Anterior and posterior corneal changes after crosslinking for keratoconus

TY - JOUR

T1 - Anterior and posterior corneal changes after crosslinking for keratoconus

AU - Steinberg, Johannes

AU - Ahmadiyar, Mariam

AU - Rost, Anika

AU - Frings, Andreas

AU - Filev, Filip

AU - Katz, Toam

AU - Linke, Stephan J

PY - 2014

Y1 - 2014

N2 - PURPOSE: To evaluate anterior and posterior changes in corneal topography and tomography after corneal crosslinking (CXL) in eyes with progressive keratoconus.METHODS: Scheimpflug analyses (Pentacam, Oculus) of 20 eyes with keratoconus performed before and after corneal CXL were included into retrospective analysis. Mean follow-up was 2 years. Changes in topographic, tomographic, and pachymetric values were statistically analyzed applying analysis of variance. Further, the distance and direction between the anterior maximum keratometry (K(max)) and the apex as well as the distance and direction between the thinnest point in corneal thickness (TPCT) and the corneal apex before and after CXL were studied.RESULTS: Two years after CXL, a statistically significant reduction of the keratometry at the flat meridian (-0.8 D, p < 0.05), the steep meridian (-0.5 D, p < 0.05), the "index of surface variance" (-5.3, p < 0.05), and the "index of highest decentration" (-0.05, p < 0.05) could be demonstrated. While the elevation of the front surface at the apex decreased (-1.5 μm, p < 0.05), the back elevation at the apex (+2 μm, p < 0.05) increased. Although not reaching statistical significance, the maximum front and back elevation demonstrated the same trend; while maximum front elevation data remained stable (-0.3 μm, p = 0.961), maximum back elevation data increased (+6.7 μm, p = 0.122). The corneal thickness at the apex (-22.0 μm, p < 0.001) and the TPCT (-20.0 μm, p < 0.001) decreased, leading to an increase of the corneal thickness progression from the corneal apex to the periphery. The position of K(max) and TPCT remained stable.CONCLUSIONS: Corneal topography proved to be useful in the follow-up for CXL because of significant changes in the keratometry. Increasing posterior elevation values, despite a stabilized anterior corneal surface, might be a sign of ongoing ectatic changes in the posterior corneal surface.

AB - PURPOSE: To evaluate anterior and posterior changes in corneal topography and tomography after corneal crosslinking (CXL) in eyes with progressive keratoconus.METHODS: Scheimpflug analyses (Pentacam, Oculus) of 20 eyes with keratoconus performed before and after corneal CXL were included into retrospective analysis. Mean follow-up was 2 years. Changes in topographic, tomographic, and pachymetric values were statistically analyzed applying analysis of variance. Further, the distance and direction between the anterior maximum keratometry (K(max)) and the apex as well as the distance and direction between the thinnest point in corneal thickness (TPCT) and the corneal apex before and after CXL were studied.RESULTS: Two years after CXL, a statistically significant reduction of the keratometry at the flat meridian (-0.8 D, p < 0.05), the steep meridian (-0.5 D, p < 0.05), the "index of surface variance" (-5.3, p < 0.05), and the "index of highest decentration" (-0.05, p < 0.05) could be demonstrated. While the elevation of the front surface at the apex decreased (-1.5 μm, p < 0.05), the back elevation at the apex (+2 μm, p < 0.05) increased. Although not reaching statistical significance, the maximum front and back elevation demonstrated the same trend; while maximum front elevation data remained stable (-0.3 μm, p = 0.961), maximum back elevation data increased (+6.7 μm, p = 0.122). The corneal thickness at the apex (-22.0 μm, p < 0.001) and the TPCT (-20.0 μm, p < 0.001) decreased, leading to an increase of the corneal thickness progression from the corneal apex to the periphery. The position of K(max) and TPCT remained stable.CONCLUSIONS: Corneal topography proved to be useful in the follow-up for CXL because of significant changes in the keratometry. Increasing posterior elevation values, despite a stabilized anterior corneal surface, might be a sign of ongoing ectatic changes in the posterior corneal surface.

KW - Adolescent

KW - Adult

KW - Collagen

KW - Cornea

KW - Corneal Pachymetry

KW - Corneal Stroma

KW - Corneal Topography

KW - Cross-Linking Reagents

KW - Female

KW - Humans

KW - Keratoconus

KW - Male

KW - Middle Aged

KW - Photochemotherapy

KW - Photosensitizing Agents

KW - Retrospective Studies

KW - Riboflavin

KW - Tomography, Optical Coherence

KW - Ultraviolet Rays

KW - Young Adult

U2 - 10.1097/OPX.0000000000000141

DO - 10.1097/OPX.0000000000000141

M3 - SCORING: Journal article

C2 - 24445720

VL - 91

SP - 178

EP - 186

JO - OPTOMETRY VISION SCI

JF - OPTOMETRY VISION SCI

SN - 1040-5488

IS - 2

ER -