Fortnightly Quiz 9

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Question 1 of 20

With regard to contact lenses which is FALSE:

  • A they are usually tinted to make them more visible for handling
  • B piggyback contact lens involves the use of two soft contact lenses one above the other
  • C tear lens can neutralize astigmatism
  • D truncation of a contact lens is used to prevent lens rotation

Question 2 of 20

The disinfection system least likely to produce an adverse reaction in the eye related to contact lens is:

  • A heat
  • B chlorine based
  • C polyquad
  • D hydrogen peroxide

Question 3 of 20

The resistance to microbial infection of the cornea is reduced in contact lens wear by all of the following EXCEPT:

  • A epithelial fragility
  • B relative hypoxia
  • C reduced sensitivity
  • D epithelial microcyst

Question 4 of 20

Which one of the following is the most frequently found gram negative bacteria associated with keratitis in contact lens wearers:

  • A pseudomonas aeruginosa
  • B serratia species
  • C proteus species
  • D candida albicans

Question 5 of 20

Contact lens wear has the following effect on tears:

  • A decreases evaporation
  • B increases viscosity
  • C increases evaporation
  • D decreases viscosity

Question 6 of 20

The telescope that provides an erect image is

  • A Dutch telescope
  • B Keplerian telescope
  • C Astronomical telescope
  • D both B and C

Question 7 of 20

What is the tube length of telescope when the ocular lens is -75.00 D and objective lens is +30.00D?

  • A 1.33 cm
  • B 2.00 cm
  • C 3.33 cm
  • D 4.00 cm

Question 8 of 20

What is the dioptric power of ocular lens of a telescope when its tube length is 3.00 cm and objective lens is +25.00D?

  • A -100.00D
  • B Plus 100 D
  • C -50.00D
  • D Plus 50D

Question 9 of 20

Which of the following telescope has the largest exit pupil

  • A 7x50
  • B 8x30
  • C 10x20
  • D 10x40

Question 10 of 20

A patient pupil size is 8 mm. Under normal lightning patient experiment through the four telescope by seeing any objects as suggested by the practitioner. Which telescope will appear to be the least brightest

  • A 7x50
  • B 8x30
  • C 10x20
  • D 10x40

Question 11 of 20

A patient in advanced stages of retinitis pigmentosa attempts to read with microscopic lens but he complains that he is able to see only two or three letters at a time. What other device may be recommended so that he can see more letters at a time with same size print?

  • A CCTV
  • B handheld magnifier
  • C stand magnifier
  • D all of the above

Question 12 of 20

A patient wears aspheric bifocal contact lenses in both eyes. All of the following could be expected with these lenses EXCEPT:

  • A multiple images
  • B difficulty in dim light
  • C glare with headlights
  • D different image sizes between the eyes

Question 13 of 20

Which of the following statement regarding refraction is correct

  • A A light ray refracted by a glass plate emerges parallel and is laterally displaced
  • B The Helmholtz keratometer not using two rotating glass plate to produce a double image
  • C During instrumentation of the anterior chamber objects appear deeper than they really are.
  • D The surface power of an optical interface is independent of its radius of curvature

Question 14 of 20

Which of the following statement concerning ocular resolution is correct

  • A Diameter of cone is 10.5┬Ám
  • B Wave theory assumes light to be composed of individual quanta
  • C Image formed from a point source of light is in the form of Airy disc
  • D Vernier acuity measurement has a greater angle of resolution than that detected by Snellen acuity.

Question 15 of 20

Which of the following statement about Stile- Crawford effect is correct

  • A It reduces the effect of chromatic aberration
  • B It may be important in the pathogenesis of amblyopia
  • C Monochromatic light not changing its subjective hue
  • D Rods and cones are more sensitive to paraxial light.

Question 16 of 20

Which of the following statement concerning Purkinje shift is correct

  • A It refers to patient visualization of retinal blood vessel when the eye is illuminated.
  • B During photopic condition the eye is most sensitive to violet light at 590 nm.
  • C It is the change of peak sensitivity of retina under photopic and scotopic condition
  • D During photopic condition the eye is most sensitive to red light at 590 nm.

Question 17 of 20

An emmetropic patient has amplitude of accommodation of 1.50D measured using the RAF rule. The patient works for 6 hours each day at computer screen at a distance of 50 cm and views reading material at a distance of 33 cm. Which of the following statement is correct?

  • A This patient is likely to be about 45 years old in light of the accommodative amplitude.
  • B For viewing the computer screen no lens will be required in theory.
  • C For viewing reading material a reading addition not required.
  • D Bifocals of power + 1.25 DS with an addition of +1DS would theoretically suit this patient if he wished to have only one pair of glasses.

Question 18 of 20

If a 6 year old patient has manifest squint measuring 20 PD esotropia:

  • A One eye should be occluded during retinoscopy.
  • B Mydriatric drug is enough to obtain the most accurate objective result.
  • C The minimum plus power that gives good distance VA should be prescribed.
  • D Pinhole test cannot usually be performed with a child of this age.

Question 19 of 20

A 52 year old computer operator is -1.00DS myopic. His accommodative amplitude is 2D. Which of the following prescription is appropriate for this patient:

  • A Bifocals -1.00DS with a +3.00DS addition for reading at 33 cm.
  • B Single vision lenses + 2.50DS for reading at 33 c m.
  • C Single vision lens +2.00DS for reading a computer screen at 50 cm.
  • D Bifocals Plano with a +1.00DS addition for reading a computer screen at 50 cm and reading at 33 cm.

Question 20 of 20

An object is 12.5 cm from a +3 D lens that is 10 cm from a plane mirror. How far apart is the image and object?

  • A 187.5 cm
  • B 100 cm
  • C 52.5 cm
  • D 22.5 cm