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50 Cards in this Set

  • Front
  • Back
HEMA is water _____.
MMA _____ strength and _____- water content.
increase, lowers
EGDMA gives _______, _____ stiffness and ______ water content.
dimensional stability, adds, decreases
NVP _____ ionicity and ___ water content.
increases, increases
MAA _____ ionicity and _____ water content.
increases, increases
silicones are _______ (phobic/phillic)
Hydrogels are ______ (phobic/phillic) and have the suffix ______.
hydrophillic, filcon
Hydrophobic materials have the suffix _____.
We normally called the lens by its _____ name.
Silicone ______ diffusion.
Fluorine _____ solubility
How does the FDA classify water content?
low = <50%
high = >50%
If a patient is a "high depositor", you should use a _______ lens. (non vx. ionic)
Group III CTL are _____. (ionic/nonionic)
Ionic (so is group IV)
Group IV is _____ (low/high) in water content.
HIgh (so is group II)
Dk is the ________ and the unit is the _____.
oxygen permeability, Barrer
Dk/t is the _______, and the unit is ______.
oxygen transmissibility, barrer/cm
What is the minimum Dk/t value needed for EW?
87 (this value keeps corneal swelling to 4%)
As you increase water content you ____ Dk/t.
What type of lens produce corneal dehydration?
thin, high water content lenses
What kind of lens offers hyper-oxygen transmissibility?
silicone hydrogels (Dk/t values can reach 120--this is GREAT for EW)
Tor F: silicone hdrogels eliminate redness and vascularization.
true! (by decreasing hypoxic stress)
A silicone hydrogel lens is made of silicone + hydrogel (duh)---which component allows for the better O2 transfer?
Which component allows for on-eye movement, fluid and ion transfer?
silicone= O2 transfer
hydrogel = fluid/ion and on-eye movement
High silicone material means the lens doesnt stretch as much. T or F? (give an example)
true, ciba N&D
Low silicone means the lens stretches better. T or F (give an example)
true, J&J Acuvue advance
a ____ modulus = better draping.
lower (has to do with the amount of silicone)
In HYDROGELS as you increase the water content, you _____ the Dk value.
In SILICONES as you increaes the water content you _____ the Dk value.
T of F: sleeping in silicone hydrogels is almost no different than sleeping w/o contacts on.
True (they both produce about 3-4% corneal swelling)
COnventional hydrogels produce about _____ corneal swelling when worn at night.
Is there any real clinical difference b/t the following lenses: PV, O2 Optix, Oasys, N&D?
NO, their water content and Dk/t values are roughly the same.
Name 3 very popular 1st generation silicone hydrogels.
1- Focus N&D
2- O2 Optix
3- PureVision
Name 2 popular 2nd generation silicone hydrogels.
1- Oasys
2- Acuvue Advance (#1 selling lens in the world)
The one and only BC for the Oasys is _____.
8.4 (98% of patients can wear this)
Do "true" silicone hydrogels require a surface treatment(for surface rewettability)?
Yes (PV, Focus N&D, O2 Optix)
How do you treat a silicone lens to enhance rewettability?
you bambard it with ionized gas that physically and chemically alters the lens surface.
What is the surface process for PureVision?
What is the surface process for CIBA N&D and O2 Optix?
Full Surface Coating
What is the method of enhancing surface rewettability in the 2nd generationi silicone hydrogels?
1- Acuvue Advance = _____
2- Acuevue Oasys = _______
1- adding Hydraclear (a humectant that attracts water)
2- hydraclear plus
What material is CIBA N&D made of ?
The deposits on silicones is comprised of mostly ______.
What are the deposits made of on hydrogels.
Everything (protein, lipids, etc..)
Name 6 hydrogel lenses.
1- Acuvue
2- Acuvue 2
3- Focus Dailies
4- Proclear
5- Frequency 55 Aspheric
6- Soflens 38
Name 5 silicone hydrogels.
1- Oasys
2- Acuvue advance
3- Focus N&D
4- O2 Optix
5- Purevision
Do 2nd generation silicone hydrogels require a surface treatment to create a wettable sureface?
NO (only 1st generation)
Do hydrogels require a surface treatment to creat a wettably surface?
Do 1st generation silicone hydrogels require a surface treament to create a wettable surface?
Water content is generally ______(higher/lower) in hydrogels?
Higher (since the whole lens is hydrophillic)
IN what type of lens is water content generally the lowest? (hydrogel vs. 1st gen SH vs. 2nd gen SH)
1st generation silicone hydrogels are generally the lowest
While thickness is about the same b/t hydrogels and silicone hydrogels, O2 transmissability is much _____ with silicone hydrogels due to the hight Dk.