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CATARACT SURGERY Optimizing Outcomes With PresbyopiaCorrecting IOLs Tips to help you achieve 20/20 postoperative visual acuity for more of your patients. BY RICHARD S. DAVIDSON, MD T he availability of presbyopiacorrecting IOLs translates as more options for vision correction than ever before. Although not perfect, these lenses provide patients with visual freedom that they could not achieve with traditional monofocal IOLs. Presbyopiacorrecting IOLs may be divided into two general categories, multifocal and accommodating. To maximize patients’ postoperative satisfaction with these lenses, consider the potential barriers to optimal vision and take the necessary steps to correct or avoid them prior to and during cataract surgery. PERFORM A COMPLETE OPHTHALMIC EXAMINATION A thorough medical history and a comFigure 1. Significant meibomian gland dysfunction/blepharitis. Note the plete ophthalmic examination are essential inspissated meibomian glands, telangiectatic vessels on the eyelid margin, to determining a patient’s candidacy for a and crusting of the eyelashes. presbyopia-correcting IOL. After all, it is unethical and inconsiderate to charge someone for a presbyopia-correcting IOL if a preexisting ocular I avoid multifocal IOLs when patients have significant condition would preclude him or her from obtaining the macular pathology. If the extent of macular pathology is best possible visual acuity postoperatively. unclear, optical coherence tomography and/or a referral In my opinion, patients with a history of recurrent optic to a retinal specialist can be helpful. I also do not use neuritis or optic nerve pathology are not the best candimultifocal IOLs in patients with significant cornea guttadates for a multifocal IOL. A single episode of optic neuritis ta or Fuchs endothelial dystrophy. The cornea guttata may not be an absolute contraindication, but I would recand/or any mild corneal edema will scatter light in such a ommend visual field testing to make sure the patient has way that, combined with a multifocal IOL, will result in not suffered significant visual field loss. Any patient with sig- suboptimal vision for the patient. nificant visual field loss from glaucoma is therefore not a I generally do not recommend multifocal IOLs for good candidate for a multifocal IOL. This individual might patients who have undergone previous corneal refractive benefit from an accommodating IOL, but it would be prusurgery, especially RK, due to an increased loss of condent to consider his or her best visual potential before sugtrast sensitivity and, ultimately, suboptimal vision. An gesting that he or she pay extra for an IOL that may not accommodating IOL may be an option for some of these provide better visual acuity than a standard monofocal lens. patients. They should be advised preoperatively, however, SEPTEMBER 2011 ADVANCED OCULAR CARE 23 CATARACT SURGERY “Astigmatic management is a key step in optimizing postoperative visual outcomes and patients’ satisfaction.” that they might not achieve the same benefits as someone who has not undergone corneal refractive surgery. Finally, presbyopia-correcting IOLs should probably be avoided in hypercritical patients and those with unrealistic expectations. OPTIMIZE THE OCULAR SURFACE A healthy ocular surface contributes to the success of cataract surgery, and it is especially important when the patient will receive a presbyopia-correcting IOL. During the preoperative visit, assess the patient’s ocular surface and eyelid margins. Treating dry eye syndrome and blepharitis preoperatively will not only contribute to a better visual outcome, it will also reduce the risk of endophthalmitis (Figure 1).1 TREAT CORNEAL ASTIGMATISM Astigmatic management is a key step in optimizing postoperative visual outcomes and patients’ satisfaction. In my practice, any patient with more than 0.75 D of corneal cylinder receives astigmatic correction at the time of cataract surgery. In most cases, I perform limbal relaxing incisions (LRIs). Other options include PRK and, in some instances, LASIK. I prefer LRIs to excimer laser correction, because an LRI does not negatively affect contrast sensitivity, as PRK or LASIK may. This is an especially important consideration for patients receiving multifocal IOLs, which will slightly decrease contrast sensitivity in most patients.2 To ensure the proper treatment of patients’ astigmatism, I obtain the following tests during their preoperative visit: manifest refraction, keratometry (manual, IOLMaster [Carl Zeiss Meditec, Inc., Dublin, CA], or another device), and topography. I also measure corneal pachymetry in order to ensure that the patient has sufficient corneal tissue prior to surgery. Be sure that the amount and axis of astigmatism correlate between these tests. Never rely on the manifest refraction alone to plan for astigmatic correction during surgery, because it does not allow you to accurately differentiate between corneal and lenticular astigmatism. If the axis of astigmatism shown by the manifest refraction, keratometry readings, and topography does not match, reexamine the eye for ocular surface disease and other 24 ADVANCED OCULAR CARE SEPTEMBER 2011 conditions that could be affecting the results. After quantifying the patient’s corneal astigmatism and defining its axis, proceed with surgical planning. Both the Donnenfeld and Nichamin nomograms are very helpful in this regard (the pros and cons of each nomogram are beyond the scope of this article). I myself use the LRI Calculator (www.lricalculator.com). This Web-based application sponsored by Abbott Medical Optics Inc. (Santa Ana, CA) allows me to accurately plan my LRIs in a fashion similar to that of the AcrySof Toric Calculator (Alcon Laboratories, Inc., Fort Worth, TX), which many surgeons use for toric IOL calculations. In some cases, an LRI may increase corneal dryness. I therefore encourage all of my patients receiving this form of astigmatic correction to use artificial tear supplements for the first several weeks postoperatively. When performing an LRI, it is important to remember that no arc length should exceed 90º, as this puts the patient at significant risk for an overcorrection and may “flip” his or her axis of astigmatism. CONSIDER BILATERAL IMPLANTATION I find that patients are much happier with the bilateral versus unilateral implantation of presbyopia-correcting IOLs. I do, however, have some monocular patients with multifocal IOLs (as well as some patients with a monofocal IOL in one eye and a multifocal IOL in the other eye), but I do not believe they are ideal candidates for these lenses. I do not think placing a presbyopia-correcting IOL in a monocular patient or a patient with a monocular lens in his or her contralateral eye is absolutely contraindicated. He or she should be advised preoperatively, however, that he or she may not obtain the same benefits as would a patient undergoing binocular implantation. CONCLUSION Presbyopia-correcting IOLs provide exciting new ways to give patients more visual freedom. With proper preoperative planning and counseling, implanting these lenses can fill your practice with happy patients. ■ Richard S. Davidson, MD, is an associate professor of cataract, cornea, and refractive surgery at the University of Colorado School of Medicine in Aurora, Colorado. He acknowledged no financial interest in the products or companies mentioned herein. Dr. Davidson may be reached at (720) 848-2500; [email protected]. 1. Speaker MG,Milch FA,Shah MK,et al.Role of external bacterial flora in the pathogenesis of acute postoperative endophthalmitis.Ophthalmology.1991;98(5):639-649. 2. Alio JL,Pinero DP,Plaza-Puche AB,et al.Visual and optical performance with two different diffractive intraocular lenses compared to a monofocal lens.J Refract Surg.2011;3:1-12.