Fuchs Endothelial Dystrophy: Pathogenesis and Management

■ Fuchs endothelial dystrophy (FED) is a progressive disorder of the corneal endothelium with accumulation of focal excrescences called guttae and thickening of Descemet’s membrane, leading to stromal edema and loss of vision ■ The inheritance of FED is autosomal dominant, with modifiers such as increased prevalence in the elderly and in females ■ Corneal endothelial cells are the major “pump” cells of the cornea that allow for stromal clarity ■ Descemet’s membrane is grossly thickened in FED, with accumulation of abnormal wide-spaced collagen and numerous guttae ■ Corneal endothelial cells in end-stage FED are reduced in number and appear attenuated, causing progressive stromal edema ■ Symptoms include visual blurring predominantly in the morning with stromal and epithelial edema from relatively low tear film osmolality ■ FED can be classified into four stages, from early signs of guttae formation to end-stage subepithelial scarring ■ Diagnosis is made by biomicroscopic examination; other modalities, such as corneal pachymetry, confocal microscopy, and specular microscopy can be used in conjunction ■ Exact pathogenesis is unknown, but possible factors include endothelial cell apoptosis, sex hormones, inflammation, and aqueous humor flow and composition ■ Mutations in collagen VIII, a major component of Descemet’s membrane secreted by endothelial cells, have been linked to FED ■ Medical management includes topical hypertonic saline, the use of a hairdryer to dehydrate the precorneal tear film, and therapeutic soft contact lenses ■ Definitive treatment is surgical in the form of penetrating keratoplasty (PK) ■ New surgical modalities such as various forms of endothelial keratoplasty are gaining popularity in the treatment of FED ■ DLEK and DSEK avoid the surgical complications of PK, such as wound dehiscence, suture breakage/infection and high postoperative astigmatism ■ Future directions in the treatment of FED include gene or cell therapy and continued advances in endothelial keratoplasty Chapter 1