What are the guideline treatments for corneal dystrophy?

Guideline Treatment for Corneal Dystrophy

The primary therapeutic goal for corneal dystrophy is to control the underlying cause and enhance quality of life by improving visual acuity and maximizing comfort through a staged approach, beginning with medical management before considering surgical interventions. 1

Diagnosis and Classification

• Corneal dystrophies are typically bilateral, inherited, slowly progressive corneal opacities that lead to visual impairment 2
• Diagnosis is based on characteristic findings during comprehensive eye examination showing typical cellular abnormalities of the corneal epithelium, stroma, or endothelium 2
• Clinical presentation varies based on the type and location of dystrophy:
  • Epithelial/anterior dystrophies (map-dot-fingerprint, Meesmann, Lisch, Reis-Bücklers, Thiel-Behnke) often present with recurrent epithelial defects 3
  • Stromal dystrophies (granular, lattice, macular) present with deposits in the corneal stroma 3
  • Endothelial dystrophies (Fuchs, posterior polymorphous) present with corneal edema 3

Medical Management

Topical Treatments

• Hyperosmotic agents (sodium chloride 5% drops or ointment) are first-line for corneal edema to temporarily reduce symptoms through osmotic effect 1
• Topical antibiotics should be considered when bullae rupture to reduce risk of secondary infection 1
• Topical corticosteroids may be used when inflammation is present, after ruling out infection 1
• Autologous serum tears can promote corneal nerve regeneration and improve symptoms in neuropathic corneal pain 1

Environmental Modifications

• Low humidity and modest air movement may improve vision in patients with endothelial dysfunction 1
• Hairdryer therapy (directing warm air at the eyes from arm's length) can temporarily reduce epithelial edema 1
• Avoidance of unshielded fluorescent lighting or reflective surfaces may help reduce disabling glare 1

Contact Lenses

• Bandage contact lenses (BCLs) can alleviate pain and discomfort from microcystic or bullous epithelial disease 1
  • Thin lenses with high water content and high oxygen diffusion coefficients are preferred 1
  • Prophylactic broad-spectrum antibiotics should be considered with BCL use 1
• Rigid gas-permeable (RGP) lenses can improve visual function by creating a smoother refractive surface 1

Surgical Management

Phototherapeutic Keratectomy (PTK)

• PTK using 193-nm excimer laser is the method of choice for superficial dystrophies when conservative therapy fails 3
• PTK can achieve three major goals:
  • Remove superficial opacities 3
  • Regularize the surface and treat irregular astigmatism 3
  • Improve epithelial adherence 3
• Visual outcomes:
  • 93% of patients maintain or improve best-corrected visual acuity 4
  • Complete relief of recurrent erosion symptoms is achievable in most patients 4
• PTK can be repeated multiple times, postponing the need for corneal transplantation 3, 4
• Consider mitomycin-C application during PTK to reduce risk of haze and recurrence, especially for deeper ablations 1

Lamellar Keratectomy

• Superficial or anterior lamellar keratectomy can be performed using a microblade, lamellar dissector, or spatula 1
• Microkeratome or femtosecond laser-assisted keratectomy provides better refractive surface and improved visual outcomes 1
• Best-corrected visual acuity shows significant improvement at 2,6, and 12 months with mechanical/femtosecond flaps combined with PTK 1

Corneal Transplantation

• Indicated when medical management and less invasive surgical options fail 3
• Type of transplant depends on the location of the dystrophy:
  • Anterior lamellar keratoplasty for anterior and stromal dystrophies 3, 5
  • Endothelial keratoplasty (DSAEK or DMEK) for endothelial dystrophies 3
  • Penetrating keratoplasty remains necessary in some cases with full-thickness involvement 5
• For Fuchs endothelial corneal dystrophy, transplantation is typically indicated when visual acuity drops below 0.4 3
• Endothelial keratoplasty has largely replaced penetrating keratoplasty for endothelial failure due to more rapid visual rehabilitation and reduced rejection rates 1

Specific Dystrophy Considerations

Epithelial and Anterior Stromal Dystrophies

• Conservative management with lubricating drops, ointments, and bandage contact lenses is first-line 5
• PTK is indicated when conservative measures fail to control recurrent erosions 3, 4

Stromal Dystrophies

• PTK may be a reasonable alternative to lamellar or penetrating keratoplasty depending on the depth of deposits 3
• Preoperative topography analysis and determination of deposit depth are essential before planning PTK 3

Endothelial Dystrophies

• Medical management with hyperosmotic agents and environmental modifications for early disease 1
• Posterior polymorphous dystrophy rarely requires transplantation but needs regular intraocular pressure monitoring 3
• Fuchs dystrophy often progresses to require endothelial keratoplasty 3
• For congenital hereditary endothelial dystrophy, timing of transplantation must balance risk of amblyopia against challenges of postoperative care in young children 3

Treatment Algorithm

1. Begin with medical management (hyperosmotic agents, lubricants, bandage contact lenses) 1
2. For superficial dystrophies with recurrent erosions or visual impairment unresponsive to medical therapy, proceed to PTK 3, 4
3. For deeper stromal involvement or after multiple PTK failures, consider lamellar keratoplasty 3
4. For endothelial dystrophies with significant visual impairment, proceed to endothelial keratoplasty 3
5. Reserve penetrating keratoplasty for cases with full-thickness involvement or when lamellar techniques are not feasible 5