CPOA Contact Lens Basics 5

Question 1

Which type of contact lens is specifically designed to vault over the entire cornea and rest on the sclera?

Accepted Answer

Scleral lens

Answer

Scleral lenses have large diameters (16–24 mm) that vault completely over the cornea and land on the scleral tissue, making them ideal for irregular corneas.

Question 2

Contact lens-induced acute red eye (CLARE) is most often associated with which lens wear pattern?

Accepted Answer

Overnight or extended wear of contact lenses

Answer

CLARE typically occurs upon waking after sleeping in contact lenses due to hypoxia and bacterial toxin accumulation under the lens.

Question 3

What is the purpose of using fluorescein dye during an RGP contact lens fitting?

Accepted Answer

To assess the fitting relationship between the lens and cornea

Answer

Fluorescein pools in the tear layer under the RGP lens and glows under cobalt blue light, revealing the fit pattern (bearing, clearance, alignment).

Question 4

Which statement is correct regarding silicone hydrogel contact lens materials compared to conventional hydrogel materials?

Accepted Answer

They have higher oxygen permeability

Answer

Silicone hydrogel materials transmit significantly more oxygen to the cornea than conventional hydrogel materials, reducing hypoxia-related complications.

Question 5

A patient's contact lens prescription specifies 'BC 8.6 / D 14.2 / -3.00 SPH.' What does 'SPH' indicate?

Accepted Answer

The lens is a spherical design with no cylinder correction

Answer

SPH (sphere) indicates this is a spherical lens without astigmatism correction, meaning no cylinder or axis is present.

(CPOA) Certified Paraoptometric Assistant Practice Test

(CPOA) Certified Paraoptometric Assistant Practice Test

CPOA Contact Lens Basics 5