-
red/green/blue cone?
- erythrolabe
- chololabe
- cyanolabe
-
What is dichromacy?
missing one cone, requires 2 other cones to see full colours
-
What are the 3 types of dichromacy?
- protanopia: missing erythrolabe
- deutanopia: missing chlorolabe
- tritanopia: missing cyanolabe
-
What is monochromacy?
- missing 2 cones
- total colour deficiency
- see differences in light
-
What are the 3 types of monochromacy?
- pi5- erythrolabe only
- pi4- chlorolabe only
- blue monocone- cyanolabe only
-
What are the 2 subtypes of monochromacy?
- rod: lacking cone receptors- va poor, aversion to light
- cone: usually has blue monocone, VA normal/slightly reduced
-
What is anomalous trichromacy?
- can visualise 3 colours
- inherit one anomalous cone
-
What are the 3 subcategories of anomalous trichromacy?
- protanomaly- modified erythrolabe cone
- deutanomaly- modifed chlorolabe cone
- tritanomaly- modiefied cyanolabe cone
-
What are the genetic patterns?
- protan/deutan: x-linked recessive
- tritan: autosomal dominant, some autosomal/x-linked recessive
- rod monochromat/blue mono/cone monochromat- autosomal recessive
-
What colours do protanopes confuse?
red-green
-
What colours do deutanopes mainly confuse?
yellow green, white green
-
What are the two types of ACVDs?
- Dsychromatopsias: include congenital
- Achromatopsias: truly colour blind
-
What are some of the factors that contribute to ACVDs?
- Physiological: yellowing lens
- Pathological: eye disease, systemic disease
- Psychological: usually colour naming – anomia, aphasia for colour names
-
What Kollner's rule?
- Diseases of the outer retina: blue-yellow deficiencies
- Diseases of the optic nerve and inner retina: red-green deficiencies
-
What conditions obey Kollner's rule?
- MS
- Leber’s optic atrophy
- Indomethacin maculopathy
- ARM
- Dignoxin neuropathy
- Chloroquine
- Diabetes
-
What conditions do not follow Kollner's rule?
- Dominantly inherited juvenile optic atrophy
- glaucoma
-
What is a type 1 ACVD?
- Red-greeno
- Pseudo-protanomaly
- Cone dystrophies, RPE dystrophies
-
What is a type 2 ACVD?
- Red greeno
- Pseudo – deuteranomaly
- Optic neuritis
-
What is a type 3 ACVD?
- Blue – yellow
- Rod and rod-cone dystrophies, retinal vascular, glaucoma
-
Severity of anomalous trichromats?
- mild: on confusion lines, colours close together mixed up, colours far apart differentiated
- severe: on confusion lines, colours far apart confused
-
Severity in dichromats?
all severe
-
What does colour confusion depend on?
- The severity of CVS
- Viewing conditions
- Available light
- Type of light
- Intensity of the colour – pale or dark
- Size of the coloured object
- Viewing time
-
How to minimise colour confusion consequences?
- use colours that don't lie ont he confusion lines
- redundant coding
- use luminance, brightness and contrast
-
What are the uses of a colour vision test?
- Detection of a colour vision deficiency- normal or abnormal
- qualitative diagnosis
- quantitatice diagnosis
- congenital or acquired
- relatable to real life- vocational test
-
What tests would you choose for the detection of a CVD- normal/abnormal?
- PIC tests- can separate normals from severe
- Anomaloscope
-
What tests would you choose for qualitative diagnosis?
- OSCAR/Medmont C-100
- Standard D15
- Anomaloscope
-
What tests would you choose for a quantitative diagnosis?
-
What tests would you choose for congenital vs acquired testing?
-
What tests would you choose that are relatable to real life?
-
What tests would you choose for a general overview of cv?
- Ishihara- qualitative
- D15- quantitative
- Medmont C-100
-
What do filter aids do for those with CVDs?
- alter relative brightness of colours- differentiate bw colours due to luminance cue
- fitted on one eye only
-
Adv and Disadv of ishihara?
- gold standard for rapid indentification of congenital RG deficiencies
- Dis: pass very mild deutans
- no tritan plate
- doesnt diagnose severity
-
How is the ishihara scored?
- record all responses
- diagnosis: "A/12"
- 0-1 error: PASS
- 2-3 errors: BORDERLINE
- >3: FAIL
-
AOHRR?
- Uses 3 shapes: circle, square and triangle
- screens for protans, deutans, tritans and tertartans
- grades severity
- scoring: record type and severity
-
SPP?
- vol 1: RG CVDs, 2 plates for tritans
- vol 2: acquired CVDs
adv: not as available, can't memorise
-
Scoring for SPP?
- OUT OF 10
- 1 error: BORDERLINE
- >1 error: FAIL
-
CVTME pros and cons?
- children- symbols
- passes mild deutans
- no qualitative diagnosis
- must know what theyre supposed to be looking for
- need to know names of shit
-
Scoring for CVTME?
>7 answers: PASS
-
HAHN NEW/MODERN COLOUR VISION TEST pros and cons?
- congenital CVDs
- includes a tritan plate
- Doesn't identify deutans well
-
Hahn New/ Modern CVT scoring?
Pass or type and severity
-
Lanthony's Tritan Album?
Congenital VS acquired tritan
-
Scoring of Lanthony's Tritan Album?
- 0-1 error: PASS
- >1 error: FAIL
-
Malingerer plate?
- significant luminous reflectance contrast with background
- CV not required
-
Disappearing/vanishing plate?
colours straddle confusion lines deutan and protans- both will fail
-
Combination plates?
- demonstration+disappearing plates
- CVD can respond to this- feel like they arent failing
-
Alteration plates?
both CVD and CV both can respond-with diff answers thou
-
Diagnostic/qualitative plate?
- disappearing, but have 2 images
- deutan/protan- one will pass
-
Hidden plates?
only able to be seen by CVDs
-
Administering PIC tests?
- Working distance = normal reading distance
- Time per page – not specified
- They are good at screening
- Fairly good at type diagnosis – qualitative
- Not good for quantitative
- Not relatable to real tas
-
Administering 100 hue test?
- 2 minutes per box is reasonable, however there is no time limit
- Working distance is typical near working disatance
- The colourmetric construction of the test is shown in the graph
- It is important that you never let the patient touch the surfaces because the Munsell colours are very absorbent.
-
How does scoring work for 100 hue?
- Calculate a score for each colour
- Calculate an error score for each colour
- Sum the error scores to a total error score
- Plot the scores on the polar diagram
- Total error score = quantitative measure of ability – it is age related
-
What happens at the end of box?
- 1. used fixed cap
- 2. find next movable cap- use this method
-
What are the typical results of a protanope in the 100 hue test?
-
What are the typical results of a deutanope in the 100 hue?
-
What are the typical results of a tritanope in the 100 hue?
-
Scoring of a D-15 test?
- > 2 crossings: FAIL
- 1-2 crossings: BORDERLINE, RETEST
- 0 crossings: PASS
-
FARNSWORTH LANTERN?
- Used by police
- 2m distance
- isochromatic colours displayed
- RGW lie along confusion lines of protan/deutan
- bright lighting
-
Scoring/procedure of Farnsworth?
- 0 ERROR RUN 1: PASS
- 1ST ERROR RUN 1: FAIL RUN 1-> RUN 2
- TOTAL <3 ERRORS RUN 2+3: PASS
- TOTAL >2 ERRORS RUN 2+3: FAIL
-
HOLMES-WRIGHT TYPE A?
- replication of acutal signals
- RGW colours used
- used by maritime services
- 6m distance
- dark adapt 10-15 mins
-
Scoring/procedure of Holmes Wright Type A?
- LARGE APETURE:
- 0 ERROR RUN 1: SMALL APETURE
- 1ST ERROR RUN 1: RUN 2
- IF FAIL RUN 2 CONTINUE SMALL APETURE BUT FAILED OVERALL
- SMALL APETURE
- 0 ERROR RUN 1: PASS
- ERROR RUN 1: RUN 2
- ERROR RUN 2 (NO PREVIOUS ERROR): RETEST FROM LARGE APETURE
-
What is the equation that the anomaloscopes are based on?
- rayleigh
- >640nm (red) + 540nm (green) = 590nm (yellow)
-
What is an endpoint on the anomaloscope?
GG// and //RR
-
What is the typical anomaloscope results of a normal?
- 42 mid point
- range ~6
- similar brightness
-
What is the difference in results between a protanope and a deuteranope on the anomaloscope?
- Protanope: match across whole range
- higher intensity at red end
- Deuteranope: match across the whole range
- similar intensity throughout
-
What is the difference in results between a protanomal and a deuteranomal on the anomaloscope?
- Protanomal: 42more green
- 55- matching
- larger matching range than normal
- intensity increases at red end
- Deuteranomal: 42 more red
- 20 matching
- larger matching range than normal
- similar intensity throughout the whole range
-
What is the difference in results between a protanope and a protanomal on the anomaloscope?
- protanope will match across the entire range
- protanomal will match at a higher number ~55
intensity for both will increase at red end
-
What is the difference in results between a deuteranope and a deuteranomal the anomaloscope?
- Both will have similar intensities thorughout the whole range
- A deuteranope will match for all colours
- A deuteranomal will match at around ~20
-
What is the difference in results between a extreme protanomal and an extreme deuteranomal on the anomaloscope?
- Xpro: match from 42-72
- intensity will increase at red end
- Xdeu: match from 0-42
- intensity will be similar throughout
-
OSCAR/ Medmont C-100?
- flicker matching of red and green
- Protan: need more red
- Deutan: need more green
-
Scoring for OSCAR/ Medmont C-100?
- Mean score >-2: NOT PROTAN
- Mean score <-1: PROTAN
-
CITY UNIVERSITY TEST?
- Uses standard d15 colours
- shows severity of RGDs
- tests congenital
-
Scoring of CUT?
- OUT OF 10
- 1 ERROR: BORDERLINE RETEST
- >1 ERROR: FAIL
|
|
