Module 6: Ophthalmic Frames Flashcards
- holds lenses
- called eyewire
- plastic/metal
- full/semi/ rimless
-semi=string mount=beleved flat lens - combination=plastic top/metal bottom
Front
-frame front joins 2 eyewires together
- supports on px nose
- Saddle/keyhole/modified saddle
- saddle= one curve> distribute weight evenly
- modfied saddle= added nosepads
-keyhole= old fashion keyhole>top flares out> rests at side nose= not on the crest
-metal frames = nosepads
Bridge
- attached to “gaurd arms/pad arms”
- guard arm shapes (horiztonal ?/inverted U) or (American arm gaurd/ European arm guard)
- attached with screws/snap on/clips (rayband)
- plastic/silicone/ceraminc/glass/titanium
- plastic = hard & durable
- silicone = soft but replaced often (allergy is red/itchy)
- can have customized guard arms onto plastic frame
Nose Pads
-located @ outer edge of frame front
- hinges located here (mounted on or in/connect to temple)
-endpiece and temple have half barrels to connect
- Barrel is where the screw goes to hold peices together
- some frames are continous (no endpiece)
- 3 types
1) Mitre (45 * angle meeting point)
2) Butt (90* angle meeting point)
3)turn-back (frame wraps around to meet temple)
Endpieces
- attach to frame front & wrap around ears
-butt end = temple location closest to frame front - bend= first starts to bend at the ear
-shank/shaft/length to bend (LTB)= distance between butt end/bend
-earpiece = part that wraps around ear
-skull/paddle/spatula= most common, silicone tips (doesn’t wrap ear) - Library- wraps skull not ear (take on/off freq)
-cable= tight wound coil, wraps around whole ear to lobe (children, doesn’t slide)
-Spring hinge= take impact
Temples
- insertion/mounting/glazing = same thing
Lens insertion/removal
- heat usually used acetate (zyl)
-Optyl MUST have heat or will SNAP - cellulose propionate/polyamide = cold mounting/snapping (squishy thin plastic)
Plastic insertion
-clean from debris
-warm up temple (air blower)
-frame facing you> temple edge in first
-both thumbs> push front surface @ naval side
-double check in place around
- can do bridge adjustments while still warm
-rolling= lens rolls over frame> correct eyewire inward
Zyl/ Optyl insertion
- requires heat (optyl more so)
-wrap lens w/ soft cloth - air blower > bridge area
-thumbs back lens @ bridge> push outwards
-bead heater= frame parallel to top beads> constant movement (no lens protection)
Zyl/Optyl removal
- same as zyl but no wrapping or heating required
Polyamide/polypropionate insertion/removal
-same as zyl but use warm water to heat up
Nylon insertion/removal
- uses screws to loosen eyewire/lens
- match lower/upper curves
- use hockey puck/work bench (prevent slipping)
- consider self-tapping screw (pointed tip/can be shortened)
Metal frame insertion/removal
l - lenses mounted directly to bridge/temples
- small holes drilled nasal/temple
-screws/nylon plugs secure lens to frame
- screws earier to replace
Drilled rimless insertion/remova
- nylon cord/semi-rimless
-check cord properly threaded - place lens in top frame first
- used hook ribbon to control nylon placement
- start at nasal end> stretch over lens
- check cord tension
String mounted insertion
- use ribbon> pull string away from lens@ temple
String mounted removal
- older metal frames made of gold
- combo of alloys (nickle/copper/trace elements)
- most common
-wide range of colours - corrosion resistant
- less allergic reactions
- holds adjustments well
Monel metal Frame
- alloy metal (iron/chromium)
- mostly childrens frames
- light weight
-strong and thinner than Monel - cheaper than titanium
-corrosion resistant - hypoallergenic
- limited colours
-difficult to solder - hard to curve for high case curves
Stainless Steel Frame
- used in pure form or mixed alloy
- extremely strong/durable
- very light weight
- common in rimless frames
- hypoallergenic
- corrosion resistant (humid climates)
- blended with nickel= memory metal
- expensive
- limited colours
Titanium Metal frames
- regaining popularity
-wide variety colours - non-corrosive
- light weight
- difficult to adjust
- finish scratches easily
- cannot solder
-pad arms/hinges must be riveted - repairs difficult
Aluminum metal frames
- revolutionary titanium nickel alloy
-light weight - durable/flexible
- keep shape after twisting
- great for children
- hard to make adjustments
Flexon metal frames
-Zyl/ Zylonite
- rolled into sheets/ parts stamped out
- variety of colour/texture
- designs vary due to dye lots changing
-hinges sunken by heat/rivet
-can be tinted
- heated for adjustments
- has metal core to hold shape
- heavier
- tends to fade
- break in cold weather
- milk white coating with age
- overheating = blisters
Cellulose acetate plastic frames
- “propionate”
- injected into molds
- thinner plastic
- malleable feel
- must be cold mounted
- lighter than acetate
- cheaper
- very sensitive to heat
- has no material memory
- lens inserted room temp
- acetone/alcohol= discolouration
Cellulose Propionate plastic frame
- nylon blend
- injected into molds
- thinner/malleable
-cold mounting lenses - heat = shrinks eyewire
- light weight
- flexible
- strong/scratch resistant
- colours don’t fade
Polyamide plastic frames
- trademarked material
-epoxy resin - has memory
- bent any shape with heat>cooled
-re-heated returns to original shape
-high luster - will break/snap without heat first
- never opaque
-hypoallergenic
-wide range colours
Optyl plastic frames
- sports/safety/sunglasses
- durable
- not flexible
- solid colours only/limited
- light weight
- hypoallergenic
-impact resistant - adjusting/mounting difficult
- brittle when dehydrated
- soak in water monthly
Nylon plastic frame
- protective shields/sport/safety
- same material as lenses
-impact resistant - lenses can be moulded into frame (one unit)
-virtually unbreakable
-limited colours - difficult to adjust
- avoid acetone
Polycarbonate plastic frames
- “graphite”
- alternative to metal frames
- nylon mixed strands carbon fiber
-light weight - thinner than acetate
- always opqaue
- limited colours
- can snap adjustments in cold
- difficult to adjust
- not great for high base curve lens
- eyewire close with screws
Carbon Fiber plastic frames
- unfreezing
- use oil/heat/ ultrasonic cleaner
- loctite= loosen with heat
Remove stuck screws
- extractor/slotting file/punching/drilling)
-grasp with plier> twist out threads - use long screw &nut OR self-tapping screw
Remove broken screw
- barrels spread apart
- remove screws first
- use double nylon plier/needle nose plier
-press bottom/top hinge together - space with paper clip/ cardboard
Tighten loose hinge
- use quality cutter
- ant clean edges (risk of injury to fingers)
- flat rasp/thumb file to soften edges
- cover exposed frame areas prevent damage
Cut/File long screws
-peening/nail polish/ adhesive sealant
- not common
- use loctite ( not in hinges)
- peening =plier (splays) screw across opening
- clavulis press can help
Secure screws
- temple hinge= key factor
- same barrel size/ # of barrels
Replace temples
- notice mounting type/size/material
- changing style/size = frame adjustments
Replace nose pads
- match colour/length
- cut off old with pliers/ heat & slide
- straighten bend first= easier
Replace plastic earpiece covers
- cutting/filing
- thinner metal temples ideally
Shorten long temple
-some plastic frames can shrink with heat
- metal frames = lens liner (1/4 eye size)> into bevel
Loose lens in eyewire
- not all metals can be soldered
- short-term fix
Solder broken metal frame
- remove broken cord
- cut diagonal end new string
- string thru nasal end first> clamp> push thru lower hole
- check cord length> string into lower temple> insert lens> pull tight> mark/dent placement
-remove lens - re-string cord into TOP temple hole
- use ribbon to control cord
- insert lens
- clip off extra cord leaving 3mm
Broken nylon cord
- replace screws and bolts
- might need washers prevent lens damage
- nylon plugs = correct pliers
-use tape to protect lens
-clip backside of plug/ take out - move tape to front holes> puncture w/pin
- insert new at back first
-pressing backside> green handle trimmer> cut plug flush front lens
-push pin to open the cut end tubes> enlarge/flare w/ pin circular motion
-remove tape
-insert metal mount> gently rocking - blue tip gripping pleir> gently close plier
Repair rimless
- heat pan/ salt pan/ glass beads/ air blower
- rotate for even heating
- salt = hotter than air blower
- stir salt with wooden spoon
- wrap in cloth prevent damage
Heating equipment
- remove lenses before ultrasonic cleaners
- ultrasonic cleaner 1-2 mins
- soft toothbrush> mild soap
- palstic not ideal for ultrasonic (soap/water)
Cleaning equipment
- Bench alignment= aligned before adjusting frame
- benching when back from lab
- make sure all screws are tigth
- bridge> eyewire>endpieces>temples
Standard Alignment
-horizontal alignment= endpeice/eyewire/bridge are level
Bridge alignment
-one lens tilts out/ other tilts in (one lens closer to cheek)
- view bridge from side
- not parallel
X-ing
-view from the front
- one lens higher off the table (bridge bent)
Skewing
- view bridge from top
- one lens more forward than the other towards the eye/face
Coplanar adjustment
- suppose to follow curves of skull/head
- too much face form = distortion
- adjust is px PD is less than frame PD
Face form
- should be 90* parallel to eyewire/hinge
Temples
- angle of bottom lens
- usually 8-10* inward> toward cheeks> further from eyes
- both side should match
Pantoscopic tilt
- angle of bottom AWAY from cheeks> top closer to eyes
Retroscopic tilt
- no tilt/ straight verticle downwards
-2* of tilt changes OC by 1 mm
Orthoscopic tilt
- should be 45*
- same distance from hinge each side
Earpeices
- temples should cross at center bridge
- keep closed while adjusting
- use temple-angling/finger-peice (parallel jaws)
Temple fold
-use nosepad pliers/snipe nosed pliers/needle nose pliers/square-round pliers
-Frontal angle (tops closer/ bottoms further apart)
-Splay angle ( inside edge closer than outside)
-Verticle angle (bottom tip closer to eyewire/ top further from eyewire)
Nose pads
- only touching the px nose/ side of head/ ears
Fitting triangle
- check if bend is located infront of ear
- dissappear behind ear> no visible curve
1 Temple bend
- only touching slightly @ top of ear
- too much pressure= frames moving forward
- too little pressure= lacks stability
- unequal pressure = vertex distance error
- lens IN-temple IN/ lens OUT- temple OUT
- adjustments at butt ends/endpeices
2 Temple spread
- OD too high? raise OD hinge upwards
- OS too low? bend OS hinge downwards
- watch panto tilt/ cheek touching
- even with uneven ears
3 Level Front front should look horizontally level
- sitting too low/high on nose (OC decentered)
- use bridge-widening/ narrowing pliers
- change nose pad distance
- watch vertex distance (needle nose pliers)
4 Frame height
- full surface nose pad touching the nose
- uneven contact = marks/soreness
- sit halfway between crest & inner canthus
- too big if pressing into inner canthus
-silicone pads sticky OR soft (depends on px)
5 nose pad angles
- 2 bends
1) behind root of ear (ear joins head) - too far forward = temple lift up
2) inward curve match skull shape
6 temple/earpiece
- pull frame forward> check equal tightness
-lift the frame up & drop back down - ask if feeling too tight/loose
- dont place on top of head when not using
7 Final check
1)appropiate for lens Rx (consider lens weight & thickness)
2)fit px facial structure (face shape/skin tone)
3)perform for intended use (computer/sports)
4)should look attractive
- dont make assumptions about px budget
- ask open-ended questions
- listen (dont interrupt px)
- offer high qaulity/ attractive FIRST (px often buy first frame tried on)
- px concerned cost> offer mid-range next
- discuss durability
-avoid letting px browse alone> maintaine control
- don’t show more than 2-3 frames at a time
- square face = rounded edges
- wide jaw = high temples
-high bridge = saddle style (shorter illusion)
- green skin undertone= avoid yellow/green/blue
- explain WHY features of frame style
- give technical reason for disagreements
Frame selection
- offer to return with friend/family
- seek opinions of coworkers
- send the px home with 2 styles
- take a photo
- suggest returning another day (refreshed)
- encourage looking through fashion mags
Indecisive px
-also working with parent
-adress child/important opinion too
-frames flatter than adults
-wider bridges
- shorter temples
- fit around ears with high rx (balance weight)
-child must like or won’t wear
Children
- dark frame =draw attention features
- light frame = minimize facial features
- explain WHY its complimentary
-Square = rounded edges (softer angles)
-Oval = anything - Triange = oval/midheight temple
-inverted triangle = higher temples - Round = squared edges/ higher temples (create angles)
-Diamond= shallow ovals/geometrics/rectangles/
high temples - Rectangle= round/square/ mid height temple (soften)
Face Shape
- shaft/shank should not press into the side of head
- should not see any gaps side of head
- major critia of frame fit
- wide front hindge helps narrow PD
-spring hinge can accidentally look good fit
Head Width
- most important fit features
- no gaps/ no slips (px wrinkle nose)
Bridge of nose
-must match to saddle or contoured bridge
-comfortable
-bad fit = red marks on crest
-try keyhole
Crest Angle
-ideal fit (top bridge & frontal) no gaps
- poor fit = red marks/discomfort
Frontal Angle
- nose to face
- cant adjust saddle/keyhole
- nose pads with pliers
Splay Angle
- can change pantoscpoic angle
- compare ear height to eye position
- try higher/ lower temple placement styles
- low ears = mid-height/low temple (avoids retroscopic angle)
- high ears= higher temple (avoid resting on cheeks)
Ear Height
-minumum of 35mm required
-too long = discomfort/end seen below lobes
- too short=no length to bend/ will slip off
- measure length to bend (LTB)
- extra front hinge= fit longer
Temple length
-consider skin tone/hair colour/ eye colour
- colour should enhance skin colour
- right colour avoids under eye shading
- warm =camel/gold/peach/orange/warm blue
-cool=black/silver/pink/jade/plum
-skintones= pink/red/orange/blue/yellow
-under eye shading= clear/shallow bottom half
- frame colour should make face brighter
Px skin tone
Px own frame
- check durability
- choose smaller frame
- match px PD with frame PD (eye size&bridge)
- full frame
-longer front hinge
-thicker frame hides more lens - nose pads help fit
-high index with AR - request lab move bevel back
- compare vertex with phoropter
High Minus/Plus Rx
-2.00 and above
- less round (avoid axis shifting)
-bridge fit = less frame rocking/axis
- eyewire hide changes in lens thickness
High cylinder Rx
= evenly touch only 1mm movement
- lower bridge = shorter looking nose (saddle)
- keyhole= longer looking nose
Noses -fixed bridges
- minimal vertex distance (close= wider reading)
- needs more panto(reading area closer to eye)
-verticle dimension lens allow min fitting height plus 15mm - avoid large frames in high Rx
- avoid aviators
PAL
- frame matieral important
-spring hinges useful - cushioned nose pads for impact
- must comply with Canadian Standards Assoc.
Sports/Safety
-noses still growing (short and flat)
- skin more senstive
- deeper than normal eyewire groove (lens secure)
Children
- skin is thin/tender/slow to heal
- nose and behind ears more irritated
- nose pads as large as possible
- easy to put on and off (arthritis)
Elderly
- drawn box of outside lens edges
-accurately measures lens size (A) - does not measure frame size
-also measures Distance between lenses (DBL) - important for lens frabrication when sending order to lab without frames present
- allows seg. & pupil height to lowest part on lens
Boxing System
the measurement of the lens horizontally at the widest point (A)
The lens size
The measurement of the lens vertically at the deepest point of lens (B)
The lens height
The horizontal line 1/2 way bewtween top and bottom lens edges
Datum Line
The difference between (A) and (B) measurements
Frame difference
where the lens bevels are closest to another
Distance between lenses (DBL)
-The exact centre of the lens
- not related to OC
Geocentre (GC)
-Distance between geocentres
- calculated as (A) + (DBL)
Frame PD
- helps decide smallest blank size
- 2x the distance of geocentre to furthest lens edge
(the longest radius from the geocentre)
Effective Diameter (ED)
- has several meanings
- sometimes = DBL
-somtimes = width of datum line - sometimes= circumference of lens
- WATCH OUT
(C) measurement
- 3 measurements
1) eye size
2) bridge size
3) temple length
Frame markings
- First # marked on frames
Eye size
- Second # marked on frames
Bridge size
- printed/located on the bridge
- has a box symbol between both #
Accurate (A) + (DBL)
- printed/located on the temple
- dash between both #
- smaller eye size = shorter temple length
-frame might come in various size options
Inaccurate frame measurements (dont use for lab)
- # usually on the temple
- 3rd frame measurement
Frame Temple length
-not recorded on frames
- measure with PD ruler
- front temple hinge > bend of temple
Length to bend
- 2mm increments
- adult 48mm-64mm
eye size (A) options
-14mm-24mm
bridge size (B) options
- 5mm increments
- 110mm-130mm children
-120mm-150mm adults
Temple size options
-measures distance between pupils (mm)
- abbrv. PD
-OC infront of visual axes thru pupils
- several techniques available
- distance = numerator
-near =denominator
Interpupillary Distance
-used in equipment failure
- home visits
- crooked/uneven noses
Corneal reflection pupillometer
When px is focused on a distance target
Distance PD
-Narrower measurement
- eyes converging
-near targets @ 40cm
Near PD
The distance between two pupils
Binocular PD
The distance from each pupil> nose center
Monocular PD
- 40 cm infront of px
- eye level
-hold ruler horizontal on px bridge - rest hand on cheek/forehead
-px look at your open eye
-OS open> line up 0mm> px OD pupil
Binocular distance PD with ruler
- use penlight @ below px eye> point of reflection in each pupil
-outside edge OD pupil> inside edge OS
Uncommon Binocular distance PD
-you use better eye infront of px @ px nose
-px focus on open eye (@ nose)
-px OD pupil center > OS pupil center
uncommon Binocular near PD
- use regular binocular set up with ruler
- note the (mm) at the center of px nose= OD
- subtract OD(mm) from binocular # = OS
Monocular PD with ruler
- most accurate PD measurement
- hold device level
- allign vertical black line with px pupil
- set at infinity oo = distance
- intermediate= 55-75mm
- near = 40mm
Pupillometer Binocular
-use occuler
- best for px muscle issues
- px with strabismus
Pupillometer Monocular
- staff larger or narrower PD than px w/ ruler
- not at the same height at px
- px moves head
- inaccurate directions to px
PD errors
- measure outer canthus OD> inner canthus OS
-outer limbus OD cornea> inner limbus OS
-px wear frame>dot pupil center> measure distance
-Children/ parkinsons/cerebral palsy
ruler PD with special needs
-amount of near OC lens (mm) to distance OC
-near PD always smaller than distance PD
-distance PD (-) near PD = inset (binocular)
Segment Inset (PAL/Bifocal)
- amount of angle deviates from vertical
-bottom eyewire close to face
-critical from eyes distance to OC on lens
Pantoscopic Tilt
-location prism or OC
- height is important
-more than 5mm above (+)/below(-) datum line = lens too thick at edges (unappealing cosmeticall)
-not telling lab vertical measurement= lab uses datum line
- horizontally = px PD
Major Reference Point (MRP)
1) adjust frame to px
2) be at eye level to px
3) px looks at your nose
4) raise px chin= frame perpendicular to floor
5) draw horizontal line at pupil
6) measure distance from line to bottom lens
!!! missing step 2 =calc. drop of MRP based on *of panto tilt!!!
How to measure MRP
- MRP places 1mm below pupil for every 2* of pantoscopic tilt
(8* panto = MRP 4mm below pupil) - automated tech for Freeform does for you
Natural line of sight
-distance between lens and px cornea
- use px rx phoropter (12-14mm)
- high rx (7.00 -/+) = changed power with too close/too far from cornea
-measureed with distometer
Vertex Distance
-px closes eyes
-pre-adjusted frame
-at frame/face side rest flat tip @ eyelid
-press button until reaches back of lens
-read scale
-compare refracted vs frame vertex
-difference of 1-2mm can shift rx
- Freeform tech does this for you
- No vertex reconding lab uses default 12/13mm
Meausreing Vertex
-Curve of the front of the frame
-ideally curve follows px head shape
- too much/too little curve = optical issues
-Freeform requires measurement
Face form (wrap)
-use chart
-place frame OD eyewire flat @ dotted line
-line up OS and note * of angle
How to measure Face Form
-location at which multifocal power> facial structure> shape of frame
- must use extact frame size
- (+)/(-) 1mm for every 2mm of frame size required
- frame size 54mm wants (sample is 52mm) = adding 1mm vertical height
Segment Height (seg height)
- be at px eye level
- not eye level = parallax (skews mesurements)
- px be in normal/comfortable position
-focus straight ahead
-px look at your oppostie eye/nose
1) 0mm rule at pupil measure to bottom lens
2) mark pupil> draw horizontal line
3) seg devices sit inside bevel (child/ height difference OD/OS - check twice (have px relax in between)
-flattop line @ bottom pupil
-round bifocal @ bottom pupil (+) 1mm
-PAL line @ center pupil
-flattop trifocal @ bottom pupil (-) 1mm - add 0.5mm to compensate frame groove
How to measure Seg Height
- tall px= seg height lower than normal
- neck conditions(chin down)= higher height
- uneven height is ok
- show px line on bifocal/trifocal
- can balance out if less than 3mm diff OS/OD
Troubleshooting Seg Heights
- center pupil marked (fitting cross location)
- MRP usually 2-4mm below fitting cross
- use centration charts
PALSeg. Heights
- must be using lower portion for near work
-reading area must be placed higher - flat top = measure @ center pupil
- PAL = center pupil (+) 4mm
Childrens seg height
-lenses before cut/shaped to frame
-the smallest lens size that will fit
-keeps lens edges thinner
- reduces lens weight
-SV can be kept at stock (pre-made)
- MF seg determines MBS large enough (using scale chart)
Minimum Blank Size (MBS)
