Visual and Topographic Outcomes of Corneal Collagen Cross Linking for Post LASIK Ectasia

Figures & data

Table 1 Changes in Refractive Measurements Within the Follow-Up Period following Corneal Collagen Cross Linking

	Baseline	Postoperative
		Month 6	Month 12	Month 18	Month 24
CDVA (logMAR)	0.22 ± 0.2	0.18 ± 0.14	0.14 ± 0.11	0.16 ± 0.22	0.16 ± 0.22
p value	–	0.646	0.169	0.254	0.254
Sphere (diopters)	−1.0 ± 1.7	−0.9 ± 2.0	−0.6 ± 1.7	−0.9 ± 2.1	−1.0 ± 2.4
p value	–	0.512	0.345	0.522	0.917
Cylinder (diopters)	−2.0 ± 1.1	−2.1 ± 1.0	−2.1 ± 1.0	−2.1 ± 1.1	−2.0 ± 1.3
p value	–	0.751	0.751	0.744	0.842
SE (diopters)	−2.0 ± 1.8	−2.0 ± 2.1	−1.7 ± 1.9	−1.9 ± 2.4	−2.0 ± 2.7
p value	–	0.842	0.159	0.428	0.876

Abbreviations: CDVA, corrected distant visual acuity; SE, spherical equivalent.

Figure 1 Corrected distant visual acuity at month 24 after corneal collagen cross linking.

Figure 2 Change in spherical equivalent at month 24 compared to baseline after corneal collagen cross linking.

Table 2 Changes in Topographic Measurements Within the Follow-Up Period Following Corneal Collagen Cross Linking

	Baseline	Postoperative
		Month 6	Month 12	Month 18	Month 24
Kmean (diopters)	42.2 ± 3.3	42.2 ± 2.8	42.4 ± 2.7	42.5 ± 3.7	42.5 ± 3.8
p value	–	0.992	0.862	0.819	0.818
Topographic Cylinder (diopters)	2.5 ± 1.6	2.5 ± 1.5	2.4 ± 1.4	2.3 ± 1.4	2.3 ± 1.4
p value	–	0.915	0.626	0.332	0.326
Kmax (diopters)	48.6 ± 4.6	48.5 ± 3.5	48.0 ± 3.4	47.5 ± 4.0	47.4 ± 4.1
p value	–	0.822	0.421	0.363	0.347
CCT (microns)	457.6 ± 48.4	447.3 ± 55.9	442.6 ± 56.9	439.6 ± 57.9	438.2 ± 59.3
p value	–	0.041*	0.022*	0.009*	0.003*

Notes: *p < 0.05, statistically significant difference compared to baseline.

Abbreviations: Kmean, mean keratometry; Kmax, maximum keratometry; CCT, central corneal thickness.

Figure 3 Change in maximum keratometry (Kmax) at month 24 compared to baseline after corneal collagen cross linking.

Figure 4 Change in pachymetry at month 24 compared to baseline after corneal collagen cross linking.