Accommodating IOL: 2 years follow-up

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The Synchrony dual-optic accommodative intraocular lens (Abbott Medical Optics) seems to be clinically safe and effective after 2 years of follow-up. The visual function at intermediate and far improved rapidly postoperatively. Half of patients require a +1 D prescription for near vision.

By Lynda Charters; Reviewed by Matteo Piovella, MD
 

Monza, Italy-The Synchrony dual-optic accommodative intraocular lens (IOL) (Abbott Medical Optics [AMO]) seems to be clinically safe and effective after 2 years of follow-up, according to Matteo Piovella, MD.

In the study, visual function improved rapidly with uncorrected visual acuity (UCVA) that was safe for driving within 1 month postoperatively, said Dr. Piovella, medical director of the Centro Microchirurgia Ambulatoriale, Monza, Italy. The computer distance vision was satisfactory within 1 week of implantation, however, half of patients require a +1 D prescription for near vision.

The Synchrony IOL is a one-piece, dual-optic silicone IOL that has a three-dimensional lens designed to fill the capsular bag. The IOL is 5.5 mm high plus the anterior optic (+32 D) with a 6.0-mm variable negative posterior optic. The optics are connected by spring haptics, and the overall size of the IOL is size 9.5 mm x 9.8 mm.

The implantation procedure includes inserting the preloaded injector tip to the edge of the capsulorhexis and releasing the first optic by pushing the leading optic against the posterior capsule. The second optic is then delivered into the capsular bag, Dr. Piovella said., MD.

Dr. Piovella advised about the importance of the capsulorhexis.

“It must be perfectly round, centered, symmetric, intact, free of notches, and about 5 mm in size,” he stated. Femtocataract laser is the perfect technology to match all the needs for accommodative IOL implantation, he added.

Key Synchrony features

One of the key features of the Synchrony IOL are the posterior wings, which ensure proper posterior position, compensate for variations in the capsular bag size, and importantly, prevent decentration.

Spacers, another important characteristic, provide a consistent separation distance at emmetropia and prevent lens adhesion.

Aqueous channels in the IOL support the anterior bag while providing fluid channels, facilitate fluid exchange, and cause the anterior capsule to tent, which works to prevent capsule-IOL sealing and rubbing.

Spring haptics keep the system open, provide a consistent separation force, and optimize movement.

“At distance, theoretically, the two optics are close together to provide emmetropia,” Dr. Piovella said. “When the ciliary body contracts, which reduces the capsular bag and zonular tension, the anterior lens moves forward, changing the eye’s focus to near and intermediate.”

However, the manner in which the dual-optics system works is still under investigation.

Clinical study

Dr. Piovella, and co-author, Barbara Kusa, MD, studied the far, intermediate, and near visual outcomes after implantation of the Synchrony IOL in 33 eyes of 19 patients. The mean patient age was 71.52 ± 7.02 years. The mean preoperative BCVA was 0.66 ± 1.64, and the mean preoperative spherical equivalent was 0.32 ± 1.42.

The patients were followed for a mean period of 764.43 ± 145.38 postoperatively. The incision size was 3.75 mm, which was created using a calibrated metal knife.

Dr. Piovella reported that the distance UCVA was 0.04 ± 0.05 logarithm of the minimum angle of resolution at 2 years postoperatively. The near vision was 20/26.75 ± 3.50 measured with the Early Treatment Diabetic Retinopathy Study (EDTRS) chart with correction of 0.81 ± 0.91 at 24 months. The intermediate vision was 20/32 EDTRS. The contrast sensitivity was unaffected by the IOL. Evaluation of the visual quality showed that 14.3% of patients reported moderate halos after implantation.

Some potential downsides of this technology, Dr. Piovella said, are that it is a new surgical technique with a learning curve and requires a large incision of 3.75 mm and a perfect surgery for implantation. Temporary myopia for at least 2 months can develope postoperatively, and spectacle correction is needed to facilitate driving. After 2 months, patients may have difficulty reading J2 print and 50% of patients require a 1 D prescription for near vision.

Considerations

Accommodative IOLs use 100% of light rays for all distances like monofocal IOLs. Diffractive multifocal IOLs use only a percentage of light rays for different distances and have an important percentage of light loss. For example, the ReSTOR IOL (Alcon Surgical) uses 40% of light rays for distance and near vision and 0% for intermediate distance with a light ray loss of 20%. Moreover, diffractive multifocal IOLs have loss of contrast sensitivity of up to 30% and patients are obliged to dramatically increase the reading light to avoid this lack of contrast sensitivity.

Accommodative IOL technology is neutral if age-related maculopathy occurs.

“The large size of the incision and less efficiency for near vision are the main reasons to continue to develop accommodative technology IOLs despite the complicated design of the IOL. AMO is planning to improve the IOL’s efficiency and design and the Synchrony IOL currently is unavailable,” Dr. Piovella concluded.

Matteo Piovella, MD

E: piovella@piovella.com

Dr. Piovella is a consultant to AMO. The Synchrony IOL is CE Mark approved and the new IOLs generation will be available in the future.