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.

SynergEyes PS for Post-Surgery and Oblate Corneas

Use for oblate corneas resulting from refractive surgery, grafts, corneal trauma or degenerative conditions. It is a reverse geometry design. There are 3 parameters to consider: the 'base curve', 'skirt curve' and 'lift'. The 'lift' is effectively the amount of reverse curve. It controls the amount of sag that the RGP portion has with Lift 1 or 'L1' having the least sag and 'L3' having the greatest sag. (Fig. 1)

Aim 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. 2) will demonstrate::
  • 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
  • Any touch in the RGP portion of the lens will inevitably produce staining
  • Allow the lens to settle for at least 10 minutes before performing a final over-refraction and ordering the lens.

Trial Lens Selection

• Determine the mean K-reading of the central 6mm of cornea.
• Select a trial lens closest to the average K-reading rounding down to the next steepest if necessary.
• Select 'Lift 2' initially for all new fits.
• Insert the lens with a drop or two of saline and a drop of Fluoresoft and allow it to settle for approx 30 seconds then observe the fit using slit lamp and Wrattan filter.
• After the lens has settled for around 30 seconds assess the fit using a slit lamp with the blue beam and Wrattan filter.
• If the initial assessment seems good then let the lens settle for 10 mins or so as it may settle back and become flatter looking.
• Once you are happy with the fit then perform an over-refraction.

Fitting and Troubleshooting

• Air Bubbles
  • If bubbles are present, identify the shape and location.
    • If they are round and centrally located flatten the base curve.
    • If they are arc shaped and situated towards the skirt junction (Fig. 3) or if seen both peripherally and centrally, decrease the lift from L2 to L1.
• Touch:
  • If excessive touch is observed, note the location of the touch:
    • If the area of touch is central (Fig. 4), steepen the base curve.
    • If the area of touch is peripheral (Fig. 5), with central pooling, increase the lift from L2 to L3.
• Soft Skirt Fluting
  • Order the steeper 8.3mm skirt curve.
• More highly oblate corneas, (i.e. those with the greatest difference between the central Ks and the peripheral corneal curvature), are more likely to need the steeper lift (L3).
• Mildly oblate corneas will most likely benefit from the flatter lift (L1) or may even be fitted with the SynergEyes A lens design. However, for your first few fits always start with L2 and alter if necessary.

Handling SynergEyes Lenses

Insertion

• Place the lens on to the end of your 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. 6). You may prefer to use a large suction holder for this.
• Ask the patient to lean forward and tilt their head down so their nose is pointing to 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 they are 100% dry, and place your thumb and index finger together, so 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. 7).
• 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 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
PS	24	7.60 - 9.00 in 0.2 Steps / TD 14.50	Disinfect using a peroxide system and store in multipurpose solution

Parameters

Design	PS
Material	Paflufocon D centre (hemiberfilcon A skirt)
Water Content	27% soft skirt
Base Curve / Vault	7.60 to 9.00 in .2mm steps
Diameter	14.5mm
Skirt Curvature	8.3mm, 8.6mm
Sphere Power	+2.00 to -6.00 in 0.25D steps
DK	100
Wear	Daily wear
Replacement	6 Months