drusen

Drusen associated with aging and macular degeneration are distinct from another clinical entity, optic disc drusen, which is present on the optic nerve head.{{cite journal |vauthors=Davis PL, Jay WM |title=Optic nerve head drusen |journal=Semin Ophthalmol |volume=18 |issue=4 |pages=222–42 |date=December 2003 |pmid=15513010 |doi=10.1080/08820530390895244 |s2cid=8271755 }} Both age-related drusen and optic disc drusen can be observed by ophthalmoscopy. Optical coherence tomography scans of the orbits or head, calcification at the head of the optic nerve without change in size of globe strongly suggests drusen in a middle-age or elderly patient.

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.{{cite web |title=Age-Related Macular Degeneration |url=http://www.nei.nih.gov/health/maculardegen/armd_facts.asp |date=March 2008 |publisher=National Eye Institute |access-date=2008-05-21 |url-status=dead |archive-url=https://web.archive.org/web/20080512021449/http://www.nei.nih.gov/health/maculardegen/armd_facts.asp |archive-date=2008-05-12 }}

'Hard drusen' may coalesce into 'soft drusen' which is a manifestation of macular degeneration.{{cite web |url=http://www.agingeye.net/maculardegen/maculardegeninformation.php |title=Macular Degeneration types and risk factors |access-date=2010-01-26 |url-status=dead |archive-url=https://web.archive.org/web/20100110032447/http://www.agingeye.net/maculardegen/maculardegeninformation.php |archive-date=2010-01-10 }}

Around 1850, three authors, Carl Wedl, Franciscus Donders, and Heinrich Müller, gave drusen different labels. Drusen, the hallmark of AMD, were first described in 1854 by Wedl.Wedl C. Grundzüge der pathologischen Histologie Wien: Gerold, C; 1854 Wedl named them colloid bodies of the choroid and thought that they were incompletely developed cells. Franciscus Donders{{cite journal |author= Donders FC |title=Beitrage zur pathologischen Anatomie des Auges |journal=Graefes Arch Clin Exp Ophthalmol |volume=1 |issue=2 |pages=106–18 |date=March 1855 | doi=10.1007/BF02720791 |s2cid=45074362 }} called them "Colloidkugeln" (colloid spheres). Later, Heinrich Müller named them by the German word for geode, based on their glittering appearance.{{cite journal |author= Müller H |title=Anatomische Beiträge zur Ophthalmologie – Untersuchungen über die Glashäute des Auges, insbesondere die Glaslamelle der Chorioidea und ihre senilen Veränderungen |journal=Graefes Arch Clin Exp Ophthalmol |volume=2 |issue=2 |pages=1–69 |date=January 1856 | doi=10.1007/BF02720657 |s2cid=41644271 }} He was convinced that drusen originated from the nuclei of the pigment cells, which he believed to belong to the choroid.de Jong PT. A Historical Analysis of the Quest for the Origins of Aging Macula Disorder, the Tissues Involved, and Its Terminology. Ophthalmol Eye Dis. 2016;8(Suppl 1):5-14. Published 2016 Nov 1. doi:10.4137/OED.S40523 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 photoreceptor cells of oxygen and nutrients. In some cases, drusen develop above the so-called pillars of the choriocapillaris that is the area between two micro vessels;{{cite journal |vauthors=Lengyel I, Tufail A, Hosaini HA, Luthert P, Bird AC, Jeffery G |title=Association of drusen deposition with choroidal intercapillary pillars in the aging human eye |journal=Invest. Ophthalmol. Vis. Sci. |volume=45 |issue=9 |pages=2886–92 |date=September 2004 |pmid=15326099 |doi=10.1167/iovs.03-1083 |doi-access=free |url=https://discovery.ucl.ac.uk/8034/1/8034.pdf }} although important variations are observed between different subtypes of AMD.

File:Drusen in OCT.png.]]

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,{{cite journal |vauthors=van der Schaft TL, de Bruijn WC, Mooy CM, Ketelaars DA, de Jong PT |title=Element analysis of the early stages of age-related macular degeneration |journal=Arch. Ophthalmol. |volume=110 |issue=3 |pages=389–94 |date=March 1992 |pmid=1543459 |doi= 10.1001/archopht.1992.01080150087034}} probably the most concentrated being zinc. The protein composition of drusen includes apolipoproteins and oxidized proteins, likely originating from blood, RPE, and photoreceptors.{{cite journal |vauthors=Crabb JW, Miyag M, Gu X, Shadrach K, West KA, Sakaguchi H, Kamei M, Hasan A, Yan L, Rayborn ME, Salomon RG, Hollyfield JG |title=Drusen proteome analysis: An approach to the etiology of age-related macular degeneration |journal=Proc Natl Acad Sci USA |volume=99 |issue=23 |pages=14682–87 |date=November 12, 2002 |pmid=12391305 |doi=10.1073/pnas.222551899 |pmc=137479|doi-access=free |bibcode=2002PNAS...9914682C }} Drusen composition also includes members of the complement system. Zinc in drusen has been suggested to play a role in drusen formation by precipitating and inhibiting the elements of the complement cascade, especially complement factor H.{{cite journal |vauthors=Lengyel I, Flinn JM, Peto T, etal |title=High concentration of zinc in sub-retinal pigment epithelial deposits |journal=Exp. Eye Res. |volume=84 |issue=4 |pages=772–80 |date=April 2007 |pmid=17313944 |doi=10.1016/j.exer.2006.12.015 }}

The presence of molecules that regulate inflammation in drusen has led some investigators to conclude that these deposits are product of the immune system.{{cite journal |vauthors=Hageman GS, Luthert PJ, Victor Chong NH, Johnson LV, Anderson DH, Mullins RF |title=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 |journal=Prog Retin Eye Res |volume=20 |issue=6 |pages=705–32 |date=November 2001 |pmid=11587915 |doi= 10.1016/S1350-9462(01)00010-6|s2cid=7737763 }}

Usually being asymptomatic, drusen are typically found during routine eye exams where the pupils have been dilated.{{Cite web|url=https://www.aao.org/eye-health/diseases/drusen-diagnosis|title = Drusen Diagnosis and Treatment|date = 4 March 2021}}

Laser treatment of drusen has been studied. While it is possible to eliminate drusen with this treatment strategy, it has been shown that this fails to reduce the risk of developing the choroidal neovascularisation which causes the blindness associated with age-related macular degeneration.{{cite journal| pmc=4733883 | pmid=26493180 | doi=10.1002/14651858.CD006537.pub3 | volume=2015 | issue=10 | title=Laser treatment of drusen to prevent progression to advanced age-related macular degeneration | year=2015 | journal=Cochrane Database Syst Rev | page=CD006537 |vauthors=Virgili G, Michelessi M, Parodi MB, Bacherini D, Evans JR}}

• Optic disc drusen

{{Reflist}}

{{cite journal |last1=Mishra |first1=S |last2=Goel |first2=S |last3=Roy |first3=SS |last4=Garg |first4=B |last5=Parvin |first5=M |last6=Saurabh |first6=K |last7=Roy |first7=R |title=Multimodal imaging characteristics of refractile drusen |journal=Indian Journal of Ophthalmology |doi= 10.4103/ijo.IJO_867_18 |date=January 2019 |volume=67 |number=1 |pages=128–129 |doi-access=free |pmid=30574912 |pmc=6324114 }}

{{Medical resources

| DiseasesDB = 29371

| ICD10 = {{ICD10|H|35|3|h|30}}, {{ICD10|H|47|3|h|46}}

| ICD9 =

| ICDO =

| OMIM = 126700

| OMIM_mult = {{OMIM|126600||none}} {{OMIM|611040||none}} {{OMIM|603075||none}} {{OMIM|134370||none}}

| MedlinePlus =

| eMedicineSubj = search

| eMedicineTopic = Drusen

| MeshID =

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Category:Eye diseases