Epithelial basement membrane dystrophy

Signs and symptoms

Patients may complain of severe problems with dry eyes, or with visual obscurations. It can also be asymptomatic, and only discovered because of subtle lines and marks seen during an eye exam.

EBMD is a bilateral anterior corneal dystrophy characterized by grayish epithelial fingerprint lines, geographic map-like lines, and dots (or microcysts) on slit-lamp examination. Findings are variable and can change with time. While the disorder is usually asymptomatic, up to 10% of patients may have recurrent corneal erosions, usually beginning after age 30; conversely, 50% of patients presenting with idiopathic recurrent erosions have evidence of this dystrophy.

Pathophysiology

According to research published in 2006, in some families autosomal dominant inheritance and point mutations in the transforming growth factor, beta-induced (TGFBI) gene encoding keratoepithelin have been identified, but according to the International Committee for Classification of Corneal Diseases (IC3D) the available data still does not merit a confident inclusion of EBMD in the group of corneal dystrophies. In view of this, the more accurate designation of the disease is possibly not dystrophy but corneal degeneration.

The main pathological feature of the disease is thickened, multilaminar and disfigured basement membrane of corneal epithelium. The change in the structure affects the epithelium, some cells of which may become entrapped in the rugged membrane and fail to migrate to the surface where they should undergo desquamation.

For patients with granular corneal dystrophy type 2 (GCD2) who have the TGFBI p.(R124H) mutation, complications have been observed following LASIK surgery.

Treatment

Phototherapeutic keratectomy (PTK) done by an ophthalmologist can restore and preserve useful visual function for a significant period of time in patients with anterior corneal dystrophies including EBMD.

References

References

1. Cheung, Natalie. (2023-08-01). "Corneal Pathology and Cataract Surgery Considerations". Advances in Ophthalmology and Optometry.
2. Online Mendelian Inheritance in Man. "#121820: Corneal dystrophy, epithelial basement membrane; EBMD".
3. Chan, Colin. (2015-02-18). "Dry Eye: A Practical Approach". Springer.
4. John R. Martinelli, O.D.. (22 March 2010). "When Should You Treat EBMD with PTK?".
5. {{OMIM. 121820
6. (June 2006). "A subset of patients with epithelial basement membrane corneal dystrophy have mutations in TGFBI/BIGH3". [[Hum. Mutat.]].
7. (December 2008). "The IC3D classification of the corneal dystrophies". [[Cornea]].
8. Verdier, David D. (2019-02-14). "Map-dot-fingerprint Dystrophy: Background, Pathophysiology, Epidemiology".
9. (2016). "Genotype-Phenotype Correlation for TGFBI Corneal Dystrophies Identifies p.(G623D) as a Novel Cause of Epithelial Basement Membrane Dystrophy". [[Investigative Ophthalmology & Visual Science]].