Benefits

*Simple lens design/fitting procedures

*No unwanted corneal changes causing spectacle blur

*Astigmatic corneas and prescriptions can easily be fit

*Patients sees clear at night

*Optimum visual acuity at distance, intermediate and near

*Single vision back surface design

*Spherical  posterior surface

*Toric designs available

*4 dimensional design eliminates night glare

*Revolutionary 4 dimensional multifocal lens design

Empirical Fitting Procedures

1. Measure patients pupil size (each eye) using a P.D. ruler

• Measure in normal room illumination

• Measure in dim room illumination

2. Select bse curve and diameter from CV-4 base curve selection chart

3. Select distance power using full spherical power from spectacle Rx, calculating for vertex  effects if greater than +/- 4.00.  Adjust for SAM or FAP based on base curve selection

4. Select near power using full add power from spectacle Rx.

5. Order lens

BASE CURVE SELECTION CHART

• Choose base curve the same as for spherical single vision GP fits. CV-4 Base Curve Selection Chart can be used for guidance.
• Goal is to  fit a lens that positions centrally.

Diameter Selection

• Lenses must be made with a diameter between 9.2 and 9.8mm.

Distance Power Selection

• Use full spherical distance power based on patient's spectacle Rx.  Calculate for vertex distance effect if over +/-4.00D. Adjust for SAM and FAP from the CV-4 Base Curve Chart Selection Chart.

Visual Acuity Analysis

• Both distance and near vision should be evaluated with the patient holding his/her head in the straight-ahead position.
• Small lens translation are desirable as the patient moves from distance to intermediate to reading tasks.

Follow Up Care

1. Allow lens to settle for up to 20 minutes
2. Over-refract to determine distance Rx
3. Over-refract to determine near Rx
4. Re-check pupil size

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