Special Testing

Question 1

Reasons for testing VF in low vision

Answer 1

Determine functional impairment
Determine legal blindness
Correlate with pathology

Question 2

Automated VF

Answer 2

• advantage of standardization and is easier to use
• can be used to determine legal blindness (MD greater than 22DB)
• has both static and kinetic automated programs

Question 3

Arc perimetry

Answer 3

• the VF can also be tested using a hand perimeter

- came with various target sizes, generally uses 3mm first and increases the target to 5mm if the patient struggles

Question 4

Arc perimetry instruction

Answer 4

1. Cover OS, habe the patient hold instrument horizaontal and place against the patients nose
2. Position the OD a few inches above the center dot and tell the patient to fixate on the central target
3. The wand is held just temporal to the fixation point, the patient is asked if he or she can hold fixation o the central target whilst seeing th peripheral target. Can also ask if patient is able to see two dots, including the one you are moving and the one on the disc
4. The wand is moved outward gradually and the patient is instructed to report when the moving target disappears. If it disappears within appx 15 degrees, the patient is reassured that this area is the normal physiological blind spot. If the examiner suspects malingering, occasionally turn the wand around during testing so that the target disappears. If the patient still claims to see the target while it is turned, the malingering is confirmed
5. continue to test in clockwise pattern in order to maintain a systematic order
6. If the patient has poor response to the smaller target increase
7. Switch eyes and repeat until all 8 meridian ends rate eval

Question 5

Arc perimetry norms

Answer 5

For a 3mm target at 13 inches (the typical target at the distance of the radius of the perimeter), the normal findings are as follows

• 90 degrees or more temporally
• 55 degree superiority
• 60 degrees nasally
• 70 degrees downward

Norms are demonstrated on the official recording form by the shaded areas

Question 6

Arc perimetry recordings

Answer 6

• the limits of the field can change based on the level of illumination in the room-make sure tour room is adequately lit
• for patients that have difficult with speaking, you may have to move your target mroe slowly or use shorter phrases)
• make sure that the disc remains at the meridian you are testing and that you do not accidentally turn your target away from your patient during testing

Question 7

Conventional perimetry

Answer 7

• allows quantification of the visual field

- accuracy is based on two assumptions

Question 8

Accuracy of conventional perimetry is based on these two assumptions

Answer 8

Fixation is stable

Fixation is located at he fovea

Question 9

What is conventional perimetry not good for

Answer 9

Precise evaluation of macular disorders

Question 10

Microperimetry

Answer 10

• minomer: night stimulus size nor test grid are “micro”
• refers to perimetry when there is real time visualization of the fundus
• first used by Timberlake over 20 years ago

Question 11

Microperimetry and scotomas

Answer 11

Determination of scotomas

• size
• location
• relative vs absolute

Question 12

What can microperimety determine

Answer 12

Scotomas and fixation

Question 13

How can microperimetry determine fixation

Answer 13

Location
Stability
Development of preferred retinal locus (PRL)

Question 14

Preferred retinal focus

Answer 14

Retinal area that behaves as a pseudofovea and is adopted by the patient to see chosen object

Question 15

NIDEK MP1

Answer 15

• is NOT and SLO
• infrared fundus camera 45 degree FOV
• automated eye tracking
• automated static threshold or customized using liquid display

Question 16

Spectral OCT/SLO

Answer 16

A tool used with microperimetry that can show retinal damage in certain diseases

Question 17

Macualr integrity assessment (MAIA)

Answer 17

• linear SLO system and fundus controlled perimetric exam
• limited ability to adjust parameters
• can adjust stimuli locations

Question 18

MAIA useful for

Answer 18

Rehabilitation recommendations
Patient and family education
Making sense out of patient complaints

Question 19

Location of PRL and reading speeds (fletcher)

Answer 19

Not strongly associated with reading speeds

Question 20

PRL and reading speeds today

Answer 20

• PRL training using a microperimeter like the MAIA can be very successful and improve reading time
• groups trained in two different methods to adopt a more efficient retinal locus improved the median reading speed by 20-21 wpm
• when reading a 2000 word newspaper page, a reading speed of 83 wpm would require 24 minutes. When increased by 21 wpm to 104 wpm, it would require 19m, which saves 5 minutes

Question 21

Amsler grid testing

Answer 21

• patients may report normal even in the present of large macular scars
• nearly half of scotomas are missed by the amsler grid
• AG underestimates extent of scotomas
• 65% of patients placed their PRL on the center of the grid, giving the illusion of a paracentral scotoma when in fact it was central

Question 22

Facial amsler

Answer 22

• have patient view your face looking right at your nose. Which part of your face is the most clear?
• sunless found facial fields to be accurate to microperimetry results in 74% of cases. In clinics with not access to a microperimeter, facial amsler is quick and recommended
• you can hold your hand at different places around your face and ask the patient to look at your hand. At which place is your face the most clear in their peripheral vision?

Question 23

Home exercises for training locus

Answer 23

• place an object near their TV in the appropriate location that they should look at when watching TV
• use large print playing cards
• with hand held steady, patient presents the playing cards directly in front of themselves. They turn only their eyes to the appropriate EV point to identify the card. Go through the deck 3x daily. Once able to do this easily, move on to pre-reading exercises.

Question 24

Pre-reading and reading exercises

Answer 24

• often trained by occupational therapists

- more about this later in the course

Question 25

SLO and anti-VEGF

Answer 25

- always find scotomas in pre anti-VEGF eyes with wet AMD | - avastin appears to reduce size and depth of scotomas

Question 26

Colorvision

Answer 26

- the main test used for testing color vision in low vision is the large D-15, also referred to as Panel 16 - in low vision clinic, the patients conditions are already diagnosed, so colro visio testing is generally performed binocularly - educate pateitn well so that they understand the test

Question 27

Mars letter contrast sensitivity test

Answer 27

- set of 3 near charts - each letter fades by 0.04 log units - have the patient read the chart until they read two consecutive incorrect responses Pelli-Robson uses triplets -each triplet fades 0.08 log units

Question 28

Profound vision loss on mars letter contrast sensitivity

Answer 28

<0.048

Question 29

Severe vision loss on mars letter contrast sensitivity

Answer 29

0.52-1.00

Question 30

Moderate vision loss and mars letter contrast sensitivity

Answer 30

1.04-1.48

Question 31

Normal vision loss in > age 60 mars letter contrast sensitivity test

Answer 31

1.52-1.76

Question 32

Normal < 60 age vision loss and mars letter contrast sensitivity

Answer 32

1.72-1.92

Question 33

Other contrast tests

Answer 33

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