When faced with a patient who is unhappy with their refractive outcome, we follow a specific diagnostic and treatment algorithm. First, we evaluate for residual refractive error. Next, we need to ensure that the ocular surface is optimized, as light scatter can often be a contributing factor to refractive outcomes. We also evaluate for posterior capsule opacification (PCO); as early PCO can result in light scatter, which may impact visual quality. A small residual refractive error will likely be corrected through a laser vision enhancement on the cornea. For a larger hyperopic refractive error, a piggyback IOL may be considered. If it is a rare large refractive error or other indication, such as intolerable dysphotopsias, an IOL exchange may be indicated. However, adjustable lens technologies may represent a future paradigm in cataract and refractive surgery, and the algorithm for managing the unhappy patient will evolve – as will our approach to surgery.
Adjustable technologies
Adjustable lens technologies fall into two main sub-categories: directly adjustable technologies and modular approaches, each with their unique benefits and potential indications. Direct refractive adjustment technologies hold great promise. As they are minimally invasive, they can be performed in office so there is no need for the patient to re-enter the OR. The recent FDA approval for RxSight’s light-adjustable lens was a milestone in the history of refractive cataract surgery, and it represents a big ‘win’ for our profession with the first FDA approval for a modifiable IOL technology. One of the most exciting things I have had the pleasure of being involved with over the last few years is refractive index shaping of IOLs (RIS; Perfect Lens), which is designed to adjust an implanted IOL using a femtosecond laser in a minimally invasive fashion. With preliminary bench data showing that the technology can modulate and correct for most optical circumstances – myopia, hyperopia, astigmatism and spherical aberration – as well as add, reverse or customize multifocality, this extraordinarily flexible technology would applied in a very straightforward fashion with application of an in-office femtosecond laser, with the option of multiple treatment applications. We have also had the pleasure of working with evolving modular technologies which could also be game-changing for our field. The Gemini refractive capsule (Omega Ophthalmics) represents one of the first modular IOLs. I believe that the technology has great promise as it gives us scope for multiple aspects. Not only will the technology allow insertion of a prosthetic capsule, but it will also allow the possibility of IOL exchange in the future; if a patient wishes to upgrade or downgrade their lens, it will become more straightforward. The technology will also allow surgeons to account for effective lens position (ELP) fluctuation over time and, as the refractive capsule appears to have a unique characteristic of decreasing PCO incidence (through keeping the anterior and posterior capsule surfaces separated), ELP fluctuation should be minimized. Another exciting aspect of technology is the potential working space for the integration of future technologies, such as drug eluting implants or monitoring devices. And perhaps most exciting of all is the potential to integrate augmented reality technologies, which could allow the user to check their email or a google map, or watch a movie through a microchip. It is very futuristic, but it could be within the realm of possibility. Other promising modular technologies such as the Harmoni adjustable IOL (Clarvista Medical) are also in development.Technologies requiring surgical adjustment
- Multicomponent lenses featuring a base lens and an exchangeable front optic
- Precisight (InfiniteVision Optics)
- Harmoni (ClarVista Medical)
- Mechanically adjustable
- Acri-Tec AR-1 IOL
- Magnetically adjustable
- Liquid crystal technology with wireless control
- Femtosecond laser adjustment technologies
- Perfect Lens
- Alcon
- Chemical adjustment using two-photon chemistry
- Light-adjustable technology
- Light-adjustable IOL (LAL) (RxSight)
