Table 6. Summary of visual acuity outcomes across corneal collagen cross-linking protocols in progressive keratoconus.

A-CXL: accelerated corneal cross-linking; BCVA: best corrected visual acuity; CDVA: corrected distance visual acuity; CXL: corneal collagen cross-linking; logMAR: logarithm of the minimum angle of resolution; NR: not reported; NS: not significant (p-value > 0.05); P: p-value; TE-CXL: transepithelial corneal cross-linking; UDVA: uncorrected distance visual acuity

Study	Protocol	UDVA Change	CDVA/BCVA Change	Timepoint
Wittig-Silva et al., 2014 [36]	Dresden	-0.15 ± 0.06 logMAR (p < 0.01)	-0.09 ± 0.03 logMAR ( p < 0.01)	3 years
Strmeňová et al., 2015 [34]	Dresden	NR	-0.048 logMAR (p < 0.01)	2 years
Bikbova et al., 2016 [40]	I-CXL	NS	-0.07 logMAR (p < 0.05)	2 years
Bikbova et al., 2016 [40]	Dresden	NS	-0.02 logMAR (p < 0.05)	2 years
Choi et al., 2017 [16]	Dresden	-0.09 ± 0.09 (p < 0.01)	NR	6 months
Choi et al., 2017 [16]	A-CXL	NS	NR	6 months
Stulting et al., 2018 [59]	TE-CXL	-0.146 logMAR (p < 0.0001)	-0.108 logMAR (p < 0.0001)	2 years
Kobashi et al., 2020 [12]	Dresden	NS	-0.02 logMAR (p < 0.0001)	1 year
Kobashi et al., 2020 [12]	A-CXL	NS	NS	1 year
Ferdi et al. (Registry), 2023 [2]	Dresden	-0.074 logMAR (p < 0.001)	NR	1 year
Ferdi et al. (Registry), 2023 [2]	Dresden	-0.138 logMAR (p < 0.001)	NR	5 years
Kandel et al. (Registry), 2024 [24]	Dresden	-0.204 logMAR (95% CI: -0.158 to -0.25)	-0.114 logMAR (95% CI: -0.07 to -0.156)	5 years
Kandel et al. (Registry), 2024 [24]	A-CXL	-0.098 logMAR (95% CI: -0.032 to -0.164)	-0.004 logMAR (95% CI: -0.044 to +0.05)	5 years