prescribing for astigmatism
Many Lens Options Available for Astigmatic Children
BY VISHAKHA THAKRAR, OD, FAAO
Think about how often teenagers come into our offices excited at the prospect of finally being "old enough" to wear contact lenses. The misperception still exists among parents that children cannot wear contact lenses. It is our responsibility to disparage this myth. Several studies have demonstrated that children as young as 7 can successfully wear contact lenses independent of parental involvement. So isn't it time that we are more proactive about offering this option to our young patients?
Children with astigmatism are even less likely to be fit with contact lenses. These fits may be perceived as more difficult and practitioners may doubt that current lens modalities are easy to fit on children. On the contrary, many lens options are available for astigmatic children.
Silicone Hydrogel Toric Lenses
Silicone hydrogel toric lenses are excellent options for children. These lenses are available in almost as many brands and materials as their spherical counterparts. Oxygen permeability and improved physiology of the eye are the main reasons to fit these lenses. Handling of these lenses is also easier than with hydrogel materials.
Vision is an important factor as well. Consistent stabilization provides better, more reliable vision. Vision should not be sacrificed particularly in children who have higher amounts of astigmatism; however, children who wear toric lenses are not as sensitive to fluctuation in vision as are adults. Current available lenses include Acuvue Oasys for Astigmatism and Acuvue Advance for Astigmatism (both Vistakon), Air Optix for Astigmatism (CIBA Vision), and PureVision Toric (Bausch & Lomb).
Daily Disposable Lenses
Daily disposable lenses, in general, are excellent choices for children. When a patient can wear a fresh pair of lenses daily, lack of compliance is not a major issue.
Two daily disposable toric lenses are currently available. Focus Dailies Toric (CIBA Vision) has parameters of –0.75D and –1.50D and axes of 90 degrees and 180 degrees. ClearSight Toric 1 Day (CooperVision) has cylinder powers of –0.75D and –1.25D in axes of 180, 160, 90, and 20 degrees.
GP lenses are an excellent modality for children and are my primary choice for children who have greater than 2.00D of astigmatism. GP lenses provide more oxygen to the cornea than do toric hydrogels. They provide superior vision for high astigmats and are easier for children to handle. For children, high-Dk materials are recommended including Boston XO or XO2 (B&L), Paragon HDS 100 and HDS HI (Paragon Vision Sciences), or Menicon Z (Menicon). Adaptation is easier for children. The only drawback is that active children may lose lenses more easily. Make sure to educate parents about this.
Orthokeratology has become a safe method for correcting myopia; in fact evidence shows that it may slow myopia progression. However, we currently can treat only low levels of astigmatism with existing designs. Paragon will soon release a CRT lens that will better treat astigmatism. This option may be particularly beneficial for children with myopic astigmatism.
In summary, there are several modalities of contact lenses we can use to fit children who have astigmatism. This is an excellent way to grow your practice and develop lifelong patients. CLS
Dr. Thakrar has a specialty contact lens practice and is a clinical optometrist at TLC Laser Eye Center in Mississauga, Ontario. She is also a professional affairs consultant to Vistakon.