Optical supplies, Danker Lenses

SynergEyes contact lenses are a hybrid lens design. The centre of the lens is made from a highly permeable RGP material, while a soft lens 'skirt' is bonded to the edge of the RGP portion. So while the RGP portion delivers crisp, clear and stable vision, the soft 'skirt' aids comfort, centration and overall wearability.

Fitting SynergEyes A for Normal Eyes

Aim and Ideal Fit

• Soft skirt should be in alignment with the eye and the RGP portion should entirely VAULT the central cornea (without the presence of an air bubble).
• Ideal fit (Fig. 1) will have:
  • Apical clearance over the central cornea (optimum fit has little or no touch in rigid zone of lens)
  • Clearance free of bubbles over flattest corneal zone
  • Alignment under soft skirt
  • Soft skirt free of scleral impingement or fluting
  • Lens free to move on push up test
  • No bearing at soft/RGP junction
  • Allow the lens to settle for at least 10 minutes before performing a final over-refraction and ordering the lens.

Trial Lens Selection

• Select a trial lens that has a base curve of 0.3mm steeper than the flattest k-reading. Start with the steeper skirt option.
• Insert the lens filled with saline and a drop or two of high molecular weight fluorescein such as Fluoresoft.
• Immediately check for insertion bubbles using a No7 blue torch.
• After the lens has settled for around 30 seconds assess the fit using a slit lamp with the blue beam and Wrattan filter.

Fitting Tips

• If central fit is too flat (Fig. 2) steepen base curve to increase central clearance.
• If central fit is steep (Fig. 3) or insertion produces recurrent bubbles, flatten base curve to reduce excessive central clearance.
• Flatten skirt curve if scleral pinching is seen.
• If little or no lens movement or difficulty removing the lens STEEPEN the skirt curve to lift the soft/RGP junction and free up the lens. If already using the steepest skirt curve then try steepening the base curve by 0.1mm.
• If you see bearing at the junction (Fig. 4) then steepen skirt curve.

SynergEyes A for Keratoconus and Prolate Corneas

• Use SynergEyes A for patients with mild emerging keratoconus, i.e. an average K-reading of 7.35mm or flatter.
• If the patient has a more moderate to severe cone, central or otherwise begin with the ClearKone range.

Aims and Ideal Fit

• The soft skirt should be in alignment with the eye and the RGP portion should entirely VAULT the central cornea (without the presence of an air bubble).
• The ideal fit (Fig. 5) will have:
  • Apical clearance over the central cornea with little / no touch in the RGP portion of the lens.
  • Corneal clearance free from air bubbles.
  • Light touch at the 9mm chord, which should occur at the SOFT part of the lens, not at the RGP/soft junction.
  • Alignment under the soft skirt, free from scleral impingement or fluting.
  • Potentially very little movement on blink, but free to move on push up test.
• Allow the lens to settle for at least 10 minutes before performing a final over-refraction and ordering the lens.

Trial Lens Selection

• Use corneal topography to measure the curvature at the steepest part of the cone. If you do not have topography then note the steepest K.
• Select the trial lens closest to the steepest K-reading rounding down where necessary. Start with the steepest skirt curve.
• Insert the lens filled with saline and a drop or two of high molecular weight fluorescein such as Fluoresoft and let it settle for 30 seconds. Then assess using a slit lamp and Wrattan filter.
• If the initial assessment is good then let the lens settle for a further 10 minutes as it may settle back and become flatter looking.
• If you are happy with the fit perform an over-refraction at this stage.

Fitting Tips and Troubleshooting

• For the same reason, large cones will often need a steeper base curve to provide greater sag to totally vault the apex.
• Bubbles (Fig. 6)
  • Small (<1-2mm in diam) central bubbles indicate air trapped on insertion. Remove lens, refill with saline and reinsert.
  • Persistent bubbles are resolved by FLATTENING the base curve.
• Central touch (Fig. 7)
  • Resolve central touch by steepening the base curve.
• Peripheral touch (Fig. 8)
  • Resolve by steepening the skirt curve if possible.
  • If this makes no difference or you already have the steepest skirt curve then try steepening the base curve.
• Bearing at junction (Fig. 9)
  • When assessing with Fluoresoft bearing appears as dark ring at junction between the materials.
  • Causes a tight feeling for the patient and difficulty removing.
  • Steepen the skirt curve to increase sag.

Handling SynergEyes Lenses

Insertion

• Place the lens on to the end of the index finger, or balanced between the index and middle finger, and place a drop of FluoreSoft® high molecular weight fluorescein into the bowl of the lens. Fill the lens to the brim with saline (Fig. 10). 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. 11).
• 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
A	20	7.10 - 8.00 in 0.1 Steps / TD 14.50	Disinfect using a peroxide system and store in multipurpose solution

Parameters

Design	A
Material	Paflufocon D centre (hemiberfilcon A skirt)
Water Content	27% soft skirt
Base Curve / Vault	7.10 to 8.00 in 0.10mm steps
Diameter	14.5mm
Skirt Curvature	1.0 (steep), 1.3 (flat)
Sphere Power	+8.00 to -8.00 in 0.25D steps, -8.50 to -20.00 in 0.50D steps, +8.50 to +20.00 in 0.50D steps
DK	100
Wear	Daily wear
Replacement	6 Months