell-100 Hue test
b. Fransworth D-15 test
 c. Anamaloscope
Nagel’s anamaloscope

25. Some Diseases Associated with Reduced VA:
 Refractive errors
 Cataract
 Retinal detachment
 Retinopathy of prematurity
 Glaucoma
 Optic nerve atrophy
 Albinism
 Nystagmus

26. VA is the most fundamental and basic clinical examination in
eye. Meticulous visual acuity assessment is essential. We all
should practice it. VA is impotent for clinically and medico-
legally. VA acuity is the opening door for examination of
eye.
Take Home Message