Refractive Surgery Grey Zones

The ESCRS Guidelines for Cataract and Refractive Surgery reflect the current consensus on the numerous advancements and innovations. However, newer or less common refractive procedures, as well as borderline cases, still fall into uncertain areas where optimal care demands a highly personalised approach, said Béatrice Cochener-Lamard MD PhD.

“The grey zones persist despite many advances; therefore, shared decision-making [remains] vital in borderline indications [where] procedure choice must consider age, morphology, lifestyle, and a safety-first approach,” she said.

Cross-linking controversies

The use of corneal cross-linking (CXL) in corneal refractive surgery is still debated, she noted. Further studies are required to determine its long-term effectiveness and safety in improving corneal biomechanical stability for eyes undergoing lenticular surgery, surface ablations, or LASIK. Progressive flattening after cornea cross-linking might affect the long-term refractive stability, and the treatment’s impact on infection risk and fibrosis is unclear.

Additionally, stronger evidence is needed to determine the safety and long-term efficacy of CXL combined with trans-PRK in cases of subclinical ectasia or irregular topography, as well as pairing LASIK with CXL in borderline or high-risk cases. PRK and trans-PRK seem to carry a lower risk of ectasia than LASIK, although this too requires more extensive research, as do comparative ectasia rates.

Other areas of uncertainty in LASIK include the comparative benefits and limitations of wavefront-guided, topography-guided, and conventional ablation techniques. In addition, hyperopia correction with LASIK remains challenging, especially in cases of higher hyperopia, and questions persist regarding complication rates, refractive stability, and overall postoperative quality of vision.

PresbyLASIK shows promise as a means of providing presbyopic patients with an extended depth of focus. The main indication would be younger presbyopes—those younger than 55 years old with clear lenses—and hyperopes, who seem to benefit most from the procedure. However, there is a lack of long-term follow-up data, and these procedures inevitably come with some loss of visual quality.

KLEx advantages under scrutiny

Keratorefractive lenticule extraction (KLEx) offers several theoretical safety benefits compared to LASIK, though these advantages may only make a minimal difference in the long run, Professor Cochener-Lamard said. Since KLEx cuts fewer corneal nerves, it lowers the risk of dry eye and neuropathic pain, particularly within the first year after surgery. Beyond that period, however, there appears to be no distinct difference between the two procedures. Moreover, there is still no clear evidence that corneas have improved postoperative biomechanical stability with KLEx compared to LASIK.

There is currently no consensus regarding retreatment protocols following KLEx, and limited data exist on interventions such as PRK (with or without mitomycin C) or conversion to LASIK. Furthermore, there are presently no methods available for performing customised topography-guided ablations with KLEx for managing pre- or postoperative corneal irregularities.

The long-term safety and stability of phakic intraocular lenses (IOLs) require continuing vigilance. Because of their potential risk to the crystalline lens and cornea, each new class of lens design requires at least 10 years of follow-up to adequately assess its safety profile. The optimal method for phakic IOL sizing also has yet to be validated, although the use of AI for that purpose is showing promise, she said.

Furthermore, the risk of cataract induction in hyperopic and presbyopic patients remains insufficiently investigated. Clearly defined thresholds for lens model selection and patient age are still needed. There is also a lack of evidence regarding the use of these lenses for specialised indications.

While younger high myopes undergoing refractive lens exchange (RLE) have an increased risk of retinal detachment, the exact age and axial length thresholds remain uncertain. The effects of RLE on ageing eyes, such as changes to the capsular bag and risk of age-related macular degeneration, also require further investigation.

“It is essential to provide detailed and individualised informed consent to your patients, and to encourage the undertaking of standardised studies that review registry and post-marketing data,” she concluded.

Prof Cochener-Lamard made her presentation at the 2025 ESCRS Annual Congress in Copenhagen.

Béatrice Cochener-Lamard MD, PhD is Professor and Head of the Department of Ophthalmology, CHU Morvan Brest – UBO University, Brest, France. beatrice.cochener-lamard@chu-brest.fr. She is coordinator of the ESCRS refractive guidelines, along with Prof Thomas Kohnen.