CL2: mid term misses

Question 1

Who produced the first powered contact lens

Answer 1

Muller

Question 2

Who introduced the first……..

Answer 2

Johnson and Johnson

Question 3

On the Efron Grading system what does Grade 2 represent?

Answer 3

Mild, Clinical action possibly required

Question 4

When doing overkeratometry: what does it mean when the mires are blurred before the blink, clear after the blink, start to blur 5 seconds after, and are blurred 10 seconds after?

Answer 4

fit too steep

Question 5

When fitting High DK material,l do you fit Steeper, on K, or Flatter?

Answer 5

Flatter

Question 6

Characteristics of a well fitting rigid gas permeable aspheric:

Answer 6

Blinking should create about 1 mm of lens lag.
Lateral eye movement should exhibit limbus-to-limbus movement of the lens.
The fluorescein layer should be even with some pooling at the periphery or in the area of any corneal astigmatism.
Visual acuity should be equal to or better than with spectacles.

Question 7

Diabetics:

Answer 7

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Question 8

When fitting CLs what is optional? VAs, Occupation, BuT, slit lamp exam, Keratometry, Patient History.

Answer 8

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Question 9

What is a common complaint of a person with 3 and 9 staining?

Answer 9

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Question 10

The four methods for increasing the sagittal depth of a rigid aspheric lens design are:

Answer 10

The posterior apical radius is made steeper and the eccentricity and diameter remain constant.
The diameter is made larger and the posterior apical radius and the eccentricity remain constant.
The eccentricity is made steeper and the posterior apical radius and the diameter remain constant.
The posterior apical radius and the eccentricity are made steeper and the diameter remains constant.

Question 11

Overrefraction determines the final lens power by ____ the overrefraction to the _________. No further calculations are necessary.

Answer 11

adding

Diagnostic lens power

Question 12

The base curve of a rigid lens would be purposely designed flatter or steeper than K in the case of a highly toric cornea or a completely spherical cornea. A lens would be fit flatter than K on a perfectly spherical cornea in order to facilitate an exchange of tear under the lens and avoid corneal disturbances. If the lens is fit on K, there will be no passage of tear from under the lens because the contours of the surfaces would be too close to each other.

Answer 12

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Question 13

The posterior apical radius remains constant and the diameter is increased.
The posterior apical radius is made flatter and the diameter remains constant.
The posterior apical radius is made flatter and the diameter is increased.

Answer 13

Three methods for increasing the edge lift of a rigid aspheric lens design follow:

Question 14

PAPB is a derivative of Chlorhexidine gluconate (CHG). It is 30 - 50 times more concentrated in rigid gas permeable lens solutions compared to soft lens solutions.

Answer 14

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Question 15

An auto immune response to the patient’s own proteins causes GPC. It is usually associated with soft contact lenses but can occur with rigid contact lenses.

Answer 15

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Question 16

Generally, the patient will not notice 3 & 9 o’clock staining as it is happening. The most common complaint of this condition is a feeling of over-all dryness or redness at the 3 & 9 o’clock positions.

Answer 16

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Question 17

Hypoxia causes corneal warpage or moulding, which results in spectacle blur.

Answer 17

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Question 18

Fluorosilicone acrylate (FSA) lenses are more prone to lipid deposits.

Answer 18

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Question 19

Silicone acrylateSA) lenses are more prone to silicone sicca, surface haze, and protein deposits.

Answer 19

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Question 20

Radial edge lift (REL) – the distance between the apex of the lens edge and the continuation of the base curve measured along the radius of the base curve.

Answer 20

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Question 21

Axial edge lift (AEL) – the distance between the apex of the lens edge and the continuation of the base curve measured parallel to the visual axis. This is the most commonly used specification when ordering lenses.

Answer 21

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Question 22

The tear layer under the lens corrects the corneal cylinder, but astigmatism of the surfaces inside the eye (likely the crystalline lens) contributes to the overall power and is left uncorrected by the contact lens. This type of astigmatism is referred to as residual astigmatism

Answer 22

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Question 23

With the rule astigmatism is minus cylinder axis @ 180 degrees. -1.00-1.00 x 180

Answer 23

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Question 24

Against the rule astigmatism is minus cylinder axis @ 090 degrees. -1.00-1.00 x 090

Answer 24

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Question 25

Lens adherence to the cornea is increased by making the following changes in lens design:
increasing negative power
increasing lens diameter
decreasing thickness
steepening the base curve

Answer 25

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