O.o. Final

Front 1

Which lenses do the multifocals come in simultaneous AND alternating vision?

Back 1

Rigid

Front 2

With contacts, the b.c. Is always on the _____ surface

Back 2

Back

Front 3

What are the two advantages of hydrogel lenses?

Two disadvantages?

Back 3

Initially more comfy and easier to fit

Vision may not be as good as with rigid and greater incidence of microbial keratitis

Front 4

What are the three advantages of rigid lenses?

Two disadvantages?

Back 4

Better vision than hydrogel, lower incidence of microbial keratitis and greater durability

Initially not as comfy and more skill required for fitting

Front 5

Which lens conforms to the corneal topography?

Back 5

Hydrogel lenses

Front 6

Indications for either hydro or rigid:

1. If patient has manifest astigmatism or irregular astigmatism?
2. Pt is in dusty environment?
3. Pt is in dry environment?
4. Pt has hx of microbial keratitis?

Back 6

1. Rigid (hydro for NO manifest!)
2. Hydrogel
3. Rigid
4. Rigid

Front 7

T or F: if a patient wearing rigid lenses has residual astigmatism, the only other option is to wear glasses.

Back 7

F....this is an indication for hydrogel contacts

Front 8

T or F: if a patient can't adapt to rigid lenses, they probably won't adapt to soft either.

Back 8

F. This is an indication to wear soft.

Front 9

Contact lenses are thin/thick lenses. Spectacles are thin/thick lenses.

Back 9

Thick; thin

Front 10

Why are contacts considered thick lenses? What equation won't work with them?

Back 10

Bc they're so steeply curved relative to their size...approx power won't work

Front 11

A myope's contact lens Rx will be more or less than the spec Rx? What property tells us this?

Back 11

Less....effective power

Front 12

T or f: a myope will have a larger retinal image size with contacts compared to specs, and the hyperope will have the small image size.

Back 12

T

Front 13

With spectacles on, who has the least accomm demand? Most?(choices: emmetrope, myope, hyperope)

Back 13

Myope; hyperope

Front 14

If you prescribe a ____ contact lenses when they are just becoming presbyopic, you will push the over the edge due to the increased accomm demand with contacts over spectacles.

Back 14

Myope

Front 15

What two types of people will become symptomatic when going from spectacles to contact lenses due to accommodative convergence issues? What do they have to use to compensate for this?

Back 15

The esophoric myope has to use NFV (too much convergence)

The exophoric hyperope has to use PFV (too little accomm convergence)

Front 16

What type of myope would be at a disadvantage on going from specs to CLs due to prism changes?

Back 16

Exophoric myope since you're taking away their BI prism

Front 17

T or f: the keratometer only tells us about the central 3mm of our corneas.

Back 17

T

Front 18

The keratometer treats the cornea as a ____ mirror. It determines the radius by measuring the ______ reflected by the cornea of a known ______.

Back 18

Convex; image size; object size

Front 19

What the number one importance of choosing a b.c.?

Back 19

Physiological, fitting and comfort considerations

Front 20

The keratometer approximates the _____ power of the cornea (front, back, total?)

Back 20

total

Front 21

what's the index of the cornea? what's the index of the keratometer? why?

Back 21

1.376; 1.3375 (closer to tears...the keratometer measures refraction taking place at the air/tear interface; also, takes into the account the negative power from the back of the cornea)

Front 22

what's the equation for back vertex power?

Back 22

Fv= F1 / (1-t/n(F1)) + F2

Front 23

Whats the equation for effective power of a contact lens?

when do you use this?

Back 23

Fcl= Fspec / (1-d(Fspec) where d is different depending on going from CLs specs and vice versa

powers > or = 4.00

Front 24

For a steeper than K fit, what is steeper than K?

Back 24

base curve (but radius of curvature SHORTER for a STK fit and vice versa)

Front 25

What type of contact lenses is this true: all refractive astigmatism will be residual astigmatism

Back 25

soft spherical CLs

Front 26

Toric soft lenses are used when the total astigmatism is greater than what?

When it's under this number and we use spherical soft CLs, what else do we have to do to the Rx?

Back 26

0.75D

use the spherical equivalent!

Front 27

T or F: soft toric lenses are preferrable to rigid when TA does not equal CA

Back 27

T

Front 28

When a lens rotates on the eye, we usually see what type of movement? How do we compensate for this?

Back 28

nasal kick;

LARS (from the examiner's POV and always measure from the 6 o'clock! Also, the cyl axis of the MANIFEST rx is changed)

Front 29

How do we adjust the power of a CL as the TL changes?

Back 29

SAM and FAP

steeper add minus, flatter add plus

Front 30

T or F: a rigid contact lens will correct all CA as long as it retains its curvature

Back 30

T

Front 31

When CA=MA:

Spherical rigid lenses are typically used up to what cyl powers? After that, what do you fit with?

Back 31

2.50-3.00D

toric back surface

Front 32

Residual astigmatism is astigmatism present with a ____ CL on the eye.

What are the 4 causes?

Back 32

spherical

posterior corneal astig, foveal displacement, crystalline lens astig, crystallin lens obliquity

Front 33

what's the expected lenticular astigmatism according to javal?

Back 33

-0.50 x 090

Front 34

When would you use a front toric rigid lens?

Back 34

1. when most or all of the astig is internal (MA>.75 with no CA)

2. used when spherical rigid lens would result in excessive RA

Front 35

Who is the ideal patient for a distance CL with reading spectacle Rx?

Back 35

Requires BEST VA, not worried about COSMESIS, not prone to misplacing things

Front 36

What reading position is not good for a person wearing monovision CLs?

Back 36

downgaze

Front 37

What are the advantages to doing modified monovision over monovision? Disadvantages?

Back 37

A: better depth perception and less adaptation needed
D: vision not as good

Front 38

Multifocal soft contact lenses always use _________ vision. What does this mean?

Back 38

simultaneous: has center of the lens either distance or near while the periphery has the opposite...can do one over one eye and one over the other...

Front 39

T or F: Multifocal rigid alternating CLs have the worst multifocal optics

Back 39

FFF!!! best

Front 40

T or F: With monovision, the non-dominant eye gets the reading rx.

Back 40

T

Front 41

What's the only rigid bifocal that has a different power on the eye than in the air?

Back 41

one piece back surface

Front 42

For a one piece back surface rigid bifocal:

What's the ratio to apply to figure out the power of a CL on the eye and off the eye?

Back 42

3.2..off the eye the CL power will be about 3.2X more than on the eye

Front 43

What CL to use:

1. NO CA/ NO Manifest A
2. CA=MA
3. CA doesn't = MA
4. MA > .75 and no CA

Back 43

1. spherical Rigid/Soft
2. Rigid: spherical up to 2.50-3.00 (after that, use toric back surface for improved fit. Soft: spherical (with SE!) up until .75-1.00 cyl (then use soft toric)
3. Toric soft/rigid back surface
4. Toric soft/FRONT surface toric rigid

Front 44

1. Which has better optics: rigid or soft?
2. What provides the best distance and near vision for a presbyope who doesn't want to wear glasses?

Back 44

1. rigid
2. monovision

Front 45

What CL (soft or rigid):

1. dusty environment
2. aqueous deficient dry eye (Schirmer)
3. irregular astigmatism/corneal distortion
4. dry eye due to MGD (TBUT)

Back 45

1. soft
2. rigid
3. rigid
4. soft

Front 46

What are the 4 contraindications to soft CLs? Rigid?

Back 46

Soft: extreme sensitivity, extreme dry eye, allergies (relative CI- can fix with meds), hx of microbial keratitis

Rigid: sensitive to lens, dusty environment, extreme dry eye