Knowra Contact lens Contact lens A thin optical device worn on the eye’s tear film to correct refractive errors or alter eye appearance. It moves with the eye and provides vision without eyeglass frames.
Corneal refraction : The bending of light as it passes through the cornea, which supplies most of the eye’s focusing power. A contact lens sits on the tear film over the cornea and changes the eye’s effective focusing system.
Myopia : A refractive error in which distant objects appear blurred because light focuses in front of the retina. Minus-powered contact lenses move the focus back onto the retina.
Soft contact lens : A flexible contact lens made from water-containing hydrogel or silicone hydrogel material. Soft lenses are the most commonly worn design for routine vision correction.
Eyeglasses : Wearable lenses held in a frame in front of the eyes to correct vision. Unlike contact lenses, eyeglasses remain separated from the eye and do not move with it.
Leonardo da Vinci : An Italian Renaissance artist, engineer, and inventor whose notebooks explored optical devices. His early sketches included concepts for altering vision by placing a fluid-filled vessel against the eye.
Tear film : A thin, layered fluid covering the eye’s exposed surface that lubricates and protects it. The tear film separates a contact lens from the cornea and helps it move smoothly.
Hyperopia : A refractive error in which the eye focuses light behind the retina, often making near vision difficult. Plus-powered contact lenses add converging power to bring the focus forward.
Rigid gas permeable contact lens : A firm, oxygen-transmitting contact lens that retains its shape on the eye. Rigid lenses can provide sharp correction, including for some irregular corneas.
Refractive surgery : Surgical procedures that alter the eye’s focusing power to reduce dependence on corrective lenses. It changes ocular tissue, whereas contact lenses provide removable optical correction.
René Descartes : A French philosopher and mathematician whose work shaped modern philosophy and analytic geometry. He described an eye-contacting optical device in 1637, though it could not be worn practically.
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