Light Adjustable Lenses. For post refractive surgery patients, the LAL is a clear frontrunner because it essentially obviates the need for an enhancement.10 Corneal refractive surgeons are well aware of the challenges of performing enhancements on old LASIK or RK. Lifting old flaps can lead to ingrowth. Mixing different optical zone sizes can lead to unpredictable refractive shifts. PRK on old LASIK or RK can be wildly unpredictable. Though it is still possible that LAL patients will have residual refractive error after all adjustments and lock in, it is quite rare. If patients are willing to wear the UV-protective spectacles and commit to frequent visits, they know that they are going to have the most accurate lens with the lowest amount of residual refractive error of any of our available lenses. This level of accuracy leads to excellent quality of vision and excellent unaided vision.
The LAL is approved to be used on patients with 0.75 D of preoperative corneal astigmatism. The LAL has approved Toric light treatments for treating residual astigmatism of 0.50 – 2.00 D in 0.25 D steps. Note that doctors can apply multiple treatments per eye to treat greater amounts of astigmatism. Although the LAL is not approved to claim higher levels of treatment, bench and early clinical data suggest that it may be possible to correct 3D of astigmatism, but it may be less predictable and reliable outside the approved range.11,12 Utilizing this technology, we can correct astigmatism without the many sources of errors that complicate astigmatism correction with toric lenses. Taking multiple measurements to choose the toric lens power and axis, ink marking, intraoperative alignment and aberrometry, late IOL rotation, and other frustrations could be relics of the past.
For those who are tolerant of mild amounts of monovision or blended vision, excellent unaided distance, intermediate, and near vision is possible. This is because of the unique extended depth of focus properties of the lens. There is a small amount of EDOF built into the lens, and the nondominant near eye receives an additional 0.25 D of EDOF with the first myopic adjustment. Additionally, the average amount of monovision or blended vision needed for most patients is typically 1.50 D of myopia in the non-dominant eye. Since the monovision is reversible and titratable, this lens is ideal for those patients who cannot commit or decide, for those who have dense cataracts precluding demonstration of monovision preoperatively, perfectionists, or patients with unclear eye dominance. In particular, this is a great option for patients who require excellent night vision and still desire to reduce their dependence on glasses. The quality of vision is excellent, day and night, and binocular night vision can be achieved with night driving glasses. Patients generally self-select to monovision or trifocal when they realize that they can have binocular full range of vision with halos, or monovision that can be reversed with night driving glasses.
Extended Range of Vision and Monofocal Plus Lenses. The newest additions to our armamentarium are the Vivity® (Alcon) and EyhanceTM (Johnson & Johnson). These lenses are unique in that they provide an extended range of vision without sacrificing quality of vision. The way in which they work is different, and the categorization of the lenses is different.
Vivity offers patients an opportunity to correct distance and intermediate vision fully while also gaining functional near.13 Functional near vision is variable from person to person, so the expectation should be set that patients will need reading glasses sometimes, depending on size, working distance, and lighting. For patients who have ocular pathology or require good night vision, this is a great lens option.
There are some patients who will achieve spectacle independence with Vivity, but since it is a minority, this cannot be the expectation that is set. Patients often struggle to decide between AcrySof® IQ PanOptix® (Alcon) and Vivity, and in my experience, those patients who really want spectacle independence are best served by PanOptix after counseling regarding halos and neuroadaption. It is possible to mix and match these lenses, though that can sometimes lead to patient regret and compulsively comparing the 2 eyes.
In general, for Vivity patients, it is useful to first implant the dominant eye targeting plano, and then assess the patient’s satisfaction. If they require more near, the nondominant eye can easily be offset to -0.50 D with very little loss of distance UCVA. This micro-monovision can give patients a large range of uncorrected vision without the optical disturbances of a diffractive IOL. Currently this lens is only available 15.00 D to 25.00 D, up to T5, though that range is expected to increase this year. Eyhance is a similar lens in that it provides excellent distance and intermediate vision without any loss in contrast sensitivity or side effects.13 Eyhance is categorized as a monofocal lens, which is important for billing purposes.
Patient Selection: Matching the Best Lens to the Patient
When it comes to choosing the right lens, a simple, honest explanation of the benefits and tradeoffs can usually guide patients to the best lens for their lifestyle. For patients who want a binocular full range of vision, today this means they must accept the visual tradeoffs associated with a diffractive IOL since the trifocal is still the most likely lens to meet their expectations. However, the trifocal is still a diffractive lens and requires careful patient selection. Now that we have Vivity, LAL, and Eyhance, there is rarely a reason for a surgeon to place a diffractive IOL in a patient with retinal pathology or high HOAs after corneal refractive surgery.13 The risk of harm and of creating a bad outcome is not worth the potential benefit when we have safer ways to reduce spectacle dependence for these patients.
As we know, negative word of mouth can spread like wildfire, so minimizing complications and refractive misses is absolutely critical. Unfortunately, most of us have seen patients who are adamantly opposed to any “multifocal” lenses because of an unhappy neighbor, friend, or loved one. Thankfully, with better lens technology and more options, we have the power to virtually eliminate those bad outcomes in the community. We owe it to our current and future patients, and to our colleagues, to deliver outstanding results through judicious and individualized patient selection.
With a fair, honest explanation of the advantages and disadvantages, almost all patients will see the value of at least one of these lenses. Ultimately, with any of the advanced technology lenses, the deciding factor for many patients is cost. Finding ways to make them affordable though financing and other tools can make the quality-of-life improvements they offer accessible to more patients.
Using these general guidelines for patient selection, we can elevate the entire field of refractive cataract surgery and help more patients as technology continues to advance at an exciting pace.
Neda Nikpoor is a cataract, cornea, and refractive surgeon at Aloha Laser Vision (alohalaservision.com) in Honolulu, Hawaii.
Disclosure: Dr Nikpoor declared affiliations with RxSight and Johnson & Johnson.
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8. Alcon Laboratories, Inc. AcrySof® IQ PanOptix® Trifocal Intraocular Lens (Model TFNT00) and AcrySof® IQ PanOptix® Toric Trifocal Intraocular Lens (Models TFNT30, TFNT40, TFNT50, TFNT60). US Food & Drug Administration. Published online September 19, 2019. Accessed April 9, 2021.
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10 Dick HB, Gerste R. Future intraocular lens technologies. Ophthalmol. Published online December 25, 2020. doi:10.1016/j.ophtha.2020.12.025
11. Summary of safety and effectiveness data (SSED). Published online November 22, 2017. Accessed April 13, 2021.
12. Premarket approval: RxSight light adjustable lens (LAL) and light delivery device (LDD). US Food & Drug Administration. Updated April 12, 2021. Accessed April 14, 2021.
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