SCL fit assessment Flashcards
(25 cards)
What is Over-Refraction in contact lens fitting?
A subjective refraction done while the patient is wearing contact lenses to detect any residual refractive error.
Which of the following is NOT a sign of a loose soft lens fit?
A. Excessive lens movement
B. Poor centration
C. Crisp retinoscopy reflex
D. Variable vision after blinking
C. Crisp retinoscopy reflex
In an ideal lens fit, movement on primary gaze should be between ______ and ______ mm.
0.25 and 0.75 mm
Match the following movements to their acceptable values for standard soft lenses: Upgaze, Sag, Lag
Options:
a) ≤ 1.5 mm
b) ≤ 1.0 mm
c) ≤ 0.5 mm
Upgaze → a) ≤ 1.5 mm
Sag → a) ≤ 1.5 mm
Lag → a) ≤ 1.5 mm
Define ‘Empirical Fitting’ in soft contact lens practice.
Ordering lenses based on measured parameters without trial lens fitting.
A patient’s lens rotates 15° to the left. Using the LARS rule, what axis adjustment is needed?
Add 15° to the spectacle axis.
Tight lens fit shows excessive movement and poor centration.
False
A __________ push-up test recovery speed indicates a tight lens fit.
slow
Which factor is NOT part of the 6 basic qualities of ideal soft lens fit?
A. Good centration
B. Clear endpoint over-refraction
C. Lens color
D. Stable vision
C. Lens color
What’s the final CL Rx for -2.00/-1.50 x 90 with 15° rotation to the left?
-2.00/-1.50 x 105 (using LARS)
A patient experiences circumcorneal redness and lens movement <0.2mm. What’s the likely issue?
Tight lens fit
A lens with excessive movement and bubbles under the edge is likely __________.
loose
Which of the following is an advantage of diagnostic fitting?
A. No trial lens needed
B. Less time-consuming
C. Allows observation of lens fit
D. No need for over-refraction
C. Allows observation of lens fit
What is the LARS rule in toric lens fitting?
Left Add, Right Subtract — used to adjust axis based on lens rotation.
In empirical fitting, the patient does not try the lens before ordering.
True
Match lens type with movement thresholds: Disposable Lens Tight Fit, Standard Lens Loose Fit
Options:
a) < 0.2 mm
b) > 1.5 mm
Disposable Lens Tight Fit → a) < 0.2 mm
Standard Lens Loose Fit → b) > 1.5 mm
The push-up test measures lens __________ to decentration and speed of __________.
resistance; recovery
What is circumcorneal indentation?
A ditch-like depression at the limbus indicating tight lens compression.
A lens shows 80% resistance on push-up and slow recovery. What’s the fit?
C. Tight
After blinking, keratometry mires become blurred but clear up shortly. What type of fit is this?
Loose lens fit
To correct a tight lens fit, switch to a __________ base curve and __________ lens diameter.
flatter; smaller
What is ‘Edge Standoff’ commonly associated with?
Loose RGP or soft lens fit where lens edge lifts excessively.
Diagnostic fitting provides more predictable fitting outcomes.
True
In toric SCL fitting, when is lens axis compensation required?
C. >5° rotation
