EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78719
42 EW CATARACT February 2012 Treating cataract and concurrent keratoconus by Michelle Dalton EyeWorld Contributing Editor Some believe toric IOLs are the way to go, others prefer monofocal IOLs, and still others believe crosslinking may create a happy medium S From the topography, this patient has suspected keratoconus ome patients presenting with cataracts will also have mild or moderate kerato- conus—some may be aware of the keratoconus and be wearing spectacles or advanced contact lenses (CLs), others may not. The ad- vent of toric IOLs offers surgeons an opportunity to correct astigmatism, but may not be the ideal option when they are confronted with ir- regular astigmatism (a hallmark of keratoconus). Although some be- lieve toric IOLs can be a good option in this difficult patient group, others believe surgeons may want to con- sider corneal crosslinking (CXL) fol- lowing cataract surgery with a standard IOL. If the patient wants to improve best corrected visual acuity with a rigid contact lens post-op, "fitting the then-required toric CL on a highly irregular astigmatic cornea would be nearly impossible," said William G. Myers, M.D., assistant professor of clinical ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago. "If this kind of patient has never worn CLs and won't want to post- operatively, then a toric IOL could be reasonable," he said. "But with a large pupil, the possible future need for corneal transplant or crosslink- ing would make a toric IOL less ap- propriate." Dr. Myers added that if CXL or ring segment implants would be subsequently required, he'd opt for a monofocal IOL. "Torics are not an alternative to Corneal distortion can be seen on the axial map gas-permeable CLs or penetrating keratoplasty," said Steven G. Safran, M.D., private practice, Lawrenceville, N.J. "They should only be used in patients where those are not likely options. In patients with mild keratoconus who are stable—those who haven't worn CLs and are unlikely ever to need them—the toric lenses are a home run." Even when toric lenses can be used, "the patient must realize the toric lens might help reduce cylin- der, but the effect might be lost over time when the keratoconus itself progresses," said David B. Leach, M.D., ClearView Eye Clinic, Moscow, Idaho. Toric IOLs will not counter the irregular aspects of the cylinder, said Michael Wong, M.D., Princeton Eye Group, N.J., which is not to advise against their use. Dr. Wong said toric lenses are "reasonable" in an eye with high cylinder "only if the astig- matism is stable, the patient won't be wearing a hard CL in the future, and the patient can appreciate the difference treating toricity makes." The latter can be accomplished in patients with mild cataract by "showing them the difference be- tween full astigmatic correction vs. the MRSE in the phoropter. If the cataract is more serious, it's a clinical call," he said. Post-op, surgeons should avoid rigid CLs, since they "will vault over and cancel out the corneal astigma- tism, causing the toricity of the IOL to create a 'pseudo-lenticular astig- matism,'" Dr. Wong said. One reason keratoconus is so difficult to treat is that it is often ac- companied by a loss of best specta- cle-corrected visual acuity (BSCVA), Corneal distortion can be seen on the axial map of the right eye and suspected keratoconus on the left Source: Steven G. Safran, M.D.