Contact Lenses - PDF

Introduction to contact lenses Definition it is a thin lens considered to be a medical device placed directly on the surface of the eye to – correct vision – cosmetic – therapeutic r...

Introduction to contact lenses Definition it is a thin lens considered to be a medical device placed directly on the surface of the eye to – correct vision – cosmetic – therapeutic reasons  Leonardo da Vinci – first describe the concept of a lens that comes into contact with the eye. (1508) John Herschel – describe a glass contact lens designed to match the shape of the eye (1827) F.E. Muller – fitted a blown glass lens to the eye of a patient whose eye had been surgically removed. (1887)  A. E. Fick – describe the first contact lens intended to correct vision. (1888) Muller and Obrig – constructed the first plastic scleral contact lens (1938) E. Kalt – designed and fitted glass corneal contact lenses (1940’s) – All contact lenses available were scleral types Kevin Touhy – first plastic corneal lens made from PMMA (1947) Otto Wichterle – Developed HEMA According to Material – Hard Non- gas permeable Gas permeable – Soft Conventional disposable According to Design – Monocurve – Bicurve – Tricurve – Aspheric According to Size – Corneal – Semi-corneal – scleral According to Mode of Use Daily Wear – Disposable – Planned replacement Extended – Continuous wear – Flexible wear According to purpose or Use Optical – Spherical – Toric – Presbyopic Therapeutic cosmetic Spherical Contact Lens Used to correct Hyperopia, Myopia, Aphakia and small amount of astigmatism Available in wide range of correction (- 20.00D to +20.00D) Toric Contact Lens For the correction of significant amount of astigmatism Presbyopic Correction Monovision or monofit – One eye is fitted with the proper distance vision power and the other eye is fitted with the power necessary for near vision. Bifocal soft contact lens – Alternating vision Distance viewing is done through the top part of the lens and near viewing is done through the bottom portion of the lens – simultaneous vision The patient looks through both the distance and near portion of the lens at the same time Multifocal Tinted contact lenses visibility tints – Effective on blue and other relatively light colored eyes – Makes handling easier Opaque colored lenses  Lenses that can actually change the apparent color of the eye by making the original color masked while introducing a new color Therapeutic (Bandage) Lenses Used to promote healing for a variety of corneal disease conditions Ortho-K contact lens gas permeable contact lenses that temporarily reshape the cornea to reduce refractive errors such as myopia, hyperopia and astigmatism Hybrid contact lenses large-diameter lenses that have a rigid gas permeable central zone, surrounded by a peripheral zone made of soft or silicone hydrogel material Wink activated telescope contact lens 1.55 millimeter-thick contact lens contains an extremely thin, reflective telescope, which is activated by winks. The wearer winks with the right eye to activate the telescope (2.8x magnification), and with the left eye to deactivate it. Intended for for low vision and age-related macular degeneration Google contact lens contact lens prototype that monitors glucose levels in tears Triggerfish contact lens The SENSIMED Triggerfish® Sensor is a soft disposable silicone contact lens embedding a micro-sensor that measures intraocular pressure iOptik™ contact lens enhances vision and enables visualize their digital world at the same time. It allows light from the display to pass through the center of the pupil, and light from the surrounding environment to pass through the outer portion of the pupil. Each of these sets of light rays produces an image on the retina simultaneously with the other set. They are superimposed to form a single integrated image. Terminator Eyes contact lens show images such as road directions or projecting text messages from smart phones straight to the eye