Opthamalic

Question 1

The optokinetic response (OKR)

Answer 1

Using black and white stripes that rotate to find blind participants

Question 2

dry eye symptoms

Answer 2

-redness
-stigning
-burning or scratchy
stringy mucus

Question 3

causes of dry eye

Answer 3

reduced tears or composition
-turns into keratitis(chronic)
-treat with artificial tears

Question 4

Blepharitis symptoms

Answer 4

-inflammation of the eyelid
-discharge/crusting on lid margins/eyelashes
-strongly mucus

Question 5

Blepharitis causes

Answer 5

-staphylococcus infection
-treat with antibiotic and anti-inflammatory drug

Question 6

conjunctivitis symptoms

Answer 6

-pink discoloration
-burning or itching
-discharge

Question 7

Causes of conjuctivitis

Answer 7

-inflammation of the conjunctiva (bacterial or viral)
-allergic reaction
-reduce the course of infection or inflammation
-prevent spread

Question 8

Keratitis symptoms

Answer 8

-decreased vision
-ocular pain
-cloudy/opaque cornea

Question 9

causes of keratitis

Answer 9

-inflammation of cornea(bacterial, viral, or fungal
-treat with antibiotic and anti-inflammatory drug

Question 10

Glaucoma

Answer 10

-buildup of aqueous humor
-increases occular pressure
-eventually can cause blindness

Question 11

advantages of topical eye delivery

Answer 11

-easy access
-localized effect of drug action
-avoid first pass metabolism and systemic side effects

Question 12

Barriers to topical delivery

Answer 12

-efficient clearance mechanisms
-blood ocular barriers
-posterior eye diseases harder to treat

Question 13

goals of topical drug delivery

Answer 13

-target of site of action
-prolong residence time
-decrease frequency
-improve patient compliance

Question 14

barriers to topical drug delivery: cornea

Answer 14

-major barrier
-outermost layer
-70% of refractive power
-protects eyes from dust
-5 layers

Question 15

barriers to topical drug delivery: iris

Answer 15

-melanin binds drugs

Question 16

barriers to topical drug delivery: tear duct

Answer 16

-nasolacrimal clearence

Question 17

barriers to topical drug delivery: conjenctiva

Answer 17

-vascular
-increased clearance

Question 18

barriers to topical drug delivery: Ciliary body

Answer 18

-produce aqueous humor

Question 19

layers of cornea

Answer 19

-epithelium: barrier to hydrophilic drugs, tight junctions
-bowman’s layer
-stroma: barrier to lipophilic drugs
-Descemet’s membrane
-endothelium

Question 19

tear film

Answer 19

-lipid layer: protective
-aqueous layer: anti bacterial
-mucous layer: adherence
-corneal epithelia

Question 19

osmolarity and pH of saline

Answer 19

neutral

Question 20

nasolacrimal drainage

Answer 20

-drain from tear duct into nasal cavity
-when you blink, fluid forced nasally

Question 21

steps of nasolacrimal drainage

Answer 21

-inferior puncta
-lacrimal canaliculi
-lacrimal sac
-nasolacrimal duct
-nasal cavity

Question 22

aqueous humor

Answer 22

-secreted by ciliary body
-drained by trabecular meshwork and Schlemm’s canal
-removes metabolites like lactate
-200-300 microL
-maintains ocular pressure

Question 23

Vitreous humor

Answer 23

-hydrogel with fills cavity b/w lens and retina -high water content --no flow through vitreous, only diffusion

Question 24

The conjuctiva

Answer 24

-high vascular -goblet cells produce mucin -large SA is more permeable to drugs 0major route to enter circulation: major factor in pre-cornea drug loss

Question 25

Choroid

Answer 25

-highly vascularized -fenestrated capillaries

Question 26

Sclera

Answer 26

-outermost tunic of the eye -protects inner structures and cornea -made of collagen and proteoglycans in an extracellular matrix

Question 27

uptake and bioavailability: physiological factors

Answer 27

-tear film and nasolacrimal drainage -eyelid movements, blinking -protein binding -metabolism and efflux -conjunctival loss

Question 28

protein binding

Answer 28

-drug and protein binging can inactivate drugs -wait 5-10 mins if applying more than one eye drop

Question 29

metabolism

Answer 29

-lipophilic prodrugs to cross corneal epithelium -esterase and hydroxylases convert prodrug to active form

Question 30

Efflux

Answer 30

-drug transporters on corneal and conjunctival epithelia cells -amino acid and organic anion transporters may increase conc in the eye -efflux pumps