practicals Flashcards
hand held magnifier
Design features
Simple
Single plus powered lens
maybe illuminated
available from 1.8x to 12. 5x mag
Suitable for patients with AMD high refractive errors
hand held magnifier
benefits and limitations
Convenient for Short term use
Common psychologically acceptable
Compact / lightweight
flexible task distance
Requires Steady hand
still requires training
Subject to aberrations when used
binoculary due to oblique gaze
higher power = more aberrations and Smaller fov
hand held Mag
advice On use
Hold with most Convex Surface facing PX
place an page move away until image is clear
keep page flat
wear distance Spec’s or near if working within focal length
steady eye strategy move page underneath magnifier
Reduce eye may distance to increase fov
Good illumination,angle Poise lamp directly onto page
Stand magnifier
Design features
Simple magnifier
Has cuff to set lens at the correct working distance
Internally illuminated
may be available as one head or with or with interchangable heads
Available 2x to 12.5x
Cx with AMD
Stand magnifier
Benefits and limitations
Easy to maintain correct working distance
stand may hold in place allowing hands free
Internally illuminated Providing adequate lighting
fixed focus - a specific Pair of Spectacles maybe required
Bulky due to illumination component
stand magnifier
Advice on use
place directly onto Page and should be in focus
use required spectacles
keep page flat (use a clipboard)
Ensure batteries are replaced regularly as adequate Illumination is essential
use steady eye strategy keep mag still and move paper right to left
Bar magnifier
Design features
Simple loupe magnifier
Single plus Powered lens
May have line to aid tracking
may have darker edges to aid contrast
Acrylic / Perspex
can sit directly onto page
Available 1.1 x to 2x
Bar Magnifier
Benefits and Limitations
simple to use
no dexterity issues
maintain binocular vision at normal Working distance
Requires a flat firm Surface
Narrow Field of View
Bar Magnifier
Advice on use
Position Horizontally
direct onto reading material
use line to guide position
use near Spec’s
when not in use place in case
keep out of direct Sunlight
Pocket magnifier
Design features
simple magnifier
single plus Powered lens
lens folds in Protective case
Pocket size
Available 2.5x to 20x mag
Suitable for AMD and high refractive Powers
Pocket magnifier
Benefit’s and limitations
Small Portable and discreet
light weight
psychologically,cosmetically acceptable
cheap
Small fov
not suitable for Prolonged use
steady hand required
Pocket Magnifier
Advice on use
Hold on material and bring away until focused
use distance Spec’s
Bring closer to eye to improve fov
Short tasks only
good illumination angle Poise lamp directly onto Page
Prismatic Readers
Design features
High powered Reading Specs
incorporated base IN Prism to aid convergence
usually 1/2 eye design
for near vision
General Rule 1 prism base in for 1.00D of Add over plus 3.00D
available up to +10.00D 12 Prism in
Prismatic Readers
Benefits and Limitations
Allow maintenance of binocular vision for near tasks when using adds for Patients with Convergence problems
1/2 eye design allows distance vision over top
hands free
Short working Distance- may be difficult to maintain
Heavy
Unattractive
Prismatic Readers
Advice on use
wear for Specific near tasks only
close WD start away from face and move closer until clear
use good illumination angle poise lamp directly onto page
Spectacle Mounted telescope ( binocular)
Design features
Galilean System
Positive objective and negative eye piece
may have adjustable focus
Patients RX maybe glazed into housing spectacles or incorporated into eye Piece
may be permantly fused or clip on
Spectacle Mounted telescope ( binocular)
Benefit and limitations
can be used for distance and near ( adjustable focus)
Hands free
maintenance of binocular vision
High magnification
Good depth of field
Psychologically unacceptable due to appearance
Heavy / bulky
Accurate centration is essential
Requires extensive training for effective use ( 6 weeks)
small fov
Spectacle Mounted telescope ( binocular)
Advice on use
use for specfic tasks
Can adjust focus depending on working distance of task this should be demonstrated
Do not walk around in them static use only
Requires good illumination
monocular hand held telescope
Design features
keplerian Or Galilean
hand held monocular
adjustable focus
may clip into Spectacle frame
Suitable Cx AMDand Central field loss
Reverse Systems can be used for Patients with RP,DR,glaucoma
monocular hand held telescope
Benefits and limitations
Hand held
Small Portable
adjustable focus for Range of WD
Can clip onto spectacles - hands free
high magnification available
steady hand
Dexterity required
only good for stationary objects
cannot Compensate for high Rx
monocular
not Suitable for long time use
Monocular hand held telescope
Advice on use
Adjust eyepiece to focus demonstrate WD if needed
specific Spot tasks as monocular use
use with dominant eye
Hold steady may require elbow Support
Do not move around when using
Spectacle mounted magnification unit
Design features
used for crafts / models
Plus powered lens mounted or clipped onto Spec’s
Cx own Rx may be glazed into housing Spectacles
maybe binocular or monocular
Available - up to 3x binocular
7x monocular
Spectacle mounted magnification unit
Benefits and Limitations
Good fov achieved due to minimal eye mag distance
Coatings and tints available in carrier lens
Binocular vision maybe maintained
Hands free available
Range options available
maybe psychologically unacceptable - appearance
Short Working distance - difficult to Maintain
Accurate Centration - essential
Poor illumination - extra essential
Spectacle mounted magnification unit
Advice on use
Hold Page away and bring closer until clear
use for Specific tasks
Do not walk around when wearing
Maxx TV / coil TV unit
Maxx event - TV
Maxx near
Design features
Galilean telescope System
Positive object and negative eye piece
adjustable focus for room distance use frosted objective lens
eliminates reflections
2x mag
adjustable to compensate for up to 3.00D
Ametropia
Maxx TV / coil TV unit
Maxx event - TV
Maxx near
Benefits and Limitations
Simple and economic solution for room distance
can be used for distance and some intermediate ( room distance use)
hands free
Heavy and relatively uncomfortable for long periods of Wear
Requires dexterity for adjustment
cannot compensate a high RX but available as clip on
Maxx TV / coil TV unit
Maxx event - TV
Maxx near
Advice on use
use for specific tasks (TV)
Demonstrate adjustment of Working Distance
Do not walk around when wearing
sheet magnifier
Design features
fresnel lens
multiple concentric rings providing magnification
Some may have foldable stand for Support
Available in low magnification powers of 2x - 3x
sheet magnifier
Benefits and limitations
large Fov due to size of magnifier and low power
Cosmetically acceptable
Inexpensive
light easily portable
only available in low mag
Posture Sometime difficult to maintain- needs to be Parallel
optically poor - due to aberations
sheet mag
advice on use
Hold on page
move away until clear
use with near vision Specs - often be working within focal length
can be used for eccentric Viewing
keep page flat
Good Illumination angle poise lamp directly onto page
chest magnifier
Design features
low magnification plus Powered lens
Bracket and neck Strap to support against chest
may have Smaller High mag Segment
1.5 x - 2 x mag
up to 6x mag
chest magnifier
Benefits and Limitations
Constantly Supported at appropriate working distance
Hands free
low magnification means less aberrations
wider fov
Inexpensive
chest magnifier
Advice on use
Position close to eye to boost fov + magnification ol wearing reading Specs
Mark an neck Strap where appropriate fitting is
use while Seated
may need additional lighting angle poise
can be used for reading if only low mag is required
steady eye strategy
Hyperocular
(one lens)
Design features
Spectacle mounted magnification
single high Powered plus lenticular lens
the other lens to be occluded/ frosted / CX own Rx
A available up to 12 x magnification
Hyperocular
(one lens)
Benefits and limitations
Psychologically acceptable as looks Similar to normal Spec’s
Able to incorporate prescription into lenses
Hands free
large fov due to short eye mag distance
short WD maybe hard to maintain
monocular only
Requires good illumination due to short WD
.Hyperocular
(one lens)
Advice on use
Hold page in front of dominant eye and bring closer until Clear
use for specific Tasks
Do not walk around when Wearing
good lighting angle poise
Tinted over Specs
Design features
Plano tinted / filter lenses
wrap around design to shield disabling glare
Specific filters to absorb certain wavelengths
Blue light blocking ( 47Onm + less)
FL - 41 Rose filter
Px with gluacoma,retinitis pigmentosa,ARMD,Photosensitivity
Tinted over Spec’s
Benefits and Limitations
Lightweight
use over own Spec’s
many filter options
wrap around - Shields glare
psychologically acceptable- like large Sunnies
Bulky
unattractive
only benefit in day time
May restrict driving
Tinted over Spec’s
wear over existing Spec’s
wear in bright conditions or if light a problem
Do not wear for driving due to contrast filter
Diving mask
Diving and Snorkelling
Design features
silicone Cupping and head strap to create a water tight fit including over nose
tiltable to allow clearing of water
glazeable Insert to full RX
Diving mask
Diving and Snorkelling
Dispensing and fitting requirements
fit close not too tight
CD and vertical heights
Record vertex
Rinse trap water air dry
Skiing goggles Design features
Snow
Skiing
Snowboarding
Ski Jumping
bobsleigh
Snow boarding
Single shield
wrap style to protect debris + UV
Glazeable insert
Polycarbonate /Trivex
100% Uv Protection
Mirror coating
Skiing goggles
Dispensing + fitting requirements
Polycarbonate or trivex for safety
measure CD ‘s and heights
Adjustable headstrap for secure fit
Avoid lens Spray due to mirror coat
Swimming goggles
Design features
Available as Plano modular or full RX
Silicone Cups + head strap water tight
flat form lenses ( Plano front surface)
choice of bridge Size
Tints available
Maximum depth of 1. 5 m
not used for diving
Swimming goggles
Dispensing / fitting Requirements
Modular Rx = Sphere + 1 / 2 cyl
Available In 0.50D steps
check VA’S with trail frame
fit close but not too tight as can cause pinching and Increase Ocular pressure
Bridge width can alter horizontal OC /Position
Rinse in tap water air dry
Aquaviz - Design features
Swimming
Surfing
kayaking
windsurfing
rafting
Canoeing
Paddle boarding
wider field of View than Swimming goggles
Available with glazeable Insert full Rx
Tintable Inserts available
Silicone cups and head stone for water tight fitting
max depthof 1.5m not used for diving
Aquaviz
Dispensing / fitting requirements
fit close but not too tight
measure CD and vertical height
Record Vertex distance
Rinse in tapwater + air dry
shooting Spec’s
Design features
Designed for monvision non- dominant eye will be occluded
Adjustable horizontal positions of lens and occluder
Adjustable vertical positions from bridge
Adjustable apertures for depth of field
adjustable angle of side
Curled Sides forSecure fit
shooting Spec’s
Dispensing/ Fitting requirements
Dispense dominant eye
position lens and occluder before measuring CD
Dispense trivex/ Polycarb
tints or filters maybe
measure CD’s + vertical heights
Record vertex distance
Adjust Pantoscoptic angle worn depending on posture
cycling Spec’s
Design features
wrap around Protection of debris
high base curve
maybe glazable insert
straight sides
adjustable nose pads
Range of tints
interchangeable Shields maybe an option
cycling Spec’s
Dispensing + fitting requirements
may need to dispense high base curve
Trivex/ Polycarbonate
Tints as required consider road Safety
Head Strap for Secure fittings
measure CD + vertical heights
Record vertex distance
Consider face form angle and Panto angle worn
Snooker Spectacles
Design features
Snooker
Pool
billiards
bowls
large frame
increased fov
low crest to provide high fit
adjustable Joints to Induce retroscopic tilt
thin metal frame
Supra / rimless
Snooker spectacles
Dispensing / fitting Requirements
non - Aspheric SV lens
measure horizontal + vertical CD’s
mark pupil Centre in full retro + full Panto tilt place OC in middle
MAR Or photochromic tint as appropriate
Record Vertex distance
football,Rugby Judo, lacross,Ice hockey
design features
Silicone bumpers on bridge + templesto increase Impact
Bevel built up on back surface causing lenses to fall forwards on Impact
nylon frame
Air vents to Prevent steaming
Adjustable head strap
football,Rugby Judo, lacross,Ice hockey
Dispensing/ fitting requirements
Polycarbonate or trivex lenses for Safety
Demonstrates use of head Strap fit Securely
maybe tinted or photochromic for outdoor Sports
measures CD and heights
Record Vertex distance
clip on magnifier
Design features
Simple high Powered plus lens
Available up to 3x binocular
7x monocular
clip over Own Spec’s
Hands free for Occupational,vocational use
flip up when not needed
Some have extendable vertex distance
clip on magnifier
Dispensing / fitting requirements
magnification required - acuity achieved / acuity desired
ef N8 / N4 = 2x
clip over bridge on Cx can Spec’s
Adjustable vertex distance - Increased field of view
Demonstrate Working distance
clip on magnifier
Advice on use
Wear for Specific tasks
Hold task away from face + bring closer until clear
close working distance
Good illumination required
angle poise lamp directly over task
flip up when not required
fresnel Prism
Design features
Temp Prism
made of Upvc
consists of multiple Parallell Prism
1mm thick
available up to 30 Prism dioptres
fresnel Prism
Dispensing / fitting requirements
check Prism base direction
Apply underwater to remove air bubbles
Apply to back Surface of lens
check VA’S for Suitability for driving ect as can reduce VA by 2 Snellen lines
fresnel Prism
advice on use
wear as advised by orthoptist / Optometrists
Do not attempt to clean or rub back Surface
Can reapply if needed
monocle
Design features
Single lens held in gallery
Gallery gripped by Orbicolaris Oculi muscle
Gallery holds lens away from globe
neck cord to Prevent loss
monocle
Dispensing / fitting requirements
Dispense to dominant eye
Dispense best Vision Sphere
Glaze with trivex for safety
Glaze flat form lens
Glaze oC at Centre of aperture
Ensure Cx has enough muscular Control to hold in place
can be used for distance / Correction
monocle
Advice on use
use with dominant eye
use for specific tasks
Do not use for prolonged tasks
keep on neckCord to prevent loss
Half eye Spec’s
Design features
Shallow lens covering lower Portion of orbit
wide distance between Pad centres
long LTB to allow C x to sit on end of nose
ideal for emmetropic Presbyopes and CL wearers
Half eye spec’s
Dispensing / fitting requirements
adjust for lower frame fitting
Record near CD at Specified WD
Glaze OC appropriately high
Record vertex distance
Half eye Spec’s
Advice on use
sit low on nose to allow distance Vision over the top
Wear for Specific tasks ( intermediate /near ) only
Remove Spectacle to walk around
View distance objects over frame
Recumbent / belay Spectacles
Design features
Prism and Mirrors mounted into frame to deviate light by 90°
Prism displace Image
mirrors reflect image
can be worn over current Spec’s
Silicone nose pads
adjustable Sides for Snug fit
Recumbent / belay Spectacles
Dispensing / Fitting requirements
Ideal for bedbound cx/ with Stoop/ climbling
fit Snug to avoid Slipping down due to heavy prism
may require head strap
fit low and shallow to allow Cx to look of top if needed
Some tiltable may need to secure in optimum Position
Recumbent / belay Spectacles
advice on use
wear to view object below Or above
wear with specs if required
Take care if wearing while moving
look over the top to see directly in front
Patient should try before Purchase
Surgeon Spec’s
Design features
Spec mounted telescope
Galilean telescope unit
adjustable focus
used by Surgeons / dentists
Surgeon’s Spec’s
Dispensing / Fitting Requirements
must accurately measure CD’S
measure working Distance and CD’ S with frame in place
Some units adjustable focus
may need to secure at appropriate focus
Some allow Cx Rx to be glazed into Carrier
Surgeon’s Spec’s
Advice on use
Demonstrate working distance
wear for Specific tasks
do not move around when wearing
Requires Good Illumination angle poise lamp directly onto task