Color Vision 5 Flashcards
This type of color deficiency means absence of color.
Achromatopsia
- very rare
Incomplete achromatopsia has what type of PRs left? Complete?
- Long and M cones (reduced function)
- Only rods present
What is the tx for achromatopsia? What does it prevent?
- Dark Red Lenses
- Prevents rod bleaching and helps with photophobia
What PRs are functional in blue monochromacy?
- rods and S-cones
What is the treatment for blue monochromacy?
Magenta Glasses
This is a disturbance of vision where colored objets appear unnaturally colored. Usually following cataract extraction or drug use.
Chromatopsia (not a true color vision anomaly)
Color Anomalies are caused by what?
cross-overs of genetic information during meiosis
What is the less severe type of crossover? Inter or intragenetic?
Intragenetic = only part of the gene crosses over (hybrid); Intergenetic = entire gene grosses over; more severe
Acquired color deficiencies can occur ______ along the visual pathway.
anywhere
Kollner’s rule states what?
BY defects = outer retina or media changes
RG defects = diseases of the conduction pathway (inner retina to visual cortex)
If patient has non-selective color vision loss (both RG and BY), what disease are you worried about?
Multiple sclerosis
- optic neuritis (but typically RG)
In glaucoma, early color vision losses are what defect?
Blue yellow
Tritan-like defects are found in what 3 ocular diseases?
- ARMD
- Central Serous Retinopathy
- Diabetic Retinopathy
Digoxin/Digitoxin produces what type of defect?
RG
Viagra produces what type of defect?
BY
Chloroquine produces what type of defect?
- BY initially
2. Protan defect later
Ethambutol produces what type of defect?
RG
Industrial chemical produces what type of defect?
BY
Which cone is more vulnerable to disease?
S cones
SWAP is great to use for glaucoma because?
- S-cones are damaged first
- only make up 5% of ganglion cells
- if few are damaged, easier to detect
What are the 2 ways that filters work?
- move color confusion lines
2. block specific wavelengths
An X-chroma lens improves color vision by doing what 2 things?
- lets long wavelengths through filter
2. Blocks shorter wavelengths
What effect does an X-chroma lens have on a monochromat? dichromat?
- monochromat becomes dichromat
2. dichromat becomes tetrachromat
The enchroma lens improves color vision by doing what 2 things?
- Separates M and L wavelengths to increase color perception
- blocks some wavelengths