Superior epithelial arcuate lesion. Thin arcuate white lesion in the superior cornea; within 1-3mm of the superior limbus between 10 and 2 o’clock. SEALs can be up to 0.5mm wide and from 1 to 5 mm in length, sometimes with heaped edges. Diffuse infiltration underlying the lesion is possible. Unilateral or bilateral but usually asymptomatic. Occurring symptoms may include edge awareness or irritation and/or foreign body sensation.
Silicone hydrogel contact lenses were first introduced into the market in 1999. The incorporation of silicone increases the material’s oxygen transmission, while the hydrogel component allows for fluid transport and lens movement. The combination of these two components allows for extended wear of lenses. Currently available silicone hydrogel contact lenses include: Air Optix Night & Day Aqua (lotrafilcon A), Air Optix Aqua (lotrafilcon B), PureVision (balafilcon A), Acuvue Advance (galyfilcon A), Acuvue OASYS (senofilcon A), Biofinity (comfilcon A), Avaira (enfilcon A) and Premio (asmofilcon A).
The appearance of tissue disruption and other patho-physiological changes in the front surface of the eye as revealed with the aid of one or more of a number of dyes, such as fluorescein, rose bengal or alcian blue. Also see Fluorescein, Corneal staining and Conjunctival staining.
Surfactants are compounds that contain both a hydrophilic and a hydrophobic portion and serves to increase wettability on a lens surface. Some contact lenses, such as rigid gas permeable lenses, are composed of mainly hydrophobic material that will have trouble retaining a wettable surface. When surfactants are applied to the lens, the hydrophobic end will bind to the surface of the contact lens and the hydrophilic portion will bind water. This essentially lowers the surface tension of water on the surface of the contact lens, and allows the tear film to spread more easily on the surface and this potentially could increase the comfort for the contact lens wearer.