August 2019

IN FOCUS

Cataract Surgery Post-LVC
Post-refractive surgery IOL selection requires a careful tightrope walk


by Vanessa Caceres EyeWorld Contributing Writer


Dr. Williamson performs cataract surgery. The type of refractive surgery a patient has had can affect IOL selection post-cataract surgery.
Source: Charles Williamson, MD

 

Choosing the right IOL for patients who have had previous refractive surgery can become a tricky balancing act for cataract surgeons. Each type of refractive surgery has vision-specific nuances, and surgeons must also consider unique results for each patient found via imaging.
Despite the balancing act, there are some pearls that seasoned surgeons can share to help guide their colleagues. Here’s what a few of them advise depending on the type of refractive surgery.

Post-myopic LASIK


Because the cornea of post-myopic LASIK patients has increased positive spherical aberration, Charles Williamson, MD, prefers an IOL with the most negative spherical aberration available. “I usually use a Tecnis ZCB00 [Johnson & Johnson Vision] or Tecnis Toric [Johnson & Johnson Vision],” he said. “For greater amounts of astigmatism, I use the AcrySof Toric [Alcon].”
Dr. Williamson will only use a presbyopia-correcting IOL if the previous treatment was less then –4 D and there is evidence of a well-centered ablation on topography and minimal corneal coma. In those patients, he will use the Symfony lens (Johnson & Johnson Vision).
Similarly, Richard Hoffman, MD, will choose a monofocal IOL with negative spherical aberration that matches the positive spherical aberration of the post-LASIK cornea.
“Either extended depth of focus or multifocal IOLs can be used following myopic LASIK, depending on the appearance of the topography,” he said. Although Dr. Hoffman characterizes extended depth of focus IOLs as likely safer, with fewer patient complaints, multifocal IOLs can be used in these patients occasionally, he added.

Post-hyperopic LASIK

Because hyperopic LASIK generally includes negative spherical aberration, an IOL with positive spherical aberration is usually a better choice in this patient group, Dr. Hoffman said. “Extended depth of focus and multifocal IOLs can be used in patients following hyperopic LASIK depending on the demeanor of the patient and the appearance of topography,” he said.
Dr. Williamson’s choices are an aberration-free or positive spherical aberration lens such as enVista (Bausch + Lomb) or Trulign toric (Bausch + Lomb) for a monofocal or astigmatism choice.
Although Dr. Williamson will sometimes use a Crystalens accommodating IOL
(Bausch + Lomb) in patients with post-hyperopic LASIK, he’s more cautious about multifocals. “The increase in spherical aberrations alone mitigates against using a multifocal IOL in these cases,” he said. During surgical planning, consider the patient’s centration and degree and direction of astigmatism post-treatment to help evaluate if a presbyopia-correcting lens is appropriate.
“If there is significant coma, multifocal IOLs and perhaps extended depth of focus lenses should be avoided,” Dr. Hoffman
advised.

Previous PRK

For patients with previous PRK, the guidelines are essentially the same as those for post-LASIK patients.
“The corneal surface becomes a more central issue in preoperative planning because epithelial remodeling can continue for some months post-PRK,” Dr. Williamson said. “Monofocal IOLs are the easiest choice to avoid increased glare and halos.”

Previous RK

A monofocal IOL is often the best choice in patients with previous RK, Dr. Williamson
said. “Using a monofocal lens and targeting slight myopia often will allow increased depth of focus and ability to read secondary to the multifocal cornea of many RK patients,” he said.
However, surgeons have some clear opinions about the use of other IOL types post-RK. “There have been some successes anecdotally reported in implanting pseudoaccommodative IOLs in RK eyes, but I’ve seen some very unhappy patients,” said Douglas Koch, MD. “I find that RK patients are poor candidates for any of these lenses because there’s so much irregularity in their corneas, and the refractive accuracy of the surgery is so poor. They already have a multifocal cornea, so to me it makes no sense to add multifocal optics on top of that.”
Dr. Williamson usually follows the same thought pattern. “Although you can occasionally get away with it in a simple four-cut RK, the increased corneal aberrations from RK preclude the additive effect from aberrations secondary to multifocals,” he said.
In Dr. Hoffman’s hands, accommodating IOLs work well in this patient group because the multifocal corneas give patients better near vision than would result in a normal cornea. Additionally, there are no aberrations induced by the IOL. He also has found extended depth of focus lenses to be useful and well-tolerated in RK patients. “Extended depth of focus IOLs with toricity can be used if the central 3 to 4 mm of the cornea demonstrates regular astigmatism that appears to correlate with auto-keratometry and topography indices,” he said.
Dr. Hoffman avoids multifocal IOLs in patients with previous RK.
“As with all presbyopia IOLs, the patient’s attitude and reasonable expectations may exclude them from using them,” he said.

At a glance

• Post-myopic LASIK patients have increased positive spherical aberration and
are best suited for IOLs with negative spherical aberration.
• Post-hyperopic LASIK patients have increased negative spherical aberration and are best suited for aberration-free IOLs or IOLs with positive spherical aberration.
• Guidelines for post-PRK patients are similar to those for post-LASIK patients.
• Surgeons should proceed with caution when selecting IOLs for patients post-RK.

Financial interests

Hoffman: Alcon, MicroSurgical Technology
Koch: Alcon, Carl Zeiss Meditec, Johnson & Johnson Vision
Williamson: None

Contact information

Hoffman: rshoffman@finemd.com
Koch: dkoch@bcm.edu
Williamson: wecdoc@gmail.com

About the doctors

Richard Hoffman, MD
Clinical associate professor
of ophthalmology
Casey Eye Institute
Oregon Health and
Science University
Eugene, Oregon

Douglas Koch, MD
Professor and Allen, Mosbacher, and Law Chair in Ophthalmology
Baylor College of Medicine
Houston

Charles Williamson, MD
The Williamson Eye Center
Outpatient Surgery Center for Sight
Baton Rouge, Louisiana

Post-refractive surgery IOL selection requires a careful tightrope walk Post-refractive surgery IOL selection requires a careful tightrope walk
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