EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/87458
90 EWINTERNATIONAL October 2012 International outlook Cataract surgery could help keratoconus sufferers, too by Matt Young EyeWorld Contributing Writer K eratoconus is a diagnosis made by corneal topography. In its more subtle forms, it may only be clinically evident as astigmatism in the patients' refractive error. With the increased popularity of toric IOLs, we are screening cataract patients with corneal topography and perhaps not surprisingly are also uncovering many in this older age range who have mild keratoconic features. Most ophthalmologists agree that astigmatic relaxing incisions are unpredictable in these patients. Toric IOLs however may have a role in optimizing their visual outcome. John A. Vukich, M.D. international editor With topography and toric IOLs, cataract/ keratoconus patients could be happy ones C ataract surgery used to be largely about eliminating cloudiness of the natural lens. Then it turned into helping patients achieve superior vision even in older age. Now, ophthalmic news out of Lebanon suggests that cataract sur- gery might not just be for cataracts anymore. It could help keratoconus patients with cataracts, too. The Middle East is a bastion for keratoconus patients, as EyeWorld reported this past May in the "International outlook" column. As a result, Nada Jabbur, M.D., in private practice, Clemenceau Medical Center, Beirut, Lebanon, and adjunct clinical associate profes- sor of ophthalmology, American University of Beirut, has been pre-operatively screening a large portion of her cataract patients for keratoconus with topography. "In my practice, since I started using toric IOLs in the general popu- lation, I have diagnosed more kera- toconus in adults over the age of 55 that is subclinical," Dr. Jabbur said. Topography and toric IOLs go hand-in-hand, Dr. Jabbur said. The reason that one uses topography for Corneal topography of right and left eyes of a 60-year-old patient who had keratoconus and progressive worsening of vision due to nuclear cataracts. He underwent sequential cataract surgery and benefited from a toric IOL in each eye with mild astigmatism correction in the right eye (1.5 D correction) and with a more significant astigmatism in the left eye (3.5 D cor- rection). Special considerations were taken to choose the correct astigmatism and the correct IOL formula. The patient was a myope prior to cataract development and requested to stay nearsighted. Post-op, he reads J1+ OU uncorrected, and his best spectacle corrected vision without astigmatic component is 20/30- OU toric IOL cases is to optimize out- comes with these premium lenses. Generally, the common cataract population isn't screened with to- pography though. "[Standard cataract surgery without topography] doesn't mean you are going to do something bad to patients," Dr. Jabbur said. "They will have cataract surgery and need glasses to improve their blurred vision due to astigmatism. Best corrected visual acuity would still be reduced since they have irregular curvature." Keratoconus is thought to be passed on—to some extent—geneti- cally, Dr. Jabbur said. That may be the cause of the higher incidence in Lebanon and other parts of the Middle East compared to the West. As a result, Dr. Jabbur said her center screens for keratoconus before refractive surgery as well as keratoconus before cataract surery. "Typically, it's a contraindica- tion for LASIK because of the unstable condition or irregular astig- matism," Dr. Jabbur said. "There's an inability to guarantee an outcome," meaning that the outcome usually is not good, she said. In patients seeking cataract sur- gery, surgeons can consult patients better about their refractive outcome if they have pre-existing keratoconus and can recommend the possibility of implanting a toric IOL if patients' pre-op best spectacle corrected vision is not compromised, typically in non-advanced stages of kerato- conus, where glasses with astigmatic correction were used. Often, these patients are not aware that they have any corneal irregularity. "Toric lenses have been in the market for a few years," Dr. Jabbur said. "Typically, these lenses are labeled to treat regular corneal astig- matism. Using these toric IOLs in a subgroup of keratoconus patients demands that we pay more atten- tion to all our preparatory steps." First of all, surgeon experience with toric IOLs in non-keratoconus patients is critical in order to consider implanting a lens in keratoconus patients, she said. Patients who are willing to pay more for a toric IOL have high expectations of their surgery so it is critical to pick the best candidates in which corneal astigmatism is docu- mented and reproduced with differ- ent techniques (magnitude and axis of cylinder). Recent contact lens wear, dry eyes, and lid position should be eliminated as they affect the measurement of the keratome- try. Avoid patients with previous laser refractive surgery. The choice of the IOL calculation formula should be customized depending on the axial length of the eye. All surgeons should keep track of their surgery outcomes and fine-tune their target depending on type of incision and location of incision. It is recom- mended that whenever there is a doubt about target to start with the non-dominant eye if possible. Source: Nada Jabbur, M.D. "Usually one has to be careful because one has to have superior outcomes in these patients," Dr. Jabbur said. "The benefit to these patients is that it reduces their dependence on glasses." Myopic patients often request to stay near- sighted post-op and are thrilled to be able to resume their regular activ- ities for near without glasses as they do not have the astigmatic compo- nent to overcome. "Cataract surgery still is the most common surgery that ophthal- mologists do," Dr. Jabbur said. That coupled with the fact that there is a huge backlog of cataracts in the de- veloping world means that many surgeons won't be looking at corneal topography before lens removal any- time soon. But for surgeons who are im- planting deluxe IOLs and are used to dealing with corneal astigmatism, topography is a good screening tool before phacoemulsification, she said. Using these deluxe IOLs in select pa- tients raises the level of refractive cataract surgery to an even higher level. "My patient satisfaction level has been high and this encourages me to keep customizing the care. Let us not forget that patient selection is key as is the case in all refractive surgery," she said. EW Editors' note: Dr. Jabbur has no finan- cial interests related to this article. Contact information Jabbur: nsjabbur@yahoo.com