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Questions and Answers
What is Nylon?
What is a Carbon Filter used for?
Materials used to make frames containing threads of carbon.
What is Polyamide?
Material used to make frames that is nylon-based and very sturdy.
What are Polarized Lenses good at reflecting?
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What do UV protective lenses do?
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What are Single Vision Lenses designed to correct?
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What type of effect does image displacement have?
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What are mirror coated lenses primarily used for?
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What do anti-reflective lenses help with?
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What is the purpose of scratch resistant lenses?
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What are the mounting types that help ensure lenses stay fixed in a frame without using eyewires or nylon cords?
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What is the function of a Ptosis Crutch?
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Which materials are typically used for frames?
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What is the purpose of the Fresnel lens?
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What is meant by 'decenetation' in optical terms?
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What measurement is needed to determine the appropriate lens blank size?
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Study Notes
Materials Used in Frames
- Nylon: Highly elastic material commonly used for frames, notably changes in elasticity when wet.
- Carbon Filter: Threaded carbon frames are known for being strong, slim, and lightweight without flexibility, typically used for frame fronts.
- Polyamide: A nylon-based material that is sturdy and lightweight, weighing only 72% of cellulose acetate.
- Monel: An alloy containing 63-70% nickel, providing corrosion resistance and flexibility.
- Titanium: Exceptional for being lightweight, strong, rust-resistant, and hypoallergenic, although costly to produce.
- Stainless Steel: An iron-chromium alloy that is resilient, pliable, and sleek.
Lenses Types and Features
- Polarized Lenses: Specialized for reducing glare from surfaces like water and snow, enhancing vision in bright conditions.
- UV Protective Lenses: Designed to block harmful ultraviolet rays, safeguarding eye health.
- Single Vision Lenses: Uniform prescription suitable for correcting common refractive errors across the entire lens.
- Scratch Resistant Lenses: Coated to minimize scratching, though no lens can be completely scratch-proof.
- Anti-Reflective Lenses: Coated to reduce reflections, aiding vision in low-light conditions and reducing glare.
- Photochromatic Lenses: Adjust darkness in response to UV exposure, transitioning from clear indoors to darker outdoors.
- Fresnel Lenses: Feature concentric ridges providing a prism effect for specific optical applications.
Lens Mounting and Fit
- Rimless Mounting: Lenses secured without frames using screws or adhesive solutions, offering a minimalist look.
- Semi-Rimless Mounting: Combines screws with a metal reinforcer for lens support, maintaining a stylish aesthetic.
- Numont Mounting: Offers a unique bridging system securing lenses only at the edges near the nose, limiting contact points.
- Critical Measurements: Vertex distance is crucial for fitting individuals with aphakia to ensure appropriate lens positioning.
Temple and Bridge Designs
- Riding Bow Temple: Curved design that wraps around the ear, ideal for active individuals including children.
- Skull Temple: Matches the natural curve of the head, providing a comfortable fit.
- Saddle Bridge: Distributes frame weight evenly across the nose area, enhancing comfort.
- Keyhole Bridge: Designed for shorter noses, allowing for exposed upper nasal regions.
- Convertible Temple: Versatile design that can be straight for library use or curved for skull fitting.
Optical Principles and Measurements
- Prentice's Rule: Quantifies prism power based on lens distance from optical center.
- Aperture: Refers to openings that allow a controlled amount of light to enter.
- Decentration: The offset of the lens optical center from the frame's central position, affecting visual clarity.
- Segment Depth: The maximum vertical measure of bifocal segments on multi-segment lenses.
Practical Considerations for Opticians
- Patient Options: Provide a range of lens types, materials, frame styles, and accessories tailored to individual needs.
- Measurement Requirements: Important dimensions include pupillary distance (PD), temple length, and frame fit to ensure proper alignment and comfort.
- Frame and Lens Choices: Should consider the user's prescription, lifestyle, fashion preferences, and occupational needs.
Tools and Instruments
- Corneal Reflex Pupillometer: Accurately measures pupillary distance for precise lens fitting.
- Pick-up Screwdriver: Specialized tool for handling small screws in eyewear repairs.
- Blocker and Block: Devices used to hold lenses in place during the surfacing process.
Optometry Terms
- Astigmatism: A refractive error resulting from an uneven curvature of the eye, leading to distorted vision.
- Anisometropia: A condition characterized by a significant difference in refractive power between the eyes.
- Prism Diopter: Measuring unit for prism power, indicating the degree of light deviation caused by a prism.
Studying That Suits You
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Description
These flashcards are designed to help you prepare for the Optician License Exam. Each card highlights key terms and their definitions related to optical materials and frame construction. Use these to reinforce your understanding of essential concepts in opticianry.
