Enhanced IOL depth

A new generation of extended depth of focus intraocular lenses (IOLs) may change the way surgeons approach presbyopia treatments, according to a presentation at the 2015 Congress of the European Society of Ophthalmology (SOE) in Vienna, Austria.

“The latest generation IOLs provide excellent quantity and quality of vision at all distances with a greatly reduced incidence of the adverse optical symptoms that have historically been associated with multifocal IOLs,” said Aylin Kilic MD, adding that patients have been demanding such a solution for years.

Dr Kilic, Dunya Eye Hospital, Istanbul, Turkey, said that today’s patients are more demanding about their visual requirements after cataract surgery.

“Most patients now expect to maintain functional near vision in low light conditions, to have perfect distance vision and high contrast sensitivity, and to be independent from glasses for most if not all of their daily activities,” she said.

Dr Kilic noted that the Symfony extended depth-of-vision IOL (Abbott Medical Optics) uses three principal optical strategies to achieve optimal visual quality for the patient: a proprietary diffractive echelette design to elongate the focus of the eye and deliver an extended range of vision; achromatic technology to reduce chromatic aberration and enhance contrast sensitivity; and, finally, spherical aberration control.

Explaining the echelette design concept, Dr Kilic said that it is essentially an optical component with a periodic structure that splits and diffracts lights into several beams travelling in different directions. “With this approach the split of light is incomplete, and therefore the same is true for the separation of foci. This incomplete separation of foci contributes to an extended depth-of-focus and the attenuation of dysphotopsia phenomena such as halos and glare,” she added.

Dr Kilic said that early clinical trials of the lens showed that the binocular defocus curve of the Symfony was associated with a clinically significant increase in depth-of-focus compared to a monofocal IOL. Patients implanted with the extended range-of-vision IOL had a sustained mean visual acuity of 20/20 or better through 1.5D of defocus and a full range of functional vision of 20/40 or better through 2.5 of defocus.

While her own clinical experience with the lens was limited to 18 eyes of nine patients, Dr Kilic said that the results thus far have been positive overall, with all eyes achieving uncorrected binocular distance vision of 20/20 or better and no problems of halos or glare. Binocular near vision outcomes were also very good, with only one patient requiring reading glasses for some tasks, and that particular case was due to an error in preoperative biometry, explained Dr Kilic

Aylin Kilic
aylinkilicdr@gmail.com