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05-10-2011 | General practice | Article

Solid results with multifocal lens after cataract and clear lens extraction


Free abstract

MedWire News: Implantation of multifocal intraocular lenses results in excellent near visual acuity following cataract or clear lens extraction without compromising distance visual acuity, research shows.

More than 80% of treated patients were free from spectacles following the implantation of multifocal intraocular lenses, report Charles McGhee (University of Auckland, New Zealand) and colleagues in the journal Clinical and Experimental Ophthalmology.

Intraocular lenses have improved in recent decades, with the use of monofocal intraocular lenses providing excellent visual acuity outcomes.

The monofocal lenses, however, have limited depth of focus and are unable to provide maximum visual acuity for distance and near tasks.

A multifocal lens, on the other hand, was developed for cataract patients and provides a wide distance range of uncorrected vision.

In the present study, the researchers evaluated an apodized, diffractive, multifocal intraocular lens in 363 eyes of patients undergoing surgery for cataract or clear lens extraction.

One month after surgery, 351 eyes (96.5%) achieved uncorrected visual acuity, defined as 6/12 or better, with 52% of eyes achieving 6/6.

In the cataract and clear lens extraction patients, 78.9% and 71.3%, respectively, gained at least one line of vision, and no eye lost more than one line of vision.

Six months following surgery, all patients achieved 6/6 bifocal corrected visual acuity in the corrected eye, except for one patient who did not improve beyond 6/15 vision due to a subclinical macular abnormality.

At the last review, 82% of patients reported freedom from eyeglasses and 92% of all patients reported they would have the lens implanted again.

The biconvex optic of the lens contains the diffractive element in the central 3.6 mm of the anterior surface of the optic, and comprises 12 concentric steps that decrease from 1.3 to 0.2 µm. This helps provide a transition between near and far vision.

The researchers say the multifocal intraocular lens "provides predictable postoperative refractive results, with good vision at distance and near in the majority of subjects, [but] patients must still be informed that complete spectacle independence cannot be guaranteed."

One in 10 patients reported halos around lights in the postoperative period, but none of these cases were considered visually disabling or required an exchange of the intraocular lens.

Satisfactory results, according to the researchers, depend not only on patient selection, as well as focusing the patient's motivation and expectations, but also on an accurate biometry and intraocular lens power calculation.

They note that secondary procedures, such as laser-assisted in situ keratomileusis, may be needed in a small number of patients to correct any refractory errors and improve satisfaction.

By MedWire Reporters

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