Multifocal IOL with +3 D add outperforms +4 D add lens at intermediate distances

Two versions of an apodized diffractive multifocal IOL yielded similar near and distance visual acuity, contrast sensitivity, quality of life and spectacle independence.

A multifocal IOL with a lower addition at the lens plane yielded better intermediate visual acuity than a version of the lens with a higher addition, a study found.

However, the two lenses showed similar results in terms of distance and near visual acuity and quality of life, the study authors said.

Marcony R. Santhiago, MD, PhD, and colleagues compared versions of the AcrySof ReSTOR apodized diffractive multifocal IOL (Alcon) with a +3 D addition and a +4 D addition.

“It was our concern to include in this study every examination that is needed to derive the conclusion that there is no difference but the near addition,” Dr. Santhiago said in an email interview. “Some studies were not randomized, some studies did not comprise a questionnaire concerning satisfaction with intermediate visual acuity and some did not perform contrast sensitivity.”

The study was published in the Journal of Refractive Surgery.

Patients and protocols

The prospective, randomized, double-masked study included 80 eyes of 40 patients. Twenty patients underwent bilateral implantation of the ReSTOR IOL with a +3 D addition, and 20 patients underwent bilateral implantation of the ReSTOR IOL with a +4 D addition.

Mean patient age was 57.9 years in the +3 D group and 56.7 years in the +4 D group.

The main requirement for inclusion in the study was corneal astigmatism of less than 1 D. Patients with previous intraocular surgery, ocular disease such as corneal opacity or irregularity, dry eye, amblyopia, anisometropia, glaucoma, retinal disease, surgical complications, or incomplete follow-up were excluded.

Both patient groups were similar in terms of gender, anatomic, visual and refractive characteristics.

“Patient selection is very important in a controlled, randomized study,” Dr. Santhiago said. “In a comparative study that investigates multifocal IOLs, it is important to avoid situations that could deteriorate vision and bring potential bias to a very detailed analysis.”

Primary outcome measures were near, intermediate and distance visual acuity, which were evaluated monocularly and binocularly. Defocus curves, best reading distance, mesopic and photopic contrast sensitivity, quality of life, and spectacle independence were also assessed.

Emmetropia was the targeted outcome in all cases.

In addition, patients completed a questionnaire on lifestyle factors, and spectacle independence and visual disturbances were gauged.

Investigators conducted examinations preoperatively and at 1 day, 7 days, 30 days, 3 months, 6 months and 1 year postoperatively.

Visual acuity outcomes

Study results showed that at 1 year, total mean postoperative spherical equivalent refraction was 0.11 D in the +3 D group and 0.12 D in the +4 D group. Mean astigmatism was 0.34 D in the +3 D group and 0.35 D in the +4 D group. The between-group differences were not statistically significant.

Both groups also had statistically similar distance and near visual acuity at 1 year. The +3 D group had better intermediate visual acuity than the +4 D group at 50 cm, 60 cm and 70 cm, but the difference was statistically significant only at –2 D (P < .001).

“What accounted for implantation of the +3 D ReSTOR IOL providing better intermediate visual acuity is the lower addition at the lens plane (+3 D compared to +4 D),” Dr. Santhiago said. “That was exactly an attempt to meet patient needs for optimal near vision and a more functional intermediate vision.”

Mean preferred best reading distance was 39.2 cm in the +3 D lens group and 31.2 cm in the +4 D group; the between-group difference was statistically significant (P < .001).

Both lenses yielded acceptable range of vision, based on mean binocular defocus curves.

Quality of vision, lifestyle

Pupil diameter under photopic and mesopic conditions was similar in both groups, as was contrast sensitivity.

“As far as similar contrast sensitivity performance, we believe that is because both IOLs have a similar design, which in this case is an aspheric design. Both IOLs share an aspheric surface that theoretically contributes to better optical quality and contrast sensitivity results, especially under mesopic conditions,” Dr. Santhiago said.

Both groups reported similar visual disturbances such as glare, halo and night vision issues; depth perception; comfort with visual activities such as computer and cell phone use, reading a watch, driving at night and driving in the rain; and spectacle independence.

“In terms of quality of life, although some drawbacks still remain such as glare and halo effects, most of the patients are happy being independent of glasses and having a significant improvement in their functional vision with either IOL model,” Dr. Santhiago said. – by Matt Hasson

Reference:

• Santhiago MR, Wilson SE, Netto MV, et al. Visual performance of an apodized diffractive multifocal intraocular lens with +3 D addition: 1-year follow-up. J Refract Surg. 2011; 27(12):899-906.

• Marcony R. Santhiago, MD, PhD, can be reached at Cole Eye Institute, Cleveland Clinic, 1700 E. 13th St., Apt. 15W, Cleveland, OH 44114; 216-374-1178; email: marconysanthiago@hotmail.com.
• Disclosure: Dr. Santhiago has no relevant disclosures.