contact lens design and materials
Will New Silicone Hydrogels Help More Mature Presbyopes?
BY NEIL PENCE, OD, FAAO
Some of the most challenging presbyopic patients to satisfy with contact lenses are the more mature presbyopes—those requiring a +2.25D add or higher. As more multifocal designs continue to enter the market, the increased fitting choices and options should translate into better success for more patients. With two relatively recent silicone hydrogel multi-focal introductions, we now have three designs in this category to choose from. Many multifocals have good success rates for early or less advanced presbyopes, but it may be of interest to speculate on how these recent silicone hydrogel introductions might benefit the group of more demanding mature presbyopes.
The previously available PureVision Multi-Focal (Bausch & Lomb) is a center-near, annular design with a low and high add power available. Both of the new multifocal lenses have three add choices—low, medium, and high. The Air Optix Aqua Multifocal (Ciba Vision, launching this month) is also a center-near annular design. Acuvue Oasys for Presbyopia (Vistakon) utilizes a type of center-distance design with blended zones.
Because PureVision has the longest track record, how do the new lenses compare? Some early clinical impressions indicate that for the low adds they all seem comparable, although we've seen both newer designs act less strong in some patients.
The Oasys and Air Optix multifocal designs both offer the medium add, which does seem to perform somewhere between the PureVision high and low adds in most cases. For the high add designs, again all three seem similar on many patients as to the amount of near add they provide.
Finding the Right Combination
So if neither of the new lenses' high adds are noticeably stronger compared to the PureVision high add, it might not seem that they would help mature presbyopes much. This is not necessarily true, however. I've found that fitting the high add of any of these designs in both eyes tends to hurt the distance vision. A low add in the dominant eye or more minus in the distance lens power of one of the high add lenses can make distance vision more acceptable.
With the option of medium adds, you can pair a medium add design in the dominant eye with a high add in the fellow eye, and this may result in better near and intermediate vision compared to the low add/high add combination. You may at times need to increase the plus power in the distance in one eye to help boost the near add a little more as well. There may also be cases for which a center-near design might combine with a center-distance design for a best result.
We all want as many tools in our fitting “tool box” as possible. With the increased options in silicone hydrogel multifocals now available, we should be able to better meet the visual and ocular needs of more patients. Mature presbyopes should also benefit from the addition of more medium and high add options.
Success in this group, however, ultimately depends more on patient management skills than on fitting parameters. Reasonable expectations and an emphasis on meeting about 85 percent of patients' daily vision needs while still maintaining adequate patient motivation are examples of these skills. Combine these with a willingness to adapt the available lenses to the unique individual needs of each patient—rather than applying the same cookbook approach to all cases—and you will increase your success with your presbyopic contact lens patients. CLS
Dr. Pence is director of the Contact Lens Research Clinic, Indiana University School of Optometry in Bloomington, Indiana. He is a consultant or advisor to B&L, Ciba Vision, and Vistakon, and has received research funding from AMO.