MULTIFOCAL SOFT CONTACT LENSES
| Material choices: |
ACCUSOFT PLUS (hioxifilcon B)
ACCUSOFT 53 (ocufilcon B) |
Lens Parameters
The Multifocal Soft Contact Lens is available in the following parameters:
| |
ACCUSOFT PLUS |
ACCUSOFT 53 |
| Base Curves |
8.20, 8.50 & 8.75 |
8.20, 8.40 & 8.60 |
| Powers |
+6.00 to -8.00/.25D steps |
+6.00 to -8.00/.25D steps |
| Diameter |
14.5 |
14.5 |
| Add Powers |
Continuous add +0.75 to +2.00 (Low Add Series) continuous add +2.25 to +3.50 (High Add Series) |
Continuous add +0.75 to +2.00 (Low Add Series) continuous add +2.25 to +3.50 (High Add Series) |
| Central Add Zone |
1.5, 1.9 & 2.18mm |
1.5 & 1.9mm |
|
Lens Design
The Multifocal Soft Contact lenses are labeled using distance power, and have a translating range of powers which enable a patient to see near, as well as intermediate work and distance very distinctly. Most plus power in center, progressing to more minus in the periphery.
Initial Lens Selection
Take patient's keratometer readings for your records and future reference.
- Convert the spectacle Rx to minus cylinder form.
- Compensate for vertex distance if the power is greater than 4.00 diopters.
- Convert to spherical equivalent power.
- Add +0.50D for the tear layer.
| K's |
SUGGESTED BASE CURVES/DIAMETERS |
| |
Accusoft Plus |
Accusoft 53 |
| 40.00 to 43.00 |
8.75/14.5 |
8.60/14.5 |
| 43.25 to 45.00 |
8.50/14.5 |
8.40/14.5 |
| Steeper than 45.75 |
8.20/14.5 |
8.20/14.5 |
|
Fit Evaluation
It is best to use the base curve that provides satisfactory fit and patient comfort with a minimum of lens movement. Due to the precision optics incorporated into the central 4.0mm of the Ocu-Flex Aspherical Lens, excessive lens movement may cause intermittent blurring of visual acuity after blinking or during rapid eye movement.
Acuity Evaluation
- The lens should center well with some movement, usually 0.5mm or less. The lens should decenter slightly down when the eye is in straight ahead gaze.
- Satisfactory comfort response from the patient.
- A clear distinct retinoscope reflex should be observed with the lens in place. The mires in the keratometer should be clear with the lens in place.
- Perform an over-refraction on both distance and near using hand-held trial lenses.
- If the visual acuity is no less than 20/30, allow your patient to wear the lens for at least ten (10) days before making any adjustments. Patient's perception of visual quality in some instances can change considerably after an adaptation period.
Distance acuity is usually correctable to that of standard soft contact lenses and requires little or no multifocal optic adaptation. When the pupil diameter is greater than 3.5mm start with a 1.9mm zone. If necessary, you can then try to improve distance acuity by using a 1.5mm zone in the dominant or both eyes.
Clinical Assessment
The ideal lens fits should exhibit good centration with approximately .50mm or less of lens movement in primary position.
