Ocular surface Flashcards
What are the 3 layers of the tear film?
Lipid layer, aqueos layer, mucin layer
What produces lipid, aqueous and mucin
Lipid –> meibomian glands
Aqueous ==> lacrimal gland
Mucin –> goblet cells
What are three parts of the conjunctive?
Palpebral conj,
Bulbar conj.
Forniceal conj.
What are the layers of the cornea?
Epithelium Bowman's layer Stroma Descemet's membrane Endothelium
Layers of epithelium of cornea? (3)
Superficial cells Middle zone (wing cells) Basal cells (stains with periodic acid)
What do dermatan sulphate and keratan sulphate do?
Bind to colleagen at specific points to regulate fibril spacing and thickness of interfibrillar space
What do dermatan sulphate and keratan sulphate do?
Bind to colleagen at specific points to regulate fibril spacing and thickness of interfibrillar space
in corneal endothelium, what cell density causes oedema,swelling ettc
<800 cells/mm2
How many cells are required for transplantation
1500/mm2 in a donor is too low for transplantation
What is the sensory supply to the cornea?
V1 –> long ciliary nerves –> annular plexus near limbus –> form a subepithelial plexus after losing their myelin sheath –> Intraepithelial plexus
Iris divided into 2 via?
collarette
Iris sympathetic/parasympathetic supply?
sympatheic –> long ciliary neres
parasympathetic –> short ciliary nerves
Type of Collagen found in iris?
Type 1 and 3
• Ciliary body dis-insertion from scleral wall is called??
ciliary body cleft
• Pilocarpine lowers IOP via?
contraction of longitudinal muscles of ciliary body causes distrention of the inter and intra trabecular spaces of the trabecular meshwork and lowers IOP
• Rods to cone ratio?
20:1
Most retinal cell nuclei lay in what layer?
OUTER NUCLEAR LAYER
• Components of the blood retinal barrier
Outer BRB - tight junctions b/w ONL
Inner BRB - junctions b/w retinal vessel endothelium
What are the main collagen types in following tissue?
Sclera ———–
Lens capsule ———–
Vitreous ———–
Sclera ———– 1 and 3
Lens capsule ———– 4
Vitreous ———– 2
Where is the thinnest part of sclera? Why is it important?
Behind recti/EOM insertio. Forms a frequent site of scleral rupture following trauma
What is the blood supply of rectus muscles? Which one has
only one blood supply?
Anterior ciliary artery
The lateral rectus has one associated anterior ciliary artery
Refraction power (dioptre) of eye ------ lens ------ air-tear +43.6 D tear-cornea +5.3 D cornea-aqueous -5.8 D
eye —— 58 D
lens —— 15 - 18 D
Refractive index of lens ------ vitreous ------ air 1 tear 1.336 aqueous Humor 1.336 cornea 1.376
lens —— 1.406 (nucleus). 1.36 (cortex)
vitreous —— 1.33
Three layers of tear film?
Mucin
Aqueos
lipid
