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Flashcards in Low Vision Techniques Deck (53):
1

what is the set of guidelines called that outline the respectful way to interact with a patient who is visually impaired or blind

sighted guide

2

what are the first 2 steps in sighted guide

ask patient if they need assistance and then make contact with their arm

3

what is your arm position in sighted guide

relaxed by your side- bend elbow for patients who are unstable or frail

4

what is your body position in sighted guide

the patient is a half-step behind you- they follow the movements of your body

5

what are you telling the patient in sighted guide

providing verbal cues about environment, location, direction traveling, inform what is in rooms and if there are people in the room

6

what do you do in sighted guide while going through a door, narrow space or crowd

move your arm behind back and position yourself to open the door with your free hand

7

what is the sighted guide procedure for stairs

alert the patient when you approach stairs, say up or down, inform them where the hand rail is and tell them when the last step is coming

8

what are the steps to taking a distance VA

reduce test distance, hand motion (record distance), light projection and light perception *Do not do count fingers!

9

which chart method is in meters

ETDRS

10

what chart method is in feet

Feinbloom

11

what chart is the gold standard in low vision

ETDRS (also used in research)

12

what are some advantages of an ETDRS chart

improves standardization and accuracy in measuring VA, same number of optotypes per row, equal spacing and uses log scale, variable test distance, equal optotype difficulty, and high contrast optotypes

13

what are some benefits of the Feinbloom chart

portable, test at any distance, high contrast numbers, large optotypes, can measure less than 20/800

14

what are 2 disadvantages of the Feinbloom chart

variable number of optotypes per page and variable spacing between optotypes

15

what is M notation used for

metric system for measuring VA in vision rehabilitation distance and near testing

16

what is the starting distance for ETDRS

2m (can move to 1m if needed) - easy conversion to 20 feet

17

what is the starting distance for Feinbloom

10 feet (move closer if needed 5, 4, 2, 1 feet)- multiple of 20 for easy conversion

18

which chart is useful for eccentric viewing testing

Feinbloom

19

when can you not use reduced snellen near VA

if test distance is different than 40cm

20

what is the equation to convert to snellen equivalent

VA= test distance / letter size and cross multiply and divide by acuity (2/16=20/x --> x=160)

21

how can you do the snellen conversion in your head

when testing at 2 meters- multiply both numerator and denominator by 10 (if 1 meter multiply by 20)

22

what is point notation

based on typography (computers)- measures the size of typeface or the height of the letter

23

what is the conversion triangle for snellen - point - meters

Snellen –(Divide by 6)→ Point –(divide by 8)→ Meters –(multiply by 50)→ Snellen

24

what is JND

just noticeable difference - minimum lens change that a patient can appreciate during a trial lens refraction

25

what does JND equal

the denominator of equivalent snellen VA (move decimal place to 1/100 position) units are diopters

26

what loose lens do you choose for a trial frame refraction

+/- JND/2

27

You have the ETDRS chart at 1 meter and the patient reads the 8 M line. How do you record the visual acuity?

1M/8 (20/160)

28

Kathy read all of the letters on the 15M line when you placed the chart at 2 meters away from her.
How do you properly record her visual acuity?

2M/15 (20/150)

29

You use the Feinbloom chart at 10 feet and the patient reads the 150 foot line. How do you record the visual acuity?

10ft/150 (20/300)

30

how do you record near VA in low vision

record exact test distance and actual letter size - measure near VA at patient's preferred working distance (record in METERS)

31

how would you record if a patient read 1.6M letter size at 20cm

0.20/1.6M

32

Karen is wearing her glasses. The chart is held at 20 cm, The patient reads to 1.25 M with both eyes open. how would you record near VA

OU cc 0.20/1.25M (20/125)

33

Stacey needs to read 6 point type bank statements while working at a financial institution. What is the M-Unit?

0.75M

34

During the vision rehabilitation examination, Josh was able to read the 1.25M letter size on the Lighthouse near acuity chart. What is the equivalent point type that he’ll need to use on his computer in order to see it?

10 point

35

OD 2M/16 (20/160)
OS 2M/25 (20/250)
What is the OD JND?

1.60D

36

OD 2M/16 (20/160)
OS 2M/25 (20/250)
What are the loose lenses you will select to produce JND for OD?

1.00D

37

OD 5ft/120 (20/480)
OS 5ft/240 (20/960)
What is the JND for OD?

4.80D

38

how do you determine the distance magnification needed

denominator of actual VA/ denominator of goal VA

38

what is distance magnification specified in terms as

angular magnification with unit "x"

38

what is the purpose of predicting magnification

determine the starring power of optical devices

38

what is the formula we will use for predicting near magnification

Equivalent viewing distance

38

what is angular magnification

using an optical system to increase the angular subtense of the image compared to the angular subtense of the object itself

38

OD 2M/25 (20/250) OS 2M/8 (20/80) and goal VA 2M/4 (20/40) for driving- what is distance magnification for OD and OS

25/4 = 6.25x
8/4 = 2x

38

what is the equivalent viewing distance (EVD) formula

(actual near VA denominator/goal near VA) x (accommodative demand or reference add power)

38

OD 0.20M/2.5, OS 0.20M/3.2, reference add used +5 D
Goal VA for reading large print fiction books 1.6M
what is the near magnification needed

OD: 2.5M/1.6M x +5D = +7.8D
OS: 3.2M/1.6M x +5D = +10D

38

if a patient need +12D near magnification, what is the working distance going to be?

8cm --> focal distance of 12D lens = 1/12

38

what are 5 categories of optical devices

near, intermediate, distance, adaptive/assistive technologies and non-optical

39

what are some examples of near optical devices

specs: high +, microscopic lenses, base-in prisms, doublet lenses, hand or stand magnifiers, and reading telescopes

40

what are 2 examples of intermediate optical devices

loupes and telescopes

41

what are some distance optical devices

monocular telescopes, spec mounted telescopes, and binocular telescopes

42

what are some adaptive/assistive technologies for optical devices

desktop CCTV, computer software programs, OCR technology, GPS navigation systems

43

what are some non-optical devices

absorptive filters (sunglasses), fitover sunglasses, typoscope, liquid level indicator, lamps, felt tip pens, talking watch/clock, dots

44

what is the california central visual field test

several laser brightness intensities to allow for more sensitivity in plotting clinically significant scotomas