Contact Lens 2013 Exam 1

Front 1

T or F: Scleral lenses are good for irregular astigmatism

Back 1

T (ex: keratoconus and the like, post-refractive sx errors)

Front 2

What is the goal for scleral lenses in terms of corneal vaulting?

1. what area of the lens sets the SAG height?
2. what is the area of the lens called that rests on the cornea?

Back 2

300 microns (range is 100-600 microns)

1. transition zone (mid-peripheral/limbal zone)
2. landing zone (scleral/haptic zone)

Front 3

T or F:

1. a small scleral lens provides better VA
2. a large scleral lens is easier to handle
3. you get more decentration with a larger diameter scleral

Back 3

1. T
2. F
3. T

Front 4

How many microns is the cornea? A scleral lens?

Back 4

cornea= 530
lens= 200-300

Front 5

Vessel blanching vs. conjunctival impingement:

1. may cause conj staining after removal
2. rebound hyperemia at the location of compression may be seen
3. conj hypertrophy may be seen after long-term occurrence

Back 5

1. conj impingement
2. vessel blanching
3. conj impingement

Front 6

Leaving as much conditioning solution as possible on a scleral lens before filling with saline will prevent __________.

Back 6

poor wetting

Front 7

T or F: scleral lenses are supposed to have their landing zone bear on the cornea/limbus to prevent bulbar injection

Back 7

F!!! this causes bulbar injection

Extra credit: what else could cause bulber injection?

hypoxia, toxic rxn to solution

Front 8

What could cause corneal staining from wearing scleral lenses?

Back 8

corneal hypoxia and toxic rxn to solution

Front 9

How do you solve compression (ex: conj impingement) from a scleral lens?

Back 9

1. increase diameter
2. flatten the landing zone

both disperse the pressure of the lens on the eye

Front 10

T or F: the same amount of movement is desired with scleral lenses as silicone hydrogel lenses

Back 10

F! no movement is desired (a little is fine)

Front 11

What are the two indications listed for the Boston Scleral Lens Prosthetic Device? What is the contraindication?

Back 11

indications: severe ocular surface disease and masking corneal astig that is inadequately correct with other means.

contraindication: inadequate endothelial function (including pre-existing microcystic edema and failing grafts)

Front 12

Reasons to use a tinted prosthetic lens include enhancement of __________ and/or alteration of ________ __________.

Back 12

cosmesis; light absorption

Front 13

In a functional eye with aniridia, you would give them a prosthetic lens with underprint and a black pupil to prevent photophobia.

Back 13

Do not give a black pupil to a functional eye

(this is the only thing that I'm getting from this lecture...what else do we need to know? just that underprint is for photophobic patients?)

Front 14

Which tinted prosthetic lens company has customizable lens colors as well as the ability to add underprint?

Back 14

Adventures in Color

Front 15

Toric RGPs:

remember that the ____ BCR will align with the flat merdian of the eye and that the more/less minus lens power will be assoc with the flat meridian

Back 15

flat; less

Front 16

Toric RGPs: let's say that you get a sphero-cylindrical over-refraction on your patient who complained of blurry vision. when you order a new lens, what must you know about how that lens fits on the eye?

Back 16

you have to know how the lens orients on the eye

TQ: expect front toric/back sph

Front 17

Toric RGPs have a higher/lower Dk than hydrogel toric lenses.

Back 17

higher (a benefit of using them)

Front 18

What is the ratio for:

1.SPE bitoric
2. CPE bitoric
3. back toric

Back 18

1. 1:1
2. neither 1:1 or 1:1.4
3. 1.4 (1.5 for pmma but that's not used)

Front 19

Smaller/larger lenses recommended for a saddle fit.

Back 19

smaller (because these lenses fit tighter)

Front 20

Saddle fit lenses are best used on lower/higher toricity corneas.

Back 20

lower

Front 21

___ ____ corneal toricity is a highly desirable fitting relationship

Back 21

Low WTR (centers well with improved tear exchange)

Front 22

When ordering front toric/back sphere RGPs, what do you ALWAYS have to do regarding alignment on the eye?

Back 22

order as if the lens will rotate nasally 10-15 degrees!

Front 23

Recite the quinn low toric simulation nomogram

Back 23

see paper

Front 24

How much prism is reasonable for use in prism ballast front toric lenses?

Back 24

.75-1.5

Front 25

_______________: recommended when patients have lower lids at or below the limbus, the patient has a larger aperture with loose lids, or there is discomfort with the other method of stabilization

Back 25

prism ballast

Front 26

T or F: truncation will not help stabilize a lens in a patient with a low-lying lid

Back 26

T

Front 27

T or F: Front toric lenses usually provide better vision than soft toric lenses

Back 27

FFF!!!

Front 28

T or F: avoid soft lenses for irregular corneas

Back 28

T (clinical prof check list)

Front 29

_____________ are appropriate when soft lenses are not optimal and corneal cylinder ≥ 3.00 D

Back 29

Bitoric lenses (clinical prof check list)

Front 30

What are the RGP aspheric MFs?

Back 30

Reclaim HD and Renovation

Front 31

The lenses in the STAPLE workshop (presbyopic hydrogels) were what kind of design?

Back 31

aspheric

concentric/annular is other kind

Front 32

What is the segmented RGP MF?

Back 32

XCEL Solutions (translating lens)

Front 33

Where do you want the seg on a segmented translating GP lens?

Back 33

you want the top of the seg in the lower pupil

Front 34

T or F: computer users would do better with a simultaneous GP rather than an alternating GP

Back 34

T

Front 35

With a soft MF, large/small pupils are a problem.

Back 35

large (and poor lighting)

Front 36

T or F: with BOTH RGPs and hydrogel lenses, lower adds as well as higher sphere powers (>= +/-1.00D) are better prognostic factors

Back 36

T

Front 37

A critical observer will do better with an alternating or simultanous design? (all other factors aside)

A person with a large pupil will do better with alternating or simultaneous?

Back 37

alternating

alternating

Front 38

The lower lid positioned ___ or ___ the limbus is critical for alternating lenses.

Back 38

near to or above

Front 39

What two types of lenses must be truncated or weighted with prism?

Back 39

RGP segmented BFs and front toric RGPs

Front 40

Problem solving for translating lenses:

1. excessive rotation?
2. lens positions superiorly?
3. poor translation?
4. seg height incorrect?

Back 40

1. flatter BCR by 0.50D
2. increase prism by 0.50D
3. flatten BCR
4. change prism, seg height, BCR or truncation

Front 41

The hybrid lenses have a ___ center and ___ surround.

Back 41

near; distance

Front 42

The RGP aspheric MFs fit slightly ____ than typical RGPs, so expect final Rx to be around _____ more.

Back 42

steeper; -0.50D

Front 43

When a spherical lens will correct the astigmatism but physically won't fit well, use a ___________.

Back 43

SPE bitoric (got this from the internet but it makes sense)