2. WELCOME
We are pleased to present this guide which outlines the essential rules
for the successful fitting of progressive lenses to your presbyopic patients.
Overall, it guides you through successful fitting from first contact to the final delivery
of the spectacles.
A genuine working tool, this guide will be found useful in your daily routine and will help
you to be successful in fitting progressive lenses and help to guarantee patient
satisfaction.
Please use it regularly!
2
3. FITTING VARILUX STEP BY STEP
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3
4. 1 UNDERSTANDING THE PATIENT
This first step is essential to the success of lens fitting
1 What was the patient
wearing before?
Type of lenses worn Analyzing the previous lenses 2 What are the visual needs?
I Single Vision for Distance, Single Vision I Measure the previous correction: What are the spectacles used for?
for Near, Mid-distance, Bifocal, sphere, cylinder, axis, addition and
Progressive (brand and type)… prismatic correction if any. I Permanent or occasional wear?
I Material, colour, coatings… I Date when given the previous lenses I Working distances?
I Visual performance with former lenses: Specific requirements?
measure acuity for distance and near I Profession, hobbies, leisure.
vision.
I Clarity of vision necessary.
Understand the reasons for any lens I Field of vision needed.
change and confirm its need.
DÉCOUVRIR LE CONSOMMATEUR 4
5. 2 ANALYZING THE PRESCRIPTION
An overview of the refraction techniques
1 Compare the new correction 2 Compare the value of
with the previous one the addition with the ones
If the difference is equal to
suggested in the table Age Addition
(or more than) … These typical values should only be 40 years 0.75 D
exceeded in cases of real necessity.
I 0.75 D on the sphere 44 years 1.00 D
I 0.50 D on the cylinder 47 years 1.25 D
49 years 1.50 D
I 10° on the axis
51 years 1.75 D
I 0.75 D on the addition 54 years 2.00 D
... confirm its necessity with prescriber 58 years 2.25 D
and ensure its acceptance. 63 years 2.50 D
67 years 2.75 D
70 years 3.00 D
75 years 3.25 D*
80 years 3.50 D*
* Additions 3.25 and 3.50
are rarely ever necessary.
5
6. CHECKING WHETHER THE ADDITION IS TOO STRONG
Too strong an addition is often the reason for adaptation problems with progressive lenses
1 Checking near vision
correction
Using the Essilor “CheckTest”
The subject wearing the near vision With an additional power of -1.00 D
correction, places the CheckTest at the
usual reading distance. Place the -1.00 D lenses in front of the
near vision correction of the subject: if the
• With the Helmoltz test pattern smallest characters can still be read, even
If the circles in the centre of the pattern if with some difficulty, the addition is
are seen without deformation, the near probably too strong.
vision correction is correct for the reading
distance. If the circles are seen deformed,
the near vision correction is either correct
or too weak. The CheckTest is available for free from
• With the red-green test Varilux University. Don’t hesitate to ask
If the letters are seen more clearly on for it while visiting our web site at:
the green background, the near vision www.varilux-university.org
correction is either correct or two weak.
If they are seen more clearly on the red
background, the near vision correction Image of pattern’s
centre
is probably too strong.
6
7. CHECKING WHETHER THE ADDITION IS TOO STRONG
Too strong an addition often results from an under-correction of distance vision
2 Detecting under-corrected
hypermetropia
This is often the cause of too strong an
addition because it relates directly to the
value of the addition.
With the red-green test in distance With an additional power of + 0.50 D
vision
Place the + 0.50 D lenses in front of the
If the subject has a clear preference distance vision correction of the subject
for reading on the green background and and ask the subject to look in the distance:
the letters appear blurred on the red if vision remains clear, or is improved,
background, the hyperopia is probably the hyperopia is probably under-
under-corrected. corrected.
NB. Any prescription changes must be undertaken by a registered prescriber.
7
8. CORRECTION OF DISTANCE VISION
An accurate distance prescription results in the most comfortable near prescription
Deal with each eye separately starting 2 Determination of the cylinder b) Verify the cylinder power
S U P P L E M E N T
from a trial correction (old prescription or I Place the minus axis of the cross
results from an autorefractor). Using the cross cylinder method (± 0.25 D)
cylinder along the direction of the
1 Determination of the sphere a) Verify the cylinder axis:
correcting minus cylinder.
I Position the handle of the cross cylinder
I With the subject looking at a line of small
Using the fogging method along the cylinder axis direction of the
letters, rapidly twirl the cross cylinder
1) Place the trial prescription before trial prescription (it should produce a
and ask the subject which position of the
the subject’s eye and measure the drop in acuity).
cross cylinder is preferred.
visual acuity. I With the subject looking at medium size
I If the subject prefers the position when
2) Fog the eye by adding +1.00 D letters, rapidly twirl the cross cylinder
the minus axis of the cross cylinder lies
or +1.50 D to cause a drop in visual and ask the subject which position of the
along the axis of the correcting minus
acuity. cross cylinder is preferred.
cylinder, add -0.25 D to the correcting
3) Unfog progressively by -0.25 D steps I Turn the axis of the correcting minus
cylinder.
and check that the visual acuity cylinder by 5° towards the minus axis
I Repeat this process until the subject
improves. of the preferred cross cylinder.
cannot (or can hardly) tell the difference.
4) Continue until the best acuity is I Repeat this process until the subject
I Record the minimum value of the
obtained. cannot (or can hardly) tell the difference.
cylinder power found.
5) Record the power of the strongest plus
sphere that provides maximum acuity. c) Check the sphere power
I Add +0.25 D to the sphere for each
-0.50 D added to the cylinder and check
that the best visual acuity is still obtained.
8
9. CORRECTION OF DISTANCE VISION
An accurate distance prescription results in the most comfortable near prescription
3 Binocular balance 4) Binocularly, unfog the eyes in -0.25 D I For the cylinder
S U P P L E M E N T
steps until the maximum acuity is obtained. • Correct the astigmatism only if it results
In distance vision, by dissociating the eyes
in a noticeable gain in visual acuity.
and checking the visual acuity. 5) Check the acuity of each eye, making
• Be wary of weak astigmatism, it often
sure that ocular dominance has not been
1) Dissociate the subject’s eyes varies.
reversed between the eyes.
• by alternate occlusion: rapidly occlude • Moderate prescriptions with oblique
one eye, then the other, with an occluder Some rules axes that may give rise to distortion.
or and recommendations
I Binocular vision
• with vertical prism: introduce 3∆ base I For the sphere
• Carefully check binocular balance.
down before one eye and 3∆ base up • Always fully correct the ametropia,
• Give priority to the dominant eye: do
before the other or particularly any hypermetropia, but do
not reverse ocular dominance between
• by polarization: use a polarization not overplus.
the eyes.
test for visual acuity together with the • Do not over-correct, rather prefer a slight
• In cases of anisometropia, give the mini-
corresponding polarizing filters. under-correction. In the red-green test:
mum possible difference between the
– for hyperopia, “equalize” the red and the
2) Fog both eyes with +0.50 D spheres right and left eyes.
green or leave “slightly clearer on the
and confirm that there is a drop in acuity.
green”. I As a general rule
3) Balance vision in the right and left – for myopia, “equalize” the red and the • Avoid large changes in prescription: do
eyes by refogging the eye with the green or leave “slightly clearer on the red”. not exceed 0.75 D on the sphere, 0.50 D
better acuity with a +0.25 D sphere. • Remember that refraction has not been on the cylinder or 10° on the axis, unless
undertaken for infinity: add -0.25 D to it is really necessary.
the sphere if necessary.
9
10. DETERMINATION OF THE ADDITION
THE “FIXED CROSS CYLINDER” METHOD
A reference method for determination of the addition
Using the refractor with both eyes open.
S U P P L E M E N T
1 Fully correct distance vision 2 Determination of 3 Verify that the subject
Use the highest plus sphere which the addition can read comfortably
provides maximum visual acuity I Ask the subject to fixate a cross made I Put up the distance correction with the
(see previous pages on “Correction of up of vertical and horizontal lines at a proposed near addition in a trial frame.
Distance Vision”). distance of 40cm (16 in). I Ask the subject to confirm that vision is
I Position ±0.50 D cross cylinders with comfortable when reading.
their minus axes at 90° before both I Adjust the value of the addition for the
eyes: the subject should report that the subject’s normal working or reading
horizontal lines are clearer. distance.
I Progressively, place +0.25, +0.50,
+0.75 D…lenses before the eyes until
the vertical and horizontal lines appear
equally black.
I The addition is the value which gives
the best equality between the horizontal
and the vertical lines.
10
11. DETERMINATION OF THE ADDITION
THE “ACCOMMODATIVE RESERVE” METHOD
A classic method for determination of the addition
1 Measure the amplitude 2 Determination of 3 Verify that the subject
S U P P L E M E N T
of accommodation the addition can read comfortably
Using binocular vision with the distance correc- Normally, subjects should be allowed to use I Put up the distance correction with the
tion in place and the use of a near vision chart. two-thirds of their total amplitude of accom- proposed near addition in a trial frame.
modation at their usual working distance I Ask the subject to confirm that vision is
I With moveable near vision chart:
(leaving one-third of their total amplitude in comfortable when reading.
Bring the near vision chart in towards the subject
reserve) so as to be comfortable. I Adjust the value of the addition for the
until it is only just legible, the amplitude of
The addition is calculated from: subject’s normal working or reading
accommodation is the reciprocal of this distance.
Addition = 1 / near distance - 2 / 3 total amplitude. distance.
For example: nearest reading distance = 0.50 m,
amplitude of accommodation = 2.00 D. Total Usable Addition
amplitude of amplitude of for 40 cm
I With fixed near vision chart: accommodation accommodation (16 in)
• Position the near chart at 40 cm (16 in) 3.00 2.00 0.50
and ask the subject to read. 2.75 1.75 0.75
• If can read the smallest text, add 2.50 1.50 1.00
-0.25 D, -0.50 D etc..., binocularly, until 2.25 1.50 1.25
2.00 1.25 1.50
reading is no longer possible. 1.75 1.00 1.50
• If cannot read the smallest text put up +0.25 1.50 1.00 1.50
D, +0.50 D etc…, binocularly, until the 1.25 0.75 1.75
smallest text can just be read. 1.00 0.50 2.00
0.75 0.50 2.25
The amplitude of accommodation =
2.50 - final value which has been added. 0.50 0.25 2.50
11
12. DETERMINING THE ADDITION
THE “MINIMUM ADDITION” METHOD
A simple and proven method of determining the addition
4 Stages
S U P P L E M E N T
1 Good correction 3 Add + 0.75 D to + 1.00 D
of distance vision to the minimum addition to find the
I Fully correct the ametropia, in particular comfortable addition value.
any hyperopia.
I Do not over-correct. 4 Checking the patient’s
With the red-green test: visual comfort
• for the hyperope, keep “equal” or
I Have the patient evaluate whether reading
“sharper on the green”,
is comfortable with the addition found.
• for the myope, keep “equal” or “sharper
I Ask the subject to bring the text closer
on the red”.
until the reading of small characters is
I Correct astigmatism only when it
impossible: it should occur at approxima-
provides a real gain in visual acuity.
tely 25 cm / 10 in from the eyes. If it
2 Determining the minimum occurs closer than 20 cm / 8 in, the addi-
tion is too strong, if it occurs further than
addition at 40 cm (16 in) 30 cm / 13 in, the addition is too low.
Add binocularly + 0.25 D, + 0.50 D, etc… I Adjust the value of the addition by 0.25 D
to the distance correction until the patient just according to the usual working or reading
distinguishes the smallest characters: distance.
the value found is the minimum addition.
12
13. 3 FRAME SELECTION
The correct choice of frame is important for overall comfort
1 Selecting the frame 2 Adjusting the frame
Select a frame which is right for the Adjust the frame to fit the face of the client
wearer’s face, that is stable on the nose so that:
and offers sufficient height between the
I The vertex distance is approximately
pupil and the lower rim of the frame.
12 to 14 mm.
I The pantoscopic angle is in the region
17 mm minimum for Varilux Physio.
18 mm minimum for Varilux Panamic and Varilux Comfort. of 8° to 12°.
Proceed with the adjustments in the order:
I Adjustment of the front of the frame:
projection, inclination, horizontality.
I Adjustment of the sides of the frame:
opening, shape and length, ear pieces,
18, 16 or 14 mm for Varilux Ipseo. closure of the sides.
14 mm minimum for Varilux Ellipse.
The frame should always be adjusted
before starting to take measurements.
13
14. 4 TAKING THE MEASUREMENTS
A crucial step for the success of lens fitting
Measure then check
2 Stages
1 Taking the measurements
Measuring the pupillary distance
I Measure each eye separately
I Use the CRP (“Corneal Reflection
with both eyes open.
Pupillometer”) ensuring that the nose
pieces have been adjusted so that they
rest in the same position as the bridge I If the wearer sees 2 images, measure
of the final frame and checking that it is one eye at a time, using the eye mask
in contact with the forehead. of the pupillometer.
I Measure the monocular pupillary dis-
tances, right and left, in distance vision
(infinity) and, in near vision (at 40 cm /
16 in) if needed.
14
15. 4 TAKING THE MEASUREMENTS
A crucial step for the success of lens fitting
Measure then check
Measurement of the pupillary heights
I Use the HMS (“Height Measuring
System”) in order to obtain the Boxing
measurements of pupillary heights for
the right and left eyes.
I Adjust the frame on the face of the I Adjust the right and left cursors to I Read the right and left pupillary heights
patient and set the HMS taking care not the height of the pupil centres placing in the Boxing system: make sure that
to modify the position of the frame. yourself at the same level as the eyes the measurement is taken to the lower
I Preferably in a standing position, ask of the patient to avoid any parallax error horizontal tangent to the lens (inside
the client to adopt a natural position (it can produce an error of several mm). groove of rimmed frame).
and to look into the distance at eye
level.
For accuracy take the measurements
with the subject standing up and looking
into the distance.
15
16. 4 TAKING THE MEASUREMENTS
A crucial step for the success of lens fitting
Measure then check
2 Checking the measurements Checking in near vision (optional)
I Using the Ditest or the centring I Using the VP System, check using the
chart mark the fitting cross position mirror method the correct positioning
at monocular PD and height of the eyes in near vision: corneal
measurements, for each lens, reflections should coincide with the
as well as the position of the near near vision circles.
vision circle. Reposition the frame I If there is a manifest asymmetry take it
on the wearer’s face. into account by shifting each near vision
PD by the required value while keeping With the Ditest, select the diameter of the
the binocular PD measured at 40 cm / lenses needed or determine precisely the
16 in with the pupillometer at 40 cm / pre-calibration measurements (in the
16 in. To obtain the distance centration Boxing system) by measuring them on the
add 2.5 mm to the near vision PDs frame. The order for Varilux lenses is now
found. ready be placed.
Checking distance centration
I In a standing position ask the patient to
look into the distance, position yourself
in front at eye level and check that the
centring cross lies in front of the centre
of each pupil (see photo below).
16
17. 5 MOUNTING THE LENSES
Points to keep in mind
1 Check the conformity I Prism verification is carried out by
placing the focimeter at the prism
of the lenses
control point. The prism measured is
and of their markings
the resultant of the thinning prism
I Verification of the distance prescription: (the value of which is equal to 2/3 of
the measurement is carried out placing the addition) and of any prismatic
the concave side of the lens in contact correction prescribed.
with the support cone of the focimeter.
The control circle for distance vision I Verification of the addition: it is the
must be centred on the aperture of the difference between the power for near
focimeter, the axis of the lens being vision and the power for distance vision
horizontal. measured on the front side. It is also
possible to read its value directly from
I Verification of the near prescription:
the 2 digits engraved under the
the measurement is carried out by
temporal micro-circle.
placing the convex side of the lens in
contact with the support cone of the I Verification of markings in order to
focimeter. check their correct position compared 34
The near vision circle must be centred with the engravings (see scheme
on the aperture of the focimeter. herein).
2,5
17
18. 5 MOUNTING THE LENSES
Points to keep in mind
2 Make sure that both centring 3 Check the conformity 4 Make sure the frame
and mounting are made of the mounting is correctly set up
in the Boxing system Using the Ditest device or the centring Pre-adjust the frame paying particular
I All values must be given in the Boxing chart, check: attention:
system.
I the right and left PDs, I to the positioning of the lenses in
I Centring and edging equipment must
I the right and left heights, the same plane,
function in this system.
I the horizontality of the mounting: I to the pantoscopic angle.
by the alignment of the micro-circles.
5 Retain the lens markings
until delivery
(or retrace them if they
have disappeared)
18
19. 6 FINAL FITTING
The moment of truth
1 Adjust the frame 4 Check the vision quality 6 Inform the client about
to the patient’s face I In distance vision using a visual
the learning period
acuity test,
necessary for each new
2 Check centring using pair of lenses
I In near vision using a reading test.
markings
I In distance vision (general case): fitting 5 Give recommendations
cross in correspondance with pupil to assist adaptation
centre for the right and left eyes.
I Distance vision at eye level,
I In near vision (specific case of
looking straight ahead.
convergence asymmetry): in the client
I Near vision in the lower part of
reading position, corneal reflex should
the lens, by lowering the eyes
be seen through the near vision circle.
(and slightly raising the head if
3 Finalise the frame necessary).
I To begin, all head and eye
adjustment movement should be carried
out slowly.
19
20. 7 SOLVING ADAPTATION PROBLEMS
It is necessary to follow a precise sequence in order to determine the problem
Thorough research must be conducted
General steps
1 Record the precise 3 Remark the lenses 5 Check the adjustment
complaints of the wearer of the frame
I Fitting cross for distance vision and
I Type of problem encountered, frequency near vision circles. I Vertical and horizontal alignment,
and particular circumstances of problem, pantoscopic tilt and stability.
distances concerned, expedient solutions 4
Check the correct centration 6 Validate the subject’s
found, etc…
of the lenses
prescription
2 Measure the lenses I In distance vision and in near vision,
I Measure the acuity at distance
frame positioned on the wearer’s face.
I Power of distance vision, near vision and at near.
and addition. I Confirm the value of the addition
as related to the age.
20
21. 7 A TABLE OF CAUSES TO EXPLORE
This table relates to the complaints most often presented by wearers with characteristics which were eventually blamed.
CHARACTERISTICS EVENTUALLY BLAMED
V V me
eN eD e fra
n anc tanc ight s/ey f the s
tio dist dis g he n en
t len n o ens tism
e
ec
efl illary illary ntin visio ition stm ance inatio er l gma
WEARERS COMPLAINTS ti-r up p u r d ju t l rm sti POSSIBLE SOLUTIONS
An P Pu Mo Fa Ad Ad Dis Inc Fo A
Has to raise head or lift lenses to read I Modify the adjustment by lifting the frame
I Increase the distance or near powers
I Mount new lenses higher up
Needs to lower lenses or head to see better in dis- I Modify the adjustment by lowering the frame
tance vision I Reduce the distance or near powers
I Mount new lenses lower
I Modify the adjustment
Needs to tilt head to see clearly I Modify the centring
I Check the astigmatism
I Reduce the addition
Has a very reduced near vision field. I Reduce the addition and increase the distance power
Fatigue after prolonged work in near vision I Check the astigmatism
I Modify the centring: mount lenses higher
I Verify the balance between right and left lenses
I Reduce the distance power
Sees out of focus in lateral vision I Reduce the addition
I Check the distance PDs and modify the centring
I Check the pantoscopic angle
I Check the adjustment and the pantoscopic angle
21
22. 7 A TABLE OF CAUSES TO EXPLORE
This table relates to the complaints most often presented by wearers with characteristics which were eventually blamed.
CHARACTERISTICS EVENTUALLY BLAMED
V V me
eN eD e fra
n anc tanc ight s/ey f the s
tio dist dis g he n en
t len n o ens tism
e
ec
efl illary illary ntin visio ition stm ance inatio er l gma
WEARERS COMPLAINTS ti-r up p u r d ju t l rm sti POSSIBLE SOLUTIONS
An P Pu Mo Fa Ad Ad Dis Inc Fo A
I Check distance and near pupillary distances and
heights to confirm centring
Sees double at distance or near or both I Check distance and near powers, astigmatism and
balance between right and left eyes.
I Check the adjustment and pantoscopic angle
I Compare with the previous spectacles
Sees light sources doubled I Make new lenses with an anti-reflective coating
I Verify the astigmatism
I Check the astigmatism
I Reduce the addition
Sees lines deformed I Check the distance and near PDs and the heights
to check centring
I Modify the adjustment by lifting the frame or mount
the new lenses higher
I Check the distance and near PDs and the heights to
check centring
Has burning, itching sensation, I Check distance and near powers, astigmatism and
feels ocular fatigue balance between right and left eyes
I Compare with the previous spectacles
I Make new lenses with an anti-reflective coating
22
23. For further information
or for downloading this Varilux Fitting Guide
visit our web site at:
www.varilux-university.org