Hosam Mohamed-
a
The protective outer layer of the eye, referred to as the “white of the eye”.
It maintains the shape of the eye.
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
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b
The second layer of the eye; contains blood vessels that provide nourishment to the outer layers of the retina.
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
-
c
The innermost layer in the eye; converts images into electrical impulses that are sent along the optic nerve to the brain.
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
-
d
Located in the back of the eye, in the center of the retina. This area produces the sharpest vision.
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
-
e
The front portion of the sclera, is transparent and allows light to enter the eye
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
-
f
-The part of the eye that gives it color. It consists of muscular tissue that responds to surrounding light, making the pupil, or circular opening in the center of the iris, larger or smaller
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
-
g
-Transparent, biconvex structure, composed of tightly packed protein; its function is to refract and focus incoming light onto the retina.
a) sclera
b) choroid
c) retina
d) macula
e) cornea
f) iris
g) lens
-
anterior chamber
-smaller section in front of the lens
-contains clear, water like material called aqueous humor.
-
posterior chamber
-larger section in back of eye
-filled with colorless gelatinous mass called vitreous humor.
-
conjunctiva
-continuous anterior surface tissue which covers the inside surface of the upper and lower eyelids and the outside surface of the sclera except for the cornea
-
cornea, ciliary body, iris, lens
The anterior chamber consists of 4 parts, they are:
-
a
Which portion of the cornea consists of tight junctions?
a) bowman membrane
b) stroma
c) descemet's membrane
-
b
Which portion of the cornea consists of hydrated collagen & hydrophilic tissue?
a) bowman membrane
b) stroma
c) descemet's membrane
-
a,c
Which portion of the cornea consists of lipophilic tissue?
a) bowman membrane
b) stroma
c) descemet's membrane
-
ciliary body
-produces aqueous humor
-
sclera; choroid
The _______ is avascular while the _______ is vascular.
-
corneal; conjunctiva
________ absorption is more effective than _______.
-
blood-retina barrier, choroid's high blood flow, contains retinal pigment epithelium, intravitreal injcetion is invasive
What makes posterior chamber delivery so difficult? (4)
-
corneal epithelium; corneal stroma
________ favors lipophilic drugs while _______ favors hydrophilic drugs.
-
lysozyme; esterase
Drugs are metabolized by _______ in tears & metabolized by ________ in stroma.
-
tight intercellular junctions
Corneal epithelium has _____________ between cells.
-
passive diffusion
How does drug move through the eye?
-
1st
Ocular drug distribution exhibits ________ order kinetics.
-
low bioavailability, short contact time, inconsistent delivery, instable, preservatives
What are disadvantages associated with topical solutions & suspensions? (5)
-
True
Long term preservative use can injure corneal epithelium. T/F?
-
false
Buffers should be highly buffered in aqueous topical products. T/F?
-
antioxidants, sodium bisulfite, chelating agents
What are examples of stabilizing agents? (3)
-
viscosity agents
-increase contact time & bioavailability ; reduce surface tension and drainage rate.
-
surfactants
-aid in drug solubility & drug penetration of tissues.
-
Non-ionic
_________ surfactants are preferred.
-
in situ pseudoplastic gels
-instilled as drops into the eye and undergo a sol-to-gel transition in the tear film
-
o/w
What type of emulsions are preferred for opthalmic delivery?
-
false
Ophthalmic emulsions are used for drugs with high aqueous solubility. T/F?
-
erodible
-collagen shield
-bioerodible polymers
-insert between lower lid of eye
-
nonerodable
-reservoir or matrix structure
-release drug for longer periods of time
-insert between lower lid of eye
-
posterior segment
Where are ophthalmic implants placed?
-
a
Injected into aqueous humor and used for cataract surgery.
a) intracameral
b) intravitreal
c) subconjunctival
d) retrobulbar
e) peribulbar
-
b
Used to treat macular edema, diabetic retinopathy, infections.
a) intracameral
b) intravitreal
c) subconjunctival
d) retrobulbar
e) peribulbar
-
b,d
Periocular injections must diffuse through _____ & _____.
a) macula
b) sclera
c) retina
d) choroid
-
c
Contains a high tissue concentration and is for drugs poorly penetrating the epithelium.
a) intracameral
b) intravitreal
c) subconjunctival
d) retrobulbar
e) peribulbar
-
d
Injection primarily used for anesthesia.
a) intracameral
b) intravitreal
c) subconjunctival
d) retrobulbar
e) peribulbar
