Evaluating Natural Progression of Keratoconus in Relation to Age, Gender, and Disease Severity at Presentation

Purpose: To investigate the natural progression of keratoconus (KC) with respect to age, gender, and disease severity at presentation. Methods: This study analyzed 949 eyes from 503 patients with KC followed at Eskişehir Osmangazi University and Istanbul University-Cerrahpaşa between 2009 and 2023. Patients with ≥1 year of follow-up with ≥3 Pentacam (Oculus, Inc) scans spaced ≥3 months apart were eligible. Progression was identified using Belin ABCD Progression Display using 2 baseline visits. Progression rates were analyzed according to age groups (≤18, >18 to ≤24, >24 to ≤30, >30 to <35, and ≥35 years), and KC severity was categorized based on the Topographic Keratoconus Classification (TKC) as subclinical, early-stage (TKC 1–2) and advanced-stage (TKC 3–4). Median time-to-progression (M-TTP) for progressive eyes was calculated with reference to the first presentation. Results: Keratoconus progression rates declined significantly with age ( P < 0.001); however, 44.3% of patients aged ≥35 years still showed progression, with the highest rate in those ≤18 years (86.4%). In patients ≥35 years, advanced-stage disease (TKC 3 and 4) markedly increased progression risk (OR: 10.5 [ P = 0.03], 20.0 [ P = 0.008], respectively). The shortest time-to-progression occurred in patients aged ≤18 years (M-TTP: 8.6 and 5.8 months in TKC 1–2 and 3–4, respectively), whereas in those ≥35 years, advanced-stage disease progressed significantly earlier than early-stage (M-TTP: 18.9 vs. 38.2 months). Conclusions: Although progression typically slows with age, 44% of patients ≥35 years still progressed. The shorter time-to-progression in younger individuals and in older patients with advanced disease at presentation highlight the need for close monitoring in both groups.