Corneal Dystrophy

Definition

Corneal dystrophies are a group of genetic eye disorders characterized by clouding of one or more parts of the cornea due to abnormal accumulation of material in it. This leads to lose of the normal clarity of cornea. Corneal dystrophy may or may not produce symptoms in an individual. There are various types of corneal dystrophies that can occur at any age and cause different symptoms.

Cause of Corneal Dystrophy

• Accumulation of unnecessary material in the cornea, like:
  • Lipids
  • Cholesterol crystals
  • Scar tissue

Types of Corneal Dystrophies

There are more than 20 different types of corneal dystrophies that are grouped into three categories, depending upon the part of the cornea that they affect:

• Anterior Corneal Dystrophies
  • Epithelial Basement Membrane Dystrophy
  • Lisch Corneal Dystrophy
  • Meesmann Corneal Dystrophy
  • Reis-Buckler Corneal Dystrophy
  • Thiel-Behnke Corneal Dystrophy
• Stromal Corneal Dystrophies
  • Gelatinous Droplike Corneal Dystrophy
  • Granular Corneal Dystrophy Type I
  • Granular Corneal Dystrophy Type II (Avellino corneal dystrophy)
  • Lattice Corneal Dystrophy Type I
  • Lattice Corneal Dystrophy Type II
  • Macular Corneal Dystrophy
• Posterior Corneal Dystrophies
  • Congenital Hereditary Endothelial Corneal Dystrophy
  • Fuchs Endothelial Corneal Dystrophy
  • Posterior Polymorphous Corneal Dystrophy

  • Schnyder Crystalline Corneal Dystrophy

Similar characteristics of most forms of corneal dystrophy

Corneal dystrophy can occur at any stage of life and appears as greyish white clouding of the cornea. Although there are so many types of corneal dystrophies known, but these share some common characteristics like:

• Affect both eyes equally (bilateral)
• Progress slowly
• Begins in one layer of the cornea and late spreads to other layers
• Do not affect other areas of the body
• Tend to run in families
• Affect otherwise healthy women and men in equal numbers
• Not caused by external factors like injury
• Not related to diseases affecting other parts of the eye or body

Corneal Dystrophy Symptoms

Corneal dystrophy may or may not cause any symptom in the patient and can be diagnosed accidently during routine eye examination. The usual symptoms include:

• Affect vision in widely differing ways and may cause visual impairment (loss of vision or blurred vision due to lose of corneal transparency) or no vision problem
• Recurrent corneal erosion leading to :
  • Eye discomfort or severe pain
  • Sensitivity to light (photophobia)
  • Sensation of a foreign body (such as dirt or an eyelash) in the eye
  • Blurred vision

Diagnosis of Corneal Dystrophy

In many cases, corneal dystrophy is found incidentally during a routine eye examination. But to confirm the diagnosis, a thorough eye examination using slit lamp, a detailed patient history and a variety of molecular genetic tests are required.

Treatment of Corneal Dystrophy

The treatment of corneal dystrophy depends upon its type, severity and rate of progression along with its symptomatic or asymptomatic state. Asymptomatic dystrophy needs no treatment but should be regularly observed to detect potential progression of the disease.

Other treatments for corneal dystrophies may include:

• Lubricating eye drops & ointments

• Hypertonic eye drops and ointment

• Antibiotics

• Specialized (bandage soft) contact lenses

• Excimer laser therapy

• Corneal scraping

• Phototherapeutic keratectomy (PTK)

• Corneal transplant