specs 1.2.3 Flashcards
(17 cards)
the purpose of the front of the spectacle frame?
The front is the part of the frame that holds the lenses in place and includes components such as the bridge, rim, and lugs.
key components of the sides (temples) of the frame?
The sides or temples extend from the front of the frame and sit over the ears. They include features like straight sides, spatula sides, curl sides, and loop-end sides.
What are the different types of bridges used in spectacle frames?
Regular bridge: A standard bridge fitting.
Saddle bridge: A bridge that rests evenly across the nose.
Pad bridge: Adjustable pads for a customized fit.
Keyhole bridge: A bridge shaped like a keyhole to fit across a wider nose base.
What are the frame measurements typically used in fitting spectacles?
Lens width: The horizontal width of each lens.
Bridge size: The distance between the two lenses, resting on the nose.
Temple length: The length of the temples (sides), measured from the front of the frame to the ear.
the significance of pantoscopic tilt?
Pantoscopic tilt refers to the tilt of the frame’s lenses toward the cheeks. It is important for aligning the optical axis with the eyes, ensuring better vision and comfort.
What is the wrap angle in relation to spectacle frames?
The wrap angle refers to the angular curvature of the front of the frame, which can influence both the aesthetics and optical performance by altering the lens positioning.
What are angular measurements in spectacle fitting?
: Angular measurements include the angle of let-back, the angle of the side, and the downward angle of drop, all affecting the fit and visual alignment of the frame.
he advantages of using plastic materials for spectacle frames?
Plastic materials such as acetate and TR90 are lightweight, flexible, and colorful, making them popular choices for stylish and comfortable frames.
What are the types of metal materials used in spectacle frames?
Metal materials include titanium, stainless steel, aluminum, and memory metals like NiTi (nickel-titanium alloys). Metals are durable, strong, and easily adjustable.
: What is Optyl and why is it used in spectacle frames?
Optyl is a lightweight, hypoallergenic, and flexible plastic material used in some high-quality frames. It retains shape and is ideal for frames requiring both comfort and durability.
Q: What are the benefits of titanium in spectacle frames?
Titanium is known for being lightweight, corrosion-resistant, durable, and hypoallergenic, making it a great choice for frames, especially for individuals with sensitive skin.
: What is acetate and what are its properties for spectacle frames?
Acetate is a biodegradable, flexible, and color-rich plastic material often used in higher-end spectacle frames. It can be customized with patterns and is relatively durable.
What is TR90 material, and how is it beneficial for spectacle frames?
TR90 is a highly flexible, impact-resistant, and lightweight material often used for active wear or children’s spectacles, providing durability and comfort.
What is the difference between memory metals and regular metals in frame materials?
Memory metals (e.g., NiTi) have the ability to return to their original shape after being bent, providing extra flexibility and durability compared to regular metals, making them ideal for frames that need to be adjusted.
Why are smaller frames preferred for high prescriptions?
smaller frames reduce lens thickness and weight, minimizing the effects of magnification and distortion, especially for myopes (nearsighted patients).
How does the material of the frame influence patient comfort and frame longevity?
The frame material affects the weight, adjustability, and durability of the glasses. Lightweight materials like titanium and TR90 increase comfort, while flexible materials like acetate and memory metals improve durability and fit.
What is Knapp’s Law, and how does it apply to anisometropia?
Knapp’s Law states that spectacles work best for axial anisometropia because they equalize the image size between the eyes by aligning the optical axis. For refractive anisometropia, contact lenses are preferred because they provide a better correction of image size.
