Implantable collamer lens versus small incision lenticule extraction for high myopia correction: A systematic review and meta-analysis

Bibliometric and visualized analysis of posterior chamber phakic intraocular lens research between 2003 and 2023

Introduction

Myopia is causing a major public health concern, with its prevalence increasing globally. This study aimed to discuss posterior chamber phakic intraocular lens (pIOL) research publication trends and hotspots over the past 20 years.

Methods

Bibliometric analysis was performed using the Web Science Core Collection to investigate posterior-chamber pIOL research publication trends. The extracted records were analyzed, and a knowledge map was built using VOSviewer v.1.6.20. The analysis included visualizing the annual publication count, countries/regions distribution, international and institutional collaborations, author productivity, and journal contribution, in addition to identifying knowledge bases and hotspots. Burst keywords were extracted using CiteSpace v.6.1.R.

Results

In total, 791 articles on posterior chamber pIOLs published between 2003 and 2023 were retrieved. China had the highest number of publications, whereas Japanese papers received the most citations. Fudan University had the highest number of publications, with articles from Kitasato University having the highest number of citations. Regarding individual research, Xingtao Zhou has published the most significant number of articles, and Shimizu Kimiya had the highest number of citations. The top productive/influential journal was 'Journal of Cataract & Refractive Surgery'. The top cited references primarily focused on reporting the clinical outcomes of implantable collamer lens (ICL) for individuals with moderate to high myopia. The keywords primarily formed four clusters: posterior chamber pIOL clinical outcomes for myopic astigmatism correction, posterior chamber pIOL implantation complications, ICL size selection and postoperative vault predictions, and postoperative visual quality following posterior chamber pIOL implantation.

Conclusion

This study presents the first bibliometric analysis of research trends in posterior chamber pIOL over the past two decades. We investigated the current state and emerging trends of global collaboration and research focal points in this field, offering fresh insights and guidance for researchers.

Exploring the Research Landscape of High Myopia: Trends, Contributors, and Key Areas of Focus

BACKGROUND Myopia results when light rays focus before reaching the retina, causing blurred vision. High myopia (HM), defined by a refractive error of ≤-6 diopters (D) or an axial length of ≥26 mm, is an extreme form of this condition. The progression from HM to pathological myopia (PM) is marked by extensive ocular axis elongation. The rise in myopia has escalated concerns for HM due to its potential progression to pathological myopia. The covert progression of HM calls for thorough analysis of its current research landscape. MATERIAL AND METHODS HM-related publications from 2003-2022 were retrieved from the Web of Science database. Using VOSviewer and Citespace software, we conducted a bibliometric and visualized analysis to create document co-citation network maps. These maps detailed authors, institutions, countries, key terms, and significant literature. RESULTS From 9,079 articles, 8,241 were reviewed. An increasing trend in publications was observed, with Kyoko Ohno-Matsui identified as a top contributor. The Journal of Cataract and Refractive Surgery was the primary publication outlet. Chinese researchers and institutions were notably active. The document citation network identified five focal areas: refractive surgery, clinical manifestations/treatment, prevention/control, genetics, and open angle glaucoma. CONCLUSIONS Research emphasis in HM has shifted from refractive surgery for visual acuity enhancement to the diagnosis, classification, prevention, and control of HM complications. Proposals for early myopia intervention to prevent HM are gaining attention. Genetics and HM's link with open angle glaucoma, though smaller in focus, significantly enhance our understanding of HM.

Safety and Effectiveness of Smooth Incision Lenticular Keratomileusis (SILKTM) Using the ELITA(TM) Femtosecond Laser System for Correction of Myopic and Astigmatic Refractive Errors

Purpose

To evaluate visual outcomes following the Smooth Incision Lenticular Keratomileusis (SILKTM) procedure for correction of myopic refractive errors with and without astigmatism, using the ELITATM Femtosecond Laser System.

Patients and Methods

A prospective, multicenter, single-arm, open-label clinical study was conducted. Eighty-five myopic subjects (n = 170 eyes), aged 18 years or older, with manifest refractive spherical equivalent (MRSE) up to -12.00 D and astigmatism up to -6.00 D, were treated binocularly using the ELITA femtosecond laser and followed up for 6 months. Intended correction was emmetropia for all eyes. The primary outcome measures included post-operative uncorrected and corrected distance visual acuity (UDVA and CDVA). Secondary outcome measures included surgeon's rating for ease of lenticule extraction, predictability, safety, and stability.

Results

A total of 170 eyes of 85 patients underwent SILK. Preoperative mean MRSE was -4.14 D ± 1.32 D (range -1.38 D to -8.88 D) and the mean cylinder was -0.77 D ± 0.62 D. Intraoperative surgeon ease of lenticule dissection was rated as grade 0 or 1 in 85.3% of eyes (no/only mild dissection needed). UDVA at 1 day, 1 week, 1 month, and 6 months was 20/20 or better in 65.9%, 85.4%, 91.5%, and 96% of eyes, respectively. No eyes lost any lines of CDVA at 6 months compared to the preoperative. The postoperative MRSE was stable over time, ranging from -0.34 D ± 0.24 D at 1 month to -0.33 D ± 0.23 D at 6 months. MRSE predictability (± 0.50 D) was 93.5% (129/138) at 3 months and 91.1% (113/124) at 6 months. No serious adverse events were noted.

Conclusion

The SILK procedure with the ELITA Femtosecond Laser System is safe and effective for the treatment of myopic refractive errors with and without astigmatism. Fast visual recovery was demonstrated, with stability achieved by 3 months.

Quality of vision after myopic refractive surgeries: SMILE, FS-LASIK, and ICL

BACKGROUND

To characterize the quality of vision after SMILE, FS-LASIK, and ICL implantation and evaluate the related factors.

METHODS

131 eyes of 131 myopic patients (90 female, 41 male) who underwent refractive surgeries including SMILE (35 patients), FS-LASIK (73 patients), and ICL implantation (23 patients) were analyzed. The Quality of Vision questionnaires were completed 3 months after surgery, and the results were characterized and analyzed with baseline characteristics, treatment parameters, and postoperative refractive outcomes using logistic regression analysis to find out predicted factors.

RESULTS

Mean age was 26.5 ± 4.6 years (range: 18 to 39 years) and mean preoperative spherical equivalent was - 4.95 ± 2.04 diopters (D) (range: -1.5 to -13.5). Safety and efficacy index was comparable between different techniques: the safety index was 1.21 ± 0.18, 1.22 ± 0.18, and 1.22 ± 0.16 and the efficacy index were 1.18 ± 0.20, 1.15 ± 0.17, 1.17 ± 0.15 for SMILE, FS-LASIK and ICL respectively. The mean overall QoV score was 13.40 ± 9.11, with mean frequency, severity, and bothersome score of 5.40 ± 3.29, 4.53 ± 3.04, and 3.48 ± 3.18 respectively, and there was no significant difference between different techniques. Overall, the symptom with the highest scores was glare, following fluctuation in vision and halos. Only the scores of halos were significantly different among different techniques (P < 0.000). Using ordinal regression analysis, mesopic pupil size was identified as a risk factor (OR = 1.63, P = 0.037), while postoperative UDVA was a protective factor (OR = 0.036, P = 0.037) for overall QoV scores. Using binary logistic regression analysis, we found that patients with larger mesopic pupil size had an increased risk to experience glare postoperatively; compared to ICL, patients who underwent SMILE or FS-LASIK tended to report fewer halos; patients with better postoperative UDVA were less likely to report blurred vision and focusing difficulty; with larger residual myopic sphere postoperatively, patients experienced focusing difficulties and difficulty judging distance or depth perception more frequently.

CONCLUSIONS

SMILE, FS-LASIK, and ICL had comparable visual outcomes. Overall, glare, fluctuation in vision, and halos were the most frequently experienced visual symptoms 3 months postoperatively. Patients with ICL implanted tended to report halos more frequently compared with SMILE and FS-LASIK. Mesopic pupil size, postoperative UDVA, and postoperative residual myopic sphere were predicted factors for reported visual symptoms.

Postoperative efficacy, safety, predictability, and visual quality of implantable collamer lens implantation versus small incision lenticule extraction in myopic eyes: a Meta-analysis

AIM

To compare the postoperative efficacy, safety, predictability, and visual quality of implantable collamer lens (ICL) implantation versus small incision lenticule extraction (SMILE) in myopia eyes.

METHODS

PubMed, EMBASE, Web of Science, Cochrane Library and several Chinese databases were searched at May 2021 to select relevant studies in comparison of clinical outcomes between ICL implantation and SMILE for myopia. The primary outcomes were efficacy, safety, and predictability. And the secondary outcomes were postoperative higher-order ocular aberrations (HOAs), modulation transfer function cutoff frequency (MTF), objective scatter index (OSI), contrast sensitivity and a quality of vision (QoV) questionnaire.

RESULTS

A total of 1036 eyes from 10 studies, of which 503 eyes underwent ICL implantation and 533 eyes underwent SMILE, were enrolled in this Meta-analysis. Pooled results revealed that ICL group had a better safety index and post-corrected distance visual acuity (CDVA) (P=0.007, <0.00001, respectively), and a lower percentage of eyes with a postoperative CDVA lost 1 line (P=0.007) than the SMILE group. No significant differences were found in comparison of the other primary outcomes. In the long-term follow-up (>6mo), ICL group had a lower total HOA, coma, and spherical aberration than SMILE group (P=0.003, <0.00001, 0.04). Yet higher trefoil was found in ICL group at 6mo after surgery (P=0.003). Additionally, ICL group also had a higher MTF value (P=0.02), and a higher contrast sensitivity score for spatial frequencies of 1.5, 6, and 12 cpds (P=0.02, 0.005, 0.02, respectively). And it also had a lower score of bothersome in QoV questionnaire than SMILE group (P=0.003).

CONCLUSION

ICL implantation and SMILE have similar and comparable outcomes in term of the efficacy and predictability for correcting high myopia. However, ICL group is relatively safer and also has better visual quality in comparison of SMILE group.

Phakic intraocular lenses: an update and review for the treatment of myopia and myopic astigmatism in the United States

PURPOSE OF REVIEW

To review all phakic intraocular lenses (pIOLs) available in the United States for the correction of myopia or myopic astigmatism and offer a clinical approach to their proper use, postoperative follow-up, and analysis of visual and adverse outcomes.

RECENT FINDINGS

In March 2022, the FDA approved the EVO/EVO+ Visian ICL for widespread use, adding this lens to the two others available (Verisyse, Visian ICL). Cataract formation, endothelial cell loss (ECL) and surgical reintervention remain the most common adverse events. There are discrepancies between studies on ECL following implantation with pIOLs, although trends can be deduced with meta-analysis. Posterior Chamber-pIOLs (PC-pIOLs), especially the EVO/EVO+, have an overall lower mean adverse effect and subjective patient symptom profile when compared to Iris Fixated-pIOLS (IF-pIOLs). Advancements in PC-pIOL sizing have provided a noticeable difference in visual and safety outcomes.

SUMMARY

All pIOLs available in the United States provide high-quality visual correction of moderate to high myopia and/or myopia with astigmatism. Proper follow-up for ECL and cataract formation is warranted.

Long-Term Observation of Higher-Order Aberrations and Microdistortions in Bowman’s Layer After Small Incision Lenticule Extraction for the Correcting Myopia With Spherical Equivalent Higher Than −9.0 Diopters

Purpose

To evaluate the outcomes in corneal higher-order aberrations (HOAs) and microdistortions in the Bowman’s layer after femtosecond laser small incision lenticule extraction (SMILE) for correcting extremely high myopia.

Methods

This prospective study included patients with myopia with spherical equivalent ≥ -9.0 Diopters (D). SMILE was performed in forty eyes of 40 patients. Pentacam was used to evaluate HOAs before and at 1 day, 3 months, 6 months, and 2 years after surgery. Fourier-domain optical coherence tomography was used to evaluate microdistortions at 2 years postoperatively. Thirty-two eyes of 32 patients receiving femtosecond laser-assisted in situ keratomileusis (FS-LASIK) were enrolled as the control group. HOAs were measured before, at 1 day and at least 1 year postoperatively.

Results

After SMILE, the long-term safety and effectiveness index was 1.25 and 0.85, respectively. Microdistortions were observed in 73.5% of the eyes at 2 years, with an average number of 1.20 ± 1.22 microdistortions and an average width of 287.37 ± 259.00 μm. We detected more microdistortions in the horizontal meridian than in the vertical meridian (p = 0.035). The average number and width of microdistortions were both higher in the central region (≤4 mm) than in the peripheral region (4–8 mm) (both p < 0.001). With the exception of horizontal trefoil in the SMILE group and vertical trefoil in the FS-LASIK group, significant changes over time were observed in all other HOAs (all p < 0.05). Meanwhile, we detected significant increases in the total corneal HOA, spherical aberration (SA), and coma at all time-points after both surgeries (all p < 0.01). Compared with FS-LASIK, SMILE induced less SA (p < 0.001) and more horizontal coma (p = 0.036). In the SMILE group, the HOA, SA, and trefoil were more in the small optical zone (≤6.0 mm) than in the large optical zone (>6.0 mm) (all p < 0.05). The increase in SA and most trefoil correlated with the mean number of central microdistortions number (all p < 0.05).

Conclusion

For myopia over −9.0D, the microdistortions in the Bowman’s layer were still detectable in most eyes long-term after SMILE. Both SMILE and FS-LASIK induced more HOAs, mainly HOA, SA, and coma. The small optical zone and microdistortions may affect postoperative aberrations.