Quantifying adjective, describes how much or how many, can be done 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 numberline do?
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 sign indicates?
Positive action/movement on the numberline.
Negative sign 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 number 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
Deca da indicates?
Deci d 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 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 as particles and theory of light as waves.
Effects the form of a lens may take?
Positive 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 characterized 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
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 point 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 dertimined by what?
Opacity, translucnacy, and transparency.
What is opacity?
Something that is opaque, refers to anything that blocks normal transmission of light through a transperaant medium.
Whaat is translucency?
Kind of clear but not all 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?
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 original 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 astigmatism , compound myopic, and mixed astigmatism.
Two flat surfaces not parallel, thickest portin is at base, thinnest point is at the apex.
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...
One flat surface and one convex surface
Has plus power
One flat surface one concave
Has minus power
Both sides of a biconvex lens bulge outward
Have plus power
Both sides cave inward
Has minus power
One convex side one concave side
Convex side has steeper curve then the concave side
Has positive power
One convex side and one concave side
Concave side has a steeper curve then the convex side
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 of the lenses?
Plus lenses magnify
Minus lenses minify
what is the eys piece?
part where one looks into the lensometer
what is the table, or spectacle table and lever?
what the glasses rest on when being worked within the lensometer
Lever raises or lowers table
what is the lens holder?
this is the 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 bulls eye, first half 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
how do you focus the eye piece?
with instrument off, turn eyepiece counterclockwise untill it stops
place piece of white paper in front of eyepiece
looking into eyepiece, 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 set 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 is over lens stop
refocus until three sphere lines come into clear, sharp focus TURNING POWER WHEEL IN A POSITIVE DIRECTION
difference between original distance vision shpere reading and the second sphere reading will be the power of the multi focal segmant.
Will be a positive number always
2 methods of multifocal neutralization
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. Power greater then 4 turn glasses around
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 STORE button
move lens untill a plus sign appears in the PAL display
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
Strongest lens power is calculated using spherical equivalance
1/2 of cylinder power added to sphere power =sherical equivalance
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 greater then 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)
if PD recieved is larger than PD ordered, prism direction will be BI MLI
if PD recieved is smaller than PD ordered, prism direction will be BO MSO
if PD recieved is larger than PD ordered, prism direction will be BO PLO
if PD recieved is smaller than PD ordered, prism direction will be BI PSI
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 clock 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 of a spring
the pointer on the instrument dial and activated by movement (up or down) of 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
Black numbers indicate plus power
red numbers indicate negative power
calibrated for one 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)
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
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 CURVE 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 front side (convex) 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*
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 caused by 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
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
Air Force Flight Fram AFF
Air Force Dress Frame AFD
Black on color for aviators
if aviators require 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 which 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 black 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
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
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
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
steady 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 your 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 point
concave myopic, convex hyperopic, and cylider astimatic
hi index, must have above 6.5 power to order
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
ST straight top
SD straight top "D" looks like a D
bifocal will be place at with upper edge of segment at the lower edge of limbus
trifocal segmant will start and center of pupil and end where bifocal 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 of Double Seg Lens
pt are active duty
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