MULTIFOCAL LASIK

Ongoing advances in excimer laser technology and the use of increasingly sophisticated ablation profiles makes presbyLAsiK a safe and effective alternative for the surgical correction of presbyopia, Gustavo Tamayo MD told delegates attending the World Ophthalmology Congress. 'We are making advances all the time and are learning how to customise our presbyLAsiK treatments to ensure optimal outcomes for our presbyopic patients,' he told attendees.

Dr Tamayo emphasised that a greater appreciation of the effect of both positive and negative spherical aberrations induced in the cornea by a variety of presbyopic treatments – whether laser-induced, intrastromal inlays or multifocal iOLs – would ultimately enable surgeons to finetune their refractive outcomes according to the individual needs of the patient. 'Presbyopic treatments based on the creation of positive and negative spherical aberrations may be the future that guides us to find the best correction for every patient. We need to know more about the interaction of these aberrations in order to define the best treatment for each case and deliver optimal vision at all distances.' Dr Tamayo noted that wavefront analysis of the multifocal corneas in presbyLAsiK has shown that the aberrations produced with excimer laser are similar to those created by corneal inlays and multifocal lenses.

A clear advantage of presbyLAsiK is the fact that the complication rate is low, said Dr Tamayo, and because it is not an intraocular procedure there is no risk of complications that do arise resulting in any permanent visual damage. There is also the reassurance of knowing that the procedure is reversible and that wavefrontguided ablation can be used to erase the multifocality of the cornea and return it to its previous state if required. Another bonus is that presbyLAsiK is repeatable, once the cornea's biomechanical properties allow for a further enhancement, he said. To illustrate its utility, Dr Tamayo showed a number of different ablation profiles for myopic and hyperopic patients and explained that delivering optimal visual outcomes depends on finding the right balance of negative and positive spherical aberrations induced by the treatment.

'Multifocality has traditionally been defined as a topographic term meaning multiple and different powers on the surface of the cornea, but it can also be applied to wavefront maps based on the appearance of new negative spherical aberration or a decrease in positive spherical aberration. We need to see these different dioptric powers reflected in the aberrations that are mapped for the cornea, and we also need to see in a presbyopic treatment the combination of both positive and negative spherical aberrations. i am convinced that the right combination gives us the best results,' he said. in response to a question concerning the long-term stability and follow-up of presbyLAsiK patients, Dr Tamayo said that he has been performing the procedure since 2001 and had experienced very high patient satisfaction levels. 'There is, of course, some regression of the effect over time. The correction of presbyopia is usually very good in the cornea but it is temporary and the procedure either needs to be enhanced after several years, or you need to decide on another option,' he concluded.