Purpose: To evaluate the relationship between subjective (slit lamp examination [SLE]) and objective (densitometry) measurements of corneal haze after accelerated corneal crosslinking (aCXL), assess the relationship between densitometry and corrected distance visual acuity (CDVA), and determine the effect of baseline characteristics on densitometry after aCXL in eyes with progressive keratoconus and other ectasias.
Setting: Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada.
Design: Retrospective analysis of a prospective interventional cohort study.
Methods: Scheimpflug-derived corneal densitometry, CDVA, maximum keratometry (Kmax ), and central corneal thickness were measured preoperatively and up to 1 year after aCXL, and post-operative haze was estimated with SLE (n = 483 eyes). A random effect model was used to examine the relationship between post-operative subjective haze with SLE and densitometry. Linear mixed models were used to examine the relationship between densitometry, pre-operative baseline characteristics, and CDVA.
Results: There was a significant association between subjective haze with SLE and densitometry (p < 0.001). There was a significant relationship between CDVA and densitometry: for every 10 GSUs of increased densitometry in the 0-2 mm zone, CDVA worsened by approximately half a Snellen line (p < 0.001). Age and pre-operative Kmax were significant predictors of densitometry. For every 10 years of age, densitometry increased by 0.68 GSUs (95% CI [0.27 to 1.07], p < 0.001). For every 10 D of increased preoperative Kmax , densitometry increased by 0.69 GSUs (95% CI [0.41 to 0.98], p < 0.001).
Conclusions: Subjective haze after aCXL estimated with SLE, is significantly associated with densitometry. Increased densitometry after aCXL is associated with a reduction in CDVA.
Keywords: accelerated crosslinking; corneal crosslinking; corneal densitometry; ectasia; haze; keratoconus.
© 2023 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.