presbyopia_contact_lenses_flashcards

Question 1

What is presbyopia and when does it typically occur?

Answer 1

Presbyopia is impaired near vision due to diminished accommodation caused by the loss of elasticity in the crystalline lens. It typically occurs between ages 40-45.

Question 2

What are the CL options for presbyopia?

Answer 2

Distance lenses with reading add glasses, bifocal contact lenses, monovision contact lenses, and multifocal contact lenses.

Question 3

How do bifocal contact lenses work for presbyopia?

Answer 3

In bifocal contact lenses, the patient looks through the distance portion in primary gaze, and in down gaze, the lens is held up by the lower lid, allowing access to the near portion.

Question 4

How do monovision contact lenses work for presbyopia?

Answer 4

Monovision contact lenses work by fitting one eye with a distance Rx and the other with a near Rx, with the brain suppressing the eye that isn’t needed for the task.

Question 5

How do you fit monovision contact lenses?

Answer 5

The dominant eye is fitted with the distance Rx, and the non-dominant eye is fitted with the near Rx.

Question 6

What are the advantages of monovision contact lenses?

Answer 6

A wide range of lenses are available for different needs, and advanced wearers have good distance vision even in poor lighting.

Question 7

What are the disadvantages of monovision contact lenses?

Answer 7

Reduced binocularity, poor depth perception, slower focusing, and poor intermediate vision, especially with an add of +2.00D.

Question 8

Who are good candidates for monovision contact lenses?

Answer 8

Early presbyopes, patients with multiple pairs of glasses, and patients who haven’t adapted well to varifocal spectacles.

Question 9

Who are bad candidates for monovision contact lenses?

Answer 9

Monocular patients, patients with high levels of unequal visual acuity, patients with high expectations, or those needing fine detail and depth perception.

Question 10

How do multifocal contact lenses work?

Answer 10

Multifocal contact lenses have multiple concentric circles for different vision zones, allowing access to near, intermediate, and distance vision without changing focus.

Question 11

How do you fit Clariti 1-day monovision lenses?

Answer 11

Clariti 1-day lenses have four concentric circles (reading, reading-intermediate, intermediate-distance, distance) with low, medium, and high add options, the high add only fitted on the non-dominant eye.

Question 12

How do you fit Biofinity multifocal contact lenses?

Answer 12

Biofinity multifocals come in two designs: ‘centre distance’ and ‘centre near.’ Fit both eyes with centre distance for low adds or fit the dominant eye with centre distance and the non-dominant eye with centre near for higher adds.

Question 13

What are the advantages of multifocal contact lenses?

Answer 13

Multifocal lenses maintain binocularity and allow near, intermediate, and distance vision in the same lens.

Question 14

What are the disadvantages of multifocal contact lenses?

Answer 14

There is a period of adaptation required to get used to multifocal lenses.

Question 15

Who are good candidates for multifocal contact lenses?

Answer 15

Early presbyopes, monovision wearers, patients with multiple glasses, and those who haven’t adapted well to varifocal spectacles.

Question 16

Who are bad candidates for multifocal contact lenses?

Answer 16

Monocular patients, those with high expectations, and astigmats with more than 0.75DC as best vision sphere (BVS) might not be effective.

Question 17

What should a patient do after fitting multifocal contact lenses?

Answer 17

The patient should walk around for 20 minutes and then subjectively score their distance and near vision out of 10. If adjustments are needed, binocular flippers are used for over-refraction.

Question 18

How do multifocal GP contact lenses work?

Answer 18

Multifocal GP contact lenses create a positive tear lens at near by steepening the lens, allowing the patient to see at both near and distance.

Question 19

What are contraindications for RGP multifocal contact lens fit?

Answer 19

High riding lenses, over 2.00DC of astigmatism, or keratoconus, as they create an unstable platform resulting in unreliable vision and reading adds.

Question 20

What is the motor method for determining ocular dominance?

Answer 20

The motor method involves using a hand triangle and testing which eye less readily relinquishes fixation when binocular vision is stressed.

Question 21

What is the sensory method for determining ocular dominance?

Answer 21

In the sensory method, +1.00 blur is introduced to each eye in turn, and the patient is asked to rate comfort. The least comfortable eye when blurred is the dominant eye.