Factors influencing haze formation and corneal flattening af
The aim of the study was to determine associations of pachymetry, keratometry, and their changes with haze formation and corneal flattening after collagen cross-linking, and to analyse the relationship between postoperative haze and visual outcome.

Retrospective analysis was performed on 47 eyes of 47 patients with keratoconus using the Pentacam HR Scheimpflug camera before and 1, 3, 6 and 12 months after cross-linking. Corneal backscattered light values in grey scale unit were recorded in the anterior, center and posterior corneal layers and in four concentric rings. Surface area- and thickness-corrected grey scale unit values were assessed with an additional calculation.

--1 year after treatment, significant flattening was observed in maximum and mean keratometry readings.

--Significantly increased densitometry values were observed in three central rings compared to baseline.

--According to receiver operating characteristic curve, densitometry value of the anterior layer of 0–2 mm ring was the most characteristic parameter of densitometry changes after cross-linking.

--Changes in haze significantly correlated with preoperative maximum keratometry and with the changes in maximum keratometry.

--Changes in maximum keratometry correlated with preoperative maximum keratometry.

After cross-linking, more pronounced corneal flattening effect parallel with haze production can be detected in more advanced keratoconus, according to the findings. Postoperative corneal haze may decrease ultimate visual acuity despite a large reduction in keratometry.

Source: https://bmcophthalmol.biomedcentral.com/articles/10.1186/s12886-021-02066-3