Optical supplies, Danker Lenses

Duette™ is a breakthrough hybrid contact lens offering never-before-available technology to your astimatic patients. Duette™ is the first silicone hydrogel hybrid lens specifically designed to deliver an unprecedented combination of visual acuity, comfort and stability to truly offer your normal cornea patients an unrivaled contact lens experience.

Fitting SynergEyes Duette™

Aim and Ideal Fit

• The lens should be comfortable and the vision clear and stable
• An ideal fit (Fig. 1) will have
  • a thin, even layer of fluorescein under the RGP portion of the lens
  • The appearance of edge lift of the RGP portion towards the junction.
  • The skirt will align well with the conjunctiva without fluting.
  • No bearing at the RGP/soft junction.

Trial Lens Selection

• Take keratometry or topography sim-k readings. Note the flat k-reading.
• Use the table (Fig. 2) to select the correct base curve for the first trial lens.
• Please note that the trial lens will usually be approximately 0.2mm steeper than flattest K so DO NOT select a trial lens which matches the k-readings.
• If the patient's k-readings are similar in the two eyes insert the lens with the medium skirt curve in one eye and the steep skirt curve in the other eye.
• Lenses should be inserted filled with saline and normal fluorescein should be added to the saline in the lens before insertion.
• It is not necessary to use high molecular weight fluorescein.

Figure 2

Figure 2: Base Curve Selection Table

Keratometry	Duette Base Curve
8.20 - 8.05	7.90
8.00 - 7.85	7.70
7.80 - 7.65	7.50
7.60 - 7.45	7.30
7.40 - 7.20	7.10

Fitting assessment and tips

• Fluorescein assessment should be carried out within 3 minutes of insertion.
• If done after this the NaFl will have dissipated and the lens will appear to bear in the centre even if there is adequate clearance.
• If the skirt curve is too flat (Fig. 3) there will be an absence of fluorescein under the RGP portion of the lens and the lens will bear on cornea. Choose a steeper skirt curve to increase corneal clearance.
• If the skirt curve is too steep (Fig. 4) there will be pooling of fluorescein under the RGP portion of the lens. Choose a flatter skirt curve to reduce corneal clearance.
• If lenses with different skirt curves show similar fluorescein patterns use patient comfort to help you decide which lens to order.
• Carry out an over-refraction and order the lens.
• The over-refraction can be carried out on a lens with the incorrect skirt curve as it will not affect the power of the lens.
• Fitting adjustments are almost always achieved by changing the skirt curve. The only time that you may need to change the base curve is when the initial k-readings were on the border of two trial lens selections.

Handling SynergEyes Lenses

Insertion

• Place the lens on to the end of the index finger, or balanced between the index and middle finger, and use a fluoret to put some fluoresceininto the bowl of the lens. Fill the lens to the brim with saline (Fig. 5). You may prefer to use a large suction holder for this.
• Ask the patient to lean forward and tilt their head down so that their nose is pointing at the floor.
• Ask the patient to pull their lower lid down while you retract their top lid then pop the lens directly onto the cornea, coming up from underneath.
• Try to preserve as much saline as possible under the lens so you don't trap an air bubble under the lens.
• Allow the lens to settle for ~30 seconds before assessing the fluorescein fit.
• If there is a bubble under the lens that is larger than 2mm, you will need to remove it and start again.

Removal

• Wash your hands with moisturiser-free soap and dry hands well.
• Ask the patient to look up. Give your fingertips a final wipe on a tissue so that they are 100% dry, and place your thumb and index finger together, so that the only movement they can make is a small pinching movement.
• Pinch the lens at the soft skirt at 6 o'clock- only a very small pinching motion is needed to pucker the bottom of the lens - release the tension and allow the lens to come off (Fig. 6).
• If the lens doesn't come with the 1st pinch, dry your fingers and try again.

Sterilisation and Re-Use of SynergEyes Diagnostic Lenses

There are currently no official guidelines regarding the sterilisation and re-use of specialist soft diagnostic contact lenses. These are due to be drawn up by The College of Optometrists in Spring 2010. However, in the meantime, they have advised the following protocol:

• After use, rub the lens with Crystal Cleaner lens cleaner (Miraflow equivalent), then rinse well with saline
• Sterilise the lens with a peroxide-based cleaning system, such as Eyeye Monosept (available from No7)
• Store the lens in its glass vial in soft lens multipurpose storage solution, until next use
• Rinse the lens with saline or soft lens solution before applying it to the next patient's eye

After 12 months the lens should be discarded and replaced. It is not advised to autoclave soft lenses as this would bind any prion protein to the lens and potentially make it more infective.

Patient Guidelines for SynergEyes Cleaning and Maintenance

• If a patient finds that their lenses tend to become greasy after wear, digital rubbing with an alcohol-based cleaner such as Crystal Cleaner will help.
• The patient will need to fill the lens with saline prior to insertion, and it is important that non-preserved saline is used for this purpose. This prevents the chance of a toxic reaction to preserved solutions, which can develop after continued use.
• Standard contact lens rewetting drops can be used in cases where symptoms of dryness occur (at the discretion of the practitioner).

Fitting Sets

Design	No. Lenses	Parameters	Cleaning/ Sterilisation Protocol
Duette™	15	7.10 - 7.90 in 0.2 Steps / TD 14.50	Disinfect using a peroxide system and store in multipurpose solution

There are many soft toric contact lens designs available today for patients with astigmatism; however, all soft designs require some form of visual compromise.

		Duette™	Soft Toric
Visual Acuity/ Qulaity of Vision	Crisp, high-definition rigid optics	X
	Vision unaffected by lens rotation, blink or gaze shift	X
	Optimized lacrimal layer decreases aberrations	X
	Precise optics centred over the visual axis	X
	Contrast Sensitivity	X
Comfort All Day	Permanent surface treatment increases wettability	X
	Low wetting angle keeps lens moist and comfortable all day	X	X
Healthy For Eyes	High DK materials for optimal oxygen transmission	X	X
	Low modulus silicone hydrogel is durable and resists protien deposits	X
Practice Exclusivity	Can only be purchased through a prescribing practitioner	X

Parameters

Design	Duette™
Material	Petrafocon A centre (hemlarafilcon A skirt)
Water Content	32% soft skirt
Base Curve / Vault	7.10 to 7.90 in 0.20mm steps
Diameter	14.5mm
Skirt Curvature	Flat, Medium, Steep
Sphere Power	+6.00D to -8.00D in 0.25D steps, -8.50D to -15.00D in 0.50D steps
DK	130
Wear	Daily wear
Replacement	6 Months