Purpose: To assess corneal thickness changes with isotonic riboflavin (RF) solution with hydroxylpropyl methylcellulose in patients undergoing accelerated corneal collagen crosslinking (CXL) with and without an eyelid speculum.
Methods: Fifty-two eyes of 48 patients with progressive keratoconus were enrolled in this study. The patients in this study were divided into 2 groups: in group 1 an eyelid speculum was removed during 20-minute RF (0.1%) + hydroxylpropyl methylcellulose (Mediocross M; Avedro Inc, Waltham, MA) instillation, and in group 2 the eyelid speculum was retained in place during the entire CXL procedure. All patients underwent accelerated CXL using continuous ultraviolet-A (UVA) light exposure at 9 mW/cm for 10 minutes; total energy dose was 5.4 J/cm. Intraoperative ultrasound pachymetry measurements were obtained before and after epithelial removal, after RF loading, and after UVA light exposure at 5 and 10 minutes.
Results: The preoperative pachymetric measurements decreased in both groups after the removal of epithelium [group 1 (n = 26): -25 μm, group 2 (n = 26): -31 μm, P = 0.234]. Although the thinnest pachymetry significantly increased after soaking in both group 1 (52.26 μm) and group 2 (27.88 μm, P < 0.001), closure of the eyelids during RF instillation further increased the pachymetry readings (P < 0.0001). The corneal thickness remained stable in both groups during UVA irradiation at 5 and 10 minutes (P > 0.05).
Conclusions: Closure of the eyelids further induces corneal swelling that may offer an advantage to improve safety of the procedure particularly in thin corneas.