Test 1: Vision Rehab History and Exam

Question 1

low vision exam

Answer 1

different from PC exam
goal driven optical consultation
focus on rehab

Question 2

low vision exam scheduling

Answer 2

initial consultation
first visit 1.5-2 hours
loan devices 2-6 weeks
follow up 30-60 min
separate or combined rehab or O/M eval

Question 3

equipment

Answer 3

standard lane
magnifying devices 
optical/non-optical equipment 
VF instrument 
color vision
contrast sensitivity 
scotoma test 
maybe SLO or MP-1, slit lamp camera, retinal camera

Question 4

fee structure

Answer 4

exam fees - many ways to bill
material fees - conventional glasses, magnifying devices
home visits
telescopic driving instruction

Question 5

history

Answer 5

first impressions, psychosocial, all doctors seen: PCP, ret specialists, medical/visual, mobility/falls, activities of daily living, pt impression of vision at different distances, illumination use, devices or owned

Question 6

purpose of low vision history

Answer 6

emotional status
task analysis 
functional review 
goals
communication needs with providers

Question 7

distance VA

Answer 7

projection charts - snellen most common
light box charts - bailey lovie, ETDRS gold standard in research, high and low contrast chart versions
flip charts/handheld charts - feinbloom common clinically, ETDRS, bailey lovie

Question 8

bailey-lovie chart

Answer 8

6m/20ft distance typical
advantages - five letters in each row task is equivalent for each row, equal contour, more letters for patients with poorer acuity
letter spacing on each row is equal to one letter width
row spacing is equal to height of letters below
contour interaction is scaled in relation to letter size
test distance can be varied with simple proportional acuity conversion
letter size follow log
increasing in 0.1 logMAR steps
20/20 = 0.0 logMar, 20/25 = 0.1 logMAR
each letter on each line is assigned a score of 0.02

Question 9

ETDRS

Answer 9

early treatment of diabetic retinopathy 
sloan letters 
log progression 
NIH studies 
similar to bailey-lovie
log letter size complicates legal blindness

Question 10

feinbloom chart

Answer 10

designs fro vision 
5 or 20 feet test distance most common 
test distance can be varied proportionally 
letter size 10-700
has 20/120 and 20/160
high contrast
single optotypes
better figure ground 
easily use eccentric viewing 
more realistic test conditions

Question 11

office projection chart

Answer 11

snellen chart/letters most common 
acuities taken at 20 feet
letter size 10-400
acuities 20/400 or better 
20/200 then 20/150, some to 20/100
contrast?
single optotypes? 
figure ground? 
easy to use eccentric viewing? 
not logMAR standard - cannot vary test distance

Question 12

M notation

Answer 12

introduced by sloan to prevent confusion with non-metric snellen
metric system
M units specify the size of print by indicating the distance in meters at which the height of the letters of the printed material subtends 5 min of arc
2M subtends 5 min at 2 meters, 3M subtends 5 min at 3 meters
1M - 20/50 @ 40 cm
pt reads 1M at 1m = 1m/1M = 6/6 (in m), or 20/20 in ft

Question 13

advantages of M notation

Answer 13

test distance can be varied 
very large effective letter size 
large range of possible acuities 
same system works for dist and near 
standardizes VAs across providers
enhances inter-provider communication

Question 14

near acuity assessment

Answer 14

single letter
continuous text - better simulation of real world, very different result than single letter, words or paragraphs with or without meaning, don’t be afraid to use magazine, book or newspaper as target, MN read common chart used

Question 15

lighthouse near visual acuity chart

Answer 15

lighthouse near acuity test
letter size .3M to 8M
metric system - linear scale, recorded at any distance
lists M notation and snellen 
high contrast 
good figure ground 
logMar standards - uses sloan letters 
eccentric viewing possible

Question 16

hi/low contrast near charts

Answer 16

reduced contrast versions available
ex. colenbrander mixed contrast chart by precision vision
difference of 2 lines or more between high and low contrast lines - CS problem

Question 17

MN read

Answer 17

white on black or black on white
continuous text
same number of letters in each paragraph
can calculate reading speeds words/min, allows finding of size print pt reads most quickly, allows investigation of effect of mag on reading speed

Question 18

VF

Answer 18

confront may be adequate - apart from legal blindness determination
may need multiple assessment methods
kinetic may differ from static - kinetic may impact driving and mobility more
VF type selected depends on disease, what you need it to tell you, office availability

Question 19

common VF instruments

Answer 19

goldmann
humphrey - 24-2 threshold, 30-2 threshold, 120 pt screener, 81 pt screener, ester man
octopus

Question 20

VF testing

Answer 20

test used to understand function and or monitor disease
often confrontation VF is adequate
generally 5 degree or less VF may limit use of magnification, 10 degrees or more usually mag is not limited, 40 degrees or less magnification not limited, also consider scotomas, mobility instruction should be considered

Question 21

amsler grid testing

Answer 21

may use to understand location of scotomas
right of fixation - difficult to find the next word in a sentence
left of fixation - difficult to return to next line in left column
central - can’t see anything just black
paracentral - island effect, loses text, careful with mag, won’t eccentrically view

Question 22

fletcher california central test

Answer 22

manual way to quickly map scotomas
uses concentric grid and central fixation pt
must be able to see fixation pot - variable fixation pt sizes options
flash red laser light from behind grid along each tangential meridian - mark when light is not seen and reappears along meridian, repeat for each meridian, connect your marks to map scotoma, alternate method move light along meridian as kinetic test

Question 23

hints about CA central test

Answer 23

3 intensities of laser available to map relative vs complete scotomas
binocular provides more realistic functional conditions
binocular results usually differ from monocular
size of fixation pt you choose will depend on VA loss
this test underestimates the number and size of scotomas

Question 24

preferred retinal locus

Answer 24

a preferred retinal area to fixate targets
may be eccentric
may or may not be optimal location for maximizing VA

Question 25

preferred retinal locus detected by

Answer 25

``` amsler grid scanning laser ophthalmoscope nidek-MP1 face with feinbloom method california central test ```

Question 26

nidek MP-1

Answer 26

scotoma detection retinal photography feedback examination - to train eccentric fixation

Question 27

scanning laser ophthalmoscope

Answer 27

larger and more comprehensive version of MP-1 been around much longer - 1979 very large and expensive high contrast images retinal slicing projects reading and fixation stimuli directly on retina

Question 28

pupils

Answer 28

particularly important to evaluate neuro conditions evaluating may inhibit pt ability to try devices can go back and perform after devices is needed - do at end of exam a lot of pts have APDs

Question 29

EOMs

Answer 29

evaluate under or over actions assessment of neurological function pick large target o flight

Question 30

binocularity patient types

Answer 30

binocular - uses both eyes typically equal VA between eyes monocular - prefers the VA of one eye biocular - one eye used at distance, other used at near, or can use either eye independently retinal rivalry patients - monocular vision of better eye worsens binocularly

Question 31

cover test/binocularity

Answer 31

very important to function and treatment dominant eye suppression? may encourage suppression or patch if helps function stereopsis and effect on mobility, driving mono vs binocular devices

Question 32

methods for measuring binocularity

Answer 32

cover test - large fixation point, complicated by EV and nystagmus worth 4 dot - if they can perceive lights 10 BD tests - see 2 targets other tests of suppression inference from eye posture inference from VA difference longstanding

Question 33

contrast sensitivity

Answer 33

two patients same corrected distance VA visually impaired/legally blind function differently - ADLs, mobility, use of optical devices due to personality differences? differences in contrast sensitivity - predicts function better than VA does

Question 34

when to measure CS

Answer 34

assessment of VS should be performed when the patients performance does not match the expected results may require experience perform on EVERY vision rehab patient wonderful communication tool with pt, family and referring doc

Question 35

vistech contrast sensitivity chart

Answer 35

diagnostic chart vistech or newer version functional acuity contrast test (FACT) from stereo optical perform at 1 meter with low vision patients perform at 3 meters with normal vision patients diagnoses - high frequency, mid frequency and low frequency losses may have losses in none, one, two, or all frequencies

Question 36

bailey hi-low contrast acuity chart

Answer 36

screening chart visual acuity taken on high contrast side VA taken on low contrast side contrast problem indicated when low contrast side two lines or more worse doesn't identify high middle or low

Question 37

peli robson contrast chart

Answer 37

same letter size | contrast varies in groups of 3 letters

Question 38

MARS contrast sensitivity chart

Answer 38

similar to peli robson but smaller 50 cm test distance 3 letters of same contrast stop when miss two in a row at a contrast level record contrast of last corrected letter subtract letters missed prior to last correct use shaded grid to find result of: normal, mild CS loss, moderate loss, severe loss, profound loss

Question 39

weber contrast

Answer 39

``` common measure of contrast calculated difference between luminance of an object and its background divided by the brighter of the two contrast varies from 0-100% greater the percentage = higher contrast ```

Question 40

weber contrast of common reading materials

Answer 40

``` 71-75 daily newspaper 55-60 US currency 76-80 paperback books 81-85 large print newspaper 86-90 large print magazines 88-93 glossy periodicals ```

Question 41

weber contrast of common objects

Answer 41

``` 5 maroon chair maroon carpet 74 maroon chair gray carpet 64 wood door light wall 80 red illuminated sign 82 black car sunny day 32 gray car shady day ```

Question 42

contrast threshold

Answer 42

defined as an object with the lowest contrast that a patient can recognize CT is expressed as a percentage CS is the complement (reciprocal of CT) 100%=1, 50%=2, 25%=4 as vision improves, CT decreases and CS increases as vision worsens, CT increases and CS decreases

Question 43

if reduced VA with reduction in low spatial frequencies is more difficult to see larger objects....

Answer 43

can't change their spatial frequency so change contrast higher object contrast threshold allows this patient to see better reflector tape on stairs red plates when eating toilet seat brightly colored felt tipped pen wide lined writing paper

Question 44

management plan for high frequency CS loss

Answer 44

lighting - directional increased contrast of materials increase magnification - magnifiers at near use of closed circuit television CCTV

Question 45

management plan for mid and/or low frequency CS loss

Answer 45

vary contrast (environmental modifications) increase magnification (telescopes) filters (enhancing) mobility training

Question 46

binocular CS

Answer 46

binocular CS is higher than monocular CS usually binocular summation if a low vision patient demonstrates binocular summation, then binocular devices should be encouraged at distance and near low vision patients without binocular summation should use the eye with the better CS assuming other factors such as VA and VF don't contraindicated the use of the other eye

Question 47

clinical relevancy - blurred vision

Answer 47

mag you need may need to be increased if CS is an issue materials are a factor use the newspaper when determining reading magnification - then able to read higher contrast materials also

Question 48

clinical relevancy - mobility

Answer 48

can't prepare for all environments dusk, night, low contrast materials justifies need for white cane or guide dog

Question 49

color testing

Answer 49

``` why/when functional test - maculopathies result in a desaturation of color vision vocations avocations school ```

Question 50

types of color tests

Answer 50

large chip D-15 dichotomous test color vision made easy ishihara

Question 51

low vision refraction

Answer 51

trial frame vs phoropter central scotoma - trial frame! determine if phakic or pseudophakic if phakic a refraction may be more helpful - cataracts a consideration pseudophakes usually have minimal change refraction often helps near normally sighted 20/25 to 20/60 may help visually impaired 20/70 to 20/160 seldom helps legally blind

Question 52

refractive procedure

Answer 52

place habit Rx in phoropter or trial frame ret spherical and cylinder meridians or more commonly use lensometry as starting point subjective distance trial frame refraction using just noticeable difference or JND

Question 53

just noticeable difference

Answer 53

smallest amount of power change necessary to differentiate variation in blur JND = denominator of snellen/100

Question 54

subjective refraction

Answer 54

determine spherical sensitivity - JND choices, attempt to bracket cylinder - allow patient to rotate JCC with best single letter to find axis, bracket power using JND, cylinder power and axis equals keratometry in pseudophakes recheck sphere sphere check, refine cylinder axis, find axis power, sphere check

Question 55

JND hints

Answer 55

don't forget that your JND formula result must be divided by two for the +/- choices may change sphere lens to keep spherical equivalent or wait and recheck sphere again at end correct sphere and cylinder for room length if trial frame refraction performed at 10 or 5 feet

Question 56

skill evaluation

Answer 56

may ask patient to perform a task allows better understanding of struggles - appropriate devices, appropriate referrals may use home environment room

Question 57

device demonstration

Answer 57

reassure pts that change is frustrating and you're here to help act as coach through process of device demo start simple and increase in complexity start with achievable goal usually start with near devices start with lower powers explain basic principles of magnification

Question 58

ocular health testing in pts referred for vision rehab

Answer 58

depends on pt history, VA consistent with report if patient has recently been examined elsewhere if patient is in care of one or more other eye care providers and sees them regularly if some red flags contact the referring doctor

Question 59

education and information

Answer 59

patient must be involved in decision process when deciding what devices to take home pt needs to understand it takes time and practice to improve at using devices pt needs to understand importance of their own motivation explain disease process and functional implications explain Rx/s and what they will and won't do for the pt additional resources should be provided to take home

Question 60

referrals

Answer 60

guest speakers will introduce available services | pt ed on where to go from there

Question 61

letters

Answer 61

letter writing - templates in EHR critical to referrals and successes release of pt care release of Sex referral for additional services letter after every visit - comprehensive letter after first eval, highlight goals, functional problems, VA, VF, CS, scotomas, maybe color deficits, explain plan and propose solutions, explain additional referrals brief letter after f/u visit - what is working for pt, plan from this point, release of care