week 6 Flashcards
what is the refractive power of the cornea
40/45
what is behind the cornea
anterior chamber
what is in front of the cornea
layer of tear film
what are the dimensions of the cornea
11.75mm across
12.10.6mm height
centre thickness 520-550 micrometers
peripheral thickness - 700 micrometeres
radius of curvature 7.8mm
what is keratoconus
cornea bulges in one area to form a cone shape
name the 5 layers of the cornea
outer - epithelium
bowman’s membrane
stroma
descemet’s membrane
inner - endothelium
what cells sit on the basement membrane on the corneal epithelium
basal cells
why is the squamous smooth
prevent light scattering
what is the bowsman membrane
thick layer of collogen fibres
does not repair if damaged and will form scar tissue
what is substanial propia
stroma
layers of lamellae - fibril of collogen
in polysaccharide matrix
how is the corneal endothelium arranged
1 cell thick
intergititates - cell membranes slot into each other to provide strength in shape
with old age cells are lost and so cells spread out to fill gaps
what is corneal neovascularization
occurs where blood vessels will form on the cornea
If corrected, then ghost blood vessels will form
how do we feel pain in the eye
Nerve bundles to allow us to feel pain in the eye but we are unable to localize it
These are unmyelinated in the cornea to ensure full transmission of light
how does the stroma water level stay consistent
indigitated cells keep water out
Pump removes salts and removes water
what is a corneal edema
polysaccharide matrix causes increase in salt in cornea which brings in water > random arrangement of stroma causing eye to become cloudy
