Materials Quiz on Eyewear Frames

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Questions and Answers

What is a key identifying feature of SPX frames?

Made solely from pure nylon

Highly flammable materials used

Typically heavy and bulky

Often marked with the Silhouette brand (correct)

Which property is NOT characteristic of Nylon (Polyamides)?

Surface dyed coloring method

Can be easily adjusted with a frame heater (correct)

High resistance to breakage

Often reinforced with metal sides

What temperature adjustment is recommended for SPX materials?

95oC (correct)

Cold glaze recommended

Not applicable

67oC

What is the primary method of coloring Grilamid frames?

Laminated Signup and view all the answers

Which material is characterized by being hypoallergenic and lightweight?

SPX Signup and view all the answers

How are the joints of Nylon (Polyamides) frames constructed?

Screwed Signup and view all the answers

What stability issue can occur with cellulose flakes frames?

Can warp or blister at high temperatures Signup and view all the answers

Which characteristic differentiates Grilamid from other materials mentioned?

It is a co-polyamide Signup and view all the answers

Which material is known for its strong yet flexible properties and is commonly used for protective eyewear?

Polycarbonate Signup and view all the answers

What feature is not applicable to polycarbonate material?

Reinforced sides Signup and view all the answers

What is a key identification point of cellulose nitrate as a material?

Bright yellow with age Signup and view all the answers

Which of the following statements about cellulose nitrate is true?

It is made with cotton linters and nitric acid. Signup and view all the answers

Which property is characteristic of cellulose nitrate?

Highly flammable Signup and view all the answers

Which property is NOT typically considered when selecting an optical frame for a patient?

Color preference Signup and view all the answers

What is a crucial reason for measuring facial aspects in frame selection?

To ensure the frame fits properly and comfortably Signup and view all the answers

Which characteristic is LEAST desirable in an optical frame material?

High specific gravity Signup and view all the answers

Which of the following is NOT a benefit of understanding frame materials?

Selecting frames based on aesthetic appeal alone Signup and view all the answers

What is the significance of the amount of plasticisers used in the manufacturing of plastic frames?

It alters the frame's strength and flexibility characteristics Signup and view all the answers

Which aspect is NOT generally adjusted during fitting to optimize an optical frame's performance?

Frame weight Signup and view all the answers

What is emphasized as an important aspect of communication when advising patients on frame selection?

The balance between aesthetics and practicality Signup and view all the answers

Which material property contributes significantly to a frame's adjustability?

Flexibility Signup and view all the answers

What is a key characteristic of aluminium compared to other metals?

It is lightweight but very rigid. Signup and view all the answers

Which joint type is commonly used with aluminium?

Screwed Signup and view all the answers

What is the main advantage of using a chemical resistance layer with base metals?

To provide anti-corrosion properties. Signup and view all the answers

What is the primary feature of gold wash in manufacturing?

It involves a very thin layer of gold. Signup and view all the answers

Which material is reported to be 8 times more flexible than stainless steel?

Shape metal alloys Signup and view all the answers

What is a characteristic limitation of materials made from horn?

They are extremely rare and hard to find. Signup and view all the answers

What typically enhances the stability of aluminium?

Rigidity and corrosion resistance. Signup and view all the answers

What is a defining property of natural materials such as wood and cork in eyewear?

They are sustainable and made from managed sources. Signup and view all the answers

What is a key identifying characteristic of Polymethyl Methacrylate (Perspex) used in designs?

Typically exhibits a shiny finish Signup and view all the answers

Which statement about Production is correct?

Routing is employed, making it non-moldable. Signup and view all the answers

What is the flashpoint of the materials discussed, indicating their flammability?

70oC Signup and view all the answers

What unique property does Nickel Silver/Monel carry regarding allergenic reactions?

It can cause allergies in some individuals. Signup and view all the answers

Which of the following statements best describes the chemical resistance of the materials discussed?

They are resistant to most household chemicals. Signup and view all the answers

What is the adjustment temperature for Polymethyl Methacrylate (Perspex)?

68oC Signup and view all the answers

Which component is typically NOT part of metal frames mentioned?

Reinforced plastic sides Signup and view all the answers

What is a common property of Nickel Silver/Monel manufacturing?

It contains combinations of copper, nickel, and zinc. Signup and view all the answers

What does the box lens size measure?

The vertical and horizontal dimensions of the lens shape Signup and view all the answers

How is the distance between lenses (DBL) defined?

The distance from the apex of one lens to the apex of another Signup and view all the answers

What does the term 'bridge width' specifically refer to?

The distance measured between the pad surfaces of the frame Signup and view all the answers

What is meant by the 'angle of side'?

The vertical angle between a normal to the back plane and the line of the side Signup and view all the answers

Which measurement describes the distance from the dowel point to the ear point?

Length to bend Signup and view all the answers

Which term refers to the downward inclination of the drop?

Downward angle of drop Signup and view all the answers

What does the total length of side refer to in a curl side?

Overall length from the dowel point to the extreme end Signup and view all the answers

What is the purpose of facial measurements in eyewear fitting?

To ensure the correct frame fit and lens position Signup and view all the answers

Study Notes

OPT505: Clinical Skills and Refractive Management

Course covers frame materials and frame measurements for clinical skills and refractive management.

Core Competencies

4.1.1: Ability to advise on, order, and dispense the most suitable form of optical correction, considering durability, comfort, cosmetic appearance, age, and lifestyle (including multifocal).
4.1.2: Ability to adjust a spectacle frame or mount to optimize physical and optical performance.

Aims of Today

Understanding different types of frame materials.
Understanding their manufacturing process.
Discussing the properties of various frame materials.
Selecting the most appropriate material/frame for different patient prescriptions and lifestyles.
Describing standard frame measurements.

Ideal Properties of a Frame

Material properties.
Weight considerations.
Suitability for the patient.
Adjustable features.
Other relevant factors.

How Should It Fit?

Placement on the face.
Adjustable aspects of the frame.
Facial aspects important in frame choice.
Potential issues with a poor frame fit.
Other relevant factors.

What Measurements Would We Need?

Frame measurements.
Facial measurements.
Importance of these measurements.
Other relevant considerations.

Why is Frame Choice Important?

Frame materials affect recommendations for: allergies, lifestyle, prescription needs, and cost.
Advice is provided on the care and fit of frames.
As a practitioner, the ideal frame is: low-cost, easy to glaze and process, widely available, hypoallergenic, high thermal and chemical resistance, stable material, low specific gravity (weight), strong, and easy to adjust.

Plastic Materials

Shapeable and moldable materials.
Mixture of long-chain polymers and plasticisers.
The amount of plasticisers impacts frame properties (e.g., brittleness or hardness).
Plastic groups are categorized based on heat adjustability: thermosetting, thermoplastic, and thermoelastic.

Groups of Plastics

Thermosetting: Cannot revert to a plastic state after being molded. Examples - carbon fiber and polyester.
Thermoplastic: Can be remolded by heating and cooling. Most frame materials are thermoplastic.
Thermoelastic: Has a memory of the original shape, reverting to it when heated past the recommended temperature. Optyl is an example.

Cellulose Acetate

Most common plastic frame material.
Easy to manufacture and cheap.
Initially easy to adjust but prone to drying out with age (requiring higher temperatures).
Prone to warping, especially in harsh environments.
Dissolves in acetone.
Sides are reinforced.
Common/cheap material.

Cellulose Propionate

Very similar to acetate.
Easy to manufacture and cheap.
More resistant to aging compared to acetate.
Sides are always reinforced.
Injection-molded joints.
Very shiny, hard finish.

Nylon (Polyamides)

Commonly used in children's frames, safety eyewear, and sunglasses.
Can be pure nylon or mixed with other materials to increase flexibility and other properties.
Difficult to adjust (avoid using frame heaters).
Often has metal reinforcement.
Distinctive feel compared to other plastics.
Often reinforced or mixed with metal sides.
Blended nylon frames are commonly used for babies and toddlers.

SPX (Silhouette)

Unique; other manufacturers are now using similar materials.
Hypoallergenic.
Lightweight and elastic for easy adjustment.
Cold-glazed frames.
Almost always identified as Silhouette.
Often clear with color on the top layer.
Unusual shapes; precision glazing is used.

Grilamid (TR90 & GTR55)

Transparent co-polyamide.
Cannot be distinguished from other types with the naked eye.
Found in various products (coffee machines, petrol pumps, etc.).
Cheap and easy to produce.
Transparent plastic.
Partial reinforcement (usually at the bend).
Cold glaze.
Resistant to most chemicals (apart from alcohol cleaner).

Epoxy Resin (Optyl)

Memory plastic (thermoelastic).
Easily adjustable to any shape when maintained while cooled with cold water.
Returns to original shape when reheated.
Hypoallergenic.
Identified by "Optyl" on frames.
Short side reinforcement.

Carbon Fibre

Frame fronts only.
Cannot be adjusted (cold-glazed).
Lightweight and very strong.
Normally opaque.
Front material only with metal sides.
Limited color range.

Polycarbonate

Commonly used for safety specs and sports goggles.
Extremely strong material.
Often used for protection eyewear (sports/occupational).
Sides not reinforced.
Strong, but with flexibility.

Cellulose Nitrate

No longer used as a frame material (banned in the UK due to flammability).
Illegal to re-glaze a cellulose nitrate frame.
Made from cotton and nitric acid with a camphor elasticise.
Camphor smell when filed.
Turns yellow with age.

Polymethyl Methacrylate (Perspex)

Much less common now.
Popular in the 1960s.
Lightweight but rigid and brittle.
Difficult to adjust if not heated to correct temperature.
Usually used for supra (half-frame) designs.
Sides are not reinforced.
Very shiny finish.

Metal Frames

Metal commonly used in frame parts or complete frames.
Types include pure metals and plated/alloy metals.
Typically consist of base metals (structural), plating (layers), lacquer coating, and plastic tips/nose pads.

Nickel Silver/Monel

Most common metal frames.
Cheap and easy to manufacture and adjust.
Combinations of copper, nickel, zinc, magnesium, iron, and manganese.
Not hypoallergenic (nickel and other allergies common).
Difficult to distinguish one from another.
Cheaper than other metals.
Heavier than some other types.
Not used in rimless mounts or half frames.

Stainless Steel

Assembled by welding (not soldering).
Often used for brow bars in rimless or combination frames.
May be coated with silver, gold, or colored plastics (making identification difficult).
Lightweight, Strong, but Not flexible;
Commonly used in half frames or rim-less mounts.

Titanium

Fourth most abundant metal element.
Expensive to produce, not readily soldered (requires lasers).
Flexible and lightweight.
20% more elastic than nickel silver / half the weight.
Highly resistant to corrosion.
3 times harder than gold filled.
Hypoallergenic.
Lightweight and flexible.

Gold

Too expensive and soft to be used in many frames.
Common types include 18 carat and 12 carat (partially alloyed).
High-quality gold marked (Hallmark).

Rolled (Filled) Gold

Gold skin bonded to base metal (often nickel silver or bronze).
Quality stamped on the frame as a fraction (e.g., 1/10 or 12 carat).
Not hypoallergenic (due to metal mixture).
Easily repaired via soldering (can discolour).
Identified by a stamp on the frame, french pin joint, and/or gold color.

Gold Plated

Cheap inferior version of rolled gold with less gold used.
Easily produced.
Often finished with an anti-corrosion layer.
Looks like costume jewelry (yellow color).
Ages improperly.
Cheaper frame.

Aluminum

Lightweight, strong, and very rigid.
Difficult to manufacture but more expensive than Nickel silver.
Very difficult to adjust.
Lightweight but very rigid.
Cold to the touch.
Typically thicker than stainless steel and titanium.
Matt finish.

Other

Gold Wash: Chemical deposition of a thin gold layer on a base metal, often found in inexpensive sunglasses.
Shape Metal Alloys: Alloys of copper, aluminum, zinc, and titanium. More flexible than other metals, often used in bridge and side components to create a more flexible frame

Natural Materials (Wood/Cork, Horn, Turtleshell)

Wood/Cork: Sustainable, 42% natural materials (wood, cork or plant-based cellulose). Recycled plastic sides are sometimes included for ease of adjustment.
Horn: Extremely rare (mostly Buffalo or Yak horn). Very difficult to adjust.
Turtleshell: Primarily Hawksbill Turtle shell (endangered). Made by layering plates together under steam, colored according to the part of the shell used (green, red, or amber). Metal is frequently included to create joints but could be adaptable up to 75°C.

Frame Types

Supra: Semi-rimless frame.
Full Frame: Encompasses the entire lens.
Rimless Mount: Without a frame rim.

The Bridge

Regular: Standard bridge.
W: Wide bridge.
Saddle: Bridge with a saddle shape.
Keyhole: Bridge design with keyhole shape.
Pad on Arm: Adjustable pads supporting the arms.
Comfort: Comfortable fit.

Joints

Plastic - Heat inserted: Plastic joint inserted with heat.
Plastic - Pinned: Plastic joint fastened by pins.
Rimless- Screw & bolt: Rimless type fastened by screws and bolts.
Pinned: Joints secured with pins.
Plugged: Joints inserted via plugs.

Sides

Reinforced: Strength-added to the side for reinforcement.
Not reinforced: Lacks reinforcement.

Ends

Drop end: Downward sloping end.
Curl: Curved end.
Loop ends: Loop-shaped ends.

Frame Fitting Scenarios

Description of how a frame is misaligned, with suggestions for correcting positioning.

Facial Measurements

Procedures for taking facial measurements to ensure correct frame and lens positioning. Necessary equipment includes a city rule and potentially calipers. Video tutorials and guides are available on the platform.

How to Measure a PD

AOP student guide to measuring a PD.

Box Lens Size

Dimensions of the rectangle encompassing the lens. Vertical and horizontal box lens sizes are measured and recorded.

Distance between Lenses (DBL)

Distance between nearest points on apices of two lenses.

Box Centre Distance

Distance measured between the most nasal and most temporal points (of opposing lens).

Bridge Width

Minimum distance between pad surfaces measured along the bridge width line.

Bridge Height

The vertical distance from the bridge-width line to the lower edge. 5mm more than crest height.

Splay Angle of Pad

Angle of pad plan, related to front plane to position the pads.

Frontal Angle of Pad

The angle between horizontal and intersecting pad plane.

Distance between Rims (at 10mm and 15mm).

Measurements of the distance of the rims below nose crest that are at 10 and 15mm, respectively

###Apical Radius

Radius around nose crest. Determines contact fit of the bridge. Larger is better if unsure.

Crest Height

Distance from the crest of the nose to the lower eyelid or lower limbus. 5mm more than crest height is the bridge height.

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Description

Test your knowledge about the various materials used in eyewear frames, including SPX, Nylon, Grilamid, and cellulose nitrate. This quiz covers key features, properties, and manufacturing methods that define each material. Ideal for students and professionals interested in eyewear material science.