For cataract surgery patients who want the most accuracy, postop is the new preop.

We’ve always had difficulty counseling patients on refractive targeting when cataracts are in the way. With RxSight’s Light-Adjustable Lens (LAL), surgeons can now adjust the IOL power after the eye heals from surgery — not only to correct actual postoperative astigmatism after the lens has been stabilized but also to adjust the focal point of the eye.

Most importantly, patients get to trial their vision before performing the final, stabilizing light treatment. The lens can regularly achieve adjustments of up to 2 D of sphere and 0.5 D to 3 D of astigmatism.

That isn’t to undermine the importance of modern IOL formulas armed with quality, repeatable topographies that agree with modern biometry in the setting of an optimized tear film. Healthy eyes and good preparation still get better results. After all, our practices are built on happy patients; that day 1 “wow” effect is still very important, even as we recognize that adjustability opens a new window for postoperative change.

Some surgeons may look at the extra postoperative visits and decide not to pursue the technology. I recall a recent conference (pre-COVID) in which refractive and cataract surgeons spent an hour discussing with industry leaders the need for new refractive outlets in growing the refractive surgery market. Then, some of these same surgeons struggled to see that the postoperative LAL course is indeed just that: a new refractive market with a brand-new timeline of refractive work. Unlike discussing apodized, diffractive multifocal optics with patients, discussing adjustability after the eye heals is a patient-friendly discussion. It is exciting to have this new refractive option, which adds further accuracy and precision, in the cataract space.

While the big picture of postoperative adjustability is easy to grasp, I’d like to share some practical tips that can ease both the surgeon’s and practice’s learning curves to make the adoption of the LAL smother.

INITIAL PATIENT SELECTION, COUNSELING

The best initial LAL patients are good dilators (7 mm preop to ensure 6 mm postop due to dilator muscle fatigue over time), with regular astigmatism, healthy corneas with good tear film and healthy maculas. Importantly, they must be trusted to be compliant because UV-protective eyewear, which is provided, must be worn whenever the eyes are open, to protect the LAL from changing shape in response to inadvertent UV light exposure.

Generally, the median time period is 4 weeks until the LAL is fully treated, and the UV protection is no longer required.

Avoid nystagmus patients and those on retinotoxic medications such as tamoxifen, and ensure patients can hold photosensitizing medications for the light treatments (see page 38). Hydrochlorothiazide (HCTZ) is the main culprit here, and we have had very little pushback from primary-care physicians when asking to hold HCTZ for seven doses before a light treatment. Expectation management is key, particularly regarding the importance of compliance and patience. For those whose astigmatism is moderate to high, reminders that their astigmatism won’t be corrected until later are important when discussing day-1 expectations.

IN THE OR

Surgery day with an LAL is great. There is no need to mark for astigmatism or position the IOL other than routine good centration. A well-centered rhexis for 360° optic overlap is best for avoiding IOL tilt. Since postoperative refractions are important, make sure to polish the posterior capsule well to improve clarity.

Additionally, polishing to reduce the need for early YAG capsulotomy (prior to final treatment) is helpful, as we wouldn’t want a patient to later become non-compliant and degrade the IOL optics with an open capsule. If a newer surgeon is unaccustomed to a silicone IOL, the unfolding speed can seem fast at first. However, the implantation learning curve for the three-piece LAL is a quick one.

We currently enlarge to a 2.8-mm incision before inserting the lens. Future injectors could make the size smaller. Of course, this enlargement of the incision still results in a well-sealing wound due to the edge’s lack of exposure to the phaco. As one might imagine, the requirement of a suture slows the entire process of postoperative adjustment, so I’d recommend trying a Wong incision-style irrigation pocket above an incision if a surgeon feels that a suture might be needed.

HOW TO HANDLE MINI-MONOVISION

The discussion of refractive targeting is an interesting one. Some surgeons aim for their expected targets upon LAL implantation. Other surgeons aim for distance OU before postoperatively bringing one eye nearer. Either option can be successful, but there are two potential reasons for the latter strategy.

First, according to Schwartz and Yatzviv in 2015, approximately 20% of patients switch their dominance after cataract surgery, and this gives patients more freedom to determine each eye’s focal point. Second, while the LAL has negative spherical aberration built into the lens (as is mostly standard in IOLs these days), engineers have cleverly designed that specific light treatments deliver additional negative spherical aberration to boost near and intermediate range. Thus, more near can be achieved with less anisometropia.

All other light treatments are neutral with respect to spherical accommodation, leaving the native spherical aberration in the LAL.

POSTOPERATIVE CLINIC SCHEDULING

Other than wearing the provided UV-protective glasses from the moment the patient leaves the OR, the initial postoperative course is normal. Patients only take off the glasses for the moments at the slit lamp on day 1. We start the light treatments at approximately 2 weeks.

Two types of light treatments are available: adjustments for changing power and stabilizing treatments for completing the chemistry. We start with at least one adjustment (maximum of three), and we end with at least one stabilizing treatment (maximum of two). Most patients have about three treatments in total.

When adding clinic schedule space for adjustment visits — which we typically space about a week apart — create enough space for a good refraction and targeting discussion. One helpful option is refracting with the red/green duochrome test. But, regardless of the preferred method, ensure that the refraction gives a commensurate improvement in vision before programming the light delivery device (LDD). We’ve never before routinely refracted in the 2-to-4-week postop window, and healing variability that gives subjective refraction improvement but minimally improved acuity should be viewed suspiciously.

Should the surgeon have any concern that the correct refraction has been obtained, re-refracting in another few days to ensure stability is not a problem. Treat vision, not mere numbers (look for at least a three- to five-letter difference between uncorrected and best-corrected acuity).

Patients may also be provided UV protective bifocals to facilitate reading with distance-targeted LALs during the adjustment phase. I recommend using the lowest amount of reading add possible. Rarely, patients may forget that their final vision will not have the bifocal, and we want to ensure they are truly evaluating their visual needs during the adjustment period.

DILATION FOR LIGHT TREATMENTS

Achieving postoperative dilation becomes more important with the LAL. Sometimes eyes dilate more slowly after surgery than they did before, as the repetitive demands on the dilator muscles result in fatigue. Counsel patients that their light treatment visits might be lengthy due to the importance of dilation.

We use tropicamide, phenylephrine and cyclopentolate. I even trialed intracameral dilation with epinephrine, and while the speed of dilation was predictably fast, the degree of dilation was not superior. Consider setting aside a comfortable dilation area for patients to use their phones, and have a technician regularly check their dilation levels, as dilation speeds vary. Consistent messaging that this is the best way to achieve the most accuracy helps encourage patience.

Once patients have received counseling, the targeting discussion and dilation, the actual treatment itself is straightforward. Double check the entered numbers and LAL serial number, then use a focusing lens similar to a YAG laser. Get the lens well centered, in good focus, with good patient fixation, and the treatment lasts only 40 to 120 seconds, depending on the parameters.

NEW TECHNOLOGY, NEW INSIGHT

The technology has shined a new light — pun intended — on a previously overlooked time in the cataract surgery journey. Because we have never routinely performed surgical-quality refractions between weeks 2 and 4 postoperatively, navigating the variability of healing and ocular surface irregularity requires some experience. We do use the lens in radial keratotomy (RK) patients, for whom we have opportunity to postoperatively refract to decide whether to add toricity to the IOL or simply adjust sphere in favor of a rigid or scleral contact on the surface. This is a nice preop dilemma to avoid!

We do ask for more time to stabilize in RK patients (starting the adjustment at 1 month and waiting 1 month between adjustments). It is a slow process, but most RK patients can acknowledge their eyes are more complex.

We will continue to learn about other issues as we embark on the LAL experience, but these practical tips may smooth the adoption curve for your practice. It’s an exciting time to have another refractive option, as patients have higher and higher hopes for their vision after cataract surgery. OM

About the Author

O. Bennett Walton IV, MD, MBA, is a cataract, refractive and cornea surgeon at Slade & Baker Vision in Houston, Texas. In addition to clinical practice, Dr. Walton is a surgeon for clinical trials and evaluation of new refractive and cataract technologies.

Disclosure: Dr. Walton reports financial relationships with Alcon, Avedro, Carl Zeiss Meditec, EyePoint Pharmaceuticals, Johnson & Johnson Vision, Nevakar, Omeros, RxSight and Staar Surgical.