Opthalmic Flashcards
What are 4 different eye formulations?
- Eye drops/Solutions
- Eye ointments
- Eye Lotions
- Sub-conjunctival injection
What 2 drug classes are administered through sub-conjunctival injections?
- anti-infective drugs
- corticosteroids
What comprises the outer layer of the eye?
2 spheres: the cornea and sclera
How much of the outer layer does the cornea cover?
the transparent forward 1/6th
How much of the outer layer does the sclera cover?
the back 5/6th of the globe
What is the sclera made of?
tough fibrous (dense connective) tissue, forming the ‘white’ of the eye
What are the 2 functions of the slcera?
- Protects the eye from the internal and external forces
- Maintain its shape + intraocular pressure
The tough, fibrous nature of the sclera also protects the eye from serious damage such as rupture from external trauma
What structure is in front of the iris and pupil?
the cornea
What nerves densely innervate the cornea
sensory nerves
What are the 2 functions of the cornea?
- refracts + transmits light to lens + retina
- protection of eye against infection and structural damage to deeper parts
What is the conjunctiva and where is it found?
- thin, transparent mucous membrane
- Covers the visible part of the sclera
- Extends to the inside of the eyelids
Where does the optic nerve emerge from?
the sclera
What covers the cornea and conjunctiva surfaces?
a film of tears produced by lacrimal gland
lubricates the eye surface and protects it from chemicals, microbes, airborne solid particles
What are the 3 layers of the film of tears?
- Mucous layer
- Aqueous layer:
- Superficial lipid layer
What does the mucous layer of the film of tears do?
- interact with cornea’s epithelial cells
- each eye blink allows the spread of the tear film over the eye surface
What composes the aqueous layer of the film of tears? (6)
electrolytes, proteins, glycoproteins, biopolymers, glucose, urea
What composes the superficial lipid layer of the film of tears?
sterol esters, wax esters and fatty acids
Why is it said that there’s a dynamic equilibrium in the pre-corneal tear film?
because there’s a continuous cycle of production, evaporation, drainage
What are the three chambers of the eye?
Anterior , posterior and vitreous cavity
What fills the anterior & posterior chambers of the eye?
aqueous humour
What does aqueous humour look like? What’s it made of? What does it do?
- Clear, colourless, watery fluid
- Electrolytes, organic solutes, growth factors, other proteins
- feeds non-vascularised tissue of the anterior chamber
Through which chamber does aqueous humour leave?
the anterior chamber through conventional and unconventional pathways
How does glaucoma arise? (hint: aqueous humour exit)
- exit in anterior chamber is blocked (aq humour cant leave)
- fluid accumulates
- increased pressure
- glaucoma + damage to optic nerve
What percentage volume of the eye does vitreous cavity make up and what does it look like?
- 80%
- transparent, colourless, gelatinous