Impact of corneal guttata severity on visual quality in early-stage Fuchs' endothelial corneal dystrophy

To quantitatively evaluate the relationship between corneal guttata and visual quality in early-stage Fuchs' endothelial corneal dystrophy (FECD) without corneal edema.

Twenty eyes from twenty patients with FECD were enrolled at Tianjin Medical University Eye Hospital. Guttata were classified into three grades, and objective visual quality parameters, including objective scatter index (OSI), modulation transfer function cutoff frequency (MTF cutoff), Strehl ratio, and predicted visual acuity at 100%, 20%, and 9% contrast levels (OV100%, OV20%, OV9%), were measured using Optical Quality Analysis System II (OQAS-II). Corneal densitometry, as an indicator of backward light scatter, was assessed using a corneal Scheimpflug tomography (Pentacam HR), including anterior and posterior corneal layers. Best-corrected visual acuity (BCVA) was recorded in logMAR. Differences among guttata grades were analyzed using Kruskal-Wallis tests followed by Mann-Whitney U tests with Bonferroni correction. Correlations between guttata and visual quality were analyzed using Spearman's correlation.

Guttata severity correlated positively with OSI(0.822, P<0.001) and negatively with MTF cutoff, Strehl ratio, OV100%, and OV20%(-0.750, -0.554, 0.744, 0.567, separately, P < 0.05), while correlation with OV9% was weak(0.479, P = 0.033). No significant correlations were observed between guttata severity and either anterior or posterior corneal densitometry. BCVA showed no correlation with guttata severity or OSI but correlated moderately with MTF cutoff and Strehl ratio (-0.520, -0.551, separately, P < 0.05).

In early-stage FECD, patients' visual quality begins to decline as the density and confluence of guttata increase despite the absence of visual acuity loss or corneal edema. Quantitative guttata assessment combined with objective visual quality inspection provides a more sensitive indicator for early functional impairment and may guide earlier clinical intervention.