Uvea Flashcards
(128 cards)
What are the parts of the uvea?
- Iris
- Choroid (with tapetum)
- ciliary body
Where is the choroid in relation to the retina?
- It is posterior to it
Where does the iris sit?
- In front of, and rests on the lens
What is the central opening of the iris?
- Pupil
What is the role of the iris?
- Controls amount of light entering the back of the eye with sphincter and dilator muscles
What does a blue iris mean?
- Lacks pigment
Pupil type and PLRs in the dog
- Round
- Strong consensual PLR
What is the main blood vessel in the iris?
- Greater arterial circle
What is the pupillary ruff?
- little projections from the center of the iris
Equine pupil and PLR
- Horizontal when constricted , round when dilated
- Moderate consensual PLR
- Corpora nigra seen in the superior (and inferior) pupil
Camelid pupil and PLR
- Moderate consensual PLR
- Elliptical pupil with large plicating corpora nigra on upper and lower pupillary margins
Cat pupil and PLR
- Strong consensual PLR
- Vertical pupil when constricted and round when dilated by sympathetic input
Which CN is involved in constricting the cat pupil?
- Parasympathetic CN III
Bird PLR and pupil
- Round pupil
- No consensual PLR
- Hard to assess
- Can’t menace
Heterochromia
- 2 colors in the iris or two colored eyes
What type of blood vessel in the iris is abnormal?
- Blood vessels reaching towards the pupil
- The greater arterial vessel is normal around the peripheral iris
Can you normally see the ciliary body?
- NO
Where is the ciliary body?
- At the posterior base of the iris
What part of the ciliary body epithelium secretes aqueous?
- Pars plicata
What is the flat area between the ciliary processes and the retina?
- Pars plana
What is the choroid?
- Vascular layer between the sclera (posterior) and the retina (interior)
- Contains the tapetum
When is the choroid visible?
– In non-pigmented eyes (blue eyed animals)
Persistent pupillary membrane
- Can be from the iris to the cornea
Significance of PPM
- Residual and often incidental
- In some breeds it can cause cataracts