Fuchs endothelial corneal dystrophy (FECD) is the most frequent form of posterior corneal dystrophy (see this term) and is characterized by excrescences on a thickened Descemet membrane (corneal guttae), generalized corneal edema, with gradually decreased visual acuity.
The exact prevalence is not known but extreme geographical variability has been reported. FECD is the most prevalent corneal dystrophy in the USA but has been found to be uncommon in Saudi Arabia and in Singaporean Chinese, and very rare in Japan.
The condition is more common and more severe in women (sex ratio 3-4:1). Patients with FECD are initially asymptomatic. Clinical onset is generally in the 5th or 6th decade of life. Discomfort and painful episodes of recurrent corneal erosions occur, along with gradually developing opacification leading to hazy vision. Over time, discomfort may diminish but severe impairment of visual acuity, and even blindness in elderly patients, may be observed. The clinical course often spans 10 to 20 years. The condition is often associated with cataracts. Microbial keratitis and corneal neovascularization are extremely rare complications. Stromal edema produces a blue-gray haze anterior to Descemet membrane followed by eventual thickening of the entire corneal stroma and development of a ground-glass corneal appearance.
The etiology of FECD is unknown, but it seems to be a heterogenous complex inherited disorder caused by the interaction of genetic and environmental factors. Mutations in certain genes have been reported in some cases of FECD. Rare cases of early onset have been related to mutations in the COL8A2 gene (1p34.2-p32.3). Heterozygous mutation in the SLC4A11 gene (20p12) has been reported in some late-onset cases of FECD. Other cases have been mapped to chromosomes 13 (13pter-3q12.13) and 18 (18q21.2- q21.32)(TCF4) and to ZEB1 (10p11.22).
Although most patients with FECD lack a positive family history, blood relatives sometimes manifest corneal guttae. FECD may also affect siblings and two or more successive generations, apparently as an autosomal dominant disorder having incomplete penetrance, but a simple autosomal dominant pattern is unlikely.
Most patients with FECD ultimately require a penetrating keratoplasty or a procedure for repairing the posterior surface of the cornea, such as a deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), or Descemet stripping automated endothelial keratoplasty (DSAEK). Visual acuity is markedly improved after a penetrating keratoplasty, DSEK or DSAEK.
Last update: May 2012