What visual outcome can we wait for?
Technology progress in the last decades got us used to move forward at the speed of the light.
This is true in the field of telecommunication, where the digital revolution is already a reality, but especially in healthcare, where the new technologies have reached goals in diagnosis and therapy that would be considered impossible just 20 years ago.
Updates by Robert Montés-Micó
All of us will age and almost each of us will suffer from the visual problems caused by our eyes becoming physiologically presbyopic. Therefore we are really interested about the results achievable by the most advanced technologies in cataract surgery for presbyopia correction.
We have asked for the latest updates to Robert Montés-Micó, Professor of Optics at the University of Valencia, Spain.
Refractive cataract is already a common surgical practice but ocular surgeons are going to aim at a “golden” goal: presbyopia surgical treatment. Could you please illustrate to our readers the “state of the art” of the new EDOF IOLs?
R. Montés-Micó: On the whole, extended depth of focus (EDOF) lenses are aimed to achieve a continuum range of vision. Nowadays, two different EDOF intraocular lenses (IOLs) have been released with different optical designs. On the one hand, the Mini WELL ready (SIFI Medtech, Catania, Italy) is a progressive multifocal lens that includes a monofocal zone in the lens periphery. On the other hand, the TECNIS Symfony (Abbott Laboratories, Illinois, USA) is a diffractive lens that corrects chromatic aberration.
To date, only one study compared the in-vitro optical quality of these lenses as a function of the aperture and vergence. According to this study, both IOLs showed comparable image quality at the best distance-, intermediate-, and near-vision of each lens for the 3 mm optical aperture. Nevertheless, the Mini WELL ready showed better image quality than the TECNIS Symfony at the same positions when the aperture was set to 4.5 mm.
Which are the main differences between EDOF IOLs and trifocal multifocal IOLs?
R. Montés-Micó: The main difference between EDOF and trifocal lenses is related to their optical design. On the one hand, trifocal lenses are designed to have three foci named as distance-, intermediate- and near-focus. Nevertheless, EDOF lenses offer continuum foci between distance and near vision.
In terms of optical quality, the through focus MTF of trifocal lenses, which describes the MTF as a function of the vergence, showed steeper transitions between its foci than EDOF IOLs. From these results, EDOF lenses are expected to have wider defocus tolerance than trifocal ones. In this regard, scientific evidence has confirmed this hypothesis recently.
How has changed the concept of “Quality of vision” that we can promise to our patients?
R. Montés-Micó: With the introduction of EDOF lenses, the concept of quality of vision has been broadened through all vision ranges due to its wider defocus tolerance.
Robert Montés-Micó is Full Professor of Optics at the University of Valencia, Spain. Actually he is member of the Editorial Board of the Journal of Cataract and Refractive Surgery, Journal of Refractive Surgery and Ophthalmic and Physiological Optics. He has published more than 200 peer review papers published and works on presbyopia solutions, myopia development and tear film analysis.
For further updates see our articles about presbyopia surgery:
– New IOLs: Tomorrow is already today
– New EDOF IOLs for presbyopia correction
– New horizons in presbypia surgery
– Biometry and success in cataract refractive surgery
– Presbyopia and economic growth