Soft Lens & Soft Toric Calculations
A soft toric lens rotates 5° nasally.
Using LARS, what does this mean?
Add 5° to the axis
K’s: 44.00 @ 180 / 44.25 @ 090
Rx: –7.00 –0.25 × 180
Which GP design is best?
Spherical GP
Which care system is hydrogen peroxide–based?
Oxidative system
Which slit lamp technique best evaluates corneal edema?
Sclerotic scatter
How soon is the first follow-up for extended wear?
24 hours
A soft lens flares outward when liquid is added. This indicates:
The lens is inverted.
Which GP fitting philosophy places the lens between the lids?
Intrapalpebral
Which soft lens preservative is no longer used due to corneal toxicity?
Thimerosal
A GP lens with 3–9 staining indicates:
Lens too flat (excessive edge lift)
After the initial 24-hour visit, extended wear follow-up continues at:
1 week, 1 month, then 3–6 months
Which lens material group (I–IV) is ionic and high water?
Group IV
K’s: 42.50 @ 180 / 44.00 @ 090
Rx: –2.00 –1.50 × 180
Which GP design is best?
Back surface toric (corneal toricity > 2.00 D)
A continuous wear lens is FDA-approved for what maximum schedule?
Up to 30 nights
Therapeutic lenses provide what 3 functions?
Protection, healing promotion, pain reduction
A 2-year-old patching case:
OD: +5.00 at 20/40
OS: +1.00 at 20/20
Which eye do you patch?
OS (patch the stronger eye)
A 50-year-old presbyope is interested in monovision soft contact lenses. Her spectacle prescription is:
OD: –3.50 DS
OS: –3.50 DS
Add: +2.00 D
Her right eye is dominant. For a monovision fit, what contact lens power would you select for each eye?
OD (distance / dominant): –3.50 DS
OS (near / non-dominant): –1.50 DS
Which GP evaluation tool best shows edge defects?
Shadowgraph
Which patients are not ideal for extended wear?
Those with reduced TBUT or dry eye (example: <10 seconds)
What does a parallelpiped beam evaluate?
Corneal layers & epithelial thickness
Which sign indicates a child is not tolerating lens wear?
Excessive tearing, rubbing, or photophobia
For soft lenses, increasing diameter by 0.5 mm usually has what effect on fit?
Steepens fit / increases sagittal depth
K’s: 43.50 @ 50 / 46.50 @ 110
Rx: –4.00 –4.00 × 110
Which GP design is indicated?
Back surface toric
Why do we avoid rinsing lenses with tap water?
Acanthamoeba risk
You are evaluating a soft contact lens on the eye using optic section illumination. You observe a thin, bright band of light on the cornea with a sharply defined shadow behind it.
Describe what optic section is used to evaluate, and name one clinical finding this technique can help you identify during a contact lens assessment.
Optic section illumination creates a thin slice of light through the cornea to evaluate corneal depth and layer integrity.
It can identify findings such as: corneal edema, stromal thinning, corneal scars, microcysts, or corneal neovascularization depth.
A baby with VA 20/400 is approximately what age?
2 months