CPOT CPOT Optical Dispensing & Lens Technology

Question 1

Which lens material has the highest Abbe value, indicating the least chromatic aberration?

Accepted Answer

CR-39 plastic

Answer

CR-39 plastic has an Abbe value of approximately 58, the highest among common ophthalmic lens materials, resulting in the least color fringing.

Question 2

A lens prescription written as -2.00 -1.50 × 090 indicates:

Accepted Answer

Myopia with astigmatism, axis at 90 degrees

Answer

A minus sphere power indicates myopia, the minus cylinder corrects astigmatism, and the axis of 090° specifies the orientation of the cylinder.

Question 3

Pupillary distance (PD) is measured to ensure that the optical centers of the lenses align with the:

Accepted Answer

Center of each pupil

Answer

PD measurement centers the optical zones of the lenses over each pupil to minimize induced prism and provide optimal visual comfort.

Question 4

Antireflective (AR) coating on ophthalmic lenses primarily works by:

Accepted Answer

Using thin-film interference to cancel reflected light

Answer

AR coatings use multiple thin layers that create destructive interference, canceling reflected light and increasing light transmission to the eye.

Question 5

Which type of lens is recommended for patients who need correction for distance, intermediate, and near vision in a single lens without visible lines?

Accepted Answer

Progressive addition lens (PAL)

Answer

Progressive addition lenses provide a smooth, gradual power change from distance at the top to near at the bottom, with no visible segment lines.

CPOT - Certified Paraoptometric Technician Practice Test

CPOT - Certified Paraoptometric Technician Practice Test

CPOT CPOT Optical Dispensing & Lens Technology