Fl Patterns

Question 1

When is viewing the Fl pattern necessary?

Answer 1

when the fit has been assessed to be undesirable - lower lid fit, lens too loose, etc.

Question 2

MW of FL?
MW of FluoreSoft dye?
Absorbs what type of light? UV-__ to short ___
Emits what color/wavelength light?

Answer 2

376
710
UV-A, short blue (485-500)
Green (525-530)

Question 3

What’s the minimum detectable tear thickness?

-What’s the minimum detectable gradation of intensity difference?

Answer 3

.0022mm - any thinner and it’ll look black
.02mm - to see diff b/w shades of green
-green is more intense if thicker

Question 4

ideal tear film thickness:
centrally:
peripherally:

Answer 4

central: 5-10 microns (dull, trace green haze)
peripheral: 100-180 microns (bright green)

Question 5

You can view the Fl pattern with either the ____ UV lamp, or the slit lamp with the ___ ___ filter
-enhance pattern w/ Which four filters? [WTSL]

Answer 5

burton UV - not on Boston pdts! (UV filter)
cobalt blue filter- low 10x mag, wide filter

-Wratten 12, Tiffen, Schott, Lee

Question 6

What’s the problem w/ too MUCH Fl?

-too little?

Answer 6

too much - obscures real pattern

too little - looks like alignment; it’s not

Question 7

Apical Zone - usually the central __-__ mm

-three ways to define it?

Answer 7

central 7-8mm
Alignment: light green haze throughout
Clearance: excess bright green central
Touch: Dark centrally, brighter green peripheral

Question 8

Doing what to a lens too much causes it to make bubbles?

Answer 8

steepening too much

Question 9

Mid-peripheral zone: important for lens p____ and s____

-three ways to define it?

Answer 9

positioning, stability

• alignment: even, light green in mid-peri zones
• clearance: bright green in mid-peri
• touch: most often accompanies apical clearance - lens is steeper than cornea

Question 10

Mid peripheral clearance is greater with a (steeper/flatter) lens? Most often accompanies what pattern apically?

Answer 10

flatter; apical touch

Question 11

peripheral zone: how to classify? Which is ideal?

Answer 11

low, medium, high - medium/moderate is ideal (maximize tear flow/comfort balance)
-bubbles may also occur w/ lens too FLAT - get up underneath the edges

Question 12

Which pattern - static or dynamic - gives the true apical relationship of a lens?

Answer 12

static (when the lens is CENTERED)

-dynamic - when lens is in normal RESTING position

Question 13

Toricity

• WR: steepest corneal curvature (horiz/vertical), causes clearance (horiz/vertical) - darker (touch) area along the (90/180)?
• AR?
• Obl: band of touch with the longer dimension goes along the (flatter/steeper) meridian

Answer 13

steepest vertically(yes it is - x180 means power is in the 90), clearance vertically, darker band horizontally

-flatter (more touch along longer dimension)

Question 14

AR corneas will show clearance in what orientation?

Answer 14

180 - horizontal

Question 15

the larger the OZD is made, the (easier/more difficult) it is to maintain alignment - WHY?

Answer 15

harder as the OZD becomes larger - MORE eccentricity (increase in corneal FLATTENING) as you move away from the corneal apex

Question 16

A “donut” pattern is revealed when what is too large?

Answer 16

Optic zone

Question 17

dynamic Fl patterns give a better assessment of the lens to cornea relationship during n___ l___ w___
-what relationships are you looking for here?

Answer 17

normal lens wear

• decentration: lens tilt, companion touch, mid-peripheral arcuate pooling, Fl pattern changes
• tear flow dynamics

Question 18

Which fits/cornea types will cause mild decentration?

Answer 18

flat fits, lid attachment fits, toric corneas

Question 19

Lens tilt causes the lens to tilt (toward/away) from the direction of decentration.

I.e. Lens tilted superiorly. Where will you see clearance/touch?

Answer 19

TOWARD direction of decentration

superior touch, inferior clearance (like a see-saw)

Question 20

companion touch occurs in the direction of decentration and causes what shape to appear w/ clearance?

Answer 20

oval/crescent IN THE DIRECTION OF DECENTRATION - that part of cornea is flatter (because it’s the peripheral cornea) and causes lots of dye to get up in there

Question 21

what is mid peripheral arcuate pooling?

Answer 21

area of clearance b/w the area of companion touch and the apex

Question 22

With good tear exchange, fluorescein should appear under the lens within __-__ blinks

Answer 22

2-3.