Accuracy and stability of hyperopic treatments

Efficacy and safety of small-incision corneal intrastromal lenticule implantation for hyperopia correction: a systematic review and meta-analysis

Purpose

To assess the efficacy and safety of intrastromal lenticule implantation for the treatment of hyperopia.

Methods

A systematic search of PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Internet, and Wan Fang Database identified studies on small-incision intrastromal lenticule implantation for hyperopia correction until January 2023. The Joanna Briggs Institute (JBI) critical appraisal tool was used to assess the quality of the retrospective research, and the Methodological Index for Non-randomized Studies (MINORS) was used to assess the quality of the prospective research. This study included postoperative visual outcomes, corneal morphology, and biomechanical outcomes.

Results

A total of 456 articles were identified, of which 10 were included in the meta-analysis. Ten single-arm studies involving 190 eyes were included. A meta-analysis demonstrated that corneal intrastromal lenticule implantation treatment significantly improved hyperopia. Uncorrected distance visual acuity (UDVA) significantly improved compared to the preoperative value (p = 0.027), corrected distance visual acuity showed no difference compared to the preoperative value (p = 0.27), and 87% eyes have no loss of one or more lines in the Snellen lines of CDVA (p < 0.00001). There was a significant difference between the spherical equivalent refractive (SE) and preoperative examination (p < 0.00001), 52% of eyes had ±0.5 diopters (D) postoperative SE (p < 0.00001), and 74% eyes had ±1.0 D postoperative SE (p < 0.00001). The central corneal thickness (CCT) increased by 72.68 μm compared to that preoperatively (p < 0.00001), and corneal curvature increased by 4.18D (p < 0.00001). The Q-value decreased by 0.82 (p < 0.00001), and higher-order aberration (HOA) decreased by 0.66 (p < 0.00001).

Conclusion

Small-incision intrastromal lenticule implantation may be an effective solution for correcting hyperopia. The effect of improved vision is significant, but further exploration is needed for changes in corneal biomechanics and long-term safety.Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42023432343.

Small incision lenticule extraction (SMILE) combined with allogeneic intrastromal lenticule inlay for hyperopia with astigmatism

Purpose

To quantitatively evaluate outcomes after small incision lenticule extraction (SMILE) combined with allogeneic intrastromal lenticule inlay for hyperopia with astigmatism.

Methods

It’s a retrospective cohort study. Twenty-four eyes of 15 patients with more than 0.75 diopters (D) of astigmatism in hyperopic eyes were enrolled in this study. The hyperopic eye with astigmatism was first treated with SMILE to correct astigmatism; then a lenticule was extracted from a donor myopic eye and subsequently implanted into the hyperopic eye with astigmatism. Patients were examined preoperatively and 1 day, 1 week, 1,3 months and 1 year after surgery. The main outcome measures were the uncorrected and corrected distance visual acuity (UDVA and CDVA), uncorrected near visual acuity (UNVA), spherical equivalent (SE), corneal topography, anterior segment optical coherence topography (OCT) and ocular response analyzer (ORA) parameters: corneal hysteresis (CH) and corneal resistance factor (CRF). Repeated–measures analyses of variance (ANOVA) and post hoc tests were used to analyze data of different follow-up visits.

Results

The mean preoperative cylinder was 1.95±1.04(D). The UDVA (from 0.37±0.23 to 0.09±0.09), UNVA (from 0.49±0.21 to 0.08±0.06), SE (from +7.42±3.12 to -0.75±0.79) and astigmatism (+1.95±1.04 to -0.65±0.63) postoperatively were obviously better than those before surgery. Five eyes (26.3%) gained one line of CDVA, and 3 eyes (15.8%) gained two lines of CDVA one year after surgery compared with preoperative levels. The average corneal curvature was changed from (43.19±4.37) D to (49.19±3.87) D one year after surgery. The anterior segment OCT images of corneas with lenticule inlays at each follow-up visit showed that the implanted lenticule was shaped like a crescent in the corneal stroma. The CH and CRF didn’t change significantly after surgery (p = 0.189 and p = 0.107respectively).

Conclusions

SMILE combined with intrastromal lenticule inlay can be used to correct high hyperopia with astigmatism with good safety, efficacy and reproducibility.

A pilot study: lenticule quality of hyperopic small incision lenticule extraction (SMILE) in rabbits

BACKGROUND

To evaluate lenticule surface characteristics of small incision lenticule extraction (SMILE) for hyperopia correction in rabbits.

METHODS

The left and right eyes of 8 rabbits were divided into two groups. The right eyes were assigned to a myopia group, and the left eyes to a hyperopia group. The rabbits received SMILE procedures with + 3.00 D and - 3.00 D correction for the hyperopia and myopia groups, respectively. Extracted lenticules were examined via scanning electron microscopy. Lenticules from odd-numbered rabbits were accessed with the anterior surface, and lenticules from even-numbered rabbits were observed with the posterior surface. A previously established scoring system was used to evaluate lenticule surface characteristics. Statistical analysis was conducted to compare the scores between the two groups.

RESULTS

All procedures were performed successfully, and the lenticules were extracted smoothly. One myopia lenticule that was facing downward was handled failed in preparation for imaging, thus 15 lenticules were ultimately graded. Twelve lenticules exhibited smooth surfaces, and regularly arranged tissue bridges were observed in almost all regions. Three lenticules exhibited a partially rough surface and irregularities affecting more than 10% of the lenticules (2 in the hyperopia group and 1 in the myopia group). Rough lenticules occurred in twice as many lenticules in the hyperopia group compared to the myopia group.

CONCLUSIONS

Scan quality of lenticules after SMILE for hyperopia correction is comparable to that of myopia lenticules. The shape of hyperopic lenticule may increase the difficulty of surgical manipulation and result in surface roughness.

Six-Month Outcomes After High Hyperopia Correction Using Laser-Assisted In Situ Keratomileusis With a Large Ablation Zone

PURPOSE

To evaluate refractive and visual outcomes of laser-assisted in situ keratomileusis (LASIK) to treat high hyperopia using an aberration-neutral profile and large ablation zone.

METHODS

This was a retrospective, consecutive observational case series at Helios Ophtalmologie, St. Jean-de-Luz, France. One hundred forty-six consecutive eyes of 77 patients who underwent LASIK with mechanical microkeratome to correct hyperopia with correction in the maximum hyperopic meridian strictly higher than +5 D (mean + 6.6 ± 1.0 D) were included. Procedures were performed with an Amaris 750S excimer laser (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany) using an aberration-neutral profile, a 6.7 ± 0.1 mm optical zone, and a 9.2 ± 0.1 mm total ablation zone. Refractive results, predictability, safety, and efficacy were evaluated at 6 months postoperatively.

RESULTS

At 6 months postsurgery, the mean manifest refraction spherical equivalent was -0.06 ± 0.83 D and the mean cylinder was 0.42 ± 0.35 D. Sixty-six percent of eyes were within ±0.50 D of the attempted spherical equivalent correction. Six months postoperatively, 60% of eyes achieved an uncorrected distance visual acuity of 20/20 or better. Ten percent of eyes lost 1 line of corrected distance visual acuity and 4% gained a line. No eyes lost more than 2 Snellen lines of corrected distance visual acuity at any follow-up.

CONCLUSIONS

High hyperopia correction with LASIK using an aberration-neutral profile and large ablation zone provides good efficacy, safety, predictability, and visual outcomes.

Bioptics for high hyperopia with combined multifocal intraocular lens implantation and excimer ablation in young patients

PURPOSE

To analyze the visual and refractive outcome of the bioptics procedure combining multifocal intraocular lens implantation and excimer laser surgery in young patients with high hyperopic eyes not suitable for a single surgical procedure.

METHODS

This retrospective case series included 10 eyes of five patients (age range 18-30 years) with high hyperopia (spherical equivalent +8.51 ± 0.85 diopters (D)). They had been treated with serial multifocal intraocular lens implantation followed 6 weeks later by laser in situ keratomileusis for residual hyperopia. Uncorrected distance visual acuity, uncorrected near visual acuity, corrected distance visual acuity, corrected near visual acuity, and manifest refraction were evaluated before surgeries, after multifocal intraocular lens implantation, and 3 months post laser in situ keratomileusis.

RESULTS

No patients were lost to follow-up (6 months). The mean spherical equivalent decreased to +2.05 ± 1.33 D after multifocal intraocular lens implantation and to -0.10 ± 0.58 D after the laser in situ keratomileusis procedure. Success of the procedures was determined by uncorrected visual acuity. LogMAR uncorrected distance visual acuity improved by a total of more than six lines from 1.05 ± 0.18 LogMAR to 0.46 ± 0.12 LogMAR post multifocal intraocular lens implantation and to 0.15 ± 0.06 LogMAR after both surgeries. The LogMAR uncorrected near visual acuity increased by 0.81 ± 0.82 LogMAR after lens implantation due to loss of accommodation, and all eyes reached a LogMAR of 0 at 1 month postoperatively following laser in situ keratomileusis.

CONCLUSIONS

A bioptics approach involving multifocal intraocular lens followed 6 weeks later by a laser in situ keratomileusis procedure for the correction of very high hyperopia enabled the resolution of the residual refractive error in young very high hyperopic patients.

Three-year outcomes after high hyperopia correction using photorefractive keratectomy with a large ablation zone

Aim

To evaluate refractive and visual outcomes of photorefractive keratectomy (PRK) to treat high hyperopia using an aberration-neutral profile and large ablation zone.

Methods

This was a retrospective, consecutive observational case series at the Oftalmika Eye Hospital, Bydgoszcz, Poland. We included 51 consecutive eyes of 34 patients who underwent alcohol-assisted PRK to correct hyperopia within the range of +3.6 to +6.15 D (mean+4.61±0.67 D). Procedures were performed with an Amaris 750S excimer laser (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany) using an aberration-neutral profile and a 10 mm total ablation zone. Refractive results, predictability, safety and efficacy were evaluated 3 years postoperatively.

Results

At 1-year postsurgery, the mean manifest refraction spherical equivalent (MRSE) was −0.002±0.43 D and mean cylinder was −0.181±0.31 D, while the values were +0.09±0.46 D and −0.15±0.26 D, respectively, at 2 years (MRSE p<0.001) and +0.15±0.44 D and −0.15±0.26 D, respectively, at 3 years (MRSE p<0.001). 78% of eyes were within ±0.50 D of the attempted spherical equivalent correction. Three years postoperatively, 22% of eyes lost one line of corrected distance visual acuity and 27% gained a line or two. The change in the mean corneal spherical aberrations for the 6 mm zone was from 0.27±0.07 to 0.08±0.13 µm.

Conclusions

High hyperopia correction with PRK using an aberration-neutral profile and large ablation zone provides good efficacy, safety, predictability and visual outcomes. Relatively low change of corneal spherical aberrations and low increase of hyperopia in the first three postoperative years were observed.

Hyperopic refractive correction by LASIK, SMILE or lenticule reimplantation in a non-human primate model

Hyperopia is a common refractive error, apparent in 25% of Europeans. Treatments include spectacles, contact lenses, laser interventions and surgery including implantable contact lenses and lens extraction. Laser treatment offers an expedient and reliable means of correcting ametropia. LASIK is well-established however SMILE (small-incision lenticule extraction) or lenticule implantation (derived from myopic laser-correction) are newer options. In this study we compared the outcomes of hyperopic LASIK, SMILE and lenticule re-implantation in a primate model at +2D/+4D treatment. While re-implantation showed the greatest regression, broadly comparable refractive results were seen at 3-months with SMILE and LASIK (<1.4D of intended), but a greater tendency to regression in +2D lenticule reimplantation. Central corneal thickness showed greater variation at +2D treatment, but central thickening during lenticule reimplantation at +4D treatment was seen (-17± 27μm LASIK, -45 ± 18μm SMILE and 28 ± 17μm Re-implantation; p <0.01) with expected paracentral thinning following SMILE. Although in vivo confocal microscopy appeared to show higher reflectivity in all +4D treatment groups, there were minimal and inconsistent changes in inflammatory responses between modalities. SMILE and lenticule re-implantation may represent a safe and viable method for treating hyperopia, but further optimization for lower hyperopic treatments is warranted.

A Pilot Study of SMILE for Hyperopia: Corneal Morphology and Surface Characteristics of Concave Lenticules in Human Donor Eyes

PURPOSE

To evaluate the corneal morphology and surface characteristics of concave lenticules after small incision lenticule extraction (SMILE) for hyperopia.

METHODS

SMILE procedures were performed on two human autopsy corneas in vitro to correct +4.00 diopters of hyperopia. Slit-lamp microscopy and anterior optical coherence tomography (OCT) were performed after lenticule creation and extraction. The extracted lenticules and modified corneas were sent for transmission electron microscopy imaging.

RESULTS

Interlamellar gas bubbles were detected at 3 minutes and almost burst at 30 minutes after lenticule creation. A few interlamellar bubbles were detected after lenticule extraction. There was an obvious interlamellar concave gap under OCT. Transmission electron microscopy showed the front and back surfaces of the lenticules were smooth, with some tissue bridges, cavities, and grooves.

CONCLUSIONS

A good quality concave lenticule can be created via SMILE for hyperopia. The impact of interlamellar gap on visual quality needs further investigation. [J Refract Surg. 2016;32(10):713-716.].