[Single-center analysis of 20-year trends in surgical approaches and timing for keratoconus]

Objective: To explore the changing trends in surgical approaches and timing selection for patients with keratoconus in a single center from 2004 to 2023. Methods: A retrospective case series study was conducted. Clinical data of patients diagnosed with keratoconus and who underwent surgical treatment at the Eye Hospital of Shandong First Medical University from January 2004 to December 2023 were collected. Statistical analysis was performed on the distribution of surgical procedures for keratoconus treatment, including femtosecond laser-assisted penetrating keratoplasty (FL-PK), conventional penetrating keratoplasty (C-PK), deep anterior lamellar keratoplasty (DALK), femtosecond laser-assisted deep anterior lamellar keratoplasty (FL-DALK), epikeratophakia (EP), thermokeratoplasty followed by lamellar keratoplasty (TK-LK), corneal cross-linking (CXL), and femtosecond laser-assisted minimally invasive lamellar keratoplasty (FL-MILK), as well as the clinical staging of keratoconus at the time of surgery, to evaluate the changing trends in surgical approaches and timing selection over time. Nonparametric tests were used for comparisons between groups and for gender composition across different surgical types, and the Mann-Kendall trend test was used to analyze the temporal growth trend of surgical volume. Results: A total of 1 497 patients (2 093 eyes) with keratoconus were included, including 1 132 males and 365 females, with a median age of 32.5 years at the time of surgery. The number of surgeries increased from 28 cases in 2004 to 335 cases in 2021 (an 11.0-fold increase, τ=0.784, P<0.001). C-PK decreased from 36 eyes (22.2%) in 2004-2008 to 13 eyes (1.0%) in 2019-2023; the overall proportion of lamellar keratoplasty (LK) decreased from 126 eyes (77.8%) in 2004-2008 to 626 eyes (49.2%) in 2019-2023; DALK decreased from 88 eyes (54.3%) in 2004-2008 to 64 eyes (5.0%) in 2019-2023; FL-DALK increased from 0 eyes in 2004-2008 to 261 eyes (20.5%) in 2019-2023. FL-MILK was first applied in 2017 and increased to 216 eyes (17.0%) in 2019-2023. Femtosecond laser-assisted LK accounted for 72.1% (721/1 000) of all LK procedures during 2014-2023 and dominated corneal transplantation in 2019-2023. After CXL was introduced in 2016, its volume increased to 632 eyes (49.6%) in 2019-2023; the combined proportion of FL-MILK and CXL accounted for 66.6% of the total surgical volume (1 273 eyes) in 2019-2023. The proportion of surgeries for stage Ⅰ and Ⅱ patients increased from 23 eyes (18.5%) in 2004-2008 to 1 013 eyes (79.6%) in 2019-2023, while that for stage Ⅲ and Ⅳ patients decreased from 139 eyes (81.5%) in 2004-2008 to 260 eyes (20.4%) in 2019-2023. There were statistically significant differences in surgical approaches for the same keratoconus stage between 2004-2008 and 2019-2023 (P<0.001). Conclusions: Over the past 20 years, the main surgical approaches for keratoconus have shifted from PK to less invasive DALK, MILK, and CXL. The proportion of more precise femtosecond laser-assisted corneal transplantation surgeries has continuously increased.