Test 167  (Ocular anatomy )

1. Ora serrata:

a. forms the boundary between the retina and the 
    ciliary body

b. is closer to the Schwalbe's line temporally than nasally

c. forms part of the pars plana

d. does not contain photoreceptors

e. is loosely adherent to the vitreous
 

Answera.F   b.T  c.F   d.F  e.F
Ora serrata forms the boundary between the retina 
and the pars plana. It contains photoreceptors which 
are usually malformed. Vitreous is attached firmly to ora serrata and forms the vitreous base.
 
 

2. Vitreous:

a. is acellular in normal eye 

b. is about 4.0 ml in normal adult

c. contains mainly type II collagens

d. contains a lower concentration of hyaluronan and 
    collagen in high myopia than the normal population

e. inhibits angiogenesis
 

Answera.F  b.T  c.T  d.T  e.T
Cells can be seen in vitreous in normal eye.
 
 

3. Lutein:

a. is a carotenoid

b. is an antioxidant

c. is concentrated in fovea

d. is found within the retina pigment epithelium

e. gives the macula a yellow colour
 

Answer
a.T   b.T  c.F   d.F  e.T
Lutein and zeaxanthin are carotenoid (s). 
Lutein is dispersed throughout the retina and is not found within retina pigment epithelium

 

. 4. Zeaxanthin: 

a. is concentrated in the fovea

b. is found within the retina pigment epithelium

c. is similar in molecular weight to lutein

d. has equal distribution in rods and cones

e. reduces the incidence of exudative age-related macular 
    degeneration 
 

Answer
a.T  b.F  c.T  d.F  e.T
Zeaxanthin is concentrated in fovea and found in a higher concentration within the cones than rods. 
Eye Disease Case-Control Study (EDC CS ) Group: Risk factors for neovascular age-related macular degeneration. found that patient with a high serum level of carotenoids including lutein and zeaxanthin are associated with a lower incidence of exudative macular degeneration
.

5. The lens capsule:

a. is the basement membrane of lens epithelium

b. is made up mainly of type IV collagen

c. is impermeable to proteins

d. becomes thinner with age

e. is five times thicker thicker anteriorly than posteriorly in an adult lens
 

Answer
a.T   b.T  c.F  d.F  e.T
The lens capsule is not barrier to ions, water or small molecules of proteins. It is secreted throughout life by the lens epithelium and therefore becomes thicker with age. 

 

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