Gross Anatomy of Eye Flashcards
Normal adult has an eye diameter of what?
24-25mm
What is the average distance of the eye medial to the bony orbit?
5-7mm
Which lid moves more upon closing?
Upper
The three layers of the eye are what?
- Fibrous tunic (cornea and sclera, outermost and strongest)
- Vascular Tunic (Iris, ciliary body and choroid, middle also called Uvea)
- Neural tunic (retina, inner most)
As the iris moves posterior what happens?
it becomes thinner becomes ciliary body/processes then becomes the choroid
Anterior chamber includes what? Posterior? Vitreous?
Everything in front of Iris
Everything behind Iris
Entire eye
(dont get confused with anterior segment: everything in front of vitreous and posterior segment everything behind and including vitreous).
What is the main refracting structure? what does the rest? changes in shape/size of eye due to which structure?
cornea (80%), lens.
Sclera.
Collarette is what?
Ring of muscle around Iris
The average eye is how long across? vertical distance? and circumference?
Across: 12 mm
Down: 11 mm
Circumference: 37 mm
Ciliary body is made up of what two structures?
pars plicata: tissue folds (also called ciliary processes around 80 of them)
Pars plana: no tissue folds
Ora Serrata is what?
transition zone between anterior uvea and posterior uvea
The rounded edges of the pars plana are called? the indentations are called? what do these make up?
Oral bay, deutate process makes up ora serrata.
The three layers of the choroid are?
- Choriocapillaris: tiny holes for capillaries, right next to RPE
- Sattlers Layer (stromal): small/medium blood vessels
- Haller’s Layer (suprachoroid): contains large blood vessels
Is the choroid pigmented? is it vascular? it is a blood supply for what tissue?
yes, dark brown.
yes
retina
What are the three chambers?
- Anterior: 200ul
- Posterior: 50ul (smallest one)
- Vitreous
What structures line the anterior chamber? posterior chamber? Vitreous?
Ant: Anteriorly, cornea and posteriorly, anterior iris
Post: anteriorly, posterior iris. Posteriorly, anterior lens and zonules. laterally: junction between iris and ciliary body.
Vitreous: anteriorly, lens and ciliary process. Posteriorly, retina (back of eye)
Zonule fibres connect to what?
connects lens to ciliary processes (pars plana)
Pathway of trabecular meshwork? which fluid takes this route?
series of small canals, goes to schlemms canal and then to venous system.
Aqeuos humor
What are three transparent tissues?
Cornea, lens and vitreous
the viscoelastic gel present in vitreous humor is what percent water? what is the refractive index? what are the two zones in the vitreous? what type of cells are found here?
98%. n=1.33
Cortical zone: outer most, denser collagen fibres
Central zone: more liquid
hyalocytes (thought to be macros)
Where do the zonules attach to the lens? they are in what shape?
anteriorly, posterioly and centrally.
a ring
What happens when ciliary muscles contract?
releases tension on zonules which icnreases curvature of lens increasing dioptic power.
Define presbyopia. you wont get this if you are what?
reduced accommodative ability happens around 40-50 years old, loss of elasticity, corrected with + lens.
myopic
The viscosity in the vitreous humor is due to what?
sodium hyaluronate and collagen type 11
