Q. A 59-year-old cataract patient with mild Fuchs’ endothelial corneal dystrophy presented to the clinic with minimal stromal haze and no epithelial edema. Her cell counts were relatively good—approximately 1,700 cells/mm2. She reported interest in multifocal IOL implantation. Is there an expert consensus on whether this is a safe modality for this type of patient?
A. “In order to maximize our outcomes, it is important for us to match the technology to the patient and the patient to the technology,” says Walter O. Whitley, OD, of Virginia Eye Consultants. Typically, once a patient with no signs of a progressive disease is implanted, they are good to go. However, Fuchs’ dystrophy is a condition that can progress over time, he says, lending credence to the reasoning why he and his colleagues typically do not recommend multifocal IOLs in this population.
“We don’t feel it’s a match,” Dr. Whitley says. “Even with mild Fuchs’, the cornea can become compromised several years down the road, which can leave the patient with less than optimal vision.” Instead, standard or toric IOLs would be better, he concludes.
Aaron Bronner, OD, of the Pacific Cataract and Laser Institute, also agrees that the first rule for multifocal IOL success is good patient selection.
“The current generation of lenses work using diffraction optics, which effectively split light into two simultaneous optical packets: a distance-focused packet and a near-focused packet. This allows the retina to receive an image with less contrast as compared to a monofocal system,” he explains.
“This system works well in a healthy visual system, but its shortcomings are compounded by any other source of visual deterioration,” Dr. Bronner says. As such, “multifocals are generally contraindicated for patients with conditions that either reduce retinal image quality (such as Fuchs’ dystrophy) or those that reduce retinal image processing (such as macular degeneration or epiretinal membrane).”
Brian Den Beste, OD, of LASIK Pro Eye Consultants in Orlando concurs. He points to a study in which monovision and multifocal IOLs were compared, with the monovision IOLs scoring higher in terms of satisfaction and lower in terms of complaints and out-of-pocket costs, while visual outcomes were essentially the same.1
Derek Cunningham, OD, director of optometry at Dell Laser Consultants, notes that patients with Fuchs’ dystrophy are generally considered high risk due to probable progression of the condition and are not usually even given the option.
Indeed, “a good deal [of the choice to move forward with implantation does] depend on the severity of the disease and transparency of Descemet’s membrane,” says Eric Donnenfeld, MD, of Long Island LASIK.
“Often, patients with Fuchs’ dystrophy will have a beaten metal appearance to the endothelium,” he says. “This opacification of Descemet’s membrane degrades the quality of vision following cataract surgery with all IOLs, but is more significant with a multifocal IOL.”
Given all these caveats, if the patient still insists on a presbyopia-correcting IOL, both Dr. Cunningham and Dr. Den Beste recommend the Crystalens (Bausch + Lomb) to reduce patient spectacle dependence. As an accomodating IOL, it does not use apodized diffractive optics, Dr. Den Beste adds.
On the other hand, new generations of multifocal IOLs with low adds like the Tecnis 2.75 (Abbott) and the Restor 2.5 (Alcon) might be tolerated in mild cases of Fuchs’ dystrophy, Dr. Donnenfeld notes. “However, once patients start developing stromal edema and certainly epithelial edema, they are generally not good candidates for multifocal IOLs,” he cautions.
|1. Zhang F, Sugar A, Jacobsen G, Collins M. Visual function and patient satisfaction: comparison between bilateral diffractive multifocal intraocular lenses and monovision pseudophakia. J Cataract Refract Surg. 2011 Mar;37(3):446-53.|