Optics III

• Eyewire
• bridge
• endpieces (where temples attach to the frame front)

• butt portion
• shaft
• bend
• earpiece

small wire arm that holds the nose pad in place

makes up majority of plastic frames on the market.  Made from cotton linters, some liquid chemicals and plasticizer.

nickel (65%) based metal with copper and iron

disadvantages--plating can wear off--skin allergies, heaviest of metal frame materials

at least 90% of frame is titanium with no nickel

• Cellulose Nitrate (zylonite)--FLAMMABLE
• Propionate--Lighter weight than zyl
• Optyl--Stronger and lighter than zyl, epoxy resin with thermo-elastic memory, hypoallergenic
• Nylon/Polyamide--lightweight, flexible, durable, translucent, hyperallogenic, chemical resistant
• Carbon Fiber--combined with nylon/thin, light, strong, NOT ADJUSTABLE
• Polycarbonate--sport/safety purposes
• Kevlar--combined with nylon/strong and lightweight, IMPOSSIBLE TO ADJUST
• Rubber--sports eyewear, sunglasses frames, swim goggles

at least 70% titanium and no nickel

metal frame has a solid metal band that surrounds the entire lens.  Lens is held in place in a groove in the eyewire, which is tightened around the lens with a screw.

When one lens appears higher than the other

• Start at bridge and work out towards temples
• look for skewing (horizontal alignment)
• 4-point touch for vertical alignment (face form, x-ing, variant plane)
• temple spread
• temple parallelism--flat surface touch test
• pantoscopic tilt
• temple bend
• temple fold (case angle)

• Temple spread--does your PD ruler fit between the temple and side of patient's head?
• Vertex distance--is it equal?  Have pt. look down, view from above
• Pantoscopic Tilt--look at patient's profile
• Level eyewires--is one side higher than the other?
• Temple bend position--look behind ears to evaluate

the vertical position of the pads when viewed from the front (should be ~20 degrees)