MODULE 4: ASSESSMENT OF OCULAR FUNCTION (Part 1) Flashcards
What are the 4 types of VA?
- Detection (minimum visible)
- Resolution (minimum resolvable)
- Recognition (minimum recognizable)
- Hyperacuity (minimum discriminable
- Refers to the smallest test object that can be detected.
Detection (minimum visible)
- May grossly overestimate va in visually impaired children
Detection (minimum visible)
stycar balls and ‘hundreds and thousands’
Detection (minimum visible)
- Detection tasks are often less affected by visual impairment than complex acuity tasks
Detection (minimum visible)
- Motor problem reducing control of fine hand movements rather than the inability to detect the targets could cause failure to the test.
Detection (minimum visible)
- Measures the smallest angular separation between adjacent targets than can be resolved
RESOLUTION (MINIMUM RESOLVABLE)
PL TEST AND VEP
RESOLUTION (MINIMUM RESOLVABLE)
- More useful and sensitive measure of va than detection tests.
RESOLUTION (MINIMUM RESOLVABLE)
- Can be successful in estimating acuity in infants from birth
RESOLUTION (MINIMUM RESOLVABLE)
- Children from about 2.5 years of age can be tested successfully
RECOGNITION (MINIMUM RECOGNISABLE)
- Refers to the ability to identify a form or its orientation
RECOGNITION (MINIMUM RECOGNISABLE)
snellen chart, acuity tests that use both letters or other optotypes
RECOGNITION (MINIMUM RECOGNISABLE)
smaller target size
RECOGNITION (MINIMUM RECOGNISABLE)
larger target size
RESOLUTION (MINIMUM RESOLVABLE)
affected by contour interaction - crowding phenomenon
RECOGNITION (MINIMUM RECOGNISABLE)
not affected by contour interaction
RESOLUTION (MINIMUM RESOLVABLE)
less degraded in peripheral retina, stimulates parafoveal area
RESOLUTION (MINIMUM RESOLVABLE)
more degraded in peripheral retina, does not stimulate parafoveal areas
RECOGNITION (MINIMUM RECOGNISABLE)
_____________ acuities are more sensitive to pathological and physiological degradation when compared with __________ acuities.
Recognition, resolution
vernier acuity and stereoacuity
HYPERACUITY (MINIMUM DISCRIMINABLE)
- Ability to determine differences between two stimuli (size, orientation and position)
HYPERACUITY (MINIMUM DISCRIMINABLE)
- Limited less by optical and retinal factors
HYPERACUITY (MINIMUM DISCRIMINABLE)
- Believed to reflect cortical processing
HYPERACUITY (MINIMUM DISCRIMINABLE)
Can detect children with reduced binocular acuity
VA
- Detect interocular acuity difference
VA
VA doesn’t need to be test monocularly
TRUE OR FALSE
FALSE
* Need to test va monocularly otherwise amblyopia will not be detected
- A VA test with one eye open only represents the VA in the good eye
TRUE OR FALSE
FALSE
* A va test with both eyes open only represents the va in the good eye
To monitor the treatment efficacy (change in acuity resulting in spectacle rx)
VA
Test target are white balls with diameter ranging from 3mm - 6.16cm
STYCAR GRADED BALL TEST
In stycar graded ball test, the biggest ball fixed is recorded as estimate of child’s acuity
TRUE OR FALSE
FALSE
The smallest ball fixed is recorded as estimate of child’s acuity
The child watches as the balls are presented (_____ or mounted on stick) against a ___________ _________ by the hidden examiner.
rolled, black screen
Screening Test for Young Children and Retardates
* Age: 3 months to 2 years
STYCAR GRADED BALL TEST
A not a reliable measure of VA
HUNDREDS AND THOUSANDS
- sprinkles are held in the palm of the hand are used to gain attention for infants over 6 months old
HUNDREDS AND THOUSANDS
At 9 months in hundreds and thousands, the baby may attempt to?
prod the decorations
At 1 yr old in hundreds and thousands, the baby may?
attempt to pick them up
A child will prefer to look at an object with visual interest (grating) rather than a plain field of the same luminance
PREFERENTIAL LOOKING
- Used from birth and most appropriate acuity test for children under 2.5 years
PREFERENTIAL LOOKING
- When the grating is too narrow to be differentiated, the child will ____ ________ at one side or the other
gaze randomly
What are the 2 types of PL pattern?
- SQUARE-WAVE GRATINGS
- VANISHING OPTOTYPES
alternating black and white lines of equal thickness and length
SQUARE-WAVE GRATINGS
use pictures constructed of black and white lines
VANISHING OPTOTYPES
the higher the _______ __________, the finer the grating
spacial frequency
What is the test distance and cardiff of PL?
o Test Distance: 40 cm
o Cardiff: 1m or 50cm
What is the procedure for PL?
- A gross target is presented first
- Cards are presented (unseen by the optom)
- Optom watches the infant through the peephole
- A judgement must be made by the optom if child is fixating to right or left/up or down (force-choice)
- VA is estimated as the highest spatial frequency (finest grating) the child was able to see.
In PL cards are presented only once.
TRUE OR FALSE
FALSE
* Cards are presented atleast twice for a definite response.
In PL cards examiner should be aware of the position of the stimulus when presenting
TRUE OR FALSE
FALSE
* Examiner should be unaware of the position of the stimulus when presenting to avoid bias
In PL, judgements must be based on eye movements rather than pointing/verbal response
TRUE OR FALSE
TRUE
letters or picture
MATCHING AND NAMING
Optotypes are?
isolated (uncrowded) or linear (crowded)
In matching and naming, older children are not allowed to use this test
TRUE OR FALSE
FALSE
* Older children can name the picture or letter
Test distance of matching and naming?
3m or 6m
- Examiner presents the letter or picture targets
- Child chooses a match from the key card
MATCHING AND NAMING
A single picture -Snellen format 3/3 (6/6)-3/30 (6/60)
KAY PICTURE TEST
2-3 years of age
KAY PICTURE TEST AND LEA SYMBOLS
symbols are uniform in detail, line width and size
LEA SYMBOLS
What are lea shapes?
square, circle, house and apple (heart)
- uses Sheridan- Gardiner letters but presents letters in linear format
SONKEN-SILVER ACUITY SYSTEM
- 3.5 years of age
SONKEN-SILVER ACUITY SYSTEM
uses sheridan gardiner letters
CAMBRIDGE CROWDING CARDS
child has to identify the letter surrounded by four others
CAMBRIDGE CROWDING CARDS
- Contains contour interaction to elicit crowding phenomenon
CAMBRIDGE CROWDING CARDS
logMAR acuity test is previously known as?
Glasgow Acuity Cards
- Applies the Bailey-Lovie test
LogMAR ACUITY TEST
- Letter size decreases in logarithmic fashion
LogMAR ACUITY TEST
- Scoring system: each letter is scored ______ in logMAR acuity test
0.025
Uncrowded version of LogMAR ACUITY TEST are for?
2.5 - 3 years
Crowded version of LogMAR ACUITY TEST are for?
3.5 - 4 years
What are versions of LogMAR ACUITY TEST?
Illiterate/tumbling E
Landolt C
- those with neurological impairment or LV may have ___________ _______________
reduced accommodation
(NEAR VISION TESTING)
- children have ample accommodation and few near vision problems when distance EOR is corrected
TRUE OR FALSE
TRUE
NEAR VISION TESTING
KAY PICTURE
SHERIDAN-GARDINER
LEA NEAR CHART
CARDIFF NEAR TEST
HIDING HEIDI
CONTRAST SENSITIVITY
CARDIFF CONTRAST TEST
CONTRAST SENSITIVITY
- important for career related decisions and school related activities
COLOR VISION
Most commonly used test for CV?
ISHIHARA TEST
- crucial for children with visual impairment / defects
CONTRAST SENSITIVITY
- red-green color deficiency screening test
- do not screen for blue-yellow defects
ISHIHARA TEST
1st plate of ishihara test is not visible to all
TRUE OR FALSE
FALSE
* 1st plate is visible to all regardless of CV status
14 plate edition of ishihara test px must get 14 correct to pass
TRUE OR FALSE
FALSE
px must get 10 correct to pass
- 24 plate edition: plates 1-17 are administered to children who can’t recognize numbers
TRUE OR FALSE
FALSE
* 24 plate edition: plates 1-17 are administered to children who can recognize numbers
15 out of 17 is required to pass
TRUE OR FALSE
FALSE
o 13 out of 17 is required to pass
o 18-24 - if px cannot identify numbers
traceable curving lines
- CV test that does not classify type or severity
- only normal vs abnormal CV
- 12 - 14 plate pseudoisochromatic test
- 3-5 years
- 75cm
COLOR VISION TEST MADE EASY
What contains the part 1 of CV test made easy?
circle, square and star targets
What contains the part 2 of CV test made easy?
boat, house, dog
part 1 of CV test made easy is not visible to all
TRUE OR FALSE
FALSE
* 1st plate is test plate and visible to all
- helpful in identifying congenital and acquired CV defects
HARDY-RAND-RITTLER (HRR)
- can detect and classify R-G defects & B-Y defects
HARDY-RAND-RITTLER (HRR)
- child friendly shapes and mini paint brush
HARDY-RAND-RITTLER (HRR)
px is asked to arrange 15 colored discs in order of hue and intensity
FARNSWORTH D-15
- if the child fails demo plates?
px may be malingering or not cooperating, stop the test
- if child fails the 6 screening plates?
there are 14 subsequent plates to diagnose extent and type of defect
plates 5-6 are missed
B-Y defect is suspected
if error in 5-6 but no error in 21-24
mild defect
21-22, no error in 23-24
moderate defect
23-24 error
severe defect
- 7-10 error
R-G defect suspect
o only plates 5-6 are shown to concentrate on R-G defects
TRUE OR FALSE
FALSE
o only plates 11-20 are shown to concentrate on R-G defects
o 11-15
defect is mild
o 16-18
defect is moderate
o 19-20
defect is severe
Ocular health of evaluation of ocular anterior
o Lids and Lashes
o Bulbar Conjunctiva
o Palpebral Conjunctiva
o Cornea
o Ant. Chamber Angle
o Iris
o Lens
Ocular health of evaluation of ocular posterior segment
o Cup/Disc Ratio
o A/V Ratio
o Vessel
o Venous Pulse
o Foveal Reflex
o Macula
o Vitreous
o Peripheral fundus
o indirect ophthalmoscope with ____D or ____D lens
20D or 28D
- older child: ______ ______
Slit lamp
- younger / uncooperative child?
hand held slit lamp
for px with short attention
- directed towards cc
