Epithelial basement membrane dystrophy
{{Short description|Disorder of the cornea of the eye}}
{{Infobox medical condition
| name = Epithelial basement membrane dystrophy
| synonym = Map-dot-fingerprint dystrophy and Cogans's microcystic dystrophy or Cogan's dystrophy
| image = Cornea.png
| image_size = 280px
| alt =
| caption = A schematic diagram of the human eye
| pronounce =
| specialty = Ophthalmology
| symptoms = Irregular astigmatism, misty vision, monocular diplopia and visual distortion
| complications =
| onset =
| duration = Lifelong
| types =
| causes =
| risks = Recurrent corneal erosion, dry eyes
| diagnosis =
| differential =
| prevention =
| treatment = Surgical and non-surgical options available
| medication =
| prognosis =
| frequency =
| deaths =
}}
Epithelial basement membrane dystrophy (EBMD) is a disorder of the eye that can cause pain and dryness. EBMD, also known as map-dot-fingerprint dystrophy and Cogan microcystic epithelial dystrophy, is a corneal epithelial disease that may result in recurrent corneal erosions, irregular corneal astigmatism, and decreased vision.{{Cite journal |last=Cheung |first=Natalie |last2=Shands |first2=Philip |last3=Ahmad |first3=Ashraf |last4=Daroszewski |first4=Daniel |last5=Jelineo |first5=Shelley |date=2023-08-01 |title=Corneal Pathology and Cataract Surgery Considerations |url=https://www.sciencedirect.com/science/article/abs/pii/S2452176023000070 |journal=Advances in Ophthalmology and Optometry |series=Advances in Ophthalmology and Optometry |volume=8 |issue=1 |pages=123–138 |doi=10.1016/j.yaoo.2023.02.007 |issn=2452-1760|url-access=subscription }}
It is sometimes included in the group of corneal dystrophies.{{Citation|author=Online Mendelian Inheritance in Man |title=#121820: Corneal dystrophy, epithelial basement membrane; EBMD |url=http://www.omim.org/entry/121820 |archive-url=https://web.archive.org/web/20170430032721/http://www.omim.org/entry/121820 |url-status=dead |archive-date=2017-04-30 |postscript=. }} It diverges from the formal definition of corneal dystrophy since it is non-familial in most cases. It also has a fluctuating course, while for a typical corneal dystrophy the course is progressive. When it is considered part of this group, it is the most common type of corneal dystrophy.{{Cite book|title = Dry Eye: A Practical Approach|url = https://books.google.com/books?id=92O4BgAAQBAJ|publisher = Springer|date = 2015-02-18|isbn = 9783662441060|language = en|first = Colin|last = Chan|pages = 111–112}}
Signs and symptoms
Patients may complain of severe problems with dry eyes, or with visual obscurations.{{cite web |url=https://www.reviewofoptometry.com/article/when-should-you-treat-ebmd-with-ptk |title=When Should You Treat EBMD with PTK? |author= John R. Martinelli, O.D. |date=22 March 2010 |website= Review of Optometry |access-date=16 March 2017}} 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.{{OMIM|121820}}
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,{{cite journal |vauthors=Boutboul S, Black GC, Moore JE, Sinton J, Menasche M, Munier FL, Laroche L, Abitbol M, Schorderet DF |title=A subset of patients with epithelial basement membrane corneal dystrophy have mutations in TGFBI/BIGH3 |journal=Hum. Mutat. |volume=27 |issue=6 |pages=553–7 |date=June 2006 |pmid=16652336 |doi=10.1002/humu.20331|s2cid=41528624 }} but according to the International Committee for Classification of Corneal Diseases (IC3D){{cite journal |vauthors=Weiss JS, Møller HU, Lisch W, Kinoshita S, Aldave AJ, Belin MW, Kivelä T, Busin M, Munier FL, Seitz B, Sutphin J, Bredrup C, Mannis MJ, Rapuano CJ, Van Rij G, Kim EK, Klintworth GK |title=The IC3D classification of the corneal dystrophies |journal=Cornea |volume=27 |issue= Suppl 2 |pages=S1–83 |date=December 2008 |pmid=19337156 |pmc=2866169 |doi=10.1097/ICO.0b013e31817780fb }} 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.{{cite web | last=Verdier | first=David D | title=Map-dot-fingerprint Dystrophy: Background, Pathophysiology, Epidemiology | website=Medscape Reference | date=2019-02-14 | url=https://emedicine.medscape.com/article/1193945-overview | access-date=2024-08-06}}
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.{{Cite journal |date= |year=2016 |title=Genotype-Phenotype Correlation for TGFBI Corneal Dystrophies Identifies p.(G623D) as a Novel Cause of Epithelial Basement Membrane Dystrophy |url=https://iovs.arvojournals.org/article.aspx?articleid=2569579#141742583 |journal=Investigative Ophthalmology & Visual Science |volume=57 |issue=13 |doi=10.1167/iovs.16-19818}}
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.