Single use lenses that are worn during the waking hours and then discarded.
A lens wear schedule requiring daily or more frequent removal for cleaning and other purposes. Lenses are not worn during sleeping hours.
Waste products located between the contact lens and cornea. Post-lens tear debris has traditionally been considered to have the appearance of amorphous cellular material. If substantial amounts of debris are trapped under a lens, staining will be present upon lens removal and fluorescein instillation. Post-lens tear debris is a fairly common observation in patients who wear soft lenses on an EW basis. It should not be confused with Mucin balls.
Defined by the FDA as contact lenses worn for 1 week of extended wear and those discarded daily (or after one-time use). Defined clinically as contact lenses worn for 1 week of extended wear and up to 2 weeks of daily wear.
Oxygen permeability of a contact lens material. Dk usually depends on the water content of a hydrogel lens material and the silicone content of a silicone hydrogel lens material. Oxygen is more soluble in water than in PMMA, but far more soluble in Silicone rubber than in water. Also known as P (permeability). P = Dk = diffusion (D) * oxygen solubility (k) Also see high Dk and low Dk.
Oxygen transmissibility of a contact lens material with consideration of the thickness of the lens. Dk/t = Dk / average thickness (L) of the contact lens