14 - Scratch Resistant Coatings (Exam 3) Flashcards
What optical material has the best abrasion resistance?
Glass
Still no lens is scratch proof
What optical material has the best optics?
Glass
What impact do scratched lenses have on impact resistance?
Scratched lenses lower impact resistance
What is the only lens material that has the option to not have a scratch coating and why?
CR-39
Inherently hard material
Where do coated stock (finished) lenses have their scratch coating?
Both front and back surfaces
Where do semi-finished lenses have their scratch coating?
Front surface only
What are 2 types of hard coatings?
- Thermally cured hard coatings
2. UV cured hard coatings
Who typically uses thermally cured hard coatings?
Lens manufacturers
Who typically uses UV cured hard coatings?
Processing laboratories
What type of environment is essential to applying UV cured hard coats?
Dust-free
What is the difference between scratch resistant coatings and hard coats?
SRCs are tintable and less expensive
Hard coats are not tintable and are more expensive
Are there any benefits to SRC lenses other than abrasion resistance?
Yes
Reduce surface reflections slightly
Allow poly to accept some tint
Can polycarbonate lenses accept a tint without a scratch resistant coating?
No
What is the maximum tint possible on a SRC poly lens?
2
What is our obligation to patients who elect to have coated lenses?
Ensure they understand proper care of the lenses at purchase and at dispense
