Corneal stromal demarcation line after collagen cross-linking in corneal ectatic diseases: a review of the literature

Abstract

Collagen cross-linking (CXL) is a relatively new conservative approach for progressive corneal ectasia, which is able to strengthen corneal tissue reforming new covalent bonds. Subjective and objective results following this method seem to be promising. In recent years, newer CXL protocols have been developed to perform more effective and less invasive procedures. The increasing diffusion of CXL in the corneal ectatic disease has increased the need to have actual indices regarding the efficacy of the treatment. Evaluation of demarcation line (DL), a transition zone between the cross-linked anterior corneal stroma and the untreated posterior corneal stroma, is considered a measurement of the depth of CXL treatment into the stroma. Some evidence in the literature emphasize that DL could be a measure of effectiveness of the CXL. On the contrary, some authors believe that the “the deeper, the better” principle is rather a simplistic approach for interpreting the clinical importance of the corneal stromal DL.

Standard cross‐linking versus photorefractive keratectomy combined with accelerated cross‐linking for keratoconus management: a comparative study

“…Brittingham et al (2014) stated that AXL has negative effect on the demarcation line at 12 months after cross-linking with increased steepening of the anterior corneal surface. Spadea et al (2016) reported that the depth of the stromal demarcation line after standard CXL ranged from 300 to 500 lm while in pulsed AXL about 210 lm and only about 150 lm in continuous mode AXL. Mazzotta et al evaluated the qualitative micromorphological postoperative outcomes of the cornea following AXL using confocal microscopy.…”

“…Spadea et al. () reported that the depth of the stromal demarcation line after standard CXL ranged from 300 to 500 μ m while in pulsed AXL about 210 μ m and only about 150 μ m in continuous mode AXL. Mazzotta et al.…”

Superior outcome of corneal collagen cross‐linking using riboflavin with methylcellulose than riboflavin with dextran as the main supplement

“…The concept ‘the deeper, the better’ in evaluating efficacy in CXL treatment has been discussed in a recent paper (Spadea et al. ). The present study supports this concept.…”

Corneal refractive surgery combined with simultaneous corneal cross‐linking: Indications, protocols and clinical outcomes—A review

“…[64][65][66][67][68] Demarcation line is a transition zone between the crosslinked anterior corneal stroma and the untreated posterior corneal stroma. [64][65][66][67][68] Demarcation line is a transition zone between the crosslinked anterior corneal stroma and the untreated posterior corneal stroma.…”

“…There is evidence in the literature emphasizing that demarcation line could be a measure of effectiveness of CXL. [64][65][66][67][68] Demarcation line is a transition zone between the crosslinked anterior corneal stroma and the untreated posterior corneal stroma. It is considered as a marker of depth of CXL treatment into the stroma.…”