Epithelial Basement Membrane Dystrophy (EBMD) is the most common form of corneal dystrophy. It is believed some 2% of the population is affected by it. Most patients never develop any symptoms, or have some minor discomfort at irregular times. However, around 10% of people will experience recurrent episodes and some visual disturbances. Usually, recurrent erosions happen in the early stages of EBMD, and visual disturbances happen in later stages.
What Is EBMD?
EBMD basically means that the membrane adhesion complex’s epithelial basement malfunctions, either in its formation or in its maintenance. The condition was first described over 100 years ago by Hansen, and further studies were conducted around 50 years later by Thygeson, who discovered that most people experience the most significant symptoms when they first wake up. They may then also experience significant pain in their eyes, which can last for just a few hours or several days. Sometimes, the condition becomes so bad that people become classed as disabled.
Signs and Symptoms of EBMD
As stated, many people do not notice any symptoms of EBMD, or very few. However, if a patient complains of recurrent problems, a physician could identify erosions in multiple sites. In the later stages of the condition, patients will notice so-called ‘map-dot-fingerprint’, which is a sign of epithelial breakdown. The table below highlights the ‘map-dot-fingerprint’ symptom in greater detail.
|Map||Fibrogranular deposits below the basement membrane makes the cornea look like a map.|
|Dot||Fibrogranual deposits above the basement membrane causes the appearance of dots on the cornea.|
|Fingerprint||Seeing fingerprint lines on the cornea due to the epithelial basement membrane duplicating and regenerating abnormally.|
As time progresses, the map-dot-fingerprint symptoms become worse.
EBMD is classed as a disease that leads to corneal erosions and decreased vision. It is not clear, however, whether it is a corneal degeneration, meaning that it is a random condition, or a true dystrophy, which means genetics may play a role in its development. One of the reasons for this confusion is that most people do not report a family history. However, this could be due to the fact that EBMD is often asymptomatic, meaning people may simply not know they have it. Research now suggests that a mutation in the TGFBI gene, found on chromosome 5, may play a role in the development of the disease, which would point to it being a true dystrophy.
Who Gets EBMD
EBMD can affect anyone, although it is most common in those aged between 40 and 70. It can affect just one eye, but it is more common to affect both. However, when it does appear in both eyes, it is asymmetric. There are a number of potential risk factors:
- Family history
- LASIK eye surgery
- Trauma to the eye, including corneal abrasion
How to Prevent EBMD
Unfortunately, there is no real prevention for EBMD, other than ensuring the eyes stay healthy and avoid trauma. Once EBMD is diagnosed, or if someone knows they are at particular risk, physicians may prescribe night time lubricating drops, as well as hypertonic saline ointments. Surgery may be required during later stages.
How EBMD Is Diagnosed
EBMD is diagnosed when patients report a number of symptoms, including:
- Blurred vision
- Fluctuating vision
- Intermittent pain
Generally, however, these episodes are very short-lived and the discomfort is only minor. As a result, few people actually seek medical attention. Furthermore, physicians often miss the condition because, while the map-dot-fingerprint symptoms may be there, these are often very subtle. It is important, therefore, for patients to be looked over by properly trained physicians and ophthalmologists in order to have the condition diagnosed properly. Some of the things they will do include:
- Investigating a family history
- Using yellow dye to show the map-dot-fingerprint pattern more clearly
- Corneal topography or keratometry to measure the cornea’s shape
- Tear film investigations, which look at whether the patient has dry eye syndrome (DES) or keratoconjunctivitis
Sometimes, a patient or a physician believes EBMD is present, when the issue is actually Reis-Bucklers’ Dystrophy or Meesman’s Juvenile Epithelial Dystrophy. Seeking a second opinion, therefore, is something that patients are encouraged to do.
There is no cure for EBMD. Hence, the goal is simply to lower the rates of recurrences. This is achieved through lubricants and special drops. Other types of treatment include:
- Bandage contact lenses
- Antibiotic ointments
- Oral doxycycline
- Topical steroids
- Anterial stromal punctures
- YAG laser micropncture
- Epithelial debridement
- Phototherapeutic keratectomy (PTK)
- Diamond burr polishing
The table below highlights some of the available treatments.
|Epithelial debridement||· Has been used for over 100 years.
· Works best alongside night time lubrication
· 85% success rate reported in clinical studies
|Removal of fibrosis, debris, and membrane||· May not be successful
· If unsuccessful, will lead to recurrences
· Generally offered if other treatment forms do not work
|Disruption of the Bowman’s Layer||· Some physicians believe this to be the most successful procedure
· Other physicians believe it is the worst one, as it causes further injuries
· Most studied of all treatment options
· Should be used aggressively, or not at all
|Medication||· Usually offered as part of the after care for one of the options above
· Topical corticosteroids
Complications and Prognosis
The greatest complication of EBMD is that it can lead to corneal scarring. This could cause a permanent reduction in quality of vision, even leading to full loss of sight. The prognosis of EBMD varies. Most people who have it find that it gets progressively worse as they age. Patients usually experience flare ups, followed by periods of not noticing the issue at all for months or years.
Resources and References:
Treatment of Epithelial Basement Membrane Dystrophy with Manual Superficial Keratectomy – Study on the use of manual superficial keratectomy to treat EBMD. (University of Iowa Health Care: Ophthalmology and Visual Sciences)
Recurrent Corneal Erosions and Epithelial Basement Membrane Dystrophy – Treatment for severe cases of corneal erosions. (NCBI)
Epithelial Basement Membrane Corneal Dystrophy – Information on EBMD. (NIH)