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Though extended depth-of-focus lenses tend to be more forgiving of residual refractive error and mild decentration than other presbyopia-correcting IOLs, it is important to select patients carefully and follow good preoperative protocols for a successful outcome.
By Sumit “Sam” Garg, MD; Special to Ophthalmology Times
Extended depth-of-focus (EDOF) IOLs are an exciting new option for presbyopic patients.
Though these lenses tend to be more forgiving of residual refractive error and mild decentration than other presbyopia-correcting IOLs, it is still important to select patients carefully and follow good preoperative protocols to maximize the chance of a successful outcome.
When introducing EDOF lenses to the surgical regimen, I recommend selecting uncomplicated cases (e.g., no concomitant ocular disease or prior surgery) at first, with the aim of building confidence in the lens. Choose patients with bilateral cataracts so that you can give them the same optics in both eyes. Certainly, EDOF lenses can still be a good option for a patient with unilateral cataract or for a post-LASIK eye-but save those cases for later, if possible.
EDOF lenses provide a very functional range of vision for patients who still have active lives and want to be less dependent on spectacles for their daily activities. However, it is important not to mislead patients that their vision will be perfect.
I tell patients to expect they will still need glasses for some tasks, such as small print or prolonged reading.
I also talk about glare, halo, and starbursts. I explain that the incidence is lower and the symptoms seem to be less bothersome than with multifocal IOLs, but they may still experience some night-vision symptoms. Patients who seem like they will not be able to tolerate any night-vision symptoms at all might be better served with a monofocal IOL.
Early on, I implanted an EDOF lens (Symfony, Johnson & Johnson Vision) in a hyperopic attorney who I later realized would have benefited from a more in-depth preoperative conversation about the potential for starbursts while driving at night.
Ultimately, he was satisfied with his vision and did not want to give up the spectacle independence that he enjoyed, but it would have been easier on both of us if I had confirmed what he understood about the possibility of having night-time starbursts.
Preop measurements, power calculation
A healthy ocular surface is important for success with any refractive IOL, so it is a good idea to set the stage months (if not years) before cataract surgery by counseling patients about therapy and prevention as soon as there are early signs of ocular surface disease.
During initial consultation, I emphasize that early treatment can make a difference in their future vision after cataract surgery, including which lenses they are candidates for. With patients who have dry eye, I often repeat biometry multiple times before surgery, especially if there are discrepancies in the keratometry or other measurements.
EDOF lenses are more forgiving of residual refractive error, but it is still important to be meticulous about preoperative measurements and management of astigmatism. Compare topography and tomography to make sure that any astigmatism is regular and relatively consistent, and obtain optical coherence tomography imaging to help identify any macular pathology.
I also watch for subtle conditions, such as Fuchs’ dystrophy, anterior basement membrane dystrophy, and amblyopia, and perform a pinhole near-vision test to ensure that there are no non-refractive issues that could affect visual outcomes.
My A-constant for the Symfony lens is 119.35, very similar to that of another lens (Tecnis monofocal, Johnson & Johnson Vision).
For power calculation, I prefer the Barrett Universal Formula or the Barrett Toric Calculator, which helps ensure that posterior corneal astigmatism is taken into account. I also perform intraoperative aberrometry on most of my patients.
I always test for eye dominance, because I prefer to operate on the dominant eye first and try to maximize distance vision in that eye. I like to center the IOL on the patient-fixated coaxially sighted corneal light reflex but it is also comforting to know that clinical studies have shown that these lenses perform well with up to 0.75 D of decentration.
That means we do not have to be as concerned about eyes with higher angle kappa.
I recommend waiting a few weeks after implanting your first EDOF lenses to evaluate the initial outcomes. In my early cases, the day 1 outcomes were slightly myopic, which at first led me to believe my power calculations might be off. However, I found that patients settled toward emmetropia within 2 weeks.
As with any other premium lens, patient counseling and good measurements are critical to good outcomes with EDOF lenses. In order to really embrace this technology, it is important to have a good early experience, so choose your cases wisely and invest the time to take a careful approach preoperatively.
Sumit “Sam” Garg, MD
P: 949/824-0327 E: firstname.lastname@example.org
Dr. Garg is associate professor of ophthalmology, vice chairman of clinical ophthalmology, and medical director, Gavin Herbert Eye Institute, University of California-Irvine. Dr. Garg is a consultant to Johnson & Johnson Vision.