IOLs

Question 1

What are the three uses for IOLS?

Answer 1

• surgical solution for vision loss due to cataract formation
• continuous vision solution for presbyopia
• accommodating vision similar to the lens

Question 2

What size apertures do spherical lenses work well for?

Answer 2

Smalllllllll

Question 3

What do spherical lenses generate with large apertures?

Answer 3

Spherical aberrations

Question 4

Which rays focus first on spherical lenses?

Answer 4

Parasail rays (center)

Question 5

Aspherical lenses provide what?

Answer 5

Higher image quality with minimal spherical aberrations

Question 6

With increasing refractive power, what happens to the MTF of a perfect eye?

Answer 6

It increases at a certain spatial frequencies

Question 7

What happens to the resolution for lenses with aberration as you increase the power above a certain limit?

Answer 7

The modulation (resolution) decreases

Question 8

Symmetrical IOLs with a refractive index of 1.46 and a 3.0mm show perfect modulation at what power?

Answer 8

+15D

Question 9

For powers between 15 and 25D in IOLs, what happens to the modulation? What happens when they are more than 25?

Answer 9

• remain constant

- significant loss of modulation

Question 10

What are monofocal IOLs good for?

Answer 10

• distance vision correction

- verse high image quality

Question 11

What does the refractive index of monofocal IOLs need to be?

Answer 11

-above 1.406

Question 12

What is the equation you would use to determine the power of the IOL needed?

Answer 12

A-(2.5)(axial length)-(0.9)(keratometry reading)

Question 13

What does A stand for in the equation to figure out the power for an IOL?

Answer 13

It is a constant that reflects what the manufacturers have set for the IOL position

Question 14

For every 1mm difference in the measurement for axial length of the patient, there is a difference of how much in the power needed for the IOL?

Answer 14

2.5D

HELLA SIGNIFICANT

Question 15

Do monofocal lenses provide “spectacle independence”?

Answer 15

Nope. They do not help near vision, just distance

Question 16

The base power of the IOL is found in what part of the lens?

Answer 16

The nucleus! The fresnel gives you add

Question 17

For bifocal lenses, the central zone has what kind of design? The peripheral zone has what kind?

Answer 17

Central: diffractive design
Peripheral: refractive design

Question 18

Why do bifocal IOLs act as monofocal IOLs in mesopic and scotopic conditions? (At night)

Answer 18

-the pupil gets larger and there is not sufficient energy for diffractive zones

Question 19

Will bifocal lenses ever give you 20/20 vision at near?

Answer 19

Hell no

Question 20

Trifocals IOLs provide what kind of correction?

Answer 20

-distance, intermediate, and near vision

Question 21

If you want a freaking good image quality, what kind of IOL should you have?

Answer 21

Monofocal only

Question 22

Multifocal IOLs claim to provide __________________, but at what cost?

Answer 22

• claim to provide decent continuous vision
• low quality image, unwanted phenomenon like glare and halos
• they have minimal success!

Question 23

The extended range of vision IOL is also called what?

Answer 23

Extended depth of focus IOL

Question 24

What do extended range of vision IOLs claim?

Answer 24

To provide continuous vision AND minimize unwanted phenomena like glare and halo and star burst

Question 25

How do EDF IOLs do what they do?

Answer 25

• extend your depth of focus by adding and subtracting power to find your max vision and extending it a longer distance
• it gives you a U curve to find your true focus

Question 26

What is the holy grail of IOL?

Answer 26

Accommodative IOL

Question 27

What does the accommodative IOL do?

Answer 27

• mimics the natural lens behavior

- provides additional 1D of vision compared to monofocal lens

Question 28

Are is the accommodative IOL actually accommodative?

Answer 28

No, sucks

-it provides the change in location, but it does not change shape or power, so it cannot be considered accommodative

Question 29

What is the challenge with wanting to have a smaller incision for IOLs?

Answer 29

Under 2mm is goals, but you would need a lens that would be able to fold

Question 30

What is PCO?

Answer 30

Posterior capsule opacification

-there is lens epithelial growth

Question 31

What are the components that lead to lens epithelial growth?

Answer 31

• lens material

- lens edge

Question 32

What are the problems associated with PCO and what is the treatment?

Answer 32

• decreased VA
• impaired contrast sensitivity
• glare disability

-YAG laser capsulotomy