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Patient selection, expectations key for presbyopia-correcting IOLs
The premium procedure can help patients become glasses independent during their daily lives.
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Presbyopia-correcting IOLs can help patients who undergo cataract surgery remain active and independent from glasses, but expectations need to be tempered before undergoing the procedure.
Preoperative evaluation of a patient interested in receiving presbyopia-correcting IOLs is key to achieving the best possible outcomes, Karolinne M. Rocha, MD, PhD, director of cornea and refractive surgery at the Storm Eye Institute, told Ocular Surgery News.
“The key issue is to discuss realistic expectations, especially if you’re offering EDF or EDOF technology. I always tell my patients that they may need over-the-counter reading glasses (+1 D) for small prints, J1 to J2+. I explain to all my patients they may experience dysphotopsias at night, and they may see starbursts and spider webs around lights. Most patients are fine; approximately 93% of my patients do not complain of dysphotopsias but 7% may experience night symptoms, so it’s very important to discuss with patients in advance. The preoperative evaluation is the key,” she said.
Additionally, new surgeons may want to avoid operating on pilots or those in professions who drive at night, such as truck drivers, until they are more adept at the premium procedure.
Surgeons need to first address and treat dry eye in their patients and focus on ocular surface optimization. To do so, Rocha suggested cataract surgeons should repeat topography and optical biometry measurements to ensure the measurements are reliable.
“For example, I’ll always look at the Placido topography, the Scheimpflug tomography (Pentacam, Oculus) and optical biometry measurements (IOLMaster, Zeiss). In patients with severe dry eyes, the measurements are not reproducible. Irregular tear film will affect measurements used for surgical planning as well as induce irregular astigmatism and higher-order aberrations. In general, I would recommend taking two or three measurements in dry eye patients. If the keratometric values are all over the place, there is something wrong. You may just need to treat the dry eye and the meibomian gland dysfunction component, use plugs or topical medications, bring the patients back and redo the measurements,” she said.
Lens categories
Presbyopia-correcting IOLs can be broken down into three main categories based on their optical performances. Multifocal IOLs, accommodating or pseudoaccommodating IOLs, and extended depth of focus (EDOF) IOLs can all be used to address different types of patients. Understanding the functional outcomes associated with the different multifocal IOLs is also critical so that the technology can be matched to the patient’s visual needs, Rocha said.
In a guest editorial in the Journal of Refractive Surgery, Rocha wrote that multifocal IOLs “aim to focus an image onto more than one focal plane,” while accommodating IOL designs theoretically enhance depth of focus by changing the optical power of the optical system.
In the same editorial, Rocha noted “the echelette design of the Symfony IOL forms a step structure whose modification of height, spacing and profile of the echelette extends the depth of focus.” The Symfony IOL (Johnson & Johnson Vision), approved by the FDA in July 2016 and the first IOL with a labeling for extended depth of focus, was designed to improve near and intermediate visual performance.
“The best patients for advanced presbyopia-correcting IOLs are those patients who wish to achieve freedom from spectacle use for activities that require near and intermediate vision in our modern world, such as laptops, smartphones and tablets. I think more and more we’re trying to find that balance, providing multifocality without compromising quality of vision,” she said.
Technology improving
The current technology is more forgiving than in years past, Rocha said, enabling surgeons to offer premium procedures to patients with mild dry eyes, few hard drusen, extrafoveal drusen and possible glaucoma suspect patients. Patients with previous refractive surgery with regular topography can be good candidates as well.
The great innovation for low-add multifocal and EDOF lenses, at least in the United States, was the approval of toric versions for astigmatism correction.
“It’s definitely a no-brainer for patients that they already know have astigmatism. Now we have the option of correcting astigmatism with EDF and low-add multifocal lenses,” Rocha said.
Consider measurements
For any of the premium IOL procedures, Rocha said it is important for surgeons to avoid highly aberrated corneas (higher-order aberration greater than 0.5 µm for a 6-mm pupil size) and patients with chord µ, the distance between the pupil center and the subject fixated coaxially sighted corneal light reflex, greater than 0.6 mm.
However, for all patients, Rocha said customized biometry and good measurements are key to ensure the best outcomes. Presbyopia-correcting IOL calculations require refractive accuracy, with the goal of having 0.5 D or less of defocus and astigmatism.
“I always get Placido topography and corneal tomography (Scheimpflug) in all my cases. In post-refractive cases, I also get corneal spectral domain OCT (RTVue, Optovue) measurements. I double-check my measurements with immersion A-scan biometry in high myopes and patients with dense cataracts,” she said. – by Robert Linnehan
- Reference:
- Rocha KM. J Refract Surg. 2017;doi:10.3928/1081597X-20170217-01.
- For more information:
- Karolinne M. Rocha, MD, PhD, can be reached at Storm Eye Institute, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425; email: karolinnemaia@gmail.com.
Disclosure: Rocha reports she is a consultant for or on the advisory board of AMO, Alcon and Bausch + Lomb.