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Fuchs Endothelial Dystrophy

ROUTINE — Cornea

Symptoms

glare and blurred vision, typically worse on awakening

vision improves throughout the day as the cornea dehydrates

severe pain if epithelial bullae rupture

onset typically in the 5th–6th decades

Clinical Findings

Corneal guttae

  • pathognomonic central refractile "dewdrop" excrescences of descemet membrane
  • "beaten metal" or "orange peel" appearance on specular reflection
  • best visualized via retroillumination or non-contact specular microscopy

Endothelial & stromal signs

  • fine brown pigment dusting on the endothelial surface
  • descemet membrane folds and progressive central-to-peripheral stromal edema
  • hallmark pattern: morning worsening with afternoon improvement

Late-stage complications

  • epithelial microcystic edema and bullae
  • ruptured bullae causing severe pain, foreign body sensation, and recurrent erosions
  • subepithelial fibrosis and pannus in chronic cases (may limit visual potential post-ek)

Etiology

Pathophysiology

  • primary endothelial dystrophy with accelerated apoptotic cell loss
  • endothelial pump failure and stromal edema occur when density drops below ~500 cells/mm²
  • phacoemulsification significantly accelerates endothelial cell loss

Genetics & risk

  • female predominance (~3:1); typically autosomal dominant
  • tcf4 gene (ctg18.1 trinucleotide repeat) is the most common variant
  • col8a2 gene associated with rare early-onset disease

Red Flags

central corneal edema with bullae and acute pain

rapid progression in middle-aged patients (reconsider ice or ppmd)

concurrent cataract with borderline low endothelial cell counts

pseudophakic bullous keratopathy from marginal endothelium

Investigations

Clinical assessment

  • retroillumination to highlight guttae; fluorescein to identify ruptured bullae
  • iop measurement (address elevations to reduce edema)

Imaging & measurements

  • pachymetry: rising central corneal thickness signals impending pump failure
  • specular microscopy: quantifies endothelial cell density (limited in advanced edema)
  • corneal tomography: useful for monitoring progression

Treatment

Medical management

  • topical sodium chloride 5% drops (4x daily) and ointment (bedtime)
  • hairdryer method: gentle warm air at arm’s length each morning to assist dehydration
  • bandage contact lens and antibiotic prophylaxis for ruptured bullae

Surgical options

  • endothelial keratoplasty: dmek (preferred) or dsaek
  • descemet stripping only (dso): for milder forms of central disease
  • penetrating keratoplasty (pk): reserved for cases with deep stromal scarring

Surgical precautions

  • baseline specular microscopy is mandatory before any intraocular surgery
  • combined phaco-dmek indicated if cell count is <1000–1500 cells/mm²

Differential Diagnosis

  • postsurgical corneal edema
  • iridocorneal endothelial (ice) syndrome
  • posterior polymorphous corneal dystrophy (ppmd)

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