Contrast sensitivity is the ability to detect differences in luminance or contrast between areas. There are two main types: spatial contrast sensitivity, which involves detecting striped patterns of varying contrast and width, and temporal contrast sensitivity, which measures contrast sensitivity over time for a modulated target. Contrast sensitivity can be measured through tests using letters, gratings, or other patterns with decreasing contrast levels, such as the Pelli-Robson test, Bailey-Lovie chart, Cambridge Low Contrast Grating test, and FACT (Functional Acuity Contrast Testing) chart. These tests help evaluate contrast sensitivity for early detection of visual impairments.

1. contrast sensitivity
MENTORED BY
ANSHUKA MAM
KHULESH SAHU
B.OPTO 5 SEM

2. Definition
• The ability to perceive slight changes in
luminance between regions which are not
separated by definite borders and is just as
important as the ability to perceive sharp outlines
of relatively small objects.
• lt is the ability to detect separation of the area of
different contrast level.

3. TYPES OF CONTRAST
SENSITIVITY:
1. Spatial contrast sensitivity
2. Temporal contrast sensitivity

4. Spatial contrast sensitivity
• Detection of striped pattern at various
levels of contrast and spatial frequency.
• Sine wave gratings of parallel light and
dark bands.
• Width of the bar is defined as spatial
frequency
• High spatial frequency- narrow bars.
• low spatial frequency- wide bars.

5. • The spatial frequency increases
exponentially from left to right. The contrast
also varies logarithmically from 100% at the
bottom to about 0.5% at the top

6. Temporal contrast sensitivity
• Contrast sensitivity function is generated
for the time related processing in the visual
system by presenting a uniform target field
modulated sinusoidal in time.
• The shape of the contrast sensitivity
function varies with factor
1. Luminance
2. Target size
3. Grating motion
4. Grating shap

7. Measurment of contrast
sensitivity
• Pelli Robson test
• Bailey Lovie chart
• Cambridge low contrast grating
• Regan charts
• FACT (functional acuity contrast testing) chart.
• Arden plat test.

8. PELLIROBSOM CONTRAST
SENSITIVITY CHARTS
•

9. • letters of the samesize but with reducing
contrast .
• Two charts and two scoring pads.
• Each chart has 6 letters in each row
organized into two triplets of varying contrast.
• illumination of the chart is 85 cd/mm21 meter
distance
• The score of the test is recorded by the
faintest triplet out of which at least 2 letters
are correctly identified.
• The log CS value for this triplet is given by the
number on the scoring pad.

10. BAILEY LOVIE CHART
• Low contrast acuity testing & acuity testing in
presence of glare.
• Each row has same no. of symbols & constant
spacing is used between rows & letters.
• Chart is logarithmic based & visual acuity is
based on log of minimum angle of resolution or
logMAR.
• Berkely Glare Test provides 10% of contrast & is
provided with glare source

12. CAMBRIDGE LOW CONTRAST
GRATING
• It is a rapid and simple screening test for
contrast sensitivity.
• Performed at a distance of 6m.
• It comprises of 12 pair of plates consisting of
stripes of varying contrast.
• First one is for demonstration and rest are for
the proper testing and are numbered from 1-10.
• The plates are changed sequentially starting
from plate 1 till the patient fails to respond.

13. • Then a new series is begun starting 4 plates prior
to where the patient failed to respond.
• Four such series are completed and the score of
each series is noted (numbered as per the number
of plate read) and added.
• The final total value is converted into contrast
sensitivity fromthe provided table.

14. REGAN LOW CONTRAST
LETTER CHARTS
• Consists of three letter charts, printed on white
cardboard having contrast of 97%, 7% and 4%
• 3 meter with eight letters in each line
• Patients are instructed to start at the top and to
continue reading until they can correctly identify no
letters on a line.
• For one chart letter size goes on reducing and
contrast remains constant
• Regan in 1988 suggested there chief role in
detecting early visual loss in diabetes and glaucoma

15. A) One of the four Regan low-contrast acuity charts. (B)
High-contrast acuity chart. (C) Repeat-letter chart.

16. FUNCTIONAL ACUITY CONTRAST
TESTING
• FACT charts were developed by Dr. Arthur
Ginsburg.
• FACT comprises of a chart with sine-wave gratings
of varying frequencies.
• The chart tests five spatial frequencies (sizes) and
nine levels of contrast
• The Contrast varies in a row, decrease from left to
right
• And the spatial frequencies increase as one move
down the various columns from top to bottom

17. • This test is performed at a distance of 10 feet.
• The patient determines the last grating seen for
each row (A, B, C, D and E) and reports the
orientation of the grating: right, up or left.
• The last correct grating seen for each spatial
frequency is plotted on a contrast sensitivity
curve.

19. THE ARDEN PLATE TEST
• Introduced in 1978.
• Consists of a booklet containing several sine
wave gratings patterns
• Each grating is oriented vertically
• The contrast varies from the top to the bottom
of the grating, lowest at the top and highest at
the bottom.

21. Refrence
• Primary care of optometery
• Sport vision book 2nd capter
• image by google