Article
Accommodating lenses: the solution to presbyopia
Howard Fine, MD, speaking at the ISRS/AAO symposium, believes that the answer to correcting presbyopia lies in accommodating lenses rather than multifocal intraocular lenses (IOLs).
Howard Fine, MD, speaking at the ISRS/AAO symposium, believes that the answer to correcting presbyopia lies in accommodating lenses rather than multifocal intraocular lenses (IOLs).
Multifocal lenses are the current market favourites for correcting presbyopia. The Array multifocal IOL (AMO), for example, has an aspheric design that contains an entire refractive sequence in each zone and uses 100% of the incoming light. Clinical results showed that 41% of patients, implanted bilaterally with the Array lens, no longer required spectacles. The Array lens has been available for sometime now with the newer generation of multifocal IOLs now dominating the multifocal market. Lenses such as ReZoom (AMO), AcrySof ReSTOR (Alcon) and the Tecnis multifocal (AMO) are now taking centre stage.
However, even though the new generation of multifocal IOLs offer improved visual outcomes over the first generation of models, Dr Fine insists that accommodating lenses will supersede them in the future.
Currently, accommodating IOL technology has produced lenses that move within the eye, such as the currently marketed crystalens (eyeonics). A study of binocular implantation with this lens in 130 eyes found 73.5% of subjects either no longer required spectacles or wore them only occasionally following implantation. A further study, in 124 subjects, found binocular uncorrected vision at 11 to 15 months postoperatively to be 20/25 or better in 92%, 98% and 73% of patients for distance, intermediate and near vision, respectively.
Dr Fine proposes that these good results are set improve even further with the advent of new accommodating lens technology. On the horizon are dual-optic IOLs such as Synchrony (Visiogen) and Sarfarazi IOL (Bausch & Lomb), deformable IOLs, such as NuLens, Power Vision IOL and FlexOptic IOL, injectable IOLs, such as the SmartIOL (Medennium) and the light adjustable IOL (Calhoun Vision).
Fine believes that accommodative lenses offer numerous advantages over multifocals: they mimic patient?s experience as a pre-presbyope; all light comes from the object of regard; there is potential for good vision at all distances; no unwanted retinal images; no loss of light energy; no loss of contrast sensitivity; no central nervous system adaptation. He concedes that they do require adequate amplitude of accommodation to avoid reading fatigue and adequate capsule clarity and elasticity. However, he believes that they offer far fewer negative effects than multifocal IOLs, which, according to Fine, consistently produce halos and blur circles, result in a loss of contrast sensitivity and may not be a suitable option when age-related macular degeneration is present in the eye.
Dr Fine concluded that accommodating IOLs offer the perfect solution to presbyopia and that they will become the dominant surgical option in the future, completely replacing multifocal IOLs.
Ophthalmology Times Europe reporting from the XXIV Congress of the ESCRS, London, 9-13 September, 2006.
