Short-Term Effects of Swimming Goggle Use on Anterior Segment Parameters in Patients with Keratoconus

Background and Objectives: Keratoconus is a bilateral but often asymmetric ectatic corneal disease characterized by progressive thinning, increased curvature, and conical shape of the cornea. Previous studies have reported that the use of swimming goggles in patients with keratoconus can lead to increased intraocular pressure (IOP) and a transient reduction in anterior chamber volume (ACV), potentially affecting anterior segment morphology. This study aimed to evaluate the short-term effects of periorbital pressure induced by swimming goggles on corneal parameters in keratoconic eyes. Materials and Methods: A total of 44 eyes of 44 patients (mean age: 26.1 ± 5.1 years) diagnosed with keratoconus Stage 1-4 according to the Amsler-Krumeich classification were included. Measurements were taken using a Pentacam^® Scheimpflug camera before swimming goggle application and immediately after 20 min of wear. The parameters assessed included keratometry values (K1, K2, Km, Kmax), central and thinnest corneal thickness, corneal volume within the 10 mm zone (CV10), ACV, anterior chamber depth (ACD), iridocorneal angle (ICA), and pupil diameter (PD). Results: No statistically significant changes were observed in keratometric values, central and thinnest corneal thickness, ACV, ACD, ICA, PD, or IOP (all p > 0.05). CV10 showed a small reduction following goggle wear (Δ = -0.18 mm³, corresponding to a 0.3% decrease), which was statistically significant in the unadjusted analysis (p = 0.008) but did not remain significant after correction for multiple comparisons (p for false discovery rate [FDR] = 0.10). Conclusions: Short-term swimming goggle use may induce subtle reductions in CV10 in keratoconic eyes, suggesting a potential biomechanical sensitivity to transient periocular pressure. Although the observed change in CV10 did not retain statistical significance after multiple-comparison correction, it may reflect an early physiological response in structurally compromised corneas. CV measurements could serve as exploratory indicators of mechanical responsiveness in keratoconus, warranting further investigation in larger controlled studies.