Daily Disposables (DD)
Single use lenses that are worn during the waking hours and then discarded.
Glossary
Daily Wear (DW)
A lens wear schedule requiring daily or more frequent removal for cleaning and other purposes. Lenses are not worn during sleeping hours.
Debris
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.
Deposits
An acquired protein and/or lipid film or haze on the anterior or posterior lens surface.
Disposable lenses
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.
Distortion
see Corneal distortion.
Dk
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.
Dk/L
See Dk/t
Dk/t
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
DSCL
Disposable soft contact lens. Also see Disposable lenses.
