Pres

Question 1

all binocular summation/stereo is lost in CL pts w/ adds greater than what power?

Answer 1

+2.00D. Start to lose for middle and high SF ~+1.50D

Question 2

adaptation for monovision fit?

Answer 2

2 weeks; try to discourage night driving or comparing eyes - give realistic expectations

Question 3

T/F: 0.25D change makes a huge difference in vision w/ bifocal CLs

Answer 3

true. SMALL steps at a time - RTC 2-3 wks to reassess

Question 4

two multifocal CL systems? which is easier to fit?

Answer 4

simultaneous: look thru all parts of lens @ all times - must decide which to focus with - easier to fit than alternating
alternating: two distinct D vs. N systems - more challenging (prism ballast)

Question 5

fused GP bifocal designs use different ____, one-piece designs use different ____ - which is more popular?

Answer 5

indices (of refraction); curvatures - more common

Question 6

alternating design GPs have WHAT to maintain rotational stability? - how much thickness is added per diopter of prism?

Answer 6

• prism ballast (1-3.5 P.D.)

0. 10mm

Question 7

alternating fitting goals:

• position on ___ lid
• t/f: lens should move down when the eye looks down
• how much of the pupil needs to be covered by the near zone for optimal near VA?

Answer 7

lower

• FALSE: lens should stay on lower lid–> eye moves down, lens translates up
• 80%

Question 8

more alternating fitting goals:

• the seg should be near the ____ pupil margin (pri. gaze)
• should be within __mm
• allow for (nasal/temporal) rotation

Answer 8

• inferior
• 2mm - but really, that’s way too low
• nasal (eye moves nasal and downward when reading)
  - -> temporal rotation = detrimental to VA

Question 9

3 ways to improve translation:

Answer 9

• flatten BC
• increase prism ballast
• increase truncation (keep lens on lower lid and prevent from sliding under)

Question 10

where is the distance power in a front aspheric lens?

-becomes more ____ as you go toward periphery

Answer 10

distance: in the center

- plus (add it toward the periphery) - may be affected by small pupils

Question 11

where is the add power on a single aspheric lens?

-should this type of lens be fit steeper, flatter, or on-K?

Answer 11

on the single aspheric back surface of the lens

-STEEPER - d/t asphericity/eccentricity of back surface

Question 12

Bifocal SCLs tend to have near in (center/periphery), while bifocal GPs have near in the (center/periphery) - what’s the main factor why this is the case?

Answer 12

SCLs: near in CENTER
GPs: near in PERI
-driving factor - TRANSLATION. In GPs, dist is in center b/c when pt looks down they can see at near (d/t good translation - it’s lacking in SCLs)

Question 13

how many presbyopes are there in the U.S.?

Answer 13

140 million; very small percentages of pts wearing monovision or multifocal CLs!

Question 14

Give 2 important POSITIVE Hx factors:

Give 1 important NEGATIVE Hx factors:

Answer 14

Positive: MOTIVATION, REALISTIC expectations. Also- moderate VA demands, hate specs, etc.

Negative: UNREALISTIC EXPECTATIONS, excessive critical visual demands, low illumination env.

Question 15

biggest advantage to multifocal lenses?

Answer 15

binocularity; stereopsis maintained

Question 16

fitting procedure: bifocal lenses

• check (mono/binoc) VA first
• T/F: subjective VA more important than actual (w/i limits)
• use ____ room illumination
• trial lens outside phoropter/change in (large/small) increments
• how long is the adaptation period?

Answer 16

• binocular VA first
• True
• moderate illumination
• SMALL (0.25D) changes - make big difference
• 2-3 week adaptation period

Question 17

Prism ballasting is used in alternating designs; what other property is used extensively to provide rotational stability in an alternating design?
-is this more beneficial for (+) or (-) lenses?

Answer 17

truncation - chop off bottom to align it w/ lower lid and allow it to rest on lid

-better for (+) lenses - edge becomes thicker the more you chop off

Question 18

where should you put the seg line on an alternating design?

-may be adjusted to ensure at least ___% of pupil is looking thru near zone after translation

Answer 18

near the vertical CENTER of the lens

-80%

Question 19

A (flat/steep) lens promotes good translation - by how much should you flatten or steepen?

Answer 19

flat = GOOD translation

-flatten lens by ~0.50D

Question 20

Will a large LD promote or impair good translation?

-what’s the limiting factor?

Answer 20

Large LD –> LIMIT translation

-once the lens hits the UPPER LIMBUS, it can’t move up any higher

Question 21

Troubleshooting Segmented (alternating vision) lenses:

• poor DIST VA - what to do?
• poor NEAR VA - what to do?

Answer 21

poor DIST - ensure sitting on LL, truncate the lens, increase LD
poor NEAR - improve TRANSLATION

Question 22

three ways to improve translation? [FIT]

Answer 22

FLATTEN BC, INCREASE prism ballast, Truncate lens

Question 23

FRONT surface aspheric:

• (dist/near) in center, (dist/near in periphery)
• fit on ____ K (like SV lenses)
• OR @ (dist/near), and use the SAME OR for dist and near!!
• Are they pupil-size dependent?

Answer 23

Dist in center, Near at periphery

• FLAT K; aspheric front surface provides add power
• OR @ Dist; use the SAME OR for D+N
• yes! smaller pupil - less add to look thru

Question 24

Would you expect a BACK aspheric to align well on the cornea? Why/Why not?

Answer 24

NO; back surface is what’s highly eccentric on a back aspheric - WON’T align well b/c the BACK surface is what creates the add (even though most is neutralized by the tear film)

Question 25

SINGLE aspherics - which surface provides the add power?

-should they be fit on flat K like front surface aspherics?

Answer 25

BACK surface - single aspheric curve across entire back surface
-NO!!! FIT STEEPER-THAN-K! Single eccentricity means single add; requires a steep-fit lens to compensate or it’ll be flat and decenter

Question 26

SINGLE aspherics: fit:

• BC: __ to __ diopters STEEPER than K
• Dist power: -____ to -____ MORE MINUS to compensate for LL
• because of the steep fit, you’d expect significant ____ clearance and very good c_____

Answer 26

1 to 6 D steeper;

• 1.00 to -6.00D more minus;
• apical clearance; excellent centration

Question 27

MULTI aspherics

• what does the CENTER curve do?
• what do the PERIPHERAL curves do?
• what fit are you expecting?
• how steep do you fit these suckers?

Answer 27

• center: distance and add power
• periphery: peripheral cornea
• ALIGNMENT fit expected
• not nearly as steep as single: 0.50-1.00D steeper BC and (-0.50 to -1.00) more minus

Question 28

Troubleshooting aspherics:

• blur @ DIST: assume it’s D/T d__
• two options?

Answer 28

dist: assume D/T DECENTRATION: steepen BC, or decrease eccentricity (add power)

Question 29

Troubleshooting aspherics:

• blur @ NEAR: assume it’s D/T t___
• one option to fix it?

Answer 29

near: assume D/T TRANSLATION (or that pt is not looking down far enough)
- soln: flatten BC, and make sure pt is looking down to allow proper translation

Question 30

what’s the most POPULAR type of GP MF?

• is dist or near in the center?
• T/F: simultaneous and alternating vision
• Are they pupil-size dependant?

Answer 30

CONCENTRIC

• dist OR near; can do either
• TRUE
• YES

Question 31

The SynergEyes MF lens has what type of design?

-which part of the lens is different from the rest?

Answer 31

CONCENTRIC; in the CENTER only: it’s a hybrid-type lens w/ NEAR center and a very sharp transition after ~1.9mm

Question 32

Duette has both a MF lens and a PROGRESSIVE lens; which has a SINGLE add power profile?
-which has the option of a small OR large center-near zone?

-the MF Duette has a s_____ vision design

Answer 32

MF - SINGLE add
MF - TWO options for center-near size

-simultaneous

Note: the PROGRESSIVE has three add powers available but you can’t change zone size like the MF - so the qualities are OPP!