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The new year—What will it bring?
Gerald E. Lowlher, PhD, co-editor
CL Commentary
The New Year--What Will It Bring? '11" / h e beginning of a new year is a good time to speculate about the developments we may see in the contact lens field during this year. There will certainly be continued activity in the difficult area of a contact lens correction for the presbyopic patient. A new lens you will be hearing a lot about is a diffractive bifocal. Both Hydron and Pilkington have similar designs. PUkington has marketed a lens in England. The principle can be used with either rigid or hydrogel lenses. Hydron has a hydrogel design approved by the FDA. It consists of a modified back surface with 8 diffraction rings which split the light by diffraction between distance and near. The rings formed in the back of the lens are called eschelets. Their depth is only about 0.002mm deep. The depth and contour of the eschelets determines how much light goes to the distance and near images. The central zone is about 0.75mm and is set by the near power. The manufacturing technology used to make these lenses is exacting and incredible. The clinical advantage is that it is a simultaneous vision lens where centration apparently is not as critical as with other designs and 50% of the light will go to the distance and near image regardless of pupil size. Therefore, fitting will be easier and the lens performance more reliable. However, it is still a simultaneous 6
vision lens with the adaptation to the presence of two images required. In addition, there is the problem of less than 50% of the light going to near and distance images causing problems under low illumination. Only time and experience will tell us if this design will be viable for a significant number of patients. Rigid lens technology will continue to move forward. The 3M material (Advent Lens) marketed by Allergan is now on the market and represents a new type of material. With its high Dk, it is a viable candidate for extended wear but due to its flexibility it may not correct as much astigmatism as we would like. Many fluorinated siloxane/acrylate lenses in different Dk's are now available for our use. The question is whether there will be any new rigid polymers available in the near future. New hydrogel polymers are on the way. Ciba Vision has a polyvinyl alcohol (PVA) lens which is reported to be a breakthrough with respect to the hounding problem of deposits. Hopefully this will prove to be a help with the deposit problem. However, we remain pessimistic about such claims because of the difficulty of this problem not only in the contact lens field but in the whole area of implants where coatings are such a problem. New hydrogel polymers where the oxygen permeability is not dependent on water content may be just around the corner as well. This will be a major breakthrough for both
daily and extended wear. Soft silicone lenses will probably reappear on a limited basis for the myopic patient this year. Bausch & Lomb is working on a new design with this material which will hopefully overcome many of the previous problems. Because of the high oxygen permeability it still offers such physiological advantages. Disposable lenses will obviously continue to receive a lot of attention from the professionals as well as the public. This year will probably determine if this concept will really take off or be relegated to a minor market. I just hope disposables do not cause significant clinical problems which could set extended wear back again, just as higher Dk materials, which will solve many of the severe clinical problems, become available. Over the past year or so we have seen the introduction of some new preservatives for hydrogel solutions, such as Opti-Free and ReNu disinfecting solutions. These will receive more usage this year. Ultrazyme was a major advance in cleaning and patient compliance. I am sure there will be some new introductions in the solutions field this year but I don't foresee as many significant advancements as in the recent past or as in the polymer area. We at ICLC will continue to do our best to provide you with sound, scientific clinical information on the changing field. We hope you have a prosperous and healthy year. ICLC
CL Commentary
The New Year--What Will It Bring? '11" / h e beginning of a new year is a good time to speculate about the developments we may see in the contact lens field during this year. There will certainly be continued activity in the difficult area of a contact lens correction for the presbyopic patient. A new lens you will be hearing a lot about is a diffractive bifocal. Both Hydron and Pilkington have similar designs. PUkington has marketed a lens in England. The principle can be used with either rigid or hydrogel lenses. Hydron has a hydrogel design approved by the FDA. It consists of a modified back surface with 8 diffraction rings which split the light by diffraction between distance and near. The rings formed in the back of the lens are called eschelets. Their depth is only about 0.002mm deep. The depth and contour of the eschelets determines how much light goes to the distance and near images. The central zone is about 0.75mm and is set by the near power. The manufacturing technology used to make these lenses is exacting and incredible. The clinical advantage is that it is a simultaneous vision lens where centration apparently is not as critical as with other designs and 50% of the light will go to the distance and near image regardless of pupil size. Therefore, fitting will be easier and the lens performance more reliable. However, it is still a simultaneous 6
vision lens with the adaptation to the presence of two images required. In addition, there is the problem of less than 50% of the light going to near and distance images causing problems under low illumination. Only time and experience will tell us if this design will be viable for a significant number of patients. Rigid lens technology will continue to move forward. The 3M material (Advent Lens) marketed by Allergan is now on the market and represents a new type of material. With its high Dk, it is a viable candidate for extended wear but due to its flexibility it may not correct as much astigmatism as we would like. Many fluorinated siloxane/acrylate lenses in different Dk's are now available for our use. The question is whether there will be any new rigid polymers available in the near future. New hydrogel polymers are on the way. Ciba Vision has a polyvinyl alcohol (PVA) lens which is reported to be a breakthrough with respect to the hounding problem of deposits. Hopefully this will prove to be a help with the deposit problem. However, we remain pessimistic about such claims because of the difficulty of this problem not only in the contact lens field but in the whole area of implants where coatings are such a problem. New hydrogel polymers where the oxygen permeability is not dependent on water content may be just around the corner as well. This will be a major breakthrough for both
daily and extended wear. Soft silicone lenses will probably reappear on a limited basis for the myopic patient this year. Bausch & Lomb is working on a new design with this material which will hopefully overcome many of the previous problems. Because of the high oxygen permeability it still offers such physiological advantages. Disposable lenses will obviously continue to receive a lot of attention from the professionals as well as the public. This year will probably determine if this concept will really take off or be relegated to a minor market. I just hope disposables do not cause significant clinical problems which could set extended wear back again, just as higher Dk materials, which will solve many of the severe clinical problems, become available. Over the past year or so we have seen the introduction of some new preservatives for hydrogel solutions, such as Opti-Free and ReNu disinfecting solutions. These will receive more usage this year. Ultrazyme was a major advance in cleaning and patient compliance. I am sure there will be some new introductions in the solutions field this year but I don't foresee as many significant advancements as in the recent past or as in the polymer area. We at ICLC will continue to do our best to provide you with sound, scientific clinical information on the changing field. We hope you have a prosperous and healthy year. ICLC