Functional outcomes point to success
The multifocal surface of the novel IOL lies on the posterior aspect of the lens and comprises three zones: a 1.5 mm central zone of progressive refractive powers, an apodized diffractive zone with a 2.5 D effective add for near lying between 1.5 and 3.8 mm, and a peripheral refractive zone shaped for bi-sign aspherization. Together, these features provide far, near, and intermediate foci, minimize light loss at all pupil sizes for improved contrast sensitivity and reduced nighttime dysphotopsias, and allow for optimal image quality even in the case of lens tilt or decentration.
"Other multifocal diffractive IOLs essentially have bifocal optics that distribute light for far and near, but not for intermediate foci. The OptiVis IOL combines the best of progressive refractive and diffractive bifocal technology to provide good near and distance acuity, but also dedicates light to intermediate foci and reduces loss of light by up to 3-fold compared with other multifocal IOLs due to unique appodization," explained Dr Piovella, Centro Microchirurgia Ambulatoriale, Monza, Italy.
Mean ETDRS distance UCVA was ~20/23, mean ETDRS near UCVA was ~20/34 at an average best distance of about 40 cm, and mean ETDRS intermediate UCVA was ~20/40 at an average best distance of about 70 cm. Results for near and intermediate VA were similar when patients wore best distance correction.
Contrast sensitivity testing was performed using the Optec 6500 Functional Vision Analyzer that provides control values for testing under daytime, nighttime, and nighttime with glare conditions from healthy phakic eyes representing five different age groups. The control data are derived from a published paper by Dr B. Hohberger et al.1 that demonstrated the effect of age on contrast sensitivity, Dr Piovella explained.
For the eyes implanted with the OptiVis multifocal IOL, contrast sensitivity results for testing in daytime conditions were as good as or better than those for healthy controls of age >60 years, while there was a small reduction in contrast sensitivity at 12 and 18 c/deg in testing under nighttime conditions in some patients.
"These are favourable contrast sensitivity results for patients with a multifocal IOL. That it is an important observation because management of reduction of contrast sensitivity, the most relevant complaint from patients implanted with a diffractive multifocal IOL, represents an opportunity to provide better outcomes for our patients," said Dr Mocellin, chairman, department of ophthalmology, Vito Fazio Hospital, Lecce, Italy.
Notably, no patients spontaneously reported optical/visual symptoms, and of the symptoms that were elicited through a questionnaire, none were described as severe.
Dr Piovella also presented through-focus response curves from optical bench testing that demonstrate the OptiVis IOL has a broader distance focus peak compared to other diffractive multifocal IOLs, which he noted should provide greater depth of focus around far into the intermediate range and more tolerance to power calculations for achieving emmetropia along with a sharp near focus peak that is similar to that of simple diffractive bifocal IOLs.
Dr Antonio Mocellin is chairman of the department of ophthalmology, Vito Fazio Hospital, Leece, Italy.
Dr Matteo Piovella, Centro Microchirurgia Ambulatoriale, Monza, Italy. He can be reached by E-mail: email@example.com
Dr Mocellin and Dr Piovella have no financial interest in the subject matter they discussed.
1. B. Hohberger et al., Graefes Arch. Clin. Exp. Ophthalmol., 2007; 245:1805–1814.