Outcomes of Corneal Topography among Progressive Keratoconus Patients 12 months following Corneal Collagen Cross-Linking

Figures & data

Table 1 Demographical Characteristics of Cases

Variables		Frequency(%)/Mean (SD)
Gender	Female	12 (41.4%)
	Male	17 (58.6%)
Age		27.76 (4.206)
Degree of myopia		2.24 (2.515)
Degree of manifest astigmatism		3.16 (1.95)
Grade 1 Amsler-Krumeich classification		10 (34.48%)
Grade 2 Amsler-Krumeich classification		8 (27.59%)
Grade 3 Amsler-Krumeich classification		11 (37.93%)

Table 2 Prevalence of Topographical Characteristics

Variables	Pre-CXL	Post-CXL
Normal corneal thickness	6 (20.7%)	8 (27.6%)
Borderline corneal thickness	4 (13.8%)	5 (17.2%)
Thin cornea	19 (65.5%)	16 (55.2%)
Clinically significant astigmatism	28 (96.6%)	26 (89.7%)
High risk front elevation in apex	28 (96.6%)	28 (96.6%)
High risk back elevation in apex	23 (79.3%)	23 (79.3%)

Table 3 Wilcoxon Signed Rank Test Applied for Topography Parameters Before and After CXL

Topographical Parameters	Pre-CXL Mean Value (SD)	Post-CXL Mean Value (SD)	Pre-CXL Median Value (Range)	Post-CXL Median Value (Range)	Z	Lower–Upper 95% CI	P-Value
Cornea thickness	473.45 (38)	465.72 (41.78)	463 (142)	471 (152)	−1.936	0.048–0.057	0.053
Degree of topographic astigmatism (D)	3.37 (2.25)	3.67 (2.61)	2.5 (9.6)	3 (11.6)	−1.696	0.085–0.096	0.09
Maximum keratometry (K-max) (D)	55.53 (7.99)	55.43 (8.43)	54.3 (27.9)	51.8 (30.1)	−0.529	0.599–0.619	0.597
Inferior minus superior value (I-S value)	6.51 (6.22)	6.134 (6.15)	4.5 (23.4)	3.7 (24.1)	−1.146	0.250 –0.267	0.252
Front elevation in apex (μm)	33.90 (20.13)	36.10 (21.09)	33 (94)	38 (100)	−2.792	0.003–0.006	0.005
Back elevation in apex (μm)	68.48 (35.66)	69.90 (35.89)	67 (161)	67 (166)	−0.934	0.343–0.366	0.35

Figure 1 Forrest blot demonstrates a multivariable logistic regression model for postoperative changes in corneal topography parameters for advanced stage KC compared to mild stage of KC.