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. 2015 Apr-Jun;22(2):212-9.
doi: 10.4103/0974-9233.151877.

Changes in corneal topography and biomechanical properties after collagen cross linking for keratoconus: 1-year results

Mohammadreza Sedaghat  1 , Mansooreh Bagheri  2 , Shahri Ghavami  1 , Shahram Bamdad  2
Affiliations

Changes in corneal topography and biomechanical properties after collagen cross linking for keratoconus: 1-year results

Mohammadreza Sedaghat et al. Middle East Afr J Ophthalmol. 2015 Apr-Jun.

Abstract

Purpose: To evaluate changes in corneal topography and biomechanical properties after collagen cross-linking (CXL) for progressive keratoconus.

Patients and methods: Collagen cross-linking was performed on 97 eyes. We assessed uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA). Corneal topography indices were evaluated using placido disc topography, scanning slit anterior topography (Orbscan II), and rotating Scheimpflug topography (Pentacam). Specular microscopy and corneal biomechanics were evaluated.

Results: A 1-year-follow-up results revealed that UCVA improved from 0.31 to 0.45 and BCVA changed from 0.78 to 0.84 (P < 0.001). The mean of average keratometry value decreased from 49.62 to 47.95 D (P < 0.001). Astigmatism decreased from 4.84 to 4.24 D (P < 0.001). Apex corneal thickness decreased from 458.11 to 444.46 μm. Corneal volume decreased from 56.66 to 55.97 mm(3) (P < 0.001). Posterior best fit sphere increased from 55.50 to 46.03 mm (P = 0.025). Posterior elevation increased from 99.2 to 112.22 μm (P < 0.001). Average progressive index increased from 2.26 to 2.56 (P < 0.001). A nonsignificant decrease was observed in mean endothelial count from 2996 to 2928 cell/mm(2) (P = 0.190). Endothelial coefficient of variation (CV) increased nonsignificantly from 18.26 to 20.29 (P = 0.112). Corneal hysteresis changed from 8.18 to 8.36 (P = 0.552) and corneal resistance factor increased from 6.98 to 7.21 (P = 0.202), so these changes were not significant.

Conclusion: Visual acuity and K values improved after CXL. In spite of the nonsignificant increase in endothelial cell count and increase in the CV, CLX seems to be a safe treatment for keratoconus. Further studies with larger sample sizes and longer follow-up periods are recommended.

Keywords: Biomechanics; Collagen Crosslinking; Corneal; Keratoconus; Specular Microscopy; Topography.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Scheimpflug topography from a patient with progressive keratoconus shows that anterior surface keratometry in steep and flat axes decreased over 6-month follow-up. Posterior surface keratometry remained stable in flat and mean axis and showed minimal increased in steep axis
See this image and copyright information in PMC

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