FS-LASIK For The Treatment Of Moderate To High Hyperopia

In the latest episode of the ESCRS Eye Journal Club, Dr Artemis Matsou and Dr Myriam Boehm discussed a JCRS study by Alió del Barrio (et al.1) with guest speakers Professor Paolo Vinciguerra and Dr Florian Kretz, who provided valuable insights on managing moderate to high hyperopia with femtosecond LASIK (FS-LASIK).

Despite the advancements in FSLASIK and modern excimer laser platforms, LASIK for hyperopia up to +7.00 dioptres (D) remains underutilised among refractive surgeons. One reason is the technically more challenging technique required to correct such high hyperopic prescriptions (larger peripheral ablations, necessitating larger flaps on smaller diameter corneas). Also, there is a lack of consistent scientific evidence supporting LASIK for this range of hyperopia, with varying outcomes across different excimer laser platforms.

In addition, managing latent hyperopia to minimise the risk of postoperative ciliary spasms and patient dissatisfaction is a considerable challenge, making refractive lens exchange (RLE) with multifocal intraocular lens implantation for young nonpresbyopic hyperopic patients the commonly preferred and recommended method for this group.

In this retrospective single-centre study, the authors included 92 eyes of 64 patients who underwent FS-LASIK for moderate to high hyperopia (≥3.50 D and ≤6.50 D), using a Visumax 500 kHz femtosecond laser and an Amaris 750 excimer laser. The study reported favourable outcomes for FS-LASIK with an efficacy index of 0.91 and 0.90 at 6 months and 36 months, respectively.

The safety index was 1.00, showing a low incidence of complications. Impressively, 72% of patients achieved UCVA of 20/20 or better, and 80% had a postoperative spherical equivalent within 0.50 D. However, researchers observed a slight but significant regression at 36 months. At this point, 21.73% of patients required a flap lift for laser enhancement, and 11.95% needed orthoptic visual rehabilitation for self-resolving accommodative spasms not resolving on their own.

Prof Vinciguerra commented on the study’s robust design, highlighting its strength in using a laser platform capable of tracking the visual axis versus the pupil. This feature is particularly important in hyperopic patients with a large angle kappa, as tracking the visual axis minimises the risk of decentred ablations that can lead to high-order aberrations, coma, and suboptimal vision. Large optic zones (average 6.76 ± 0.22 mm) enabled the correction of high hyperopic prescriptions, contributing to the study’s overall success. These underscore the significance of advanced laser technology in optimising outcomes of FS-LASIK for moderate to high hyperopia.

Dr Kretz also stressed the importance of large-diameter flaps and optic zones in achieving favourable outcomes in hyperopic LASIK, sharing his preference for even thinner femto-flaps, around 90 microns, as he has seen a lower incidence of microfolds that would require early flap replacements (3.26% of patients in this study). He also noted RLE still exhibits a higher degree of safety for hyperopic patients, particularly in retreatment rates. In Dr Kretz’s experience, retreatment rates after RLE in young hyperopic patients are significantly lower compared to that reported for FS-LASIK, which the study authors also mentioned.

Potential risks associated with flap lifting during retreatments, such as epithelial ingrowth, should be taken into consideration and discussed with patients. Both speakers emphasised the risk of epithelial ingrowth is higher when the ablation area is very close to the flap edge (which can happen in hyperopic treatments), where a portion of the treatment often extends directly onto the edge of the flap.

Regarding the laser retreatment rates in this study, Prof Vinciguerra observed the corneal curvature gradient plays a pivotal role in determining regression outcomes. When the corneal curvature gradient exceeds 5.00 D/mm, he said to expect some degree of regression. High regression rates in this cohort are also attributed to more aggressive epithelial remodelling of the peripheral ablated zone in high hyperopic treatments, Dr Kretz said.

He also noted the number of patients in the study requiring orthoptic treatment after the procedure—due to treatment of a varying degree of latent hyperopia— which patients are not used to. Such patients may take up to six months to adapt to a reduced need for accommodation, underscoring the need for careful counselling, as it aids in managing patient expectations and facilitating a smoother adaptation period.

If the difference between cycloplegic and manifest refraction is more than 1.50 D, both Prof Vinciguerra and Dr Kretz provide patients with contact lenses or spectacles matching that prescription to assess their adaptability and simulate the visual experience post-treatment. For patients who struggle to cope, they advise slight undercorrection, initially maintaining a degree of hyperopia and discussing the future need for retreatment once adaptation occurs. It is essential to clearly communicate the potential risks to the patient, ensuring their full awareness.

Both guests felt that there is not yet enough evidence to argue FS-LASIK should be a first-line treatment instead of RLE for this extent of hyperopia, as the paper concludes. To truly ascertain the superiority of one approach over the other, a prospective randomised study with long-term follow-up comparing RLE and FS-LASIK with modern laser platforms is essential. For now, when deciding whether FS-LASIK or RLE is the correct choice, a very customised approach considering long-term outcomes and individual patient needs and preferences is required.

For citation notes, see page 40.