Long-term follow-up adherence after implantable collamer lens implantation in high-myopia patients: a single-center retrospective cohort and KAP survey study

Technical Summary: Long-term Follow-up Adherence After ICL Implantation in High-Myopia Patients

Problem Statement
High myopia (spherical equivalent ≤ -6.00 D or axial length > 26 mm) is a significant global health burden associated with sight-threatening complications such as glaucoma, retinal degeneration, and peripheral retinal breaks. While phakic intraocular lens (PIOL) implantation, specifically the Implantable Collamer Lens (ICL), effectively corrects refractive errors and preserves corneal tissue, it does not mitigate the inherent ocular risks associated with high myopia. Consequently, regular long-term follow-up is critical for the early detection of these insidious complications. However, clinical observation suggests that long-term adherence to follow-up schedules declines significantly over time, potentially leading to delayed diagnosis and irreversible vision loss. Furthermore, there is a lack of population-level evidence regarding the behavioral, psychological, and systemic determinants of follow-up adherence in this specific patient population, and current clinical models often fail to incorporate risk stratification for high-risk subgroups (e.g., middle-aged patients).

Methodology
This study employed a mixed-methods design combining a retrospective cohort analysis with a cross-sectional Knowledge–Attitude–Practice (KAP) survey, conducted at Tianjin Medical University Eye Hospital.

• Retrospective Cohort: The study analyzed 2,393 consecutive patients with high myopia who underwent V4c ICL implantation between 2016 and 2023.
  • Longitudinal Attendance Analysis: A historical subcohort of 133 patients (surgery between 2016–2017) with documented follow-up records was used to calculate annual attendance rates from postoperative year 1 to year 9.
  • Complication Detection: A subgroup of 128 patients with over one year of follow-up data was assessed for the descriptive detection of ocular complications, including glaucoma (confirmed and suspected) and retinal lesions.
• KAP Survey: A cross-sectional survey was conducted in January 2026 among postoperative ICL patients. Of 1,064 distributed questionnaires, 174 valid responses were analyzed. The 28-item instrument (Cronbach's α = 0.89) assessed knowledge regarding high myopia risks, attitudes toward monitoring, and self-reported practices/barriers.
• Statistical Analysis: Quantitative data were analyzed using SPSS 26.0. Univariable and multivariable logistic regression models were used to identify factors associated with self-reported follow-up adherence. Qualitative data from open-ended questions underwent inductive thematic analysis.

Key Results

• Declining Adherence: Long-term follow-up attendance demonstrated a progressive and sharp decline. Adherence rates dropped from 73.7% at one year post-surgery to 39.1% at two years, 21.1% at three years, and fell below 15% after four years. By nine years, the attendance rate was only 3%.
• Detected Complications: Among the 128 patients with >1 year of follow-up, 11 insidious complications were identified:
  • Glaucoma: 3 confirmed cases (2.34%) and 4 suspected cases (3.13%). Notably, all confirmed glaucoma cases occurred in patients aged ≥ 40 years. These cases presented with normal intraocular pressure, normal central visual acuity, and atypical optic disc morphology, complicating early detection.
  • Retinal Lesions: 4 cases (3.13%) of peripheral retinal degeneration or holes were detected.
• KAP Findings:
  • Knowledge: While 90.23% of respondents knew ICL corrects but does not cure myopia, awareness of specific risks was lower (49.42% aware of glaucoma association; 73.56% aware of retinal detachment risk).
  • Attitude vs. Practice: A significant gap existed between attitude and behavior. Although 83.91% supported regular monitoring, only 69.97% reported adhering to recommended schedules.
  • Barriers: Primary barriers included lack of time (25%), long travel distance (22%), and cognitive misconceptions (e.g., reliance on good postoperative vision, 23%).
• Predictors of Adherence: Logistic regression identified positive follow-up attitude (OR = 5.85) and higher knowledge/cognition scores (OR = 2.01) as independent protective factors for adherence. Age, sex, and education level were not statistically significant predictors in this model.

Key Contributions

1. Quantification of Adherence Decay: The study provides empirical data documenting the steep decline in long-term follow-up adherence (dropping to 3% by year 9) in high-myopia patients post-ICL, highlighting a critical gap in ocular surveillance.
2. Identification of Modifiable Drivers: By integrating KAP data, the study identifies that insufficient health literacy and negative attitudes are independent predictors of non-adherence, distinct from demographic factors like age or education.
3. Clinical Detection Patterns: The study highlights the difficulty in detecting glaucoma in high-myopia patients, noting that confirmed cases often present with normal intraocular pressure and atypical optic disc features, particularly in patients over 40.
4. Barriers to Care: The research categorizes barriers into practical constraints (time, distance) and psychological/cognitive factors (misconceptions about "cured" vision), offering specific targets for intervention.

Significance and Claims
The paper claims that poor long-term follow-up adherence poses a significant risk for the delayed detection of sight-threatening complications in high-myopia patients, potentially leading to irreversible vision loss. The authors assert that the "immediate good vision" following ICL surgery creates a false sense of security for both patients and clinicians, contributing to this adherence gap.

The study concludes that current uniform follow-up strategies are insufficient. It argues for the urgent implementation of targeted health education to bridge the knowledge-behavior gap, risk-stratified monitoring (specifically for middle-aged and high-risk subgroups), and improved access to care (e.g., addressing travel and scheduling barriers). The authors emphasize that while their findings are observational and single-center, they provide a hypothesis-generating basis for developing integrated, patient-centered strategies to enhance early detection and prevent vision loss in this population. They explicitly state that further prospective, multicenter studies are required to validate these strategies and establish causal relationships.