Translating Bifocal Soft Contact Lens

PRACTITIONER FITTING GUIDE | Translating Bifocal Soft Contact Lens
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Looking good, feeling great!
Leaders in contact lens design
and manufacture for over
40 years, Gelflex has built
its reputation on innovation,
quality and research.
Gelflex Laboratories is an
innovative contact lens
manufacturer based in Perth,
Western Australia, that
produces a range of specialised
custom-made and frequent
replacement contact lenses to
improve the vision, comfort and
appearance of its wearers.
Gelflex was founded in 1971
and today the company is
operated and managed by
contact lens specialists who
understand how to deliver
quality service to practitioners
and innovative contact lens
products for their customers.
Gelflex is also Australia’s only
manufacturer of disposable
contact lenses. All Gelflex
products are fully produced
in-house under strict quality
control systems.
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TRITON®
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TRANSLATING BIFOCAL SOFT CONTACT LENS
The TRITON® Translating Soft Bifocal Contact
Lens is a translating bifocal lens that is of a true
bifocal lens design with defined areas for both
distance and near vision.
LENS FITTING
The TRITON® Translating Soft Bifocal Contact
Lens allows for full precise optical correction to
be incorporated in the lens, providing patients
with optimal visual acuity at both near and far
distances ‘without compromise’.
The lower lid is an important factor in the
correct successful fitting of the TRITON®
Translating Soft Bifocal Lens, as the lower lid
enables lens translation to occur.
The TRITON® Translating Soft Bifocal Lens is
approved by the American FDA.
LENS MATERIALS
Methafilcon A 55% water content.
Blue Visibility Tint.
Hioxifilcon 49% water content.
Blue Visibility Tint.
The fitting of a TRITON® Translating Soft Bifocal
Contact Lens must be evaluated with the use
of a TRITON® diagnostic fitting set.
There are two important considerations for the
successful fitting of the TRITON® lens:
1. Defining the correct position of the near
segment position.
2. The position of the lower lid relative to
the limbus.
DIAGNOSTIC FITTING SET
The diagnostic lens set consists of Four lenses.
Distance power: Plano
Reading addition: +2.00 D.
Each TRITON® lens has two location dots at 3
and 9 O’clock position. As the near segment
line cannot be easily seen on the lens, location
dots mark the position of the near segment of
the lens.
Location Marker Dots
1mm
Reading
Markersegment
Dots
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LENS DETAILS & INFORMATION
LENS DETAILS
Base Curve
Diameters
Segment Position
Tint
8.60
15.0/13.4 or 14.5/13.4
Seg. on centre
Blue
8.60
15.0/13.4 or 14.5/13.4
Seg. 0.5mm down
Clear
8.60
15.0/13.4 or 14.5/13.4
Seg. 1.00mm down
Blue
8.60
15.0/13.4 or 14.5/13.4
Seg. 1.50mm down
Clear
SELECTING THE BASE CURVE
Fit the lens 1.00mm flatter than the mean ‘K’
for a 15.00 mm diameter lens.
Fit the lens 0.80mm flatter than the mean ‘K’
for a 14.50mm diameter lens.
For all calculations where the mean ‘K’ is
between radii, use the flatter base curve.
The diagnostic lens fitting set is designed to
only establish the correct position of the near
segment position of the lens.
Image C
If the location dots are positioned below the
center of the patient’s pupil, the patient will
need to raise his/her chin to allow the near
portion of the lens to be in the correct place.
A lens with a higher near segment position is
indicated.
INSERT A TRITON® DIAGNOSTIC LENS
With the patient looking in the primary gaze,
use your slit lamp, to check where the location
marker dots are positioned.
Image A
The correct position of the lens near segment
is when the marker dots are positioned at the
lower edge of the patient’s pupil when the
patient is looking in the primary gaze.
Image B
If the location dots are positioned above the
center of the pupil, the patient will need to
lower his/her chin to look over the reading
portion.
Image A
Marker Dots
Image B
Marker Dots
A lens with a lower near segment position is
indicated.
Image C
Marker Dots
RECOMMENDED FITTING PROCEDURE
FOR TRITON® CONTACT LENSES
LENS POWER CALCULATION
RECOMMENDED FITTING PROCEDURE
The lens power is calculated empirically in the
same way as a normal spherical and toric
lenses.
Following a routine clinical examination, the
TRITON® diagnostic evaluation follows.
RECOMMENDATION
To allow for the range of near and
intermediate vision, it is recommended that the
reading power be reduced by 0.25D in the
dominant eye and increased by 0.25D in the
non-dominant eye.
Example: With a reading add of +2.50 and
right (OD) eye dominant.
Recommended Lens ordered:
Right eye (OD) +2.25 and
Left eye (OS) +2.75.
ASTIGMATIC CORRECTION
It is important that the patient’s full astigmatic
correction be incorporated in the lens in order
for the presbyopic patient to achieve optimal
visual clarity.
It is recommended that astigmatic powers of
0.50D and above be incorporated in the lens.
LENS IDENTIFICATION
To assist patients in identifying the right and
left lenses, the right (OD) lens is marked with a
black dot at 12 O’clock.
CONTRA INDICATIONS
Patients who are not good candidates for the
TRITON® lens include:
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Patients with very loose lower lids.
•
Patients whose lower lid is well below
the lower limbus of the eye; and
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Patients with extremely narrow lid
apertures.
For patients with large apertures, a lens with a
high near segment position is indicated.
Depending on the patients ‘K’ readings,
calculate the base curve of the indicated lens.
Use the trial lens of the indicated base curve
for the initial trail lens fitting. This will allow for
the lens to locate well and for the accurate
determination of the near segment position.
Examine the lens on the eye through the slit
lamp, with the patient looking in the normal
primary gaze position:
1. Assessment is made of the position of the
two 3 and 9 location dots . The correct
position is when the location dots are
in line with lower portion of the patients
pupil in normal lighting conditions.
2. Assessment is made of the relationship
between the contact lens truncation and
the lower lid. If the lower lid is below the
limbus, a lens of with a higher segment
position is indicated.
Note: Assessment of each eye should be done
individually Lenses with different segment
settings may be needed.
Once the correct lens reading segment
position has been established, the base curve
and the patient’s lens powers are calculated
empirically.
This can be done using Gelcalc to do the
necessary calculations.
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RECOMMENDED FITTING PROCEDURE continued >>
AT THE DELIVERY VISIT
GOLDEN RULE
1.
Do not make a change unless there is a major
problem and until the patient has worn a lens
for at least one week.
2.
3.
Check the patient’s visual acuities at both
far and at near. Explain the need for the
patient to look in the correct position so
that the far and near portion of the lens
is in the correct position for clarity at the
required distances. Check and record the
position of the marker dots.
Raise the top lid. Ask the patient to look
down. Check to see that the lens is
engaging on the lower lid and that the
translocation is effective.
A movement of 0.50mm to 1.00mm is
ideal. If translocation is not effective a
lens of a flatter base curve is indicated.
Explain that as bifocal contact lenses
need to be slightly thicker than normal
contact lenses, there might be some initial
awareness of the lens. This sensation is
normally readily adapted to.
If the patient’s visual acuities are acceptable,
then the patient is instructed in the normal
initial soft lens-wearing schedule that is
increased over the following week.
Instruct the patient to have worn the lenses
for at least 3 - 4 hours a day and to wear the
lenses at the one-week review.
At the one-week review, note distance and
near acuities and perform the slip lamp
examination as outlined above.
If the lens does not translate, a flatter base
curve is needed.
If visual acuity decreases after wearing the
lens, the lens is too steep. A looser fitting lens
or material change may be needed.
If diplopia is experienced, the patient may
be catching the edge of the reading segment.
Check the segment position. A lower segment
may be indicated.
Modifications are then ordered if needed.
Schedule an appointment for the patient to be
reviewed in one week’s time.
If you have any queries about the process,
please contact our Technical Team at Gelflex
on (08) 9443 4944.
TRITON® is a registered trademark.
TRITON® Translating Bifocal Contact Lens.
Patent - USA & Australia. (Pending Europe & Japan)
FDA Registered.
The TRITON® Translating Soft Bifocal Contact Lens
The world’s first translating soft bifocal lens.
A soft bifocal lens that provides uncompromising clarity
at both far and at near ‘without compromise’.
CONTACT LENSES
Australian made and inspired.
Looking good, feeling great!
T +61 8 9443 4944
F +61 9 9443 4147
E [email protected]
52 Mulgul Road, Malaga
Western Australia 6090
www.gelflex.com
The content of this booklet is correct
at the time of print, February 2015.