Contact Lens (midterms)
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62 questions
| 🇬🇧 | 🇬🇧 |
| Sketches of a schematic eye and describes the mechanism of image formation from cornea to the optic nerve. Some drawings represent the idea of contact lens | Leonardo Da Vinci 1508 |
| He attempted to show how various optical phenomena in myopes were corrected with spectacle glasses applied to the cornea | Philip De La Hire 1685 |
| He also used a water filled tube to study the accommodative process | Thomas Young 1801 |
| He is the first person to apply a therapeutic contact device. He used gelatin square soaked in mercury chloride | Xavier Galexowski 1886 |
| Devised a spectacle with saline-filled lens cup-'water spectacles'. This cup should be worn for 1 to 1.5 hours. He's bilateral keratonic. His device is known as hydrodiascope | Thomas Lohnstein 1896 |
| He improved the Zeiss lens by enlarging the series of the trial lenses. He also used a supplementary curve between the corneal and scleral component. | Leopold Heine 1930s |
| They produced an acrylic resin for the aviation industry | Rohm and Haas 1930s |
| They developed and patented the material poly methyl methacrylate (PMMA) | J Crawford and R Hill of ICI 1934 |
| His patent got rejected on the first PMMA corneal contact lens | Dennis C England 1946 |
| His lens was patented as the first corneal contact lens | Kevin M Tuohy 1946 |
| The National Patent Development Corporation and _____________ bought spin-casting patent rights in 1964 | Robert Morrison |
| Then the _______________ acquired Breger's technology in 1972 | Dow Corning Company |
| He pioneered the development of continuous wear of soft contact lenses. | John de Carla 1970 |
| What material did J Teissler use for his RGP CL? | Cellulose Acetate Butyrate |
| They are collaborators in making RGP contact lenses | Norman A, Leon A Reich and Edward Ivani |
| He developed collagen contact lenses and conceived the concept of throwaway or disposable lenses | Orlando Battista 1978 |
| Daily disposable lenses was first developed and marketed by? | Vistakon, Johnson and Johnson |
| SCL Design Factors | Geometric Center Thickness Lens Diameter BOZR Back Surface Design FOZR Front Surface Design Radial Edge Thickness Edge Design Material Physical/Mechanical Properties Material Physiological Properties Peripheral Junctional Thicknesses if transitions exist. |
| Center Thickness Considerations | Dk/t Pervaporation prevention Fitting considerations Little or no movement |
| Design Considerations Minus Lens Series | Select a material Practical FOZD Center thickness for lenses of about -3.00D and greater Lenses <-3.00D often made thicker and/or with a larger FOZD to improve handling Lenses >-5.00D may have FOZD decreased to reduce mid-peripheral thickness |
| Design Considerations Plus Lens Series | First junction thickness Select FOZD. Center thickness reduction by FOZD reduction is limited by vision issues No degrees of freedom remain. |
| Water Content | Low H2o - 20 to 40% Med H2o - 41 to 60% Hi >60% |
| It is also called as corneal dehydration | Pervaporation |
| If lens is too thin, corneal dehydration may result to | Due to bulk flow of water through lens and instability of water flow at a surface Subject to individual variation Worse with higher water content Results in corneal dehydration from water loss to air via lens |
| Corneal dehydration produces _____________ which is also known as pervaporation staining | Epithelial Desiccation Staining |
| SCL Design other Considerations | Centration - vision comfort mechanical Movement - debris clearance, comfort |