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Outcomes with presbyopia-correcting IOLs hinge on careful preop, postop measures
A number of options are available for fine-tuning refractive outcomes in presbyopia patients.
Physicians should be aware of the most common problems that affect refractive results of patients after presbyopia-correcting IOL implantation.
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Residual refractive errors and complications that can affect refractive results include astigmatism, dry eye, early posterior capsular opacification and cystoid macular edema (CME), William B. Trattler, MD, said in a telephone interview with Ocular Surgery News. Postoperative treatment options for these problems include YAG capsultomies laser vision correction, limbal relaxing incisions and topical medications.
When patients are dissatisfied with their visual outcomes, it is critical to identify the amount of the residual refractive error, as well as whether there is any reduction in best corrected vision. If there is reduced vision, the underlying cause should be identified and treated rapidly. More commonly, there is not a loss of best corrected vision, Dr. Trattler said.
“It is therefore important to determine the refractive error and then understand that residual refractive error is one of the major culprits of patient unhappiness after presbyopic IOLs,” he said. “Sometimes they’re happy despite some astigmatism. But more often, they have not achieved the quality of vision nor the range of vision, they had expected, and they are dissatisfied overall.”
Preop preparation is also key when implanting presbyopia-correcting IOLs. Patient counseling is one of the most vital aspects of preop care, Richard Tipperman, MD, told OSN. Patients need to understand that they might not be able to see at near vision or that they might experience halos in bright lights and at night after surgery, he said.
“I think there’s no question that residual refractive error is the No. 1 cause of dissatisfaction among all premium lenses,” Dr. Tipperman said. “Preoperative counseling is critical for all patients because there are issues with all the platforms. Patients need to understand them ahead of time, but the better result that you can deliver postoperatively, the more the whole thing is going to be streamlined and the easier it is for both patient and physician.”
Astigmatism
Astigmatism is one of the most common issues after presbyopia-correcting IOL surgery. Y. Ralph Chu, MD, said these astigmatic patients often have limited reading ability and range of focus, especially in light of their high preop expectations.
“Paying attention to smaller amounts of astigmatism is the first change in mindset that a surgeon needs to do, and they also have to become familiar with the techniques of correcting small and larger amounts of astigmatism,” Dr. Chu said in a telephone interview.
 During the course of preop testing that Dr. Trattler performs for best postop results, he learned that this cataract patient had an epiretinal membrane and was at an increased risk of developing cystoid macular edema after surgery. Image: Trattler WB |
One potential way to improve refractive outcomes when dealing with astigmatism is to perform surgery on the less astigmatic eye first, according to Dr. Tipperman.
He said the typical approach is to implant the IOL in the nondominant eye first. However, performing surgery in the dominant eye first allows patients to experience better visual outcomes and therefore be more satisfied with their outcomes, he said. As an example, if a patient had 0.25 D of cylinder in one eye and 1.2 D of cylinder in the other, Dr. Tipperman said that performing surgery on the eye with 1.2 D of cylinder will more likely require a touch-up procedure.
“If you do the more astigmatic eye first, where you’re less likely to get as good a refractive result as the eye that’s closer to spherical, it’s just harder to make the patient happy. If they’re not happy with their first eye, there are plenty of patients who are not going to let you do their second eye,” Dr. Tipperman said.
Not all patients have a wide variation in astigmatism, so preop measurements are important to determine which eye should be operated on first, Dr. Tipperman said.
Satish S. Modi, MD, FRCS(C), cautioned that keratometric cylinder might not be the only issue in all patients implanted with presbyopia-correcting IOLs. When tested, some patients are almost spherical with no corneal astigmatism, Dr. Modi said. But when those patients are refracted, they can still have high degrees of astigmatism.
“Obviously there’s some internal or pseudo-lenticular astigmatism, and that still needs to be corrected, even though they have no corneal astigmatism,” Dr. Modi said. “One has to look both at the cornea as well as the total amount of astigmatism that these patients have.”
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Correcting astigmatism
There are two main ways to correct astigmatism after presbyopia-correcting IOL surgery, according to the experts: laser vision correction and limbal relaxing incisions. Dr. Trattler said he performs PRK in about 80% of cases and IntraLase femtosecond laser LASIK (Advanced Medical Optics) in about 20% of cases for postop residual errors. He said he tends to use PRK more often because it is simple and safe, and any mild quality of vision issues, although rare with IntraLase, would exacerbate any quality-of-vision issues related to the multifocal implant.
“Laser vision correction for these patients makes a positive impact in the patient’s overall satisfaction,” he said. “By reducing residual astigmatism, the patients will experience an improvement in their uncorrected vision for distance and near. Overall, these refractive procedures typically make patients much happier with their presbyopic IOL results.”
Before Dr. Trattler performs laser vision correction, he performs a YAG capsulotomy, as the refractive error can change following the YAG procedure.
Dr. Chu also typically performs PRK most frequently. He said his patients tend to be older and have a higher risk of dry eye and epithelial defects with LASIK flap creation.
Limbal relaxing incisions are most effective in treating low amounts of astigmatism, according to Dr. Tipperman. He said that patients with higher astigmatism can be treated with incisions, but he finds that the procedure is less predictable and can induce higher-order aberrations.
Other therapies
In addition to refractive correction after presbyopia-correcting IOL surgery, some patients have co-existing dry eye or meibomian gland dysfunction. A healthy, stable tear film is critical to the success of this surgery, Dr. Chu said.
Treating patients for those conditions is key in reducing refractive issues postop.
“Some patients will get improvement in their quality of vision just by treating their dry eye. Their overall vision typically improves once dry eye treatment has started. If the vision still is not satisfactory and laser vision correction is required, it is important to have addressed these conditions prior to surgery,” Dr. Trattler said.
Dr. Trattler recommended using topical cyclosporine, punctal plugs and advanced lubricating drops for tear-deficiency dry eye. With co-existing meibomian gland dysfunction, he also recommended warm compresses and topical azithromycin (AzaSite, Inspire).
For dry eye prevention before surgery, Dr. Modi said he advises patients to take two to three capsules of flax seed oil or fish oil a day to help moisturize their eyes both preop and postop. His patients also take 500 mg of vitamin C twice a day to reduce free radicals. Additionally, patients who have dry eye preop are placed on artificial tears postop, Dr. Modi said.
Treating CME
CME must also be addressed both preop and postop, Dr. Modi said. He estimated that CME occurs in 9% to 10% of uncomplicated cases. He uses a two-pronged approach to prevention by prescribing a steroid and a nonsteroidal anti-inflammatory drug.
Early clinical signs of CME include patients who experience a sudden decrease in visual acuity or who have a sudden hyperopic shift, he said. Physicians should watch for any indication of inflammation because of the debilitating nature of the condition.
“Once a patient has CME, even if you treat it, it’s been shown by previous studies that these patients don’t see qualitatively as well after the treatment and resolution of the CME as they would if it never happened in the first place,” Dr. Modi said.
Dr. Trattler recommends preop topography in all patients to not only help select the best presbyopic lens, but also to detect any irregular astigmatism.
He also uses optical coherence tomography to image the macula to find epiretinal membranes, vitreomacular traction syndrome or other subtle macular conditions. These results help him advise patients and inform them about possible postop complications.
For more information:
- Y. Ralph Chu, MD, can be reached at Chu Vision Institute, 7760 France Ave. South, Suite 140, Edina, MN 55435; 952-835-0965; fax: 952-835-1092; e-mail: yrchu@chuvision.com.
- Satish S. Modi, MD, FRCS(C), can be reached at 23 Davis Ave., Poughkeepsie, NY 12603; e-mail: smodieyes@aol.com.
- Richard Tipperman, MD, can be reached at 40 Monument Road, 5th Floor, Bala Cynwyd, PA 19004; 610-664-8880; e-mail: rtipperman@mindspring.com.
- William B. Trattler, MD, can be reached at 8940 N. Kendall Drive, #400, Miami, FL 33176; 305-598-2020; fax: 305-274-0426; e-mail: wtrattler@gmail.com.
- Erin L. Boyle is an OSN Staff Writer who covers all aspects of ophthalmology.