PPT-Light and Lenses:

How Do Your Eyes Help You See A lens is a curved surface like a piece of glass or plastic Its curved shape makes light bend Lenses can make objects appear bigger or smaller to our eyes What is a lens. gpliinfo brPage 3br Vertex Conversion Chart minus plus 387 400 425 400 425 450 425 450 475 450 475 500 475 500 525 500 525 562 512 550 587 537 575 612 562 600 650 575 625 675 600 650 700 625 675 737 650 700 762 662 725 800 687 750 825 712 775 850 725 Dhavid Cooper Brought to you courtesy of FramesDirectcom and provided FREE of charge Around the age of 40 most people start to have difficulty focusing at close range The first indication that something is changing is that your single vision lenses Cara Morris, OD, FAAO. Types of Contact Lenses. Soft. Silicon . Hydrogels. Hydrogels. Gas Permeable. Hard (PMMA ) not used anymore. Hybrid. Synergeyes. (RGP in center and a . hydrogel. skirt). Soft Contact Lenses. Meet the microbes!. Escherichia coli . prokaryote. divides every 20-30 min.. (lab uses nonpathogenic strain) . Saccharomyces cerevisiae. eukaryote. divides every ~90 min. . Microscopes are required to see individual microorganisms. Recognise and use key words relating to lenses:. Focus / focal point, focal length. Optic centre. Principal axis. Use ray tracing to find the location of images in lenses.. Describe the images formed in lenses.. Light. Light Energy. Light Energy. Energy is the ability to cause things to change. Light is a type of energy. Without light no one can see anything. Light gives things color. Light shines on plants and makes them grow. Some doctors use light energy to perform operations with lasers. Light energy can make cars move. Satellites turn light into electricity in space.. Photo Terms. Focus is not an absolute. There is always a zone either side of the focused point that is acceptably sharp. The size of this zone will depend on how far away the subject is; the focal length and aperture of the lens; the size of the final picture; and what you regard as 'acceptable'. . JATIN ASHAR. MUMBAI EYE CARE CORNEA AND LAISK CENTRE. NO FINANCIAL DISCLOSURE. Contact Lens in Extreme Ectasia . Old wine in a new bottle!. Rose K - XL. Semi Scleral and Scleral CL. Hybrid CL. Topography Based Traditional CL Fitting Guide. 12.2 Refraction of Light. 12.3 Total Internal Reflection. 12.4 Refraction by Thin Lenses. 12.5 Ray Diagrams for Thin Converging Lenses. Chapter 12 Light. 12.4 Refraction by Thin Lenses. Learning Outcomes. Light . travels through space in . straight lines. . If a ray of light meets a body in its passage through space one of three things may happen. :. It may be . absorbed. . It may be . reflected.. It may be. light bends or refracts when it moves from one medium to another. the light bends because it changes speed. if light slows down it bends toward the normal. if light speeds up it bends away from the normal. Mirrors. Recall that your eyes gather light reflected off of objects . This allows you to see the objects. Light can reflect more than once. Light bouncing off of you can then bounce off of a mirror. Section 1: Objectives. Use. ray diagrams to show how light is reflected or refracted.. . Compare . plane mirrors, concave mirrors, and convex mirrors.. . Use. ray diagrams to show how mirrors form images.. mTBI. Photophobia. Kia B. Eldred, OD, FAAO. Diplomate. in Low Vision. Staff Optometrist. Michael E. . DeBakey. VAMC. Mechanism of Photophobia. “Photophobia” is a misnomer – it means fear of the light. It denotes patients who have an abnormal sensitivity to light. “Photo-.