Clinical Phenotypes of Fuchs Endothelial Corneal Dystrophy (FECD), Disease Progression, Differential Diagnosis, and Medical Therapy

Abstract

The hallmark of Fuchs endothelial corneal dystrophy (FECD) is corneal “guttae”. However, some eyes with cornea guttata will never progress to FECD! Thus, we should talk about FECD not before endothelial decompensation = “swelling” = “increased central corneal thickness” does occur. Early-onset FECD with well-defined genetic cause must be differentiated from late-onset FECD. Differential diagnosis to other endothelial dystrophies is typically an easy task. FECD must be differentiated from pseudoexfoliation (PEX) keratopathy with respect to incidence of secondary glaucoma, therapeutic necessities, and prognosis of corneal transplantation. Concerning microsurgery, FECD is a friend, while PEX keratopathy is a challenge. Thus, differentiation to PEX keratopathy is not just an academic problem! Progression of FECD cannot be defined via endothelial cell counts, because numbers are notoriously measured wrong. Neither manual nor automated endothelial cell count will give valid results in case of unevenly distributed guttae. Progression should be defined via best-corrected visual acuity (worse morning vs afternoon), glare, corneal thickness profile (tomography), and cell morphology. For many decades, symptomatic medical therapy consisted of unpreserved hyperosmolar (5 %) sodium chloride solution. Preclinical causative approaches include lithium, N-acetylcysteine, and the ROCK inhibitor.