NOCE Contact Lens Fitting and Dispensing 2

Question 1

During an RGP lens follow-up, a lens rides superiorly and shows temporal lag with each blink. What is the most likely cause?

Accepted Answer

The lens is fitted too flat

Answer

The lens is fitted too steeply

Answer

The lens diameter is too large

Answer

The lens power is incorrect

Question 2

What is the purpose of performing an 'over-refraction' during a contact lens fitting?

Accepted Answer

To refine the contact lens power while the lens is on the eye

Answer

To determine the patient's bifocal add power

Answer

To measure corneal curvature with the lens in place

Answer

To assess binocular vision balance

Question 3

A soft lens patient reports significant end-of-day dryness and discomfort. Which change would MOST likely improve comfort?

Accepted Answer

Switching to a silicone hydrogel lens material

Answer

Reducing the lens replacement frequency

Answer

Switching to a higher water content conventional hydrogel

Answer

Increasing daily wearing time gradually

Question 4

What does 'limbal clearance' refer to in the context of contact lens fitting?

Accepted Answer

The space between the lens edge and the corneal limbus

Answer

The clearance between the back lens surface and the corneal apex

Answer

The diameter of the lens optical zone

Answer

The amount of lens movement observed on blink

Question 5

For a patient with a spectacle prescription of -2.50 -1.50 x 180, which contact lens type would provide BEST visual correction?

Accepted Answer

Toric soft contact lens

Answer

Spherical soft lens at -2.50 D

Answer

Spherical soft lens at spherical equivalent (-3.25 D)

Answer

Monovision fitting with a spherical lens

Question 6

What is the primary purpose of sodium fluorescein dye when fitting RGP contact lenses?

Accepted Answer

To visualize the tear layer distribution beneath the lens

Answer

To disinfect the lens before insertion

Answer

To measure the optical power of the lens

Answer

To stain corneal abrasions exclusively

Question 7

What is the ideal movement of a correctly fitted soft contact lens following a blink?

Accepted Answer

0.5 to 1.0 mm of movement

Answer

No movement at all (0 mm)

Answer

2.0 to 3.0 mm of movement

Answer

More than 3.0 mm of movement