By Luke Rebenitsch, MD
IOL surgery has evolved over the last few decades. It used to be a hospital-based procedure, with patients recovering in a facility for days afterward. Then it moved to the ASC, and now, cataract surgery has become an extension of refractive surgery — it is no longer just about the pathological; it’s also about making people better. With so many new and different types of IOL options on the market, how do you choose the right one for the job? This is a big question, and while it cannot be covered completely here, understanding your patient is key to the decision-making process.
IOL Options: Know Your Patient
I like to get the ball rolling by asking basic questions. For starters, where are the patients coming from? Are they myopic? Are they hyperopic? Are they showing mixed pathology, more presbyope, or more of a cataract? Keep in mind that the shape of the eye can affect the lens position and the near point of the multifocal lens. All of these factors will affect your ultimate choice of technology and treatment plan.
I always ask patients about the quantity and quality of their hoped-for vision, especially their willingness to tolerate some dysphotopsia, such as night halos or glare versus that perfect crispness, and to still need reading glasses afterward. We might look at a specific type of multi-focal lens, an EDOF lens or single focus lens. In terms of moving from quality to quantity of vision, my approach is the ZCBOO, DIBOO, the Vivity, the Tecnis Multifocals and then the Panoptix lenses.
I also look at broad personality types: type A versus type B. Is the patient in for the long haul with us in terms of neuroadaptation? If so, we can typically manage through early dysphotopsias and night vision issues. Multifocal lenses, of course, are more sensitive to defocus and have a higher risk of needing laser vision correction enhancement. If somebody is willing to go that route for long-term good vision, then the multifocal lens or the EDOF lenses are typically the way we go. If great quality vision is important and they just want to be able to see at night without delay, then we tend to look at a single focus lens.
Of course, there may be corneal or macular pathology, post-refractive optics, vitreous and other media opacities to consider. If there are, we try to match the lens to the scenario. For example, with post-refractive post-myopic patients, we tend to go with a negative spherical aberration like a Tecnis lens, whereas with a post-hyperopic patient, we would go more with a zero spherical aberration like the Envista IOL.
Another example is the hyperope. A typical hyperope has lost some distance and most near, and we’ve found that multifocal optics are more easily tolerated. Even with a high-angle kappa, which some believe diminishes candidacy, it has not been a concern clinically. In these cases, my go-to is the combination of ZKBOO and ZLBOO. I choose these lenses because they have some of the best mesopic contrast of the multifocals. My experience with the Panoptix has also been great, as it provides a high rate of J1 vision. However, the mesopic contrast is not quite as good, so make sure to match the IOL to the patient’s needs.
Myopes, in contrast, typically have clear vision, albeit at near. As such, they can be slightly more difficult to please with multifocal or EDOF optics. In these people, multifocals and EDOF can certainly work, but it is very important to show the patients exactly what they are likely to see at near distance. I have them review and initial a J2 line, which is what nearly all might reasonably expect. Neuroadaptation tends to take a little bit longer, because they still have good vision and haven’t had to naturally neuroadapt. In these cases, I am more apt to use an EDOF lens like the Vivity or blended vision with a ZCBOO or DIBOO, as these lenses provide a higher contrast sensitivity. However, I will also use a multifocal such as the TMF or PanOptix for a patient wanting range over quality.
Finally, high myopes are similar to high hyperopes — they don’t see clearly beyond about 10 inches from the face. Typically, they have been wanting distance vision their whole lives, so that’s where I concentrate the effort. We’ll either choose a bilateral or distance monofocal lens, or in some cases I’ll do a blended vision correction: one eye for distance and one eye for near. The rule of thumb based on a chart review of patient-reported outcomes at our practice is that we consider anyone over around minus six to be a high myope, and that is where we lean toward single-focus lenses.
Enhancement Over Removal
When it comes to IOL enhancement over removal, there are many ways to approach the issue, including laser vision corrections, IOL exchanges, piggyback lenses and, of course, the light-adjustable lens. I have been doing laser vision correction for years, with more than 15,000 procedures completed. In my experience, there is nothing as precise as a laser. Especially with virgin eyes, LASIK is quick, more precise than an exchange or piggyback, and I can improve vision within a day. I do not have to worry about effective lens position of the new lens.
Photorefractive keratectomy (PRK) can also be straightforward, albeit slower for the patient. I do these in some post-refractive or post-RK eyes. When I decide to enhance, job number one is to wait a minimum of three to four months. This is for two reasons: First, because it takes at least three to four months to fully neuroadapt to a lens, sometimes longer, and then because the cornea can fluctuate greatly in the first few months. I have seen fluctuations as great as a diopter or more within that time, so enhancing too early would just result in chasing your tail and may require a second procedure in the future. When it comes to enhancement over removal, take your time, measure twice and operate once.