Evaluation of Corneal Stromal Demarcation Line Depth Following Standard and a Modified-Accelerated Collagen Cross-linking Protocol

• Published in: American journal of ophthalmology 2014-10, Vol.158 (4), p.671-675.e1
• Main Authors: Kymionis, George D, Tsoulnaras, Konstantinos I, Grentzelos, Michael A, Liakopoulos, Dimitrios A, Tsakalis, Nikolaos G, Blazaki, Styliani V, Paraskevopoulos, Theodoros A, Tsilimbaris, Miltiadis K
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Collagen; Collagen - metabolism; Contact lenses; Corneal Pachymetry; Corneal Stroma - metabolism; Corneal Stroma - pathology; Cross-Linking Reagents - therapeutic use; Female; Humans; Keratoconus - drug therapy; Keratoconus - metabolism; Keratoconus - pathology; Laboratories; Male; Middle Aged; Ophthalmology; Patients; Photosensitizing Agents - therapeutic use; Prospective Studies; Riboflavin - therapeutic use; Tomography; Tomography, Optical Coherence; Ultraviolet Rays; Vitamin B; Young Adult
• ISSN: 0002-9394; 1879-1891
• DOI: 10.1016/j.ajo.2014.07.005

Purpose To compare the corneal stromal demarcation line depth using anterior segment optical coherence tomography (AS-OCT) after corneal collagen cross-linking (CXL) using 2 different treatment protocols: the standard Dresden protocol (30 minutes with 3 mW/cm2 ) and a modified-accelerated protocol (14 minutes with 9 mW/cm2 ). Design Prospective, comparative study. Methods Forty-three keratoconic patients (52 eyes) were enrolled. All patients underwent CXL using the same high-intensity ultraviolet-A (UV-A) irradiation device. Twenty-six eyes were treated for 30 minutes with 3 mW/cm2 according to the standard Dresden protocol (Group 1), while 26 eyes were treated with a novel modified-accelerated CXL protocol for 14 minutes with 9 mW/cm2 of UV-A irradiation intensity (Group 2). One month postoperatively, corneal stromal demarcation line depth was measured by 2 independent observers using AS-OCT. Results Corneal stromal demarcation line depth was assessed with no significant difference between observer measurements for both groups ( P  = .676 for Group 1 and P  = .566 for Group 2). Mean corneal stromal demarcation line depth was 337.00 ± 46.46 μm for Group 1 and 322.91 ± 48.28 μm for Group 2. There was no statistically significant difference ( P  = .243) in the corneal stromal demarcation line depth between the 2 groups. Conclusions Corneal stromal demarcation line depth using UV-A with 3 mW/cm2 for 30 minutes and 9 mW/cm2 for 14 minutes was similar. A modified-accelerated protocol of 14 minutes of CXL provided the same treatment depth as the classic Dresden protocol.