This retrospective, multicenter study was conducted across eight J-CREST institutions between January 2019 and January 2021, encompassing 207 eyes that underwent scleral-fixated intraocular lens (SFIOL) implantation. The research compared the outcomes of the sutureless Yamane technique with conventional sutured methods for secondary IOL implantation. Data was meticulously gathered from medical records across participating hospitals and centralized at Hyogo Medical University’s Department of Ophthalmology. The study adhered to the tenets of the Declaration of Helsinki and received ethical approval from Hyogo Medical University (approval no. 3559). The need for individual informed consent was waived due to the retrospective nature and use of routine clinical data. Patient and public involvement was not part of the study design, conduct, or reporting phases.
Patient Selection and Methodology
The study included patients who received SFIOL via either the Yamane technique or conventional suturing, with a postoperative follow-up period exceeding 12 weeks. There were no age restrictions. In cases of bilateral surgery, only data from the right eye was analyzed. Eyes with pre-existing epiretinal membranes or cystoid macular edema (CME) at the initial visit, and patients with diabetes mellitus, were excluded. A total of 207 eyes from 207 patients were ultimately included in the analysis (Supplementary Figure S1). Comprehensive clinical data is accessible online (Supplementary Table S1). Building upon prior research indicating a 11% postoperative CME rate in Yamane technique cases 20, this study aimed to investigate CME incidence, hypothesizing its occurrence in approximately 23 eyes within the larger cohort. The observational design considered factors such as patient age, preoperative best-corrected visual acuity (BCVA), and surgical duration as potential influencers on outcomes. Multivariate logistic regression was planned to ensure model stability when accounting for potential confounding variables.
Surgical Procedures Compared
All surgeries involved a complete 27-gauge vitrectomy. The Yamane technique, a sutureless method for intrascleral IOL fixation, was executed according to previously established protocols 1,2. This technique is known for its sutureless approach, utilizing small gauge needles to create scleral tunnels for IOL haptic fixation, aiming to minimize suture-related complications. Conversely, the conventional technique employed sutures for IOL fixation, utilizing scleral tunnels at two suture points, as detailed in prior literature 3. This method, while more established, carries potential risks associated with sutures, such as suture erosion or breakage over time.
Data Collection and Follow-up
The study meticulously collected and analyzed a range of patient characteristics. These included: age, sex, operated eye, surgical duration, preoperative lens status (subluxated lens, IOL dislocation, or aphakia), time elapsed since previous cataract surgery, and the indication for SFIOL. Reasons for SFIOL were categorized as pseudoexfoliation syndrome, acute angle-closure glaucoma, trauma, high myopia, atopy, artificial aphakia, cataract surgery complications, unknown causes, and other less common etiologies. Visual outcomes were assessed by measuring best-corrected visual acuity (BCVA) preoperatively, and at 4 and 12 weeks postoperatively. Corneal endothelial cell counts and aqueous flare, quantified using a laser flare meter (FM-600α, Kowa, Tokyo, Japan), were also recorded. Surgery-related complications, with a primary focus on postoperative CME, were carefully documented. CME diagnosis was based on optical coherence tomography (OCT) findings of cystoid spaces in the foveal region. Visual acuity was measured using a Landolt chart at 5 meters under standardized illumination (500–1000 lx) and converted to logMAR values for statistical analysis. For very low vision, “off-chart” acuities like counting fingers, hand motion, and light perception were converted to logMAR values of 2.0, 2.3, and 2.6, respectively 21.
Patients underwent follow-up examinations at 4 and 12 weeks post-surgery. For comparative analysis, patients were categorized into the Yamane technique group and the conventional technique group.
Primary and Secondary Outcomes
The primary outcome measure was the comparison of postoperative CME incidence rates at 3 months between the Yamane and conventional technique groups. This aimed to determine if the sutureless Yamane technique offered any advantage in reducing postoperative inflammation and subsequent CME development compared to traditional sutured methods. Secondary outcomes included a comparison of postoperative BCVA at 3 months between the two groups. This assessed the visual rehabilitation efficacy of both surgical approaches. Furthermore, the study aimed to identify specific characteristics associated with postoperative CME in patients who underwent SFIOL using the Yamane technique. This exploratory analysis sought to pinpoint potential risk factors within the Yamane group that could predispose patients to CME. Another key endpoint was the identification of predictive factors for postoperative CME specifically within the Yamane technique cohort, aiming to refine patient selection and postoperative management strategies. Baseline patient characteristics were also comprehensively described for the entire study population to provide context for the outcome comparisons.
Statistical Methods
Statistical analysis employed appropriate tests for categorical and continuous variables. Categorical data, presented as frequencies and percentages, were analyzed using the χ2 test or Fisher’s exact test. Continuous variables, presented as means with standard deviations or medians with interquartile ranges depending on data distribution, were compared using Student’s t-tests or Wilcoxon rank-sum tests, respectively.
Adjusted odds ratios (ORs) were calculated to determine the relative risk for all endpoints when comparing the Yamane technique to the conventional technique. Logistic regression models were used, adjusting for potential confounding variables including patient age, preoperative BCVA, and surgical duration.
All statistical analyses were performed using JMP® Pro software (version 14.0.0, SAS Institute Inc., Cary, NC, USA). P-values were reported alongside two-sided 95% confidence intervals for point estimates, and statistical significance was defined as P < 0.05. This rigorous statistical approach ensured robust and reliable comparison of outcomes between the two surgical techniques for secondary IOL implantation.
