Evaluation Of Corneal Epithelial Thickness Map And Higher-Order Aberrations In Fuchs Endothelial Dystrophy With Subclinical Edema

In this study, the impact of subclinical corneal edema on epithelial thickness profile and higher-order aberration (HOA) parameters in Fuchs endothelial corneal dystrophy (FECD) was investigated and the findings were compared with those of healthy individuals.

Department of Ophthalmology, Bursa City Hospital, University of Health Sciences, Bursa, Türkiye.

84 eyes with FECD and 45 healthy control eyes were included. FECD eyes were classified according to the presence of subclinical corneal edema, defined by at least two Scheimpflug-Placido tomography findings (loss of parallel isopachs, displacement of the thinnest point, posterior surface depression). Demographic data, topographic and pachymetric parameters were recorded. Epithelial thickness (ET) was measured using anterior segment OCT in the central zone and eight peripheral regions (superior, inferior, nasal, temporal, superonasal [SN], superotemporal [ST], inferonasal [IN], and inferotemporal [IT]). Higher-order aberrations (HOA) were analyzed within 4-mm and 6-mm optical zones. Specular microscopy parameters were also documented.

There were no significant differences between the groups in terms of age or sex (p>0.05). FECD eyes with subclinical edema demonstrated significantly lower endothelial cell density compared to those without edema (p=0.006). Posterior corneal surface irregularity (KVb) was also significantly increased in eyes with subclinical edema (p<0.001). Central ET did not differ significantly; however, SN–IT ET difference was significantly lower compared to those without edema (6.2 ± 22.7 µm vs. 20.7 ± 20.4 µm; p<0.001). Total HOA and coma-2 values were significantly higher in FECD eyes with subclinical edema compared to both controls and FECD eyes without edema (p<0.05).

Subclinical corneal edema in FECD is associated with epithelial asymmetry alterations and increased optical aberrations. Combined epithelial mapping and HOA analysis may serve as objective markers of early functional deterioration and support timely surgical decision-making before clinically evident edema develops.