CL 2-6: GP Troubleshooting Flashcards
1
Q
Poor Initial Vision
- Stable
a. Could be 3 things? - Stable or Fluctuating
a. Could be 4 things?
A
- a. Wrong lens
b. Power Change
c. Residual Astigmatism - a. Tearing
b. Poor Wetting
c. Poor Fit
d. Lens Flexure
2
Q
Wrong Lens
- Make sure what about the CL?
- What should you do to see if VA improves?
- Then you should do what?
- Verify Diagnostic Lenses used to do what?
A
- that right lens is in OD and left lens in OS (Colors, Dot)
- Over-Refract (SOR and SCOR) to see if VA improves
- Remove and Verify Lens Parameters
- Verify Diagnostic Lenses used to fit patient
3
Q
Vertex Distance
- Any lens that does not sit directly on the eye has what?
- Vertex distance must be considered for any refraction or Over-refraction that contains Meridian Powers of what?
A
- has an Associated Vertex Distance
2. OVER +/-4.00
4
Q
Power Change
- What should you do?
A
- Either Re-ORDER, or Re-Power
5
Q
Residual Astigmatism
- Empirically, it can be predicted by Calculating what?
- Diagnostically, can be uncovered with what?
A
- CRA
2. SCOR
6
Q
Tearing
- May affect what?
- Tear lens induces what?
A
- Tear Lens
- Power
* Anesthetic vs. No Anesthetic
7
Q
Anesthetic Use Study
- What did they find?
A
- Pt Satisfaction and Perception of Adaptation was Significantly better with Anesthetic
Conclusion: Topical Anesthetic Recommended for all new GP Patients, ESPECIALLY CHILDREN, Keratoconics, SCL Refits, and any Apprehensive Patients
8
Q
Poor Wetting
- Identify
a. How do you know? - Solve
a. Clean CL with what?
b. Counsel patient on use of what?
c. Or you could do what?
A
- a. Tears Beading up on Surface
- a. with Alcohol-Based Cleaner
b. of Cosmetics
c. Change Materials (Dk and Wettability)
9
Q
Poor Fit
- Vision Clearest:
a. Just after Blink…
b. Just Before Blink…
A
- a. Indicates FLAT FIT
b. Indicates STEEP FIT
10
Q
Clinically Significant BC Changes
- How much is considered to be a Clinically Significant BC CHANGE?
a. What does this roughly equal?
b. This estimation becomes inaccurate outside of what?
c. Use what conversion to be Accurate?
A
- 0.50 D
a. 0.1 mm in MID-RANGE BASE CURVES ONLY
b. outside of Mid-range base curves
c. 337.5/mm to be accurate
11
Q
Adjusting Power to Compensate for BC Changes
- Flattening BC by a certain amt in Diopters induces what?
- Steepening BC by a certain amt in Diopters induces what?
- SAM FAP is what kind of relationship?
A
- (-) tear lens of that magnitude
- tear lens of that magnitude
- 1:1 Relationship
12
Q
Addressing haloes and Glare
- What 2 things can you increase?
a. What will this affect?
A
- OZD/OAD
a. Affects the SAG
13
Q
Clinically Significant OZD Changes
- How much change is Considered to be a Clinically Significant OZD CHANGE?
A
- 0.3 mm
14
Q
Lens Flexure
- Lens Bending is Diagnosed using what?
A
- a. Over-Keratometry (Toric vs. Spherical)
b. Sphero-Cyl Over-Refraction
Residual Astigmatism that doesn’t match up with calculated
15
Q
Causes of Flexure
- 5 things
A
- Extended Wear
- High Dk Material
- Highly Toric Cornea
- Thin Lens
- Tight Lid