LV - Low Vision Exam I - Week 2 Flashcards

1
Q

List the 9 components of a low vision exam.

A

History including goals
VA
Refraction and BCVA
Contrast sensitivity
Visual fields
Lighting/glare
Magnification
Non-optical aids/devices
Management

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List and describe 5 general observations that could be made during history in a low vision exam.

A

Mobility
-use of any devices/assistance, recognition of doorways etc
Fixation
-head positioning, eye-contact when talking, eccentric fixation, nystagmus
Cosmesis
-ptosis, scarring, prosthesis
Physical
-other problems such as hearing loss, tremors, general health appearance
Psychological
-attitude, cognitive status, independence, people who accompany them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List 6 things to ask about for vision and ocular history during a low vision exam.

A

Explore vision loss (onset, progression, cause, etc)
Current eye-care and by whom
Last review
Any previous treatment
Current spectacles, prescribed date
Special aids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How much does a 6m letter subtend at 6m, how much does a limb subtend, and what is the height in mm?

A

6 m letter subtends 5’ arc, limbs subtend 1’ at 6 m and is 8.7 mm in height

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How much magnification is every three lines? What about six and nine lines?

A

3 - 2x mag
6 - 4x mag
9 - 8x mag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the formula for the magnification required to see a specific line on a logMAR chart? Give an example with 6/24 to read 6/6.

A

Mag required = letters read / letters they wish to read
-if a patient has 6/24, x4 telescope is needed to achieve 6 lines to 6/6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What viewing distance is advised for low vision exams? What should you do when recording?

A

Reduce viewing distance - 2.4m, 1.2m
Record using actual distance as snellen numerator (2.4/x) then convert to standard 6/x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many lines of improvement is considered worth prescribing spectacles for?

A

Three or more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe how N8 print subtends at 1m. What is this notation called? How is it converted to the N notation?

A

Has a loop height that subtends 5’ a the eye for viewing distance of 1m
At 25cm, M = N/8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What snellen line is N20 at 25cm equivalent to?

A

6/60

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe how to convert from N to snellen at 25cm.

A

At 25cm, denominator of snellen is Nx3
-N8 at 25cm is 6/24

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

True or false
Most low vision patients tend to be monocular
Explain your answer.

A

True
-due to large difference in acuity of each eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can you tell if patients are binocular or monocular?

A

If their VA is better binocularly, then likely binocular
If their binocular VA is the same as their best eye VA, likly they are suppressing the poorer eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Is it possible for binocular VA to be worse than monocular VA? Explain your answer.

A

Yes it is - likely retinal rivalry is occurring
-occlude poorer eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

With how many lines of difference between the eyes should you begin to investigate binocularity? List two ways.

A

3 lines or less
Worth 4 dot test
Bar reading test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly