A contact lens is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye.
Contact lenses usually serve the same corrective purpose as conventional glasses, but are lightweight and virtually invisible. Many commercial lenses are tinted a faint blue to make them more visible when immersed in cleaning and storage solutions. Cosmetic lenses are deliberately colored for altering the appearance of the eye.
People choose to wear contact lenses for various reasons. Many consider their appearance to be more attractive with contact lenses than with glasses. Contact lenses are less affected by wet weather, do not steam up, and provide a wider field of vision. They are more suitable for a number of sporting activities. Additionally, ophthalmological conditions such as keratoconus and aniseikonia may not be accurately corrected with glasses.
Contact lenses usually serve the same corrective purpose as conventional glasses, but are lightweight and virtually invisible. Many commercial lenses are tinted a faint blue to make them more visible when immersed in cleaning and storage solutions. Cosmetic lenses are deliberately colored for altering the appearance of the eye.
People choose to wear contact lenses for various reasons. Many consider their appearance to be more attractive with contact lenses than with glasses. Contact lenses are less affected by wet weather, do not steam up, and provide a wider field of vision. They are more suitable for a number of sporting activities. Additionally, ophthalmological conditions such as keratoconus and aniseikonia may not be accurately corrected with glasses.
Copyright ©2009 What-is.Net All rights reserved.
Last Updated: Sep 2009
Last Updated: Sep 2009
What are Contact Lenses?
Multifocal contact lenses are more complex to manufacture and require more skill to fit. All soft bifocal contact lenses are considered "simultaneous vision" because both far and near vision are corrected simultaneously, regardless of the position of the eye. Commonly these are designed with distance correction in the center of the lens and near correction in the periphery, or viceversa. Rigid gas permeable contact lenses most commonly have a small lens on the bottom for the near correction: when the eyes are lowered to read, this lens comes into the optical path.
Complications due to contact lens wear are relatively common, affecting roughly 5% of contact lens wearers each year. Excessive wear of contact lenses, particularly overnight wear, is associated with the most serious safety concerns. Problems associated with contact lens wear may affect the eyelid, the conjunctiva, the various layers of the cornea, and even the tear film that covers the outer surface of the eye.
Complications due to contact lens wear are relatively common, affecting roughly 5% of contact lens wearers each year. Excessive wear of contact lenses, particularly overnight wear, is associated with the most serious safety concerns. Problems associated with contact lens wear may affect the eyelid, the conjunctiva, the various layers of the cornea, and even the tear film that covers the outer surface of the eye.
