Objective: To quantify corneal light scatter and its relationship to vision after Descemet stripping with endothelial keratoplasty (DSEK). Methods: Eyes with Fuchs corneal dystrophy were examined before and 1, 3, 6, 12, and 24 months after DSEK. Outcome measures were high- and low-contrast visual acuity, contrast sensitivity, and forward light scatter. Corneal reflectivity (backscatter), expressed in scatter units (SU), was quantified using in vivo confocal microscopy. Results: Comparing 49 study eyes with 35 normal eyes, the mean (SD) corneal subepithelial layer was more reflective than normal before (2325 vs 1208 SU, P < .001) and through 24 months after DSEK (1760 SU, P < .001). Interface reflectivity remained higher than in normal stroma through 24 months (1228 vs 827  SU, P < .001). At 1 year, forward light scatter correlated with subepithelial reflectivity (r = 0.28, P = .01) but not interface reflectivity. Recipient age was correlated with improvement in subepithelial reflectivity at 12 months (r = -0.41, P = .01, 34 eyes) and 24 months (r = -0.36, P = .02, 26 eyes) after DSEK, and the improvement of sub-epithelial haze in eyes of participants aged 62 years or younger was correlated with improvement in forward light scatter at 12 months (r = 0.52, P = .008) and 24 months (r = 0.62, P = .004). Conclusions: In Fuchs corneal dystrophy, the corneal subepithelial region is a more important source of forward light scatter than the DSEK interface. Subepithelial haze improves more in younger patients and is associated with improvement in forward light scatter. Clinical Relevance: Visual function after DSEK is affected by residual haze in the anterior host cornea more so than the surgical interface. Haze, which likely is experienced as glare disability, improves after surgical intervention but improves more in younger patients.
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