Optimology

Question 1

Orbit

Answer 1

Bony socket containing eye

Question 2

Osmolality

Answer 2

The concentration of particles dissolved in a fluid.

Question 3

Role of the orbit

Answer 3

protect the delicat eye

provide mounting point for six striatal muscle that control ocular movement

Question 4

what is the aqueous humour

Answer 4

transparent viscous fluid in the anterior chamber of the eye

Question 5

what is the function of the aqeuous humour

Answer 5

maintains intraocular pressure and inflates the globe

provides nutrition for the avascular ocular tissues e.g. lens

transports ascorbate in the anterior segment acting as an antioxidant agent

light refraction

Question 6

what is the role of the lens

Answer 6

helps to refract light to be focused onto the retina

elastic so can change shaped getting thicker to focus on close objects and thinner for distant object

Question 7

what is the lens comprised of

Answer 7

lens capsule
lens epithelium
lens fibres

Question 8

what is the vitreous humour

Answer 8

clear gell filling space between lens and retina

Question 9

what is the role of the vitreous humour

Answer 9

anatomic expansion of the globe

impedes diffusion of substances between retina and anterior segment of eye.

reservoir of substances e.g. oxygen, glucose and ascorbic acid. Which support metabolism.

Question 10

What does optic nerve link too

Answer 10

optic chiasma.

Question 11

describe the structure of the cornea

Answer 11

the epithelium and bowmans capsule form the upper 2 layers which are lipophillic

the stroma acts as the hydrophillic region with the descemets membrane and endothelium sitting underneath.

Question 12

What are barriers to drug delivery in the eye (5) (P R A D B)

Answer 12

poor permeability of the cornea

tear reflex

non corneal absorption

nasolacrimal drainage

blinking

Question 13

describe how the cornea is impermeable

Answer 13

hydrophobic epithelium making it hard for hydrophillic drugs to cross

hydrophillic tissues making it for hydrophobic drugs to cross. (Stroma)

Question 14

what is non corneal absorption

Answer 14

penetration across conjunctiva and underlying sclera into vitreous humour

Question 15

4 methods of optimising drug delivery

(PICV)

Answer 15

proper placements of the eyedrops

reduced instilled volume of eye drop

modify integrity of corneal epithelium

modify chemical structure of drug i.e. prodrug approach

Question 16

what is lantoprost used for

Answer 16

therapy for glaucoma, administered to control progression of glaucoma or ocular hypertension reducing intraoccular pressure. It has to be hydrolysed by esterases.

Question 17

what are the approaches to improve precorneal retention

Answer 17

viscous systems
mucoadhesives
phase transition systems
changes in ph
changes in temp
changes in ion composition