The document discusses various tests used in optometric testing to evaluate vision, including tests of visual acuity, contrast sensitivity, visual fields, color vision, stereopsis, and fixation disparity. It describes the stimuli and responses for each test and provides examples of common tests used to evaluate each aspect of vision.

1. Vision Science
in Optometric Testing
Jay Rumsey, OD, FAAO
College of Optometry
Nova Southeastern University

2. Vision Acuity
• Stimulus:
– Letters, Numbers or
Symbols
• Response:
– Threshold limit of
correct response to
decreasing stimulus
sizes

3. What is the
smallest row on
which you can A
read more that B
! of the letters? C
D
E
• A. 63 B. 40 C.20 D. 16 E. 10

4. What kind of task is this?
• A. Detection
• B. Descrimination

5. Vision Acuity
Variables
Size
Shape (font)
Contrast & Color
Crowding
Off-fovea viewing
Receptor sensitivity

6. What method are you using?
• A. Method of
Limits
• B. Method of
Constant Stimuli
• C. Method of
Adjustment

7. Vision Acuity Charts
• Snellen Chart
• “ETDRS” Chart
– Early Treatment
of Diabetic
Retinopathy
Study

8. In this test, do you use?
• A. Ascending
Series
• B. Descending
Series
• C. Both
Ascending and
Descending
Series

9. Vision Acuity Speciality Needs
• Music
• Newsprint / Phonebook/ Catalogues
– Medicine Labeling
– Prescribed and OTC
– Color and Packaging Effects
• Specialized occupations
– Computer Displays
– Spreadsheet printouts

10. Computer Generated
Vision Acuity Charts

11. Contrast Sensitivity
• Stimulus:
– Detail item on background
• Black on White
• vs Black on Dark Gray / White on Light Gray
• Response:
– JND of changes between item and background

12. Contrast Sensitivity
C
O
N
T
R
A
S
T
Spacial Frequency (cycles per degree)

13. Contrast Sensitivity
• Sometimes the VA
target size is constant
with the contrast display
Pelli-Robson changes to the letters.
Chart • Causes of loss of CS are
age, cataracts, media
changes, contact lenses
(among other things)
MARS Letter
Contrast Sensitivity
Chart

14. Contrast Sensitivity
• Sometimes the VA target size changes with
the contrast display staying constant.
• Example: Bailey-Lovey Chart
– Dramatic demonstration of effects of cataracts
when more than two lines lost between
presentation of same target with 100% and 10%
contrast
– Similar to ‘ETDRS’ chart (Early Treatment of
Diabetic Retinopathy Study)

15. Vision Fields
• Stimulus: Target of either
– Variable size but constant intensity
– Variable intensity but constant size
• Response:
– Threshold limits of sensitivity to
stimulus changes

16. Goldmann VS Automated VF Displays

17. Goldmann Bowl Perimeter

18. Automated Field Instuments

19. Vision Fields Scales
• Intensity to Sensitivity to Decibels
• Log Base 10 Sensitivity DB (x10)
– Bright: Log 10,000 = 4 0 0
– Log 1000 = 3 1 10
– Log 100 = 2 2 20
– Log 10 = 1 3 30
– Log 0 = 0 4 40
– Log 0.1 = -1 5 50
– Dim: Log 0.01 = -2
• Automated Instrumentation covers a 5.1 log range

20. Vision Fields Sensitivity

21. VF Relationships of
Size to Luminance
Because of retinal summation and receptor sizes:
Increasing target area by 4 times
is equivalent to
raising luminance by 0.5 log units
~ 5 dB change to sensitivity is considered
significant for VF detection of changes.

22. What is the sensitivity range for
an automated VF instrument?
• A. 0.51 dB
• B. 0.51 log units
• C. 5.1 dB
• D. 51 log units
• E. 51 dB

23. Vision Fields – Screening Test
From Central Reference
• Absolute Threshold
– Stimulus presented at maximum brightness
• Recorded only as “Seen” or “Not Seen”
• Three-Zone Test
– Stimulus shown 6dB above expected sensitivity
• If not seen, presented again at maximum
– Recorded as
• “Seen @ Expected”, “Seen @ Max” or “Not Seen”

24. Vision Fields – Threshold Tests
• Full Threshold
– Stimulus presented 6dB above expected
• If seen, reduce stimulus by 4dB, until not seen
– Increase by 2dB until seen and record dB level
• If not seen, increase stimulus by 4dB, until seen
– Decrease by 2dB until not seen and record dB level
• Full from Prior Data
– Same presentation, but initial stimulus intensity
is 6dB above data collected from past testing.

25. Full Threshold Vision Fields
Which method is this?
• A. Limits
• B. Constant Stimuli
• C. Adjustment
• D. Forced Choice
• E. Staircase

26. Color Vision
• Stimulus:
– Color discs or Colored Symbols
• Response:
– Sensitivity to detectable changes to
wavelengths at set intervals.

27. Color Vision Tests
• Cone Stimulation Color Perception

28. Color Vision Tests
Ishihara Cards
What type of test is
this?
A. Detection
B. Descrimination

29. Color Vision Tests
Farnsworth
– D-15
– D-100

30. D-15 Color Vision Testing
What method is this?
• A. Limits
• B. Constant Stimuli
• C. Adjustment
• D. Forced Choice
• E. Staircase

31. Stereopsis
• Stimulus:
– Images falling within Panum’s Fusional Area
on retinas of two eyes.
• Response:
– Ability to detect
smallest separation
of images

32. Steropsis Tests
• Red/Green (Blue) Cards
• Poloroid slides
• Free Space
(Random Dot)
Images

33. Which symbols do you see in the
fused Random Dot region?
• A. Circles B. Boxes C. Triangles
• D. Stars E. I see nothing!

34. Fixation Disparity
• Stimulus:
– Two line stimuli presented
separately to each eye
• Response:
– Subjective alignment of two vertical and two
horizontal lines on retinal receptors
– JND of separation of alignment of lines

35. Fixation Disparity
• Significant for EOM
alignment control
and measurement.

36. Has this lecture been helpful?
• A. Yes
• B. No
• C. Sorry, I fell asleep