NOCE Contact Lens Fitting and Dispensing

Question 1

In RGP contact lens fitting, a fluorescein pattern showing central touch (dark area centrally) with excessive edge lift indicates:

Accepted Answer

A flat lens fit

Answer

An optimal alignment fit

Answer

A steep lens fit

Answer

Adequate corneal clearance

Question 2

When initially selecting a base curve for a soft contact lens, which measurement is most commonly used as the starting point?

Accepted Answer

The average of both K readings

Answer

The steeper K reading only

Answer

The flatter K reading only

Answer

The vertex distance measurement

Question 3

A patient's spectacle prescription is -4.50 DS with a vertex distance of 12mm. What contact lens power would you expect to order?

Accepted Answer

-4.25 DS

Answer

-4.50 DS

Answer

-4.75 DS

Answer

-5.00 DS

Question 4

Which lens parameter describes the peripheral edge design and tear exchange area of a rigid gas permeable contact lens?

Accepted Answer

Peripheral curve radius

Answer

Optical zone diameter

Answer

Base curve radius

Answer

Center thickness

Question 5

What is the minimum oxygen transmissibility (Dk/t) recommended for daily wear soft contact lenses to prevent corneal hypoxia?

Accepted Answer

24 × 10⁻⁹

Answer

87 × 10⁻⁹

Answer

125 × 10⁻⁹

Answer

150 × 10⁻⁹

Question 6

When fitting a toric soft contact lens, which factor is MOST critical for achieving adequate visual correction?

Accepted Answer

Axis alignment and rotational stability

Answer

Base curve radius selection

Answer

Overall diameter

Answer

Oxygen permeability of the material

Question 7

A patient with keratoconus needs contact lens correction. Which lens type is MOST appropriate for this condition?

Accepted Answer

RGP lenses or specialty designs such as scleral lenses

Answer

Standard spherical soft lenses

Answer

Daily disposable soft lenses

Answer

Extended wear silicone hydrogel lenses