Piggybacking lenses can include multifocal options

An additional lens can extend the power of a previously implanted multifocal IOL or add multifocality to a monofocal pseudophakic implant.

ByMichela Cimberle

Richard B. Packard

FLORENCE – “Piggyback” implantation of a second IOL in the ciliary sulcus is a viable technique for enhancing vision in pseudophakic patients, according to one surgeon speaking at the Florence Symposium. In addition to the well-established uses of piggybacking for correcting high hyperopia or postoperative residual refractive errors, he suggested some new uses for the procedure related to multifocal IOLs.

“A piggyback implant can extend the power of multifocal IOLs or, more interestingly, offer multifocality to monofocally implanted patients,” said Richard B. Packard, MD, FRCS, FRCOphth.

An effective addition of power

“Provided that the two lenses are kept at safe distance, the technique is still a viable solution for quite a few IOL-related problems,” Mr. Packard said at the annual joint meeting of Ocular Surgery News, the Italian Association of Cataract and Refractive Surgery, the Italian Society of Ophthalmology and the International Society of Refractive Surgery.

First, the lenses represent an effective solution for hyperopic patients, for whom the IOL power required is beyond the normal power range of IOLs.

“Whereas very high power lenses would produce a large amount of aberrations, piggybacking can provide an additional correction without hindering the quality of vision,” he said.

Another well-established use of piggybacking is in the postoperative correction of residual refractive errors, “an uncommon but annoying sequelae to otherwise uneventful phaco surgery,” Mr. Packard said.

Because the reason for the miscalculation may not be known, he suggested that the most accurate method is piggybacking an IOL, which requires only a simple calculation.

“For myopia, I just follow the spectacle prescription that is required for emmetropia. For hyperopia, I add 50% to that prescription. In other words, for a –3 D spectacle error I use a –3 D IOL, and for a +3 D error, a +4.5 D IOL,” he said.

Reversed implantation

When implanting piggyback IOLs in his patients, Mr. Packard said he uses the Alcon AcrySof MA60MA with a special implantation technique.

“This lens has a meniscus-shaped optic that is suitable for my implantation technique. I turn the lens in an upside-down position, thus creating an excellent arc of contact with the underlying lens. Of course, I implant one lens in the bag and one in the sulcus. In this inverted position, the loops are going in the opposite direction than normal, and you have to reverse your normal thoughts about implanting the second loop,” he said.

By using viscoelastic and gently directing the loops into position, the lens can fit well in the sulcus and remain stable, he said.

Mr. Packard said the results of piggybacking in eight patients with postoperative ametropia showed that the technique can give good, stable vision. All patients achieved at least 20/30 unaided, no patient had decentration, and no interlenticular membrane was seen between the two lenses. No patient developed unwanted visual phenomena.

For Your Information:

Richard B. Packard, MD, FRCS, FRCOphth, can be reached a Arnott Eye Associates, 22a Harley St., London W1G 9BP, England; +44-20-7580-1974; e-mail: eyequack@vossnet.co.uk.

Michela Cimberle is an OSN Correspondent based in Treviso, Italy.