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Published on: November 12, 2015
Biomechanical and Tomographic Outcomes in Pediatric Keratoconus Treated with Conventional Epithelium-Off Corneal
Radu-Nicolae Pop1,2, Patricia Ariadna Nicula1, Cristina Ariadna Nicula1,3
1OCULENS Ophthalmology Clinic, 400501 Cluj-Napoca, Romania.
Insights
This study shows that conventional epithelium-off corneal collagen cross-linking (CXL) in pediatric keratoconus patients led to improved vision and corneal stabilization over 24 months. Findings suggest CXL is associated with enhanced visual acuity and biomechanical stiffening in young keratoconus patients.
Area of Science:
- Ophthalmology
- Corneal Surgery
- Biomechanical Engineering
Background:
- Pediatric keratoconus often progresses rapidly, necessitating timely treatment decisions.
- Conventional epithelium-off corneal collagen cross-linking (CXL) is a common treatment for keratoconus.
- Evaluating long-term outcomes of CXL in pediatric patients is crucial for understanding its efficacy.
Purpose of the Study:
- To assess 24-month visual, tomographic, pachymetric, and biomechanical outcomes following epithelium-off CXL in pediatric keratoconus patients.
- To evaluate changes in visual acuity, corneal shape, thickness, and biomechanical properties after CXL.
- To provide observational data on the effects of CXL in a young cohort.
Main Methods:
- A single-center, observational, longitudinal cohort study of 28 eyes from 23 pediatric patients (aged 13-18 years).
- Epithelium-off corneal collagen cross-linking (CXL) was performed.
- Data collected at baseline, 6, 12, and 24 months included uncorrected and best spectacle-corrected visual acuity (UCVA, BCVA), Kmax, thinnest pachymetry, and Corvis ST parameters (DA, A1T, A2T, HC radius, BAD-D).
- Statistical analysis included repeated-measures ANOVA, with findings interpreted cautiously due to study limitations.
Main Results:
- Significant improvements in UCVA (0.53 to 0.44 logMAR) and BCVA (0.31 to 0.25 logMAR) were observed (p < 0.001).
- Mean Kmax showed a modest decrease (54.36 to 53.41 D), while SP-A1 significantly increased (84.69 to 97.39) (p < 0.001), indicating corneal stiffening.
- Corvis ST parameters demonstrated significant changes consistent with increased corneal rigidity (e.g., decreased DA, increased A1T, decreased A2T, increased HC radius, decreased BAD-D).
- Thinnest pachymetry revealed initial thinning followed by partial recovery.
Conclusions:
- Conventional epithelium-off CXL in pediatric keratoconus patients was associated with stabilization, modest visual improvement, and biomechanical stiffening over 24 months.
- The findings suggest a positive association between CXL and improved visual and biomechanical outcomes in this cohort.
- Results should be viewed as cautious observational findings due to study limitations, including small sample size and lack of a control group.
Abstract:
Background and Objectives: Pediatric keratoconus may progress rapidly, and treatment decisions are often made before prolonged observation is possible. This study evaluated 24-month visual, tomographic, pachymetric, and biomechanical outcomes after conventional epithelium-off corneal collagen cross-linking (CXL) using Pentacam tomography and Corvis ST dynamic Scheimpflug analysis. Materials and Methods: This single-center observational longitudinal cohort included 28 eyes of 23 patients aged 13-18 years treated at the OCULENS Clinic, Cluj-Napoca, Romania, between 2019 and 2023. Because the study had no untreated or alternative-treatment control group, postoperative changes were interpreted as associations after CXL rather than as proof of causality. Baseline, 6-, 12-, and 24-month values were analyzed for UCVA, BCVA, Kmax, thinnest pachymetry, SP-A1, deformation amplitude (DA), first and second applanation times (A1T and A2T), highest concavity (HC) radius, and BAD-D. Repeated-measures ANOVA was used after assessment of within-eye difference normality; findings were interpreted cautiously because the analysis was eye-based, the cohort was small, and multiple outcomes were examined. Results: UCVA improved from 0.53 ± 0.16 to 0.44 ± 0.16 logMAR and BCVA from 0.31 ± 0.11 to 0.25 ± 0.11 logMAR (both p < 0.001). Mean Kmax decreased modestly from 54.36 ± 3.11 D to 53.41 ± 2.79 D, while SP-A1 increased from 84.69 ± 4.75 to 97.39 ± 5.11 (both p < 0.001). Thinnest pachymetry showed early postoperative thinning followed by partial recovery by 24 months. DA decreased, A1T increased, A2T decreased, HC radius increased, and BAD-D decreased significantly. Kmax and SP-A1 were inversely correlated at all visits (r = -0.714 to -0.773; all p < 0.001), but these correlations were considered exploratory. Post-24-month retreatment and keratoplasty-related events were recorded descriptively and were not included in the formal 24-month model. Conclusions: Within the prespecified 24-month analytic window, conventional epithelium-off CXL was associated with stabilization, modest visual and tomographic improvement, and a concordant biomechanical stiffening signal. The results should be interpreted as cautious observational findings rather than definitive evidence of long-term stability, because of the small sample, eye-level analysis, absence of a control group, limited follow-up, and lack of formal repeatability testing.
