Week 5 - Specialty Contact Lenses Flashcards
What are scleral lenses?
A large contact lens that rests on
the sclera and creates a tear-filled
vault over the cornea
Scleral lenses offer sharp vision and comfort for people with …………
Who are scleral lenses good for? 2
-severe dry eyes
-corneal irregularities
The materials used in scleral include: Menicon Z, Acuity 200 and Boston X02.
What do they have in common?
high Dk gas permeable material
What is the difference between mini-scleral and large scleral lenses?
mini-scleral - lens is up to 6mm larger than HVID
Large-scleral - lens is more than 6mm larger than HVID
What are 2 advantages to scleral lenses?
- Any eye shape can be fitted
- Protects the cornea and the bulbar conjunctiva
What are 2 disadvantages to scleral lenses?
- complicated fitting process due to the amount of curves involved.
- May be difficult for patient to insert initially
What kind of solution does a scleral lens require to fill the bowl for insertion?
preservative free saline
We check the fit of a scleral lens after waiting 4 hours.
What are characteristics of a good fitting lens? 5
- Clearance throughout the lens (150um clearance at center, 50-100um clearance at limbus)
- Well sealed environment with no fluorescein leakage until manual manipulation
- No movement
- No rotation
- No blanching
Why do we use bandage lenses? (cornea related 3, tear 1, injuries 2, general 2 )8
-Unusual or distorted corneal shape
- Relief of pain
- Recurrent corneal erosion
- Corneal dystrophies
- Chemical injuries
- Tear deficiency
- Protection from lids and environment
- Following trauma or surgery
What are 6 types of therapeutic specialty lenses?
-Myopia Control
-Orthokeratology
-Scleral Lenses
-Hybrid Lenses
-Bandage Lenses
-Medication/ Drug delivery Lenses
What makes someone a good candidate for multifocal lenses? 3
-px with previous experience
-highly motivated pxs (needs/struggling with glasses)
-Moderate-to-high myopes and hyperopes versus emmetropes
What are the different ways we can correction presbyopia in contact lenses? 6
- Distance-powered contact lenses and near-reading spectacles
- Bifocal or multifocal contact lenses
- Simultaneous image contact lenses
- Alternating image contact lenses
- Progressive RGP
- Monovision
Manage expectations for multifocal lenses.
What could be some problems a multifocal wearer could experience? 5
-size of image wont be magnified like reading gls
-VA may be reduced
-reduced depth perception
-might take multiple fit appts
-pupil size can affect success
the difference in pupil size area from a
−8.00 D myope to a +6.00 D hyperope is 24%.
This can affect the results in differences in success between myopes and hyperopes. T/F
TRUE
What is a orthokeratology lenses?
non surgical rgp lenses which reshapes the cornea overnight which allows the px to see during the day
