Measurement of corneal changes after collagen crosslinking using a noninvasive ultrasound system

Abstract

Dr. Liu has filed a patent application for the general ultrasound technique used in the study. No other author has a financial or proprietary interest in any material or method mentioned.

Spatial distribution of corneal light scattering after corneal collagen crosslinking

“…1 There is agreement that CXL is a safe and effective treatment 1,2 ; however, its exact mechanisms of action are not completely understood. There is only indirect evidence for the presence of crosslinks in the cornea after CXL, such as increased stress-strain values, 3,4 increased resistance to collagenases in vitro, 5 increased shrinking temperature, and increased collagen fiber diameter. 6,7 Given the clinical success of CXL, it is frustrating that we do not have a reliable tool to assess the crosslinking effect directly or indirectly after treatment in the individual case.…”

The Efficacy of Corneal Cross-Linking Shows a Sudden Decrease with Very High Intensity UV Light and Short Treatment Time

“…The reported stiffness increase for the lower intensities (3-45 mW/cm 2 ) of a factor of 2.2 is similar to previously published data by Wollensak and colleagues, who measured a 1.8-fold increase. 5 Other studies investigating the stiffness increase according to the standard protocol with 3 mW/cm 2 used different measurement techniques like supersonic shear imaging, 18 ultrasound, 19 or comparing corneal geometry. 20 They found stiffness increases of 4.6, 1.04, and 1.6, respectively.…”

Determination of the Excimer Laser Ablation Rate in Previously Cross-linked Corneas

“…When compared to the ultrasound pachymeter, the optical coherence pachymetry is not affected by the increase of the speed of sound after CXL. 32 Thus, it was not nec- Correlations between cumulative ablation rates in the corneal collagen cross-linking-treated (CXL) group (n = 30) versus the riboflavin (ribo) group (n = 12) (in red), and the riboflavin group (n = 12) versus the control group (control, n = 30) (in blue). The decoupled effect of CXL on the ablation rate was a -11% reduction, whereas the decoupled effect of riboflavin soaked on ablation rate was a -5% reduction.…”