Advanced presbyopes, and other patients requiring add powers greater than +2.00, are typically not successful with the standard VFL 3 design. VFL 3 SuperAdd was developed to accommodate adds in the +2.25 to +2.50 range. This was accomplished by combining the traditional VFL 3 posterior surface with an annular progressive front surface.
Since VFL 3 SuperAdd is a front surface addition to the standard VFL 3, there is no need to change your fitting philosophy. Your standard VFL 3 fitting set will still serve as a valuablediagnostic tool for fitting and over-refractive purposes.
VFL 3, with or without the front surface add(SuperAdd), is position dependent. The least plus or minus power is contained within a relatively small central section. This central distance zone must be positioned directly in front of the pupil for the best distance vision. During lens decentration, the intermediate or near powers of the lens are erroneously positioned in front of the pupil during primary gaze. Always correct lens centration problems before considering any power changes for distance or near.
VFL 3 SuperAdd is not only position dependent but pupil size dependant as well.
The front surface optical zone or (FOZ) is selected based on the patient's pupil size in normal room light. An accurate pupil measurement should be taken prior to dilation on all potential VFL 3 patients.
The front surface zone of a VFL 3 SuperAdd should always be SMALLER than the pupil diameter, by approximately 25%. VFL 3, with or without the SuperAdd front surface, is a simultaneous design. VFL 3 lenses should not translate during primary or secondary gaze. Regardless of the position of the eye, the lens should ideally remain centered on the cornea with the optical center directly in front of the pupil.
Since the pupil size of the most presbyoptic patients is 4mm or less, the average FOZ falls between 3.0 to 3.5mm. If the FOZ is not slightly smaller than the pupil, the front surface near rays will not be focused on the retina. If the FOZ is more than 25% smaller than the pupil, the near will be excellent, but the distance may be compromised. Proper FOZ selection is essential to the success of the VFL 3 SuperAdd. Take the time to measure your patients pupil size, in normal room light, during the initial contact lens examination.
SuperAdd is an annular progressive lathe cut applied to the front surface of a traditional VFL 3 design. Within a small central zone(approximately 3.5mm) the radius of curvature is spherical and contains the most minus or least plus power. Beyond this central zone, the add power increases towards the lens edge. The amount of add power, to be applied to the front surface, can only be determined by over-refracting a pair of well-centered VFL 3 lenses. Over-refract your patient with trial frames to their best binocular distance and near correction. Call consultation, at 1-800-426-1700 with your over-refraction and pupil measurements, to discuss final lens specifications.
