Effect of Riboflavin Solution With Hydroxypropyl Methylcellulose and Eyelid Speculum on Pachymetry Changes During Accelerated Collagen Crosslinking

Abstract

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/cm2 for 10 minutes; total energy dose was 5.4 J/cm2. 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.

The Intraoperative Corneal Pachymetry Changes during Accelerated Corneal Cross-linking in Progressive Keratoconus Patients with Thin Corneas

“…15,16 These studies reported that although both riboflavin solutions are iso-osmolar, RF-HPMC maintained a steady increase in the corneal thickness as opposed to RF-DX .The rate of increase in corneal thickness has been reported as approximately 10% in most publications (range:5% and 26%). 15,16,18,19 It has been shown that RF-HPMC creates a thicker preocular film due to its high viscosity, compared to RF-DX.…”

“…17,18 There are several studies showing that RF-HPMC has an increasing effect on corneal thickness. 15,16,18,19 These studies were not conducted thin corneas. In this study the changes of intra-operative thinnest corneal pachymetry (TCP) were evaluated during A-CXL protocol in thin keratoconic corneas.…”

“…Hence, although initial studies of CXL were performed with a riboflavin solution containing dextran, recent protocols for CXL have indicated the use of a riboflavin solution containing iso-osmolar hydroxypropyl methylcellulose (RF-HPMC) [ 17 , 18 ]. There are several studies showing that RF-HPMC has an increasing effect on corneal thickness [ 15 , 16 , 18 , 19 ]. These studies were not conducted thin corneas.…”