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What is a number?
Quantifying adjective, describes how much or how many, can be cone by written notation or decimal notation
Types of numbers include?
Integers or whole numbers, partial numbers fractions or decimals, combined numbers. Integers with fractions or decimals.
Whole numbers positive and includes zero and negative whole numbers.
What is punctuation used for?
Used to make numbers easy to read, includes both comas and periods.
What are comas used for?
Placed between unit groups, ex thousan, millions etc, inserted fisrt between the third and fourth digit to the left of the start point.
What are periods used for?
Also known as decimal point, used to devide the integers or whole numbers from the decimal or partial number, place to the right of the unit place or the integer.
What is a decimal?
A number representing a fraction in tenthes, hundreds, thousands etc
What is the designation of the decimal?
Number to the right of decimal point is the decimal, number to the left of decimal point is whole number.
Addition Subtraction with decimals..
Align all decimal points vertically,. Add/Subtract as in any integer operation.
Multiplication of decimals...
Multiply as in integer operation total decimal numbers and make sure total number decimal numbers are represented in answer
Division of decimals..
Move the decimal point in bothe the divider and dividend to the right to reflect the total place space of the devider....to make ita true whole number, calculate problem as you would in any division problem, position the decimal point in the quotient directly over the decimal point in the divedend.
What is a signed number?
One that is preceded by either a plus or minus sign..
What does a numberlinedo?
Shows how signed numbers are alined in relation to zero.
Where are signed numbers used?
Temp, elevation, spectacle power reading.
Addition and subtraction of signed numbers using a numberline..
Use the signs of numbers to guide the direction you travel up and down the number line, the first sign and number tell you the starting point, from starting point move the direction indicated by the sign in front of the next number and the number of spaces of that number.
Positive sing indicates?
Positive action/movement on the numberline.
Negative sing indicates?
Negative action/movement on numberline.
Two like signs in front of one number indicates?
A positive action/movement on numberline.
Two unlike signs in front of a bumber indicates?
A negative action/movement on the numberline,
Multiplication of two like sign numbers indicates?
Is a positive number.
Multiplication of two numbers with unlike signs indicates?
A nagative number.
Devision of two numbers with like signs indicates?
A positive number
Division of two numbers with unlike signs indicates?
A negative number.
Kilo k indicates?
Hecto h indicates
Centi c indicates?
Mili m indicates indicates?
1 centimeter to inches is?
1 meter to inches is?
1 kilometer to miles is?
10 grams to pounds is?
1 kilogram to pounds is?
1 liter to quarts is?
Gallons to liters is?
3.79 liters to 1 gallon.
Solving for an unknown in a simple equation is requires?
It is like a scale, in the end you want one side to equal the other side.
Refractive index is?
The messure of the changes in the direction of light that occur when light passes from one medium to another due to the volocity of the light being different in different media.
Absolute refraction index is?
Velocity of light in a vacume.
Relative reflacion index is?
Velocity of light in air or velocity of light in glass.
What is a lens?
A lens is a transparent substance bound by two surfaces, both of which may be curved or one may be curved and the other plane,or flat.
What is optical center?
The point of the lens where no refraction takes place. Point of lens where light passes straight through without being bent, refracted.
What is nuique about the optical center?
Optical center never changes location.
What is the geometric center?
This is the mechanical center of the lens.
What is ubique about the geometric center?
Geometric center will change locations if the shape of the lens changes. Has no relation to the optical center and is dependant only on the shape of the lens.
An imaginary line drawn through the optical center of the lens.
The unit of refraction power.
Surface curvature is?
The curve of a lens surface - influences lens power.
A lens surface with two different surface curvatures.
Spheres refract light how?
Focal length and focal power.
What is focal length?
Distance from lens to the point where light rays passing through the lens appear to focus.
What is focal power?
Expressed in diopters and will be positive for surface that tends to produce convergence, and negative for one that tends to produce divergence.
What is the formula for dioptric power?
Diopters=1/focal length in meters
What are the theories of light?
Theory of light at particles and thelry of light as waves.
Effects the form of a lens may take?
Positice or negative.
Properties of a positive lens include?
Also known as a convex, plus, or converging lens.
Characteristis of a positive lens?
Thicker in center, magnifies, objects appear larger, against motion is observed when moving. Lens, forms a real focal point.
Refraction by a positive lens is characterizes by?
Focal point is behind lens, parallel rays of light leave the lens and converge which forms a real focal point, short eye has to do with the overall shape of eyeball , used for hyperopia , farsightedness,
Properties of a negative lens?
Concave, negative, divergant
Characteristics Of a negative lens?
Thin in center, thicker edges, minifies, objects appear smaller, with motion is observed when moving lens, forma a vertual focal point or imaginary focal point.
Refraction charateristics of a negative lens?
Focal plint is infront of lens, parallel lines leave lens and diverge,. Long eye. Overall shape of eye is long or elongated.
Principals of optics include what?
Physical and geometric.
Physical optics describes?
The nature and properties of light itself, theories include. Light as particles and wavelike.
Geometric optics describe?
The use of laws of geometry to examine light as rays, and the effects lenses play transmitting those light rays.
Types of optics used in optometry and opthalmology include?
Both physical and geometric optics.
Light is a form of?
Electromegnetic radiation is defined by?
- Wavelengths- measured by wave of the length of the wave in a number form. From 300 to 800
- Visible spectrum- visually measured by color. R O Y G B I V
Lights ability to travel throught substances can be dertim ined by what?
Opacity, translucnacy, and transparency.
What is opacity?
Something that is opaque, refers to anything tht blocks normal transmission of light through a transperaant medium.
Whaat is translucency?
Kind of clear but not ll the way.
What is transparency?
Clear at its clearest
What is refraction?
It is when light is traveling obliquely on the surface between two media of different refractive index, its direction is changed on passing into new medium. The normal is a line drawn perpendicular to the surface of refraction,[ zero refraction happens at this line))
What is refractive. Index of water?
What is refractive index of CR 39. Plastic material?
What is refractive index of Spectecale crown glass?
What is refractive index of Polycarbonate?
What is the refractive index of M High index?
Normal is the perpendicular to surface of refractive surface, when light passes from lessor to denser medium what direction of bend will light have?
Bend will be toward normal line or towrd zero refraction point, known as optical center,
Normal is the perpendicular to surface of refractive surface, when light passes from denser to less denser medium what direction of bend will light have?
Bend will be away normal line or away from zero refraction point, known as optical center,
Focal point and focal conversions are?
Same as clinical optics formula for focal length conversions. D=M/F,. Dioptric power and focal length are related, given thr formula D=1 over the focal length.
What is Emmetropia?
Normal sight, light is focused on the retina, no lens is required to change the focal point.
What is Ametropia?
A decrease in vision in one or both eyes with no anotomical damage to optic path.
What are tyupes of amatropia?
Hyperopia- farsighted, Myopia- nearsighted, astigmatism.
What is hyperopia?
Farsightedness,. Light is focused behind the retina, a plus lens corrects hyperopia by converging light.
What is myopia?
Nearsighted,. Light is focused in front of retina, a negative lens corrects myopia by diverging light .
What is astigmatism?
- A refractive condition of the eye that has no single point focus, occurs when the eye is not spherical where light rays come to focus in two different places.
- Regular astigmatism requires a lens,which the power varies from a minimum in one meridian to a maximum ninety degrees away.
What is presbyopia?
It is an accomidation disorder characterized by physiological change in the crystaline lens resulting in an inability to fucus within arms reach, is an age related change that manifests near age 40. a converging lens is needed to supply the focusing power to see near objects clearly.
- Altering of the pathway of light from its otiginal direction as a result of passing obliquely from one medium to another of different density
- Pivoting or bending of light rays.
Laws of refraction.
- When light travels from a medium of lesser density to a medium of greater density, the path of light will be bent toward the normal.
- When light travels from a medium of greater density to a medium of lesser density, the path of light will be bent away from the normal.
- The incident ray, the normal, and the refracted rays all lie in the opposite plane
- The incident ray will always lie on the opposite side of the normal from the refracted ray.
- Light waves come together towards a focus after passing through an optical system
- Said to have a positive dioptric power..
- Light rays diverge from a source or focus.
- Said to have a negative dioptric power.
The point at which almost parallel rays of light meet after passing through a convex lens, or reflecting from a concave mirror.
The inverse of the focal length in meters, the physical unit with for lens power is 1/meter, which is called diopter
- The distance between the lens and the focal point.
- The diopter is equal to the reciprocal of the focal length in meters.
Equal power in all meridians.
Types of spheres?
Plus, minus, and plano
Plus sphere is?
- Has more power on the front surface then on the back.
- Converge light to a real point focus.
- Used to correct simple hyperopia.
Minus sphere is?
- Have more power on the back surface then on the front.
- Diverge the light and form a virtual point focus.
- Used to correct simple myopia.
Plano sphere is?
- Have equal but opposite power on the front and back surfaces.
- Neither converge nor diverge light- zero refracting power.
- Used for non-perscription eyewear like sunglasses.
Have zero power in one meridian and maximum power in the meridian 90* away.
Types of cylinders?
Plus and minus cylinders.
Plus cylinder is?
- Have zero power in one meridian and maximum plus power 90* away.
- Converge light to a real line focus.
- Not used in spectacle opthalmics.
Minus cylinders ?
- Have zero power in one meridian and maximum minus power 90* away.
- Diverge light and form a virtual line of focus.
- Used to correct simple myopic astigmatism.
- Have minimum power in one meridian and maximum power in the meridian 90* away.
- Is a combination of sphere lens and cylinder lens.
- Forms two line foci 90* apart. Light rays from strums conoid, the circle of least confusion is where a spherocylinder lens forms the clearest image.
- Used to correct simple hyperopic, compound myopic, and mixed astigmatism.
Two flat surfaces not parallel, thickest portin is at base, thinnest point is the base.
- Bending of light so that emergent ray is parallel to the incident ray.
- Ligfht is deviated towards the base.
- The object seen through the prism appears moved towards the apex of the prism.
- Breaking down of white light into component colors.
Types of lenses...
- Plano convex
- Plano concave
- Positive meniscus
- Negative meniscus
- Plano meniscus
- One flat surface and one convex surface
- Converge light
- Has plus power
- One flat surface one concave
- Diverges light
- Has minus power
- Both sides of a biconvex lens bulge outward
- Converge light
- Have plus power
- Both sides cave inward
- Diverge light
- Has minus power
- One convex side one concave side
- Convex side has steeper curve then the concave side
- Converge light
- Has positive power
- One convex side and one concave side
- Convex side has a steeper curve then the convex side
- Diverge light
- Has minus power
- One convex and one concave side
- Both sides have equal power
- Niether converge or diverge light
- Has zero power
Ways to determine if a lens has plus or minus power.
- Compre center thickness to edge thickness
- Plus lenses are thicker in the middle then at edges
- Minus lenses are thicker at the edeges than at center
what are the optical effects f the lenses?
- Plus lenses magnify
- Minus lenses minify
what is the eys piece?
part where one looks inot the lensometer
what is the table, or spectacle table and lever?
whet the glasses rest on when being worked within the lensometer.
what is the lens holder?
this is he peice that slides forward and hold glasses against lens stop.
what is the power wheel?
- Black numbers on the power wheel are plus power
- Red numbers on the power wheel are minus power
cylinder axis wheel does what?
helps find cylinder power of torque lense
what is the internal reticle?
this is the gulls eye, first hlf marks are .25 value, first circle is .5 the next circle is 1.0 etc
steps in manual prep of lensometer are?
- focus eye piece
- adjust lensometer to your height
- check calibration
how do you focu the eye piece?
- with instrument off, turn eyepiece counterclockwise untill it stops
- place piece of white paper in fron of eyepiece
- looking into eyepice, slowly turn eyepiece clockwise untill mires become clear.
how do you check calibration of lensometer?
- turn lensometer on
- turn power wheel to focus mires
- power wheel should read zero diopters
- turn on instrument
- select OCD mode
- set rounding to 0.25Dsteps
- select minus cylinder mode
steps on neutralization of sherical lens are?
- always start with power wheel in a high plus position +9.00
- insert lens concave side against lens stop
- adjust spectacle table height untill lens is centered against lens stop
- look in eyepiece and rotate power wheel until target lines come into focus, remember to turn power wheel in the - (negative) direction (mires) one set is thick the other s are thin
- recenter if necessary
- rotate power wheel until lines come into sharp focus
- record power indicated on power wheel
steps on neutralizing a cylindrical lens are?
- always start with power wheel in high position +9.00
- insert lens so that glasses face you as if you where looking at patient face to face
- turn power wheel untill mires come into focus, if both lines come into focus together this is not a cylindrical lens
- if thicker (cylinder lines) lines come into focus first, turn cylinder axis wheel about 90* untill thin (sphere linse) lines come into focus
- fine focus power wheel so the sphere (thin lines) lines look continuous.
- record power indicated on the power wheel as the sphere.
- turn power wheel in the negative direction until the cylinder ( thick lines) lines com into focus DO NOT TURN AXIS WHEEL AT THIS TIME
- fine focus cylinder lines (thick lines)
- Algebraclly subtract figure first number from second number on power wheel
- cylinder number is distance travled from first number to second number NOT AT ENDING POINT OF SECOND NUMBER
- record axis number as indicated on the axis wheel
steps on neutralizing multifocal lens are?
- take power of distance portion of lens and record may be spere or cylindrical either way follow appropriate steps
- either way before the multifocal segment is done the thin (sphere) lines need to be refocused.
- raise lens table untill multiocal lines come into clear, sharp focus
- refocus until three sphere lines come into clear, sharp focus TURNING POWER WHEEL IN A POSITIVE DIRECTION
- distance between original distance vision shpere reading and the second sphere reading will be the power of the multi focal segmant.
2 methods of multifocal neutralization
- practical method
- exact method
what is the pracical method?
- used for distance prescriptions less than or equal to +/- 4.00D
- raise lens table with bifocal segmant is over the lens stop
what is the exact method?
- used for distance prescriptions stronger than +/- 4.00D
- turn glasses around and place front of the bifocal segment against lens stop
- note the difference
steps for automated lens neutralization of single vision lens are?
- position spetacles temples down with right lens over read head
- move spetacles whith nose slider and lens table unit curser is aligned
- when curser is properly aligned and becomes bold, press STORE button
- sphere, cylinder and axis is all stored at one time
steps for automated lens neutralizattion of standard multifocal lens are?
- take the power reading of the distance portion of the lens as explained in a single vision lens and store information accordingly
- gently slide lens so bifocal segment is over read head
- when the display illuminates the Add Rx press STORE again
steps for automated lens neutralization of progressive addition lens
- change measurement screen to PAL
- position spectacles temples down with right lens over read head
- move spectacles with nose slider and lens table until line curser is aligned with the infinity sign
- when curser is properly aligned and becomes bold, press STOR button
- move lens untill a plus sign appears in the PAL deisplay
- find the position of the lens that gives you the highest reading and STORE
what is a prism?
optical device wedge shaped transparent medium that bends light rays towards its base, does not focus.
types of prisms include?
- vertical- base up or base down
- horizontal- base out or base in
neutralization of a vertical prism
- center mires of strongest lens mark for coptical center
- switch to the other lens without adjusting the table height and see if mires are still cnetered
- if still centered then there is no prism
- if mires are decentered, up or down you have a base up or base down
- the prism is meassured according to where it intersects on the reticle
- find optical center of weaker lens at this point and mark
how do you find the strongest lens?
- take half of cylinder and add it to the sphere figure both lens the strongest lens is the lens used for vertical prism neutralization
- the strongest lens may be a neg or pos reading
neutralization of horizantal prism manually
- mark optical centers of each lens according to prescription
- using mm side of ruler measure PD, which will be the center dot of both lens
- compare PD to order form
- take difference and devide by 2
- if difference is >2.5 +/- mark the difference on the lens
- mark difference meassure on the lens in mm
- center marked pt's PD in on lens stop
- veiw mires through eye piece, if mires are displaced towards temple, prism is oriented base out
- if mires are displaced toward bridge, prism is orientated base in
horizontal prism using Humphrey Lens Analyzer
- select PD mode
- place lenson read head so that sensor is on horizontal display
- slide lens left and right untill PD reading on display matches pt's monocular PD
What is Prentice's Rule?
- Prism= DECentration (mm) X (Rx/10)
- MINUS LENSES
- if PD recieved is larger than PD ordered, prism direction will be BI
- if PD recieved is smaller than PD ordered, prism direction will be BO
- PLUS LENSES
- if PD recieved is larger than PD ordered, prism direction will be BO
- if PD recieved is smaller than PD ordered, prism direction will be BI
ANSI Z80.1 Standards
- non profit institutes composed of representatives from manufactures, professional orgfanizations, scientific and consumer groups and government agencies
- serves as coordinating body in setting national standards, to guide and help manufactures, consumers and public to ensure accurate products are made
common guidelines and standards
ANSI standards on sphere
- plano to plus or minus 6.50 D can be off up to +/- 0.12D
- above +6.50 D can be off up to +/- 4%. we will use +0.25D
ANSI standards on cylinder
- plano - + 4.50D can be off up uo +/-0.12D
- above +4.50D can be off up to +4%. we will use +0.25D
ANSI standards on cylinder axis
- cylinder power from +0.12D to +0.37 can be of 014*
- cylinder power from +0.50D to +0.75D can be off 007*
- cylinder power from +0.87D to +1.50D can be off 003*
- cylinder power above +1.50D can be off 002*
ANSI standards on bifocal add
- plano to +/- 4.ooD can be off up to +0.12D
- above +/- 4.00D can be off up to +0.25D
ANSI standards on segment height
must be within +1mm of that ordered
ANSI standards on PD
both near and distance PD must be within +2.5mm of that ordered
ANSI standards on horizontal prism
must be within 0.66 of that ordered
ANSI standards on Vertical prism
must be within 0.33 of that ordered
ANSI standards on miscellaneous lens requirements
- surface should have no pits, scratches, grey areas, water spots
- internal there should be no bubbles or foreign material embedded in lens
- waves there should be no waves producing a distorted image during the lensometry inspection
- fram size must be as ordered
what is a lens clock do?
mechnical determination of the curveture of a lens is made by the lens clock
calibrating clos is done how?
- press down on clock perpindicular on a hard surface
- should read zero
- rotate center pin with pliers either clockwise or counterclockwise
- clockwise moves pointer in the minus direction
- counterclock wise moves pointer in the plus direction
the lens clock pins.
- outer 2 pins are fixed to the body of the instrument and do not move. the center pin is
- the only movable pin and is kept in contact with the lens surface by the action os a spring
- the pointer on the instrument dial and activated by movement (up or down) od the center pin
other names for a lens clock?
lens guage, lens measure, the lens clock dial
charechteristics of the lens clock?
- graduated in diopters
- clack numbers indicate plus power
- red numbers indicate negative power
- calibrated for on specific refractive index, 1.523
- the movement of the center point from its zero position when placed upon a lens surface measures the curvature of the surface
- the approximate power of a lens may be determined with a lens clock
base curve is what?
base curve is the lowest number reading given on the outside or front side of lense
procedure for spherical lenses
- measure the front (convex) side of the lens (+power)
- measure the back (concave) side of the lens (- power)
- add powers
procedure for cylinder lens
- cylinder lens will have 2 different curvatures (powers) on one side of the lens and only 1 curvature (power) on opposite side
- 2 cylinder powers will be 90* apart
- cylinder power equals the distance between the powers of the lens as measured by the lens clock or lensometer
- measure the curves on the 2 surfaces of the lens and add the powers
how do you take a reading with the lens clock?
- instrument must be placed so that it is perpendicular to the surface
- should not be leaning over in an oblique direction
- keeping all three legs lightly in contact, rotate around the middle pin
- SPHERICAL READING
- the reading of the scale will remain unchanged since the curvature is the same in all meridians
- TORIC SURFACE READING
- pointer will flucuate as you change meridins and you will get a maximum and a minimum reading
- remember BASE VURVE is the flattest, or smallest reading of numbers you take.
calculating lens power
power of a lens is on a scale
determining plus or minus lenses on a lens scale
- the side of the lens that has 2 curvatures (cylinder power) determines if the lens is labeled a plus or minus cylinder lens
- plus cylinder the cylinder power is ground on the back side (concave) side of the glasses
- minus cylinder the cylinder power is on the back (concave) side of the lens
- the axis of cylinders used to designate the 2 curves is placed in the pair of glasses to correct a known astigmatism, which will also have an axis
what is the optical cross?
- can be used to diagram lenses as well
- digramming these 2 major meridians and labeling the power in them from a prescription is how we make an optical cross
diagramming an optical cross
- draw a cross this portrays 2 major lens meridians at right angles
- one gets labeled axis meridian 180* from prescription and the other line with meridian 90* away
- the power of a sphere lens is the same in all meridians
- looking at cross for +1.00 - 2.00 X 180*
- sphere power
- top north is 90*
- right east is +1.00
- bottom south is +1.00
- left west is 180*
- SECOND ELEMENT IN RX IS CYLINDER
- remember sphere power is married to the axis in a RX NOTHING else can go on this meridian
- this leaves only one place for the cylinder, the meridian 90* -2.00
- add the cylinder power (-2.00) to the sphere power on the 90* meridian (+1.00) to get a total power of (-1.00) in the 90* meridian
Rules for diagramming a SRX on the Optical Cross
- sphere is married to the axis
- sphere goes everywhere
- cylinder goes 90* away from axis
taking the prescription off the optical cross
on one meridian is
150 and +1.25
on the other meridian is
060 and +0.50
- identify more plus number +1.25 or +0.50
- this number is the sphere
- since sphere is married to axis this makes 150 the axis
- to figure out cylinder take most plus and figure difference between the high and low numbers
- the diff is the amount of place points and direction frombig to little.
- in this example to go from +1.25 to +0.5. we traveled -0.75 this number equals cylinder
- cylinder is on opposite of axis, which is married to the sphere
- because sphere is on the 150 then the cylinder gos 90* away from axis because we moved negativly then we will subtract 90* from our 150* = 060*
- the RX will look like this
- +1.25-0.75 X 150
lens warpage can be cause dby several reasons
- most commonly do to manufacures defects
- happens with time old lens
- exposure to extreme heat
- lens that was fitted too tightly into a glasses frame
Male spectacles issue
- If Frame Of Choice is ordered then pt is only allowed one S-9 or MS-9
- Standard issue is S-9
- Active duty 2 pr
- retired 1 pr
- may be single or multifocal
- Wis +9 compared to H
- brown or black
- Eye sz in 2mm starting 46-52
- Bridge sz 2mm starting 20-26
- adjustable nose pads available
- Temples paddle or skull 1/4" starting 4"- 5"
Female spectacles issue
- If Frame Of Choice is ordered then pt is only allowed one S-8 or SF-8
- standard issue is S-8
- Active duty 2 pr
- retired 1 pr
- may be single or multi focal
- W is +8 compared to H
- brown or black
- Eys sz in 2mm starting 46-52
- Bridge sz 2mm starting 18-24
- adjustable nose pads available
- Temples paddle or skull 1/4" starting 4"-5"
- riding bow or cable temples are available
- Pts active duty only
- Actively flying military aircrew members
- Actively flying military non-aircrew memebers
- Reserve, National Guard authorized under certain comditions
Army Aviation Prescriptions
- single vision plastic
- bifocal plastic
- Army frames are to be made of SV plastic or polycarbonate dependng on Aircrew ensemble
Air Force Aviation Spectacles
- Flying Class I, II, III get aviation spectacles
- 3 types
- Air Force Flight Fram AFF
- Air Force Dress Frame AFD
- Black on color for aviators
- if aviators regquire NVG's the glasses must be made of polycarbonate
Characteristics of Army Frames
- Silver in color
- one size 52 eye X 20mm bridge
- adjustable nose pads
- bayonet or cable type temples
Characteristics of Air Force Frames
- Eye sz 52,55 or 58
- 18mm bridge sz
- Air Force Frame AFF
- Air Force Flight Frame AFF
- Air Force Flight Dress Frame AFD
- black in color for aviators
half eye spectacles
- one pr in place of single vision
- retired military are authorized 1 pr wich will replace standard issue pr
- prescription NO myoptic correction or astigmatic (cylinder) may exceed -1.25 readers
Characteristics of Half Eye Spectacles
- grey, brown fade or black cellulose acetate plastic
- smaller sz to allow distant vision over the top of the eye wear
- szs clack only comes in 46 eye sz and 24 bridge sz
- szs grey/brown fade come in 48,50 eye sz and 20,22 bridge sz
Air Force Mask Inserts
- Air Force uses MCU2P, Mags, ranger glasses, "go faster"
- pts must be active duty
- ranger, Airborne special forces
- RX may be single or multifocal
Characteristicas of Air Force Inserts MCU2P
- black nylon material
- eye sz in 2mm 46,48 or 50
- bridge sz 22 or 25
- adjustable rubber temple straps
- protective mask insert for Air Force and Navy
M40 and M42 inserts
- pts must be active duty
- must have VA visual accuity of 20/40 OU or worse
- Mil vehicle ops, flight personnel, enlisted personnel with profile I occupational requirements, when binocular VA is less than 20/20
- when bifocal correction is required to perform assigned duties satisfactorily
- when medical or employment requirements necessitate wearing inserts although the binocular VA is greater the prescribed above
- issu is 1 pr
Characteristics of M40 and M42
- RX usually above 1.00 D in distance
- bifocal if required for duty the add is set 3mm below Optical Center
- wire fram
- single sz insert
- clear plastic requires plastic carrier
M45 protective inserts
- available to active duty that meet the following
- have VA of 20/40 OU or worse
- vehicle op/ flight personnel, enlisted personnel with profile O occupational requirements, when binocular VA is less than 20/20
- when binocular correction is required to perform assigned duties satisfactorily
- when medical or employment requirements necessitate wearing spectacle insert although binocular VA is greater the rescribed above
- issue 1 pr
Characteristics of M45
- Rx usually above 1.00D in distance
- bifocal if required- the add is set 3mm below optical center
- clear plastic frame
- single siz
Army Combat Eye Protection CEP
- active duty must meet the following
- must have VA of 20/40 OU or worse
- Mil vehicle ops, flight personnel, enlisted personel with profile I occupational requirements , when VA is greater than prescribed above
- when bifocal correction is required to perform assigned duties satisfactorily
- when medical or employment requirements necessitate wearing spectacle inserts although the binocular VA is greater the the prescribed above
- issue is 1 pr
- Air Force uses products on the Air Force Protective Eyewear listing AFPE
- active duty 2 pr
- retired 1 pr
- lenses are single or multifocal
- PD of 72 or greater
- only 57 eye sz 18 bridge sz
- frame sz will be larger then S-9 S-8
other non standard frames
- pts who are eligable are so only by
- MOS/AFSC job requirement
- OSI, DIC criminal investigation
- Active Duty 2 pr
- Active Duty/Retired military with medical justification 1 pr in lieu of standard issue
- RX any single or multifocal
- different from S-9 but measuredas if for S-9
- pts active duty 1 pr
- Rx any single or multifocal
- black nylon material
- eye sz 2mm 46,48,50 only
- bridge sz 3mm 22 or 25 only
- adjustable rubber temples
- may be used as protective mask insert
what is PD
Interpupillary distance is the distance between the pupils, PD
why do we take PD?
to inssure the pts pupils are in direct line with the optical center of the spectacles
how is induced prism created?
when the pupils are not in front of the optical center
types of PD
- 3 types
- distance PD between the center of the pupils in mm when the pt is fixating on an object in the distance
- near PD distance between the center of pupils in mm when the pt is fiacting on an object close up
- monocular PD distance between the center of the pupil and the center of the bridge of pts nose each is measured in mm seperately and combined for total PD
how to measure DISTANCE PD
- pt should be 14-16" apart
- hold ruler in rt hand and place across the nose and over the bottom half of the pupils
- steady hand against pt head with 4th and 5th digit
- instruct pt to look at pupil of your RT eye
- close your right , with left eye line up zero of ruler with the outer edge of the pupil or (lateral edge of limbus) of pts rt eye
- open your RT eye and instruct pt to look at your pupil of RT eye
- close left eye, with RT eye sight the inside edge of the pt left eye Or Medial side of pts Left Limbus note the mm reading indicated on the ruler
- record reading that you obtain above as th DISTANCE Interpupillary distance
how to measure NEAR PD
- pt should be 14-16 Inches infront of you
- hold ruler with rt hand placing ruler across nose and over botom hlf of pts pupils
- steay your hand on pts face with 4 and 5 finger
- instruct pt to look at you left pupil
- close your rt eye with left eye line up zero with lateral limbus of pts rt eye to mark zero
- instruct pt to continue to look at our left eye, open your rt eye and close your left eye with your right eye sight edge of medial limbus of pts left eye
measuring Monocular PD
- pt 14-16 away
- hold ruler in rt hand place ruler across pts nose over the bottom half of the pts pupils
- instruct pt to look at you left pupil line up zero with center of pupil or lateral limbus of pts rt eye
- with your right eye site center of bridge of the pts nose over the ruler, note number in mm
- record reading as the right monocular distance PD
- if monocular near PD is required, have pt fixate on the center of the bridge of your nose and take meassure ment form lateral limbus of right eye or center of rt pupil and then the center of the pts bridge of nose
- left eys is done oppisite of right eye
characteristics of single vision lens
- correction for one focal poin
- concave myopic, conves hyperopic, and cylider astimatic
- plasric CR39
- hi index, must have above 6.5 power to order
- ST straight top
- SD Sraight top loks like a "D"
Characteristics of bifocal lenses
- corrects at distance on top and near below
- may have a plano distance (no correction) but will have near Rx (add)
- ST-28 bifocal standard issue is a 28mm width add (this is the with of the added power piece)
- hi index, must be above 6.5 power
- bifocal will be place at with upper edgs of segment at the lower edge of limbus
- trifocal segmant will start and center of pupil and end where bifocl starts
characteristics of trifocal lenses
- corrects distance at top, near at bottom and intermediate in middle
- may have plano (no correction) for distance
- must have near
- must have intermediate, usually halfway between the distance and near power
- standard issue ST 8X35
- the lab automaticlly selects 50% intermediate
Characteristics od Double Seg Lens
- pt are active duty
- bifocal Rx
- near adds are placed above and below distance portion
- placed in aviator and standard S-8and S-9 frams
- upper segmant is sometimes known as occupational segmant
- lesn may be refered to as Double "D"
repair of spectacles includes what?
replacement of any part of frame, not ot include lens
where are replacement parts ordered through?
logistics or medical supply
standard repair equipment consists of?
- PD ruler
- water proof marker
- frame warmer
- cooling pan
- opticians screw drivers
- screw holding forceps/tweezers
- screw extractor
- pliers- screw and rivet peening pliers, screw cuting pliers, lens axis aligning pliers
- initial inspection to verify whats wrong
- acquire replacement parts
- IF DISASEMBLY IS REQUIRED
- neutralize the lenses with lensometer
- mark and remove lenses
- remove screw from hinges
- remove temples from front frame
- examine lenses for defects
- ensure screw are not stripped
- check temples for cracks
- make sure frame front is not broken
- mount temples on frame front
- reinsert lenses into fram fron
- check Rx to make sure it matches original Rx
- if axis is off use axis alignment pliers to adjust rotate lanses in front frame
- be sure to warm frames
- perform final inspection
Endpiece gripping pliers are used how?
used to hold the temples when angling that temple in and out
Fingerpiece pliers are used how?
used most ofeten for angling temples in or out
Temple Angling pliers
- used for angling temples up or down
- should be used in conjunction with endpiece gripping pliers
snip nose or needle nose pliers
most often used to adjust nose pad guard arms
Nose pad piers
used to adjust nosepads
standard adjustment for frame
- should be straight and not twisted like a propeller blade
- check by holding the spectecales perpindicular to the floor and look along the lenses
- check bottom edges are aligned with the top edges
- warm frame and twist at bridge untill straight
- ensure frame fron is curved toward the pts face
stadard adjustments nose pads
- tops of pads should be closer together then the bottoms
- nosepads should folow the shape of the eyewire
- pads should slope back slightly
standard adjustment temples
- ensure temples are parallel to one another when viewed from above
- if temple is not opening wide enough, remove material from the BUTT end of the temple with a file
- if temple is sticking out to far, warm it and bend the temple inward
- check horizontal alignment- frame should touch a flat surface in all 4 places 2 eyewire and bend of temples
fiting frames to pt Frame fron
- evaluate straightness on pts face, onside is high bend sides temple up, on side lower bend sides tmple down
- adjust temples to provide 5-7* of pantoscope tilt
- Make sure lenses are an equal distance from each eye veiw glasses from above, bend temples in to increase distance between the lens and the eye, bend temples out to bring the lens closer to pts face
fitting frames to pt nose pads
- shape the pads to comfort of the pts noce
- make sure lenses are an equal distance from the nose
fitting frames to pt temples
- place he bend past the top of the ear, bend should be 45* angle bend, ensure temple end does not rub against back of ear
- shape the flat part of the temple to conform to the shape of the mastoid bone behind the ear
- perform the tug test tug on front of frame to make sure spetacles fir snugly
- if fit is loose or frame slides forward readjust temples and repeat tug test
typical fiting problems
- pads dig into nose evenly
- pads dig into nose unevenly
- spectacles slid down on nose
- lashes touch the lnses
- eyewires touch cheek
- on lens higher then the other
- bifocals segments cause blurred area
- lenses too far from eyes
- one lens out further then the other
- temples hurt behind ears
spectacle Request Transmission System
SRTS is used for?
- IBM based
- used for the ordering and tracking of military eyewear
- sends eyewear order to manufactur lab via e-mail
- consists of an ordering facility version and a fabrication facility
- same day transmission and reeipt of eyewear orders to optical labs
- provides faster procurement of military eyewear so that service members get glasses faster
- provides reduced cost of sending orders to lab
DD Form 771 includes?
- date rx prepared
- order number rx number
- to enter title address, including zip of servicing opthalmic lab
- from- complete ordering facility/clinic
- name-grade ssn age of pt
- unit- pts complete unit info
- status info- service and active reserve etc
- spectacles- type of eyewear
- when protective wear is ordered need
- mask type
- PD distance and near
- bridge sz
- temple lenth and style
- number of prs
- fabrication data- fram sz will be facricated to fit pt
- SINGLE MULTI VISSION
- enter correction required for each eye, including applicable info for each of the colums heading
- decentration- displacement of the lens optical center from the geometrical center of the frame lens aperatus
- single vission- difference between frame sz FPD and the distance pts Pupillary Distance PPD, evided by 2
- direction of decentration is detirmined by the larger, decnter figure
- if FPD is larger then decenterin
- if PPD is larger then decenter out
- remember FBI means bigger IN
- SPECIAL LENSES OR FRAMES
- basis for order
- full discription of any unusual rx
- additional info helpful for fabricarion
- signatures of autherizing individual for special specs
DD771 3 copies for?
- one for lab
- two for return with spectacles to clinic
- three pts record up initial order
- SINGLE VISION LABS
- Ft Sill, Ft Benning, Ft Knox, Ft Leonard Woood
- MULTI VISSION LABS
- Ft Sam Houston, Ft Jackson, NOSTRA
- 16 single vision Navy labs
Over seas Labs
- SINGLE VISION LAB
- MULTI VISSION
- Korea only bifocal
- Germany USAMMCE full service lab
- 226th MEDLOG Germany
- 32nd MEDLOG Ft Brag NC
- 16th MEDLOG Korea
- required to have Mil ID card
- should maintain a logbook with pt name, mil address, ssn of al individuals issued aviation spectacles
- Army Ar Force must have VA of 20/40 or worse
- Ary when primary vehicle op and VA no worse then 20/20
- Mil Vehic op, flight personnel, enlisted with profile I occupational requirements, when binocular VA is less than 20/20
- when bifocal correction is required to perform asigned duties satisfactorily issue 1 pr
spectacles with prescription tinted lenses
- Aviation low reflecive coated lenses, only pilots that are actively flying, electrical warfare officers, boom operators performing flight duties
- N-15 tinted lenses actively flying mil flight personel only
- N-31 tinted lenses active duty personnel that meet isuance criteria
- retired members when required for mediclal reason
issuance of spectacles with prescription tinted lenses
- active duty asigned to Antarctica or Arctic conditions
- a non flying full time prescription wearer when sunglasses are needed for an occupational, environmental, or geographicl need for effective performance of assigned mil duties
- when personnel are assigned to a unit in "clothing allowance zoneI"
- ocular condition requirement of tint detirmined by prescribing officer
used when sphere signs are opposite from one another
used when cylinder axis is 90* apart
adjusted nose pads
used when pt wants or requires adjustable nose pads
riding bow cables
used when the pt requests riding bow cables
half eye spectacles
then half eyes specs are required
nonstandard frame requested
pts MOS nonstandard frame is required
male frames requested
female wants male frames
prisms are ordered
executive bifocals requested
pt requires executive bifocals
pt requires executive trifocals
used when personel are processing for overseas replacement
eligibility verified by SM LES dated 31Dec SPC eyeball
used in order to request flight glasses for enlisted flight personnel
eligibility verified by the offocers signature WO2 flying, SPC eyeball
used in order to request flight glasses for officer flight personel
when tint is ordered reason why required
reason why required used whentint is ordered
spherical equivalent used for
- temporary replacement for broken or lost glasses
- used to calculate the appropriate power of a spherical contact lens for pt with lens less than -1.25 of cylinder power
calculating spherical equivalent
- take 1/2 of the cylinder power - if the cylinder power cannot be devided by 2, round the cylinder power up to the nearet 0.50D before dividing
- add power algebraicly to the sphere
procedure for converting a distance vision prescription and near prescription to a bifocal
- note both prescriptions must have identical cylinders in orde to complete this process
- record distance prescription as written
- record diference between the spherical power of the distance prescription and spherical power of the near prescription as the add segmant of the bifocal prescription
- note because you travel towards the plus direction, the bifocal power will always be a plus + spherical power
procedure for converting from bifocal prescription to near and distance
- distance prescription
- record the distance portion of the bifocal rx as the new distance prescription
- near distance prescription
- add the spherical power of the distance portion of the bifocal to the add segmant of the bifocal and record this as the near spherical power
- record the cylinde power and the axis from the distance portion of thr bifocal as they remain the same
conversion of single vision to intermediate prescription
- algebraicly add 50% of the trifocal add power to the shpere power in th distance rx
- leave cylinder power and axis as they are
transposition of presccription
- note the cylinder form i detirmined by the sign in front of the cylinder
- detirmine new spherical power by adding the cylindrical power to the spherical power
- detirmine the new cylindrical power by changing the sign of the cylinder from plus to minus or minus to plus
- detirmine the new axis (X) by changing the axis 90* 90* or less add 90, 91* or more subtract 90*
why do we wear contacts?
- refractive errors
- myopia, hyperopia, astimatism, presbyopis
- disease process
- keratoconus, corneal scarring, corneal dystrophy, aphakia, physical abnormlities, bandage lens after surgery
- color change, drama
- bandage lens
characteristics of soft contacts
- material- HEMA hydroxyethylmethacrylate , silicone hydrogel
- size- larger then the cornea, about 14mm
- fitting relation to the cornea- contacts coenes lake a bandage, smaller movement with each blink
- advamtages- easy to adapt to, grater INITIAL comfort, will not pop-out as easily as hard, good for athletic wear, increased disposability
- disadvantages- lower original cost but higher ongoing cost, vision fluxuation, shorter life expectancy, easier to tear, protien build up, easier to lose, need toric lenses to correct astigmatism
characteristics of hard contacts
- material- PMMA polymethylmethacrylate rigid gas permeable
- Size- smaller then the cornea, about 9mm
- fitting relation to the cornea- ride on tear layer, larger movement with each blink
- advantage- lower overall cost, longer life expectancy, better visual acuity
- disadvantages- long adaptation period(up to one month), some pts never adapt, greater potential for corneal insult
characteristics of extended wear (flexible wear)
- very thin, higher water content (soft lens)
- can be worn for an extended period of time
- developed originaly for aphakes
- new selicon contacts approved tor one month continuous wear
characteristics of toric lens (astigmatic)
- Hard- used when cornea is so astigmatic that ordinary lenses fir poorly
- Soft- ordinary spherical soft lenses do not correct astigmatism
- toric soft lenses will correct most astigmatisms but are limited in availavle powers and axis
characteristics of bifocal contacts
- hard or soft
- dificult to use
- most presbyopic pts wear ordinay contacts for distance with a pair of reading glassesover the contacts for near work
- Note not everyone can make this adjustment
characteristics of cosmesis lens
- contact lens can be ordered with different shades of color
- hide abnomality(scar, congenital defect, etc.)
- may have different designs on them as well
- functional colored contact
caring for contacts
- clea- remove debris and mucous
- disenfect- kill bacteria and viruses
- store- keep lenses hydrated and sterile cannot use H2O(water)
- protein removal- build up from lens
hard contact lens care
- comfort drops-
- enzymatic tablets-
soft contact lens care
- cold sterilization method-
- cleaning solution-
- storage solution-
- rinsing solution-
- enzymatic tablets-
- all in one-
- allergic reactions to solutions (5%)
- preservation or hydrogen peroxide
contact lens care DO"S
- wash hands thouroughtly with soap that contains no oils, perfumes or deoderants before handling lenses
- dry hands with lint free source
- learn to apply and remove contacts without the use of a mirror
- keep right and left lenses seperate
- clean lenses daily as instructed
- have routine contact lens evaluations every year or sooner if doctor directs
- follow wearing schedule for new lenses as prescribed by doc- adaptation phasewear hard contacts
- wear hard copntacts everyday for the same length of time (at least 6 hrs a day) untill adapted
- replace instructed lenses as indicated- not when
contact lens care DONTS
- do not sleep with contacts lenses on the eyes unless directed
- do not wear lenses longer than instructed
- do not use any drops in the eyes while wearing contact lenses unless specificaly recommended by the doctoor
- remove if ANY discomfort, redness, itching, vision changes
- DO not wearEITHER contact if infection is suspected
- do not use cold cream or deoderant soap to wash hands before handleing lenses
- do not use hairspray while lenses are in the eyes
- do not apply lenses over sink whithout drain plug or paper towel on the drain
- do not wet your lenses by placing them in your mouth or by spitting on them
- do not rub the lenses with dry tissue
- do not use other cleaners/lighter fluid/corn starch etc.
complications long term effects Hard lenses
- over wear abrasion
- may induse corneal changes in some pats
- minor corneal damage in manypts if lenses fit improperly especially suceptible
- contact lenses change shape over time secondary to cleaning inducing changes in cornea and refractive error
commplications long term effcts soft lenses
- decreased oxygen to cornea causes break down of epithelium
- they can also allow penetration of bacteria and secondary corneal ulcer
- left untreated, it can penetrate globe and cause endophthalmitis
- may also cause neovascularization
- wash hands and dry thoroughly
- rinse lens with appropriate solution
- insert lens carefully into the eye
- wah hands and dry thoroughly
- remove lens carefully from the eye
- store lens in appropriate container
insertion of Rigid Gas Permeable CL
- wash hand, plug sink
- prepare the area
- remove right lens from casr
- put wetting solution on lens before inserting
- place contact on the index finger of the dominant hand, convex surface of finger)
- with the other hand, grasp the upper lid by the margin to prevent blinking advancing the contact lens toward the cornea(pt looks straight ahead)
- place the contact on the cornea
- control of the lids must be maintained
- last step is to have pt look downward, release the lower lid then the upper lid and blink
- repeat steps 3 through 10 for left eye
centering the lens
- look in direction of lens
- if the lens doesnt centerplace ensds of index and middle finger together to form a "wedge"
- using the wedge, push lens back onto cornea while turning the eye in direction of the wedge
- lens should feel more comfortable when centered
Removal of Rigid Gas Perms lens
- ONE FINGER METHODlens must be centered before attempting removal
- have pt open eyes as wide as possible (startled appearance)
- place index finger or second finger at temporal canthus
- pull canthus back toward the ear while pt keeps eyes open wide
- then have pt blink hard and quick, the lens should be ejected by the lid margins
- use the other hand to catch the lens
Removal if Rigid Gas Perms
- TWO HANDED METHODpt with small fissures or loose lids may do better with 2 handed method
- place one finger on the lower lid and pull margin outward. this places margin tight against the globe
- squeeze lids together
- the lens will usually "tip" out of the eye, you can catch with the hand holding the lower lid
INSERTING A PT'S SOFT CONTACT LENS SCL
- after lenses have been cleaned, disinfected and rinsed, they can be placed on the cornea
- wash your hands
- remove the right lens from the case
- inspect the lesn for debris
- make sure the lens is not inside out
- do either the taco test or the bowl test
- place the moistened lens on the index finger of the dominant hand ( convex surface on the finger)
- have pt look down
- release lower lid
- release upper lid
- the lens should center itself, if not have pt close eyes and massage the lid
- repeat steps for the left eye
REMOVING A PTS SCL
- wash hands, cut fingernails if necessay
- have pt look down
- grasp upper lid
- have pt look up
- grasp lower lid with the middle finger of your dominant hand
- lightly place place the tip of the index finger on the lens surface with the dominant hand
- have pt to continue to look up and at the same time slide the SCL down onto sclera keeping the index finger on the lens
- gently pinch the lens between the thumb and the index finger and pull the lens away from the eye
- place the right lens in the compartment marked "right" of the case
- repeat steps for the left eye
TEACHING CONTACT LENS INSERTION
- wash hands and plug sink
- remove the right lens from the case and inspect it for debris
- make sure the lens is not inside out
- place lens on index finger of dominant hand, with convex side toward the finger
- pull lower lid down with middle finger of that hand. reach over your haed with the other hand and grasp the upper lid (pin lashes to the upper portion of orbit)
- while looking in the mirror, place the lens on the lower sclera
- if lens does not center itself, massage the eye
- repeat the same steps for the left eye
TEACHING CONTACT LEANS REMOVAL
- wash hands and plug sink
- hold the right lower lid down with the middle finger of the dominant hand
- make sure the lens is on the center of the cornea
- reach over your head with the other hand and grasp the upper lid
- lightly placde the tip of the index finger on the center of the lens surface with the dominant hand
- look up and at the same time slide the lens down onto the lower sclera
- gently pinch the lens between the thumb and index finger and pull the lens away
- place the right lens in the compartment marked RIGHT of the case
- repeat the same steps for left eye
AF Air Crew Contact lens program
- rated air crew
- non rated air crew
- operational support flyer
Rated air crew
- hold USAF aeronautical rating
- includes pilots navs weapons sys officers, electronic warfare officers,flight surgeons
nonrated air crew
- required to be onboard the aircraft to accomplish the primary mission
- includes load masters, flight engineers, aerial gunner, bombers, pararescue, flight nurse
operational suppoer flyer
- perform specific inflight duties- not routinly required to be onboard aircraft
- includes air traffic controllers, combat controllers, space ops personnel
medical flying classes
- flying class I
- uft students who will become rated aircrew when they graduate
- flying class II
- rated aircrew
- flying class III
- non rated aircrew personnel
Air crew vissual requirements
- 20/20 DVA and NVA with spectacles
- 20/20 DVA and NVA with SCL if worn -1 20/20 DVA and NVA with spectacles immediately after removing SCL
- Flight Surgeons Office
- responsible for health of air crew
- determines if crew is qualified to fly
- duties not to include flying
- air crew on DNIF'd when thy do not meet visual or medical standards