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Low-add multifocal IOL models improved near vision and increased spectacle independence while providing comparable distance vision and good safety outcomes.
Take-home message: Low-add multifocal IOL models improved near vision and increased spectacle independence while providing comparable distance vision and good safety outcomes.
By Cheryl Guttman Krader; Reviewed by Daniel H. Chang, MD
Bakersfield, CA-New low-add versions of the 1-piece multifocal IOL (Tecnis Multifocal, Abbott Medical Optics) afford cataract surgeons an opportunity to customize selection of the presbyopia-correcting IOL according to a patient’s vision needs.
In addition, they appear to have the potential to minimize halos, which are intrinsic to multifocal optics, said Daniel H. Chang, MD.
Dr. Chang presented results from the FDA study investigating the +2.75 D and +3.25 D add versions of the hydrophobic acrylic, aspheric diffractive multifocal IOL (models ZKB00 and ZLB00, respectively).
The theoretical reading distances for the +2.75 D, +3.25 D, and original +4.0 D add models (ZMB00) are 50, 42, and 33 cm (20, 17, and 13 in), respectively. The low-add IOLs are based on the same spherical aberration-correcting design and chromatic aberration-minimizing material as the +4.0 D add model.
A full diffractive surface provides quality vision and pupil independence with equal light distribution between distance and near, explained Dr. Chang, who was an investigator in the FDA study and is in private practice, Empire Eye and Laser Center, Bakersfield, CA.
The FDA study was a prospective, multicenter, bilateral, open-label, evaluator-masked, modified parallel group clinical trial. It enrolled 445 patients who received either the +2.75 D add multifocal IOL, the +3.25 add multifocal IOL, or the 1-piece aspheric monofocal version (Tecnis IOL, ZCB00).
Results from testing performed at 6 months after the second eye surgery showed patients in the low-add multifocal IOL groups achieved comparable distance vision relative to the controls that received the monofocal IOL.
However, the low-add multifocal IOL groups benefited with a >3-line improvement in near visual acuity, increased spectacle dependence, and a higher level of satisfaction with their uncorrected vision.
“I believe that all three versions of the Tecnis multifocal IOL are great options as each can provide comfortable uncorrected vision at distance, intermediate, and near in more than 80% of patients,” Dr. Chang said.
“However, with the two new low-add versions, I can now provide patients with a personalized best range for near and intermediate vision,” Dr. Chang said.
He added that relative to the original +4.0 D add Tecnis multifocal IOL, the low-add versions seem to be associated with fewer night vision complaints and halos in particular.
The FDA study did not directly compare the low-add IOLs with the +4.0 D version. However, the frequency of visual symptoms seem to decrease as the add power decreases, and that is particularly true for halos, according to Dr. Chang.
“Therefore, the availability of the low-add versions of the Tecnis multifocal IOL allow me to have some control over these night vision symptoms,” he said.
Patients enrolled in the FDA study chose the lens type to have implanted based on consideration of their needs for near and intermediate vision and assessment of their preferred reading distance.
At 6 months, over 99% of patients enrolled in the study were available for evaluation. In binocular testing, mean logMAR distance UCVA was similar in the control, +2.75 D add, and +3.25 D add IOL groups (–0.01, 0.01, and 0.02), and there was also no significant difference between groups in mean logMAR BCVA at distance (–0.09, –0.07, and –0.06).
However, compared with the control group, patients with the +2.75 D and +3.25 D add IOLs implanted had significantly better uncorrected near visual acuity (tested at 40 cm) (0.14 and 0.10 versus 0.44) and distance-corrected near visual acuity (0.17 and 0.11 versus 0.49).
Analyses of directed reports of optical/visual symptoms showed none of the patients in the control group was completely spectacle-independent, whereas 61.3% of patients with the +2.75 D add IOL implanted and 75.0% of those with the +3.25 D add IOL implanted said they never wear glasses.
Almost one-third of control patients said they either wore no glasses for near or wore them less than half the time, and those levels of spectacle independence were achieved by nearly 90% of patients in both of the multifocal IOL groups. Overall satisfaction with vision without glasses was expressed by 85.6% of controls, 97.2% of the +2.75 D add patients, and 93.3% of +3.25 D add patients.
In response to direct questioning, moderate to severe difficulty with halos was reported by 16% of control patients, 31% of patients with the +2.75 D add IOL, and 43% of those with the +3.25 D version. There was less of a difference between the control and +2.75 D and +3.25 D add multifocal IOL groups in rates of moderate to severe difficulty with glare/flare (19% versus 23% and 31%).
When specifically asked about difficulty with night vision, fewer patients had moderate to severe difficulty with night vision in the +2.75 D add multifocal group than in the +3.25 D add multifocal and even the control group (9% versus 16% and 14%, respectively).
“It is my experience that within 1 to 2 weeks after surgery, patients with the low-add . . . multifocal IOLs implanted had little problems with halos and night vision,” Dr. Chang said. “This rapid neuroadaptation phase seems to occur especially with the +2.75 D add version. For that reason, more-demanding patients may particularly benefit from that lens.”
The new low-add versions also offer an opportunity for customizing implant decisions using a different add power of the multifocal IOL in the second eye, if indicated by patient preference after the first eye surgery, according to Dr. Chang.
“Almost all patients are very happy with their vision after the first surgery and go on to receive the same IOL in the fellow eye,” he said. “Occasionally, however, someone desires a slightly different profile of near and intermediate vision.”
This type of variation in near focal points can occur unintentionally when implanting the same add multifocal IOL in both eyes as the result of a slight difference in refractive outcomes, Dr. Chang noted.
“We know that patients typically do fine in that situation, and sometimes we even did that intentionally,” he said. “Now with the different versions of [this] multifocal IOL we can approach this type of customization while still targeting a plano refraction in both eyes for the best distance vision.”
Daniel H. Chang, MD
This article was adapted from Dr. Chang’s presentation at the 2015 meeting of the American Society of Cataract and Refractive Surgery. Dr. Chang is a paid consultant for Abbott Medical Optics.