Vistakon is releasing a new contact lens called ACUVUE® OASYSTMfor PRESBYOPIA under the Acuvue Brand. The original Acuvue Bifocal contact lens was made from a material called Etafilcon. It worked by the wonder trademark called Pupil Intelligent DesignTM. The Acuvue Oasys Bifocal is designed on STEREO PRECISION TECHNOLOGYTM and HYDRACLEAR® PLUS technology.
HydraclearTM is a substance incorporated throughout the lens to help it remain moist. Other silicone hydrogel lenses use plasma surface treatments to help overcome the wetting problems that accompany silicone materials. Supposedly, the effect is similar in providing a wettable surface on the lenses.
It is not very clear what STEREO PRECISION TECHNOLOGYTMmeans. According to VISTAKON® the addition of an aspheric curve on the back of the lens helps eliminate the problems with ghosting. Aspheric curves flatten out as you move away from the edge similar to the shape of the eye. Aspheric lenses can improve vision by more closely resembling the corrective shape the eye needs, but it is not clear how the asphericity has an impact on ghosting. Only time will tell if this is an optical enhancing improvement.The change to the senofilcon A material will be a dramatic improvement in the oxygen permeability,comfort, and eye health the lens delivers. This is a welcome addition to the growing options we have for correcting presbyopia with contact lenses today.
The real innovation the original Avuvue Bifocal Lens contributed was a soft bifocal contact lens in a disposable format at a reasonable price. The secondary advantage was a large range of near prescription powers that could be individually adjusted, a new concept at the time. The lens design has 5 concentric rings of alternating distance and near zones. Theoretically, even if the lens does not center perfectly on the eye there are always sections of distance and near zones of the lens in your line of sight. Of course the disadvantage is there are always sections of distance and near zones of the lens in your line of sight that are responsible for ghost images. Given time, some people will adapt very well to this but in my experience that equates to about 20% of the people who try this design. The new ACUVUE® OASYSTMfor PRESBYOPIA uses the same concentric ring approach with the added back aspheric surface.
The Acuvue Oasys BifocalTMis being produced in the same Senofilcon-A material that has been used in the Acuvue Oasys Lens. This is a silicone hydrogel contact lens that works exceedingly well for about 25% of the patients I see. For the remaining 75% it is OK, just not the dramatic comfort improvement seen in certain individuals. The downside of the material is it tends to develop lens coatings in 10-14 days, sometimes a little shorter than the recommended 2 week replacement cycle.
Overall, this is another addition to help those of us with arms too short that want to continue enjoying the benefits of contact lenses