What are the recommendations for managing Fuchs' Endothelial Dystrophy and halting its progression?

Management of Fuchs' Endothelial Dystrophy and Halting Progression

For Fuchs' Endothelial Dystrophy, endothelial keratoplasty (EK) has supplanted penetrating keratoplasty (PK) as the procedure of choice for endothelial failure, as patients achieve more rapid visual rehabilitation, reduced risk of immune-mediated rejection, and less induced astigmatism. 1

Diagnosis and Monitoring

• Endothelial function is best evaluated by clinical history and examination with slit-lamp biomicroscopy, looking for characteristic endothelial guttae 1
• When diffuse endothelial guttae are present, serial pachymetric measurements and tomographic evaluation help monitor endothelial function 1
• Corneal tomography revealing irregular isopachs, nasal displacement of the thinnest cornea, and posterior depression may help predict Fuchs dystrophy patients at greater risk of endothelial decompensation 1
• Specular microscopy is not a direct measure of endothelial function or functional reserve 1

Non-Surgical Management Options

• Hyperosmotic agents (sodium chloride 5% drops or ointment) are recommended as first-line treatment to temporarily reduce corneal edema through osmotic effect 2
• Low humidity and modest air movement may improve vision in patients with endothelial dysfunction 1, 2
• Hairdryer therapy (directing warm air at the eyes from arm's length) can temporarily reduce epithelial edema 2
• Avoidance of unshielded fluorescent lighting or reflective surfaces may help reduce disabling glare that can significantly impact daily activities 1, 2
• Bandage contact lenses can alleviate pain and discomfort from microcystic or bullous epithelial disease 2
• Rigid gas-permeable (RGP) or scleral contact lenses can improve visual function by creating a smoother refractive surface 1, 2

Surgical Management

Timing of Intervention

• If corneal decompensation is likely to occur in the near future, consider modifying the intraocular lens (IOL) power calculation during cataract surgery to adjust for changes likely to be induced by future endothelial keratoplasty 1
• A full discussion with the cataract and Fuchs dystrophy patient about IOL-power selection and the added risks of subsequent corneal decompensation is very important 1

Surgical Options

1. Endothelial Keratoplasty (EK) - now the preferred surgical approach:

   • DSAEK (Descemet's Stripping Automated Endothelial Keratoplasty) - causes a hyperopic shift averaging 1.10 D 1
   • DMEK (Descemet's Membrane Endothelial Keratoplasty) - minimal hyperopic shift, more rapid visual recovery, and improved optical outcomes 1
   • Benefits over PK include rapid visual recovery, greater optical predictability, smaller and more stable wounds, and decreased risk of graft rejection 1

2. Penetrating Keratoplasty (PK):

   • Now reserved for cases with significant corneal scarring 1
   • Associated with higher risk of rejection, wound dehiscence, postoperative astigmatism, and prolonged visual rehabilitation 3

Comparison of Surgical Outcomes

• Rejection rates at 1 year: 17% for PK, 2-9% for DSAEK, 0-6% for DMEK 1
• Graft survival at 5 years for Fuchs dystrophy: 95% for both PK and DSAEK 1
• Visual acuity of 20/40 or better at 1 year: 65-84% for PK, 38-90% for DSAEK, 94% for DMEK at 6 months 1
• Mean keratometric cylinder: 3.7-4.4 D for PK versus 0.4-0.6 D for DSAEK 1

Emerging Treatments

• Descemet Stripping Only (DSO) - removal of diseased endothelium without transplantation, allowing peripheral host endothelial cells to migrate centrally 3, 4
• Descemet Membrane Transplantation (DMT) - transplantation of acellular Descemet membrane to stimulate migration of peripheral host corneal endothelial cells 4
• Research into addressing oxidative stress, mitochondrial dysfunction, and unfolded protein response that contribute to disease progression 5

Important Considerations

• The impact of corneal edema on activities of daily living is often underappreciated, as standard visual acuity measurements don't fully represent functional vision 1
• Fuchs dystrophy typically manifests in the fifth decade of life and has a greater incidence in women 5
• When using bandage contact lenses, prophylactic broad-spectrum antibiotics should be considered to reduce infection risk 2
• Inhibitors of carbonic anhydrase should not be first-line therapy when endothelial dysfunction is present, as they may interfere with endothelial pump function 6

By following these recommendations and considering the appropriate timing for surgical intervention, patients with Fuchs' Endothelial Dystrophy can maintain optimal vision and quality of life.