CPO CPO Ophthalmic Optics and Dispensing 2

Question 1

A patient with anisometropia of 2.50D complains of vertical double vision when reading through their new bifocals.
The prescription is OD: -1.00 SPH, OS: -3.50 SPH, with a reading depth of 10mm below the optical center.
To correct the vertical imbalance, what is the appropriate slab-off prism to order?

Accepted Answer

2.50Δ Base Up on the left lens (OS)

Answer

2.50Δ Base Up on the right lens (OD)

Answer

1.50Δ Base Down on the left lens (OS)

Answer

1.50Δ Base Up on the right lens (OD)

Question 2

A patient's prescription is +11.50 D sphere. The refraction was performed at a vertex distance of 10 mm, but the patient's chosen frame will sit at 15 mm from the cornea. What compensated power should be ordered to ensure the patient experiences the intended correction?

Accepted Answer

+10.94 D

Answer

+12.12 D

Answer

+11.50 D (no change needed)

Answer

+11.00 D

Question 3

A patient presents with new progressive lenses and complains that they must tilt their head down excessively to see clearly in the distance. The prescription and lens verification are accurate. Which of the following is the MOST likely fitting error?

Accepted Answer

The fitting height is too high.

Answer

The pantoscopic tilt is too great.

Answer

The fitting height is too low.

Answer

The pupillary distance (PD) is too narrow.

Question 4

Which of the following scenarios is the primary indication for prescribing iseikonic lenses?

Accepted Answer

A patient with significant anisometropia causing a perceived difference in image size between the two eyes.

Answer

A patient with high astigmatism causing meridional distortion.

Answer

A patient with presbyopia who cannot adapt to progressive addition lenses.

Answer

A patient with vertical heterophoria requiring slab-off prism.

Question 5

A patient wearing a new pair of high-wrap sunglasses with a prescription of -6.00 DS OU complains of peripheral distortion and a 'fishbowl' effect. The original refraction was performed in a standard phoropter. What position-of-wear parameter is most likely contributing to these complaints?

Accepted Answer

Uncompensated wrap angle

Answer

Incorrect monocular pupillary distances

Answer

Excessive retroscopic tilt

Answer

Insufficient B measurement of the frame

Question 6

A reverse slab-off is being ordered for a patient with anisometropia. On which lens is the base-down prism effect created?

Accepted Answer

The lens with the least minus or most plus power in the vertical meridian.

Answer

The lens with the most minus power in the vertical meridian.

Answer

The lens with the highest cylinder power.

Answer

Either lens, as it is determined by the lab.