Lens Characteristics Flashcards
What does the t stand for in the term Dk/t?
The thickness
What does the k stand for in the term Dk/t?
The solubility constant
What is the definition of the wetting angle of a gas permeable contact lens?
The angle at which a drop of water/tears spreads over the surface of a lens.
What does the D stand for in the term Dk/t?
The diffusion coefficient
Which of the FDA groups is high water/ionic?
Group 4
Low water content lenses are identified as those having ___.
Less than 50% water
Which of the FDA groups is low water/non-ionic?
Group 3
Silicone Hydrogel lenses are in which group?
Group 5
Which of the FDA groups is high water/non-ionic?
Group 2
Which of the FDA groups is low water/ionic?
Group 1
An advantage of silicone hydrogel is what?
Very oxygen permeable
Which of the following is a characteristic of ionic lens materials?
Carry negative electrostatic charge
