Published in Refractive Surgery

Emerging Trends in Refractive Surgery Management

This is editorially independent content
12 min read

In this session from Eyes On 2023, Andrew A. Kao, MD, reviews innovations and new trends in refractive surgery management.

Emerging Trends in Refractive Surgery Management

From November 18 to 20, 2022, eyecare practitioners from around the world gathered online for Eyes On 2023, a 3 day educational summit offering up to 9 hours of COPE-accredited CE and CME providing the latest innovations in the ophthalmic industry.

Enjoy this presentation from Andrew A. Kao, MD, and don't forget to check out our list of future events!

Please note these videos are provided for review only.

Modern refractive surgery includes laser vision correction (LVC) and lens-based surgeries, and new technologies are developing to correct vision and presbyopia. Some of these innovations in refractive surgery management include intraocular lens (IOL) technologies that result in better refractive outcomes and more independence from spectacles. In addition, modular IOLs may allow for more flexible vision choices or updates to IOLs in the future.
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Innovations in laser vision correction

  1. Small-incision lenticule extraction (SMILE): Currently the fastest-growing LVC procedure with visual results similar to LASIK. There are fewer flap compilations and less postoperative dryness and discomfort. It utilizes a femtosecond laser to create a corneal lenticule extracted through a small incision without a flap.
  2. Topography-guided LASIK: The WaveLight Topolyzer Vario measures topography and keratometry, allowing for wavefront optimization of the corneal optics and a custom treatment pattern for each patient. In the FDA clinical trial, 92.7% of eyes achieved 20/20 or better uncorrected distant visual acuity (UCDVA).
  3. Wavefront-guided LASIK technology: This uses the iDesign aberrometer and is performed using a laser to ablate a spatially-variant pattern based on the measurements from the aberrometer. The iDesign combines wavefront analysis with corneal topography to provide a custom treatment pattern for each patient.
  4. PresbyLASIK: Enhances the corneal depth of focus by creating a multifocal corneal surface. Treatment is pupil-dependent and requires good centration on the pupil; otherwise, it can cause higher-order aberrations such as coma. The Central PresbyLASIK has a central steep area for near vision and is flatter in the peripheral zone for distance. Peripheral PresbyLASIK has central far vision and peripheral in the near zone.

What’s new in lens-based refractive surgery?

Types of phakic intraocular lenses

The first phakic IOL was placed in the anterior chamber angle in 1953 by Strampelli, later in 1977, Worst introduced the iris-claw IOL, and then in 1986, Fyodorov introduced the posterior chamber phakic IOL (pIOL). There are currently two phakic IOLs available in the United States, the EVO Visian implantable collamer lens (ICL) made by STARR surgical, which the FDA approved in March 2022, and Verisyse from Johnson & Johnson Vision.
  1. Verisyse: A polymethylmethacrylate (PMMA) iris-claw IOL designed for implantation in the anterior chamber. It requires the creation of a peripheral iridotomy.
    • Indicated for correction of myopia from -5 to -20D, with <2.5D astigmatism, and anterior chamber (AC) depth >3.2mm with stable refraction.
    • Contraindications include <21 years of age, AC depth <3.2mm, abnormal iris/cornea, pregnant or nursing patients, and those with a decreased epithelial cell count.
  2. Visian EVO ICL: The lens is placed between the crystalline lens and the iris. It is made of collamer, a copolymer of hydroxyethyl methacrylate and porcine collagen. EVO/EVO+ ICLs have a central hole, precluding the need for a laser peripheral iridotomy.
    • Indicated for correction/reduction of myopic astigmatism from -3 to -20D, with 1 to 4D astigmatism at the spectacle plane, AC depth of 3mm, and stable refractive history.
    • Contraindications include AC <3mm, narrow-angle, pregnant/nursing patients, <21 years of age, moderate or severe glaucoma, and a decreased epithelial cell count.
  3. Visian EVO+ with extended depth of focus (EDOF) ICL: Based on the EVO+ technology, this lens has an aspheric design to provide up to +2.0D of extended depth of focus.
    • A multicenter trial with 35 subjects with the EVO+ EDOF ICL implanted bilaterally showed it was well tolerated. One patient had it explanted due to dissatisfaction with distance vision, but 91% of patients were satisfied with their vision, and no serious adverse events were noted.

Refractive lens exchange

Refractive lens exchange (RLE) is a procedure growing in popularity, especially in patients who are not candidates for laser vision correction. It is a variation of cataract surgery, where the crystalline lens is removed in the absence of a cataract and concurrent abnormal ocular anatomy that results in high refractive error. Usually, a presbyopia-correcting IOL is placed to reduce the need for spectacles after surgery.
Patients need to be selected very carefully for this procedure; age is the most important factor, as patients who haven’t yet experienced presbyopia are usually not good candidates for RLE. Also, myopic patients require extra caution for retinal detachment risk, and plano presbyopes may require secondary procedures to achieve their preoperative visual acuity.

Presbyopia-correcting intraocular lenses

Numerous studies have shown an increased risk of falls with the use of bifocal glasses—including after cataract surgery with monofocal distance correction. This fall risk may be due to a reduced inferior field of view, increased blur, reduced depth perception, and reduced contrast sensitivity when viewing through the near add portion of glasses.

Diffractive IOLs

The Restor and Tecnis provide good near and distance vision but poor intermediate. These also have a higher incidence of side effects such as haloes, glare, and reduced contrast sensitivity. The prevalence of diffractive IOLs has decreased in the last few years with the increased availability of EDOF and trifocal IOLs.

Diffractive lenses for presbyopes that can be implanted during cataract surgery:

  • Restor (Alcon): The first diffractive IOL created in 2005, it has a near-dominant central area with diffractive peripheral rings and +2.5D, +3.25D, and +4D near range.
  • Tecnis (Johnson & Johnson): Has an aspheric anterior surface with a posterior surface with diffractive rings and +2.75D, +3.25D, and +4D near range.

Trifocal IOLs

The PanOptix by Alcon is the first FDA-approved trifocal IOL in the US. The lens splits 25% of light for near, 25% for intermediate, and 50% for distance vision. Over various clinical trials, >85% of patients achieved spectacle independence, and 79 to 87% of patients achieved UCDVA of 20/20 or better in a review of studies. Haloes, glare, and night driving difficulty are common side effects that usually improve with neuroadaptation.

Extended depth of field IOLs

  1. TECNIS Symfony (Johnson & Johnson): The first FDA-approved EDOF IOl was approved in 2016. Posterior echelettes create an achromatic diffractive pattern that elongates the focal point and compensates for the cornea's chromic aberration.
    • In a large multi-center trial, >85% of patients achieved spectacle independence, with >90% experiencing no or mild haloes, glare, and starbursts.
  2. Vivity (Alcon): Approved by the FDA in March 2020 and uses novel non-diffractive design (X-WAVE), resulting in wavefront shaping.
    • The FDA trial showed distance visual acuity of 20/25 or better for 89% of patients, intermediate of 20/25, and near 20/40 vision for ~40% of participants.
  3. IC-8 Apthera (AcuFocus): An EDOF and pinhole IOL that was FDA approved in July 2022 for a refractive target of -0.75D. It uses the pinhole effect to allow central rays to enter the eye while eliminating diverging rays. This reduces the size of the circle of confusion on the retina and increases the depth of field.
    • The FDA pivotal trial showed that eyes with Apthera had 2D of EDOF, equivalent distance vision, and superior intermediate and near vision compared to control.
  4. Synergy (Johnson & Johnson): A hybrid EDOF and multifocal IOL that provides a wide range of continuous vision with excellent near vision. It was FDA approved in May 2021. The lens contains an Optiblue violet light filter and high-resolution lathing to help decrease nighttime haloes and starbursts.
    • There is a slightly smaller landing zone for the refractive target, so it’s better to aim slightly hyperopic than myopic when fitting the contacts.

Monofocal IOLs

Another potential refractive lens-based therapy to employ is using monofocal IOLs. The Eyhance by Johnson & Johnson Vision is a one-piece monofocal with an aspheric anterior surface.

Using this IOL can be a good compromise for patients who might not otherwise be good candidates for presbyopia correction due to other ocular comorbidities.

The RayOne EMV by Rayner is a preloaded non-diffractive monofocal IOL that was FDA approved in March 2021. The aspheric anterior surface adds to the positive spherical aberration of the cornea, enhancing the depth of focus.

Monovision

As “premium” IOLs may be out of reach financially for some patients, monovision therapy could be a good alternative. One eye (usually the dominant) is corrected for distance, and one eye is corrected for near (conventional).
While this is a less commonly used therapy, it can still be a great option for some patients to reduce spectacle dependence after cataract extraction IOL, especially if they have tried it in the past with contact lenses or laser vision correction.

Light adjustable lens

A newer light adjustable lens (LAL) technology, the RxLAL by RxSight is a three-piece foldable photoreactive silicone monofocal IOL that allows for the adjustment of the refractive power of optic (up to 2D sphere and 3D cylinder) to adjust for refractive error due to effective lens position and incisional healing.
This adjustment is possible because 10% of the lens material contains a photosensitive material that is not polymerized—so shining UV light on it polymerizes the material to lock in refractive power. These light adjustments must be made with a specific wavelength of 365nm.

The RxLAL is FDA-approved for 3 to 4 treatments over a 1 to 2-week period. This must be done up to 17 to 21 days after surgery; then afterward, the lock-in treatment is performed. After the procedure, patients must limit exposure to ambient UV light by wearing UV-blocking glasses indoors and out.

Innovations in refractive surgery management

Laser-induced refractive index change

Laser-induced refractive index change (LIRIC) is a technology that can be applied to both the cornea and IOLs. Clerio Vision has used this procedure to use a femtosecond laser at low energy levels to alter corneal collagen structures to change the refractive index. The procedure could treat myopia, hyperopia, astigmatism, and higher-order aberrations and create a diffractive multifocal pattern. LIRIC only treats up to a 10-micron depth of the cornea.
On the other hand, the IOL-based LIRIC uses a low-energy femtosecond laser to hydrolyze the IOL material, increasing the hydrophilicity of the material and thereby causing a change in refractive index. This can be used on hydrophobic and hydrophilic IOLs and could add (or remove) multifocality for dissatisfied patients.

Modular intraocular lenses

These IOLs are made up of separate components that allow for easier or safer IOL exchange or removal after the initial implantation.

Modular IOLs currently in development include:

  1. Gemini Refractive Capsule (Omega Ophthalmics): Circular silicone polymer capsule with a 6mm opening at the top and bottom that fills the capsular bag. It is designed to hold a single-piece acrylic IOL with a channel holding haptics in a stable position. This could be used for drug delivery, biometrics, or making IOL exchange easier.
  2. Juvene IOL (LensGen, Inc): A modular, shape-changing fluid optic IOL.
  3. Harmoni Modular IOL System (ClarVista Medical): Hydrophobic acrylic base with hydrophobic acrylic optic. The central optic can be exchanged or rotated if needed, and multifocality could be added or removed.
  4. Atia Vision modular presbyopia-correcting IOL (Shifamed): Has a shape-changing, accommodating base and exchangeable front optic. The base contacts the capsular bag, transferring force from the ciliary muscle to the optic.
Andrew A. Kao, MD
About Andrew A. Kao, MD

Andrew A. Kao, MD, is a board-certified ophthalmologist who returned to his native Bakersfield to practice ophthalmology at Empire Eye and Laser Center in 2016. He received his medical degree from UC San Francisco. Then he completed a fellowship in ocular pathology at the top eye hospital in the country, the Bascom Palmer Eye Institute in Miami, Florida.

Dr. Kao completed his residency at the longest-running eye hospital in the US, the New York Eye and Ear Infirmary, in Manhattan, NY, and was recognized as the top resident in his class. He then undertook a year-long fellowship in ocular oncology at UC San Francisco, where he learned to care for ocular surface and intraocular tumors and teach residents about cataract surgery.

He enjoys providing the most advanced ophthalmologic treatment in his hometown. Outside work, Dr. Kao enjoys traveling, reading, watching Giants baseball and Cal football, and spending time with his family and friends. Dr. Kao was voted Best Ophthalmologist in The Bakersfield Californian 2021 and 2022 Best Of Readers’ Choice Poll.

Andrew A. Kao, MD
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