Anatomy and Review of the Eye Flashcards
What kind of animals have a closed orbit?
Herbivores
What kind of animals have an open orbit?
Carnivores
What should a healthy eyelid look like?
Smooth edges with a continuous line from medial to lateral canthus. Should sit flat against the eye (small gap is normal in some breeds). Lower eyelid has no hairs
What are the white dots along the eyelid edge?
Meibomian gland openings
What is the function of the meibomian glands?
Secrete oil onto the eye forming the oil layer of the tear film to prevent the eye from drying out.
What is a sty?
An infection of the meibomian glands
What does the third eyelid look like?
Positioned at the medial canthus. Can be pigmented or not or a variation of pigmentation
What is the third eyelid made up of?
Fold of conjunctiva with a cartilaginous core to hold its shape and a tear gland buried deep in the medial edge
What differences are there between cat and dog eyes?
Cats don’t have proper eyelashes. Can often see third eyelid. Eyelids cover edges of cornea and common for proteins/dirt to sink below lower eyelid
What does the conjunctiva cover?
Lines the eyelid, folds back at conjunctival fornix, covers the globe, stops at the limbus
What is the limbus?
Junction between cornea and sclera where the conjunctiva fully attaches to the sclera
Why is the limbus clinically important?
If there is a lot of pigment a chronic irritation can cause proliferation of pigment which migrates across the cornea and obscures vision
What is the Perkinjee reflexes? How are they used clinically?
Reflection of light off the cornea. can use it to judge the surface
What are the outer layers of the eye?
Sclera, cornea and limbus
What makes up the uvea?
Iris, ciliary body, choroid
Which way does the equator of the eye run?
Runs the edge of the lens and splits the eye into anterior and posterior chamber