Drusen
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| Drusen Classification and external resources |
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| ICD-10 | H35.3 & H47.3 |
|---|---|
| OMIM | 126700 126600 611040 603075 134370 |
| DiseasesDB | 29371 |
| eMedicine | topic list |
Drusen (singular, "druse") are tiny yellow or white accumulations of extracellular material that build up in Bruch's membrane of the eye. The presence of a few small ("hard") drusen is normal with advancing age, and most people over 40 have some hard drusen. However, the presence of larger and more numerous drusen in the macula is a common early sign of age-related macular degeneration (AMD).
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[edit] Classification
Drusen associated with aging and macular degeneration are distinct from another clinical entity, optic disc drusen, which is present on the optic nerve head.[1] Both age-related drusen and optic disc drusen can be observed by ophthalmoscopy.
Whether drusen promote AMD or are symptomatic of an underlying process that causes both drusen and AMD is not known, but they are indicators of increased risk of the complications of AMD.[2]
[edit] Pathophysiology
Drusen were initially described by Donders [3] who named them for the German word for geode, based on their glittering appearance. In view of their location between the retinal pigment epithelium (RPE) and its vascular supply, the choriocapillaris, it is possible that drusen deprive the RPE and photoreceptors of oxygen and nutrients. Interestingly, drusen always develop above the so called pillars of choriocapillaris that is the area between two microvessels.[4]
The source of the proteins and lipids in drusen is also not clear, with potential contributions by both the RPE and the choroid. Several trace elements are present in drusen,[5] probably the most concentrated being zinc.[6] The protein composition of drusen includes apolipoproteins and members of the complement system. Zinc in drusen have been suggested to play a role in drusen formation by precipitating and inhibiting the elements of the complement cascade, especially complement factor H.[6]
The presence of molecules that regulate inflammation in drusen has led some investigators to conclude that these deposits are product of the immune system.[7]
[edit] See also
[edit] Notes
- ^ Davis PL, Jay WM (December 2003). "Optic nerve head drusen". Semin Ophthalmol 18 (4): 222–42. doi:. PMID 15513010.
- ^ Age-Related Macular Degeneration. National Eye Institute (March 2008). Retrieved on 2008-05-21.
- ^ Donders F. Beitrage zur pathologischen Anatomie des Auges. Archiv Für Ophthalmologie 1854; 1:106-18
- ^ Lengyel I, Tufail A, Hosaini HA, Luthert P, Bird AC, Jeffery G (September 2004). "Association of drusen deposition with choroidal intercapillary pillars in the aging human eye". Invest. Ophthalmol. Vis. Sci. 45 (9): 2886–92. doi:. PMID 15326099.
- ^ van der Schaft TL, de Bruijn WC, Mooy CM, Ketelaars DA, de Jong PT (March 1992). "Element analysis of the early stages of age-related macular degeneration". Arch. Ophthalmol. 110 (3): 389–94. PMID 1543459.
- ^ a b Lengyel I, Flinn JM, Peto T, et al (April 2007). "High concentration of zinc in sub-retinal pigment epithelial deposits". Exp. Eye Res. 84 (4): 772–80. doi:. PMID 17313944.
- ^ Hageman GS, Luthert PJ, Victor Chong NH, Johnson LV, Anderson DH, Mullins RF (November 2001). "An integrated hypothesis that considers drusen as biomarkers of immune-mediated processes at the RPE-Bruch's membrane interface in aging and age-related macular degeneration". Prog Retin Eye Res 20 (6): 705–32. PMID 11587915.
[edit] References
- Donders F. Beitrage zur pathologischen Anatomie des Auges. Archiv Für Ophthalmologie 1854; 1:106-18
[edit] External links
- Dry Macular Degeneration - What is Drusen?
- agingeye.com
- Dry Macular Degeneration
- image from macular.org
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