Comparison of Corneal Biomechanical Properties and Corneal Tomography Between Customized and Accelerated Corneal Crosslinking in Eyes with Keratoconus

Abstract

Purpose: To compare the changes in corneal biomechanical properties and corneal tomography between transepithelial customized corneal crosslinking (C-CXL) and epithelium-off accelerated corneal crosslinking (A-CXL) in eyes with keratoconus.Methods: Twenty eyes in 20 consecutive patients who underwent C-CXL (C-CXL group) and 20 eyes in 20 patients who underwent A-CXL (A-CXL group) were included in this retrospective comparative study. The corneal biomechanical properties were analyzed using a Scheimpflug-based tonometer, and all corneas were examined by anterior segment optical coherence tomography (AS-OCT) before and 3 months after surgery. The corneal biomechanical parameters analyzed were the maximum inverse radius, deformation amplitude (DA) ratio max (2 mm), stiffness parameter at applanation 1, and integrated radius. The AS-OCT parameters analyzed included average keratometry, corneal astigmatism, maximum keratometry reading (Kmax), higher-order irregularity, and asymmetry.Results: In the C-CXL group, there were significant improvements in biomechanical parameters, including the maximum inverse radius, the DA ratio max (2 mm), and the integrated radius after surgery (P = 0.037, P = 0.002, and P = 0.003, respectively). In the C-CXL group, there was a significant decrease in the Kmax, higher-order irregularity, and asymmetry components (P = 0.014, P = 0.008, and P = 0.016, respectively). The biomechanical properties and AS-OCT parameters did not change significantly in the A-CXL group after surgery. According to multiple regression analyses, C-CXL had a greater effect than A-CXL in improving the maximum inverse radius, DA ratio max (2 mm), integrated radius, Kmax, asymmetry component, and higher-order irregularity component.Conclusions: C-CXL might improve the biomechanical properties and irregular shape of the cornea from the early postoperative period to a greater extent than A-CXL.

Update on corneal collagen crosslinking for ectasia

“…It claims an inverse relationship between the applied intensity and illumination time [11]. A popular accelerated protocol is performed with riboflavin 0.1% instilled at 2-min intervals for 10 min, then UVA irradiation is performed at 18 mW/cm 2 for 5 min [12 ▪ ]. During UV irradiation, riboflavin is added after 2 min and 30 s.…”

Evaluation of the Relationship Between the Changes in the Corneal Biomechanical Properties and Changes in the Anterior Segment OCT Parameters Following Customized Corneal Cross-Linking

“…Many studies have reported changes in corneal biomechanical properties after CXL. 14 , 15 , 38–40 Furthermore, studies using the Schiøtz tonometer have reported that the lower the corneal stiffness before CXL, the greater the improvement in corneal stiffness after CXL. 41 Future studies using SBT are needed to determine whether the effect of CXL is related to corneal stiffness before CXL surgery.…”

“… 13 Previous literature showed that C-CXL improved biomechanical properties and corneal shape more than A-CXL. 14 There are many reports on the effectiveness of CXL, but most of them focus on the flattening of the corneal shape. However, it is desirable to measure and evaluate the effects of CXL based on corneal biomechanical properties.…”

The levels of hypoxia- and angiogenesis-related regulators and matrix metalloproteinase 9 activity in tear fluid of patients with non-penetrating ocular traumas

“…Ulcerations and other degenerative processes in the wounded cornea may cause dramatic complications of ocular lesions, leading to difficulties in wound management and possible loss of vision. Thus, understanding pathophysiological processes that underlie corneal epithelial lesions or eye traumas is still an important unresolved task for applied ophthalmology [19].…”