Flashcards in CL 2-4: GP Fitting 2 Deck (26):
Before Putting a Lens on:
1. What do you look for?
a. What do you use to inspect the lens?
1. Surface Quality; Any Scratches or Breaks
a. Reticle Magnifier
Before Putting the Lens on
1. CLEAN and CONDITION!
a. Two-Bottle System (Do what 3 steps)
b. 1 Step System (what 2 steps)
c. Oxidative System (What 2 steps)
1. a. Rub, Saline Rinse, Condition
b. Rub, Rinse and Condition, all with the Same solution
c. Rub, Rinse and Neutralize
Cause of Non-Wetting Lens
1. Why does the lens become non-wetting?
a. This requires the use of 1 of 2 things?
1. Due to CURVE CUTTING AND Polishing being done w/Lathe
a. use of PITCH or SOFT WAX
i. Pitch = Vegetable Tar Product (Leaves Residue)
Lid Position and Fitting Goal
1. Upper Lid Position Relative to Superior Limbus
1. a. Fit smaller lens (Goal: Interpalpebral Fit)
b. Same as (a.)
c. Fit Larger Lens (Goal: LID Attached Fit)
Time of Centration Assessment
1. When do you look at it?
a. Part of what kind of Assessment?
b. Should you hold the Lids?
c. Is Fluorescein Needed to assess it?
1. Where lid rests B/W BLINKS
a. Dynamic Assessment
What's Acceptable for Centration
(3 things to ask yourself)
1. Is Pt Comfortable
2. Is Pt complaining of Haloes and GLARE (is pupil w/in Optic Zone)
3. Is lens causing any Physiological changes to the Cornea (NaFl STAIN)
1. What 4 things do we assess?
1. Lens-Lid Relationship
4. Fitting Relationship
1. What does it promote?
a. What does it provide?
b. What does it remove?
1. Post-lens tear film exchange and Mixing
b. Waste Products
1. Quantified as Vertical/Horizontal Change in Lens Position during a NORMAL blink?
2. Think about size of the lens relative to the size of the Cornea to gauge your movement in millimeters. What is ACCEPTABLE?
3. Which GP lens will MOVE LESS: Flat or STEEP?
1. VERTICAL CHANGE
2. 1-2 mm
3. STEEP Fitting GP will MOVE LESS than a FLAT fitting GP (just like soft lenses)
More About movement
1. Watch pattern of movement: If ARCUATE MOVEMENT (S Shaped movement) is OBSERVED, or if LENS DROPS QUICKLY, lens may be what kind of FIT?
2. What 2 other things can also affect movement?
1. LOOSE/Fitting Flat
2. Lacrimation (can cause a ton of movement) and Lens Thickness (Really High Center THICKNESS, it will just DROP down, causing lens to sit on a lower eyelid...you can order a thinner center thickness to fix this)
Lens Movement over Time
1. GPs will Tighten/Loosen with wear time?
1. Tighten (due to Post-lens tear film thins and Movement Slows)
*F/U's are Important!
Insufficient Lens Movement
1. When is Vision best?
2. What kind of lenses may "BIND" to the eye over time?
3. What type of lenses MAY BE COMFORTABLE?
1. Just after a BLINK and worst just before a blink (Opposite for Lenses with EXCESSIVE MOVEMENT)
2. TIGHT/STEEP LENSES
3. TIGHT LENSES
*Loose/Flat lenses tend to move a lot and are usually not comfortable
Assessing the Fit
1. White Light used to assess what 3 things?
2. Fluorescein: Used to Assess what?
a. You can also Use a BURTON LAMP instead of Cobalt Blue Filter in the Slit Lamp, but it DOES NOT WORK if the GP Material has what?
b. Wratten Filter also USED: Where is it PLACED (we used this in fitting on tuesday)?
1. Lens Lid Relationship, Centration, and Movement
2. Lens-Cornea Relationship
a. Can't use a BURTON LAMP if GP material has a UV FILTER!
b. It's put in FRONT of the OBJECTIVE LENS, NOT the Light Source!
Presence vs. Absence of Fluorescein
1. Presence of Fluorescein
a. Looks like what Color?
b. Referred to as what 2 things?
2. Absence of Fluorescein
a. Looks like what color?
b. Referred to as what?
1. a. GREEN
b. CLEARANCE of POOLING
2. a. BLACK
b. BEARING or TOUCH
1. Describe the Fluorescein Pattern in What 3 Areas of the Lens?
1. Centrally/Apically, Midperipherally, and Peripherally
When Describing the Fluorescein Pattern in the Central, Midperipheral, and Peripheral Locations, what will you say?
a. How will you describe it?
1. Either that there's Pooling/Clearance OR that you see Bearing/Touch
a. Say that it's Minimal, Moderate, or Excessive
1. What is Acceptable for Staining?
2. What is Unacceptable?
3. When it's Acceptable: What can you see?
4. What if you are Seeing EXCESSIVE POOLING?
5. Excessive Bearing: How will you see it?
a. Causes what on the Cornea?
1. Minimal Bearing, or Minimal-moderate Clearance
2. Moderate-Heavy Bearing, and Excessive Clearance
3. Minimal Clearance; Thin NaFl; and you can still SEE THE PUPIL!
4. It will OBSCURE the PUPIL and you MAY see BUBBLES
5. Well-defined Area of Bearing (Distinct Borders)
a. Mechanical Stress on the cornea
3. Excessive Pooling: What will you see?
4. Excessive Bearing: What will you see?
a. Will cause 1/2 things?
1. Min-Moderate Bearing; Minimal Pooling
2. Heavy Bearing; Moderate-Excessive Pooling
3. Thick NaFl Band extending from Periphery into Midperiphery
4. Well-Demarcated Ring of Bearing (Distinct Borders)
a. Cause Binding and/or Corneal Compromise
a. What will you see?
3. When can you tell it's insufficient?
1. Min-Mod Clearance
a. Moderate band of NaFl at Edge
2. ANY BEARING, EXCESSIVE CLEARANCE
a. Thick Band of NaFl at Edge; Edge Standoff; May see Bubbles
3. Thin Band of NaFl at Edge and there's insufficient Tear Exchange (SUCTION)
Is the Lens Steep, Flat, or Aligned to the Cornea?
1. Apical Lens-Cornea Relationship
1. a. Back surface of lens matches the Corneal Curvature of the Apex (Aligned)
b. Space b/w the lens and Corneal Apex (STEEP)
c. Lens is touching the Corneal APEX (FLAT!)
1. Lens Centered on what?
2. Hold lids out of the way and determine relationship b/w what?
3. What does this tell us?
1. on Cornea
2. out of the way
3. gives us the TRUE APICAL RELATIONSHIP
1. What is it?
2. What the lens dynamics as the pt does what?
3. Pattern looks different than when it's what?
1. Natural Way the lens sits
3. when it's centered
1. Dynamic: Doing what?
2. Static: looking at what pattern?
1. Lid-lens relationship; Centration; Movement
2. Fluorescein Pattern
What are the 4 Things you need to comment on when fitting a GP?
1. Lid-Lens Relationship
4. Fluorescein Pattern
Toric Fluorescein Patterns
1. When a SPHERICAL BASE CURVE lens it FIT on a TORIC CORNEA, what is seen?
1. a characteristic pattern; More Corneal Toricity = More distinct Pattern
a. Pattern will be in the 180 region
b. Will be in 090 region