Test 14 ( Modified MCQs from April, 2001 Exam.)

1. Latanoprost:

a. is a prostaglandin F2a analogue

b. decreases intraocular pressure by decreasing aqueous production

c. has a short half-life in the plasma making systemic side-effects uncommon

d. is associated with conjunctival hyperaemia

e. causes increased the number of iris melanocytes.

Answera.T   b.F   c.T   d.T   e.F
It decreases intraocular pressure by increasing uveoscleral outflow.
it has a half-life of 17 minutes in the plasma and therefore systemic side-effects are uncommon.
It increases iris pigmentation by increasing the melanin production. The number of melanocytes remains unaffected.
 

2. The intraocular pressure:

a. is at its peak usually at around mid-day

b. is at its lowest in the evening

c. is higher in winter than in summer

d. shows greater diurnal variation in the glaucomatous eyes than the healthy 
     eyes

e. is higher in patients with thicker cornea when measured with applanation 
    tonometer

Answera.T   b.F   c.T    d.T   e.T
The IOP is highest at midday and lowest early in the morning at around 3:00am.
Thicker cornea gives a higher reading when the IOP is measured with applanation tonometer.
 

3. The magnocellular pathway:

a. are found in layer 1 and 2 of the lateral geniculate body

b. contains mainly X cells

c. conveys movement

d. conveys depth perception

e. conveys colour

Answera.T   b.F   c.T   d.T   e.F
The pathway contains mainly Y cells.
It is concerned with movement, depth perception and high contrast targets

4. In Sitckler's syndrome:

a. is an autosomal recessive disorder

b. the patients have body habitat similar to that of Marfan's syndrome

c. myopia is common

d. is associated with neurosensory loss

e. is associated with multiple retinal breaks

Answera.F   b.T   c.T   d.T   e.T
It is an autsomal dominant condition.
It is associated with empty vitreous,, multiple retinal breaks, lattice degeneration, rhegmatogenous retinal detachement and myopia.
Systemic manifestations include mandibular and maxiallary hypoplasia, marfanoid habitat with arachnodactyly.

5. The following collagens are found in the corneal stroma:

a. collagen type I

b. collagen type II

c. collagen type III

d. collagen type IV

e. collagen type V

Answera.T   b.F   c.T   d.F   e.T
The cornea is made up mainly of collagen type I, the rest is composed of type III, V and VI.

 

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