Refractive Lens Exchange: A Comprehensive Review

By Phornrak Sriphon, Board Certified ophthalmologist

Introduction

Refractive Lens Exchange (RLE) has become the most commonly performed refractive surgery worldwide, followed by Laser Vision Correction (LVC) and phakic intraocular lenses (pIOLs). According to the 2022–2023 EUROQUO Annual Report, RLE accounted for approximately 80% of all reported refractive surgery cases. This essay provides a comprehensive review of RLE as a method of refractive correction, covering its definition and procedure, clinical indications, types of intraocular lenses (IOLs) used, benefits and risks, patient selection and counseling considerations, and concluding with a reflection on its role in modern refractive surgery.

What is Refractive Lens Exchange (RLE) and Why Has It Gained Popularity?

Refractive Lens Exchange (RLE), also known as clear lens extraction, involves the removal of the eye’s natural crystalline lens and replacement with an artificial intraocular lens (IOL) to correct refractive errors such as high myopia, hyperopia, astigmatism, and presbyopia. Originally reserved for patients unsuitable for corneal refractive procedures like LASIK or PRK, RLE has gained popularity due to advances in surgical techniques and lens technology.

In recent years, RLE has expanded its indications beyond hyperopia and high myopia. It now offers presbyopic patients an opportunity to correct both distance and near vision — a solution that traditional corneal laser surgeries often cannot fully achieve. Modern lens designs enable simultaneous correction of multiple visual distances, significantly increasing the appeal of RLE.

Unlike corneal-based procedures, which modify only the corneal surface and provide limited presbyopia correction, RLE replaces the aging natural lens, thereby also preventing the need for future cataract surgery. RLE is particularly suited for older patients, typically over the age of 43, whose needs include not just distance correction but restoration of functional near vision as well.

Improved patient education regarding lens replacement options and outcomes has further contributed to the rising popularity of RLE in refractive surgery.

Patient Selection: Who is a Good Candidate for RLE?

Ideal candidates for RLE are generally adults over 50 years of age who have significant refractive errors, particularly high hyperopia or high myopia, and who are unsuitable for corneal refractive surgeries such as LASIK. Hyperopic patients with refractive errors of +3.00 to +4.00 diopters benefit greatly, as hyperopic LASIK outcomes are often less predictable in older individuals due to early lens changes.

Presbyopic patients seeking both distance and near vision correction are also excellent candidates, as RLE provides the opportunity to restore accommodation while eliminating future cataract risk. Patients with pre-existing posterior vitreous detachment (PVD) may have a reduced risk of postoperative retinal detachment, making RLE an even safer option for some high myopes.

Candidates should have healthy ocular surfaces, a stable tear film, and no active ocular disease such as uncontrolled glaucoma, corneal dystrophies, or uveitis. Systemic conditions, such as diabetes, should be well-controlled, and patients must possess realistic expectations regarding postoperative visual outcomes.

Contraindications

Contraindications to RLE include:

• Ocular conditions: Corneal dystrophies, significant corneal scarring, age-related macular degeneration, diabetic retinopathy, and a high risk of retinal detachment (e.g., lattice degeneration, lacquer cracks).

• Systemic conditions: Uncontrolled diabetes or glaucoma.

• Other considerations: Poor ocular surface health or unrealistic patient expectations regarding spectacle independence.

Intraocular Lens (IOL) Options in RLE

The selection of an appropriate IOL is critical for successful RLE outcomes. Implanting an IOL is necessary not only to restore focusing ability but also to minimize risks such as posterior capsular opacification (PCO) and retinal detachment.

• Multifocal IOLs have been instrumental in the resurgence of RLE, offering patients a wide range of vision including near, intermediate, and distance vision. However, multifocal lenses can compromise contrast sensitivity and may not be suitable for patients with significant astigmatism unless toric multifocal IOLs are used. Trifocal IOLs have been developed to enhance intermediate vision, although they may demonstrate slightly lower modular transfer function compared to bifocal lenses.

• Accommodative IOLs aim to replicate the eye's natural accommodation by shifting lens position within the eye. Devices like the Eyeonics Crystalens and Synchrony AIOL offer some flexibility, although clinical studies suggest they provide less near and intermediate vision than multifocal lenses. Their performance can also decline over time due to capsular fibrosis and contraction.

• Monofocal IOLs with Monovision present a cost-effective alternative for patients unsuitable for multifocal or accommodative IOLs. In this approach, one eye is corrected for distance vision and the other for near vision, relying on the brain’s ability to suppress blur. This method may not be tolerated by all patients but offers a reasonable degree of spectacle independence when successful.

Risks and Complications

Although RLE offers many advantages, it carries certain risks:

• Retinal Detachment (RD): RD is the most serious postoperative complication, with reported incidence ranging from 1.5% to 8%. Myopic patients are at particularly high risk due to factors such as longer axial lengths, lattice degeneration, and intraoperative changes in vitreous volume and pressure. Moreover, Nd:YAG capsulotomy performed for posterior capsular opacification can increase the risk of RD by up to 3.9 times.

• Posterior Capsular Opacification (PCO): PCO is a common late complication, where the posterior capsule becomes cloudy, impairing vision. Preventive surgical techniques, such as thorough cortical clean-up and use of square-edged IOL designs, can minimize its incidence. Nd:YAG laser capsulotomy remains the treatment of choice if PCO develops but carries an increased risk of retinal detachment.

• Choroidal Neovascular Membranes (CNVM): CNVMs are occasionally observed in patients with lacquer cracks or pre-existing CNVM in the fellow eye. Although the mechanisms are not fully understood, RLE is associated with an elevated risk in predisposed individuals.

• Cystoid Macular Edema (CME): CME is another potential postoperative complication, particularly among myopic patients. It usually occurs within weeks of surgery and can affect central vision.

• Endophthalmitis: Although rare, postoperative endophthalmitis remains a severe and vision-threatening infection. Strict aseptic technique and vigilant postoperative care are essential to minimize this risk.

Clinical Evidence and Limitations

While expectations for RLE are high, the volume of published outcome data remains relatively limited. A large UK study by Hannan et al. reported that although 86.2% of multifocal IOL recipients achieved within ±0.5 diopters of their refractive target, only 42.9% attained an uncorrected distance visual acuity (UDVA) equal to or better than their preoperative corrected vision, highlighting the necessity of careful preoperative counseling.

Presbyopic hyperopes are the most favorable candidates for RLE. In contrast, younger hyperopes are often better served with laser vision correction or phakic IOLs to preserve natural accommodation. Evidence for RLE in myopic patients remains limited, primarily due to the increased risk of postoperative RD. Key risk factors for RD include younger age, male sex, longer axial length, lattice degeneration, and Nd:YAG capsulotomy. Preoperative evaluation for posterior vitreous detachment (PVD) is crucial, as its presence may lower the risk of RD.

Ultimately, thorough patient education and careful selection are fundamental to achieving satisfactory surgical outcomes.

Conclusion

Refractive Lens Exchange offers a unique and versatile solution for refractive correction across a broad range of visual needs, while simultaneously eliminating the risk of future cataract development. The Dysfunctional Lens Index serves as a valuable tool for educating and counseling patients with symptoms of dysfunctional lens syndrome despite clear lenses.

Optimal results depend on meticulous patient selection, comprehensive preoperative assessment, and refined surgical techniques, including micro-incisional bimanual phacoemulsification. However, it is vital to address potential complications proactively and to ensure patients have realistic expectations regarding the benefits and risks associated with RLE.

Reference

European Society of Cataract & Refractive Surgeons. (2023). Annual report 2022: Based on data from the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO). https://www.escrs.org/media/vospk2gx/eurequo-annual-report-2022-2023_final.pdf

Stephenson, M. (2022, November 10). A review of refractive lens exchange: Age and refractive error are the main factors when surgeons consider this procedure. Review of Ophthalmology. https://www.reviewofophthalmology.com/article/a-review-of-refractive-lens-exchange

Kaweri, L., Wavikar, C., James, E., Pandit, P., & Bhuta, N. (2020). Review of current status of refractive lens exchange and role of dysfunctional lens index as its new indication. Indian Journal of Ophthalmology, 68(12), 2797–2803. https://doi.org/10.4103/ijo.IJO_2259_20

Chan, E., & Varma, S. (2024). Refractive lens exchange – the evidence behind the practice. Eye, 39, 208–209. https://doi.org/10.1038/s41433-024-02713-4

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