WordNet

the act of releasing from an attachment or connection (同)disengagement
a small unit of troops of special composition
located at or near or behind a part or near the end of a structure
relating to or resembling or derived from or containing glass; "vitreous rocks"; "vitreous silica"
of or relating to or constituting the vitreous humor of the eye; "the vitreous chamber"

PrepTutorEJDIC

〈U〉(…から…を)分離すること,取り外すこと《+『of』+『名』+『from』+『名』》 / 〈U〉超然としていること / 〈U〉私心(偏見)のないこと / 〈C〉(特別の任務を帯びた)分遣隊,特派部隊
《名詞の前にのみ用いて》(生物学的に,位置が)後ろの,後部の / (時間・順序が)後の;(…より)後の《+『to』+『名』》(later) / しり(buttocks)
ガラスの;ガラス製の;ガラス状の

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/11/22 01:51:29」(JST)

wiki en

A posterior vitreous detachment (PVD) is a condition of the eye in which the vitreous membrane separates from the retina. It refers to the separation of the posterior hyaloid membrane from the retina anywhere posterior to the vitreous base (a 3 - 4 mm wide attachment to the ora serrata.)

Broadly speaking, the condition is common for older adults and over 75% of those over the age of 65 develop it. Although less common among people in their 40s or 50s, the condition is not rare for those individuals. Some research has found that the condition is more common among women.^[1]^[2]

Causes and risk factors

The vitreous (Latin="glassy") humor is a gel which fills the eye behind the lens. Between it and the retina is the vitreous membrane. Over time the vitreous humor changes, shrinking and developing pockets of liquefaction, similar to the way a gelatin dessert shrinks, or detaches, from the edge of a pan over time. At some stage the vitreous membrane may peel away from the retina. This is usually a sudden event, but may also occur slowly over months.

Age and refractive error play a role in determining the onset of PVD in a healthy person. PVD is rare in emmetropic people under the age of 40 years, and increases with age to 86% in the 90s. Several studies have found a broad range of incidence of PVD, from 20% of autopsy cases to 57% in a more elderly population of patients (average age was 83.4 years).

People with myopia (nearsightedness) greater than 6 diopters are at higher risk of PVD at all ages. Posterior vitreous detachment does not directly threaten vision. Even so, it is of increasing interest because the interaction between the vitreous body and the retina might play a decisive role in the development of major pathologic vitreoretinal conditions, such as epiretinal membrane.

PVD may also occur in cases of cataract surgery, within weeks or months of the surgery.

The vitreous membrane is more firmly attached to the retina anteriorly, at a structure called the vitreous base. The membrane does not normally detach from the vitreous base, although it can be detached with extreme trauma. However, the vitreous base may have an irregular posterior edge. When the edge is irregular, the forces of the vitreous membrane peeling off the retina can become concentrated at small posterior extensions of the vitreous base. Similarly, in some people with retinal lesions such as lattice retinal degeneration or chorio-retinal scars, the vitreous membrane may be abnormally adherent to the retina. If enough traction occurs the retina may tear at these points. If there are only small point tears, these can allow glial cells to enter the vitreous humor and proliferate to create a thin epiretinal membrane that distorts vision. In more severe cases, vitreous fluid may seep under the tear, separating the retina from the back of the eye, creating a retinal detachment. Trauma can be any form from a blunt force trauma to the face such as a boxer's punch or even in some cases has been known to be from extremely vigorous blowing of the nose.

Symptoms

When this occurs there is a characteristic pattern of symptoms:

Flashes of light (photopsia)
A sudden dramatic increase in the number of floaters
A ring of floaters or hairs just to the temporal side of the central vision

As a posterior vitreous detachment proceeds, adherent vitreous membrane may pull on the retina. While there are no pain fibers in the retina, vitreous traction may stimulate the retina, with resultant flashes that can look like a perfect circle.^{[citation needed]}

If a retinal vessel is torn, the leakage of blood into the vitreous cavity is often perceived as a "shower" of floaters. Retinal vessels may tear in association with a retinal tear, or occasionally without the retina being torn.

Complications

The risk of retinal detachment is greatest in the first 6 weeks following a vitreous detachment, but can occur over 3 months after the event.

The risk of retinal tears and detachment associated with vitreous detachment is higher in patients with myopic retinal degeneration, lattice degeneration, and a familial or personal history of previous retinal tears/detachment.

Treatment

Therapy is not required or indicated in posterior vitreous detachment, unless there are associated retinal tears, which need to be repaired.^[3] In absence of retinal tears, the usual progress is that the vitreous humor will continue to age and liquefy and floaters will usually become less and less noticeable, and eventually most symptoms will completely disappear.^[3] Prompt examination of patients experiencing vitreous humor floaters combined with expeditious treatment of any retinal tears has been suggested as the most effective means of preventing certain types of retinal detachments.^[4]

References

^ Yonemoto, J; Noda, Y; Masuhara, N; Ohno, S (June 1996). "Age of onset of posterior vitreous detachment.". Current opinion in ophthalmology 7 (3): 73–6. doi:10.1097/00055735-199606000-00012. PMID 10163464.
^ "Posterior vitreous detachment". rnib.org.uk. Retrieved 3 November 2015.
^ ^a ^b Posterior Vitreous Detachment from Cleveland Clinic. This document was last reviewed on: 12/24/2008
^ Byer, NE (September 1994). "Natural history of posterior vitreous detachment with early management as the premier line of defense against retinal detachment.". Ophthalmology 101 (9): 1503–13; discussion 1513–4. doi:10.1016/s0161-6420(94)31141-9. PMID 8090453.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 網膜剥離 retinal detachment
2. 幻視患者へのアプローチ approach to the patient with visual hallucinations
3. 糖尿病性網膜症：分類および臨床的特徴 diabetic retinopathy classification and clinical features
4. 網膜色素変性症：臨床症状および診断 retinitis pigmentosa clinical presentation and diagnosis
5. 非動脈炎性虚血性視神経症：予後および治療 nonarteritic ischemic optic neuropathy prognosis and treatment

English Journal

Two Likely Pathogenic Variants of COL2A1 in Unrelated Korean Patients With Ocular-Only Variants of Stickler Syndrome: The First Molecular Diagnosis in Korea.

Yoon JM1, Jang MA2, Ki CS3, Kim SJ4.
Annals of laboratory medicine.Ann Lab Med.2016 Mar;36(2):166-9. doi: 10.3343/alm.2016.36.2.166.
Stickler syndrome is a genetically heterogeneous disorder that affects the ocular, auditory, and musculoskeletal systems. Ocular-only variant of Stickler syndrome type 1 (OSTL1) is characterized by high risk of retinal detachment without systemic involvement and is caused by alternatively spliced ex
PMID 26709265

The Prevalence of Vitreomacular Interface Pathology in a Spanish Tertiary Hospital.

Flores-Moreno I1, Arias-Barquet L, Vidal-Martí M, Muñoz-Blanco A, Rubio-Caso MJ, Ruiz-Moreno JM, Duker JS, Caminal JM.
Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde.Ophthalmologica.2016 Feb 18. [Epub ahead of print]
PURPOSE: To determine the prevalence of vitreomacular interface (VMI) pathology, using spectral-domain optical coherence tomography (SD-OCT).METHODS: VMI status was classified into macular posterior vitreous detachment (PVD), focal vitreomacular adhesion (VMA; ≤1,500 μm), broad VMA (>1,500 μm
PMID 26886685

Improved outcome after primary vitrectomy in diabetic patients treated with statins.

Tuuminen R1,2, Sahanne S3, Haukka J4, Loukovaara S5.
European journal of ophthalmology.Eur J Ophthalmol.2016 Feb 15;26(2):174-81. doi: 10.5301/ejo.5000657. Epub 2015 Aug 26.
PURPOSE: To evaluate the effect of preoperative statin treatment on the outcome of primary vitrectomy in type 1 and 2 diabetic patients.METHODS: In this open, observational institutional study, a total of 192 eyes of 171 type 1 and 2 adult diabetic patients admitted for primary vitrectomy for manage
PMID 26350989

Japanese Journal

後部硝子体剝離により自然軽快したと考えられる中心窩分離症,黄斑剝離の1例 (特集第67回日本臨床眼科学会講演集(1))

岩久文,榎本暢子,富田剛司 [他]
臨床眼科 68(3), 329-332, 2014-03
NAID 40020003764

硝子体手術後に網膜静脈分枝閉塞症を来したタモキシフェン内服患者の1例

岩浅聡,田中美和,水川憲一,三木敏耶,桐生純一
川崎医学会誌 40(2), 129-133, 2014
タモキシフェンは主に乳癌治療薬として使用されているが,眼副作用の報告は非常に少ない.今回,タモキシフェン内服患者における,硝子体手術後に発症した網膜静脈分岐閉塞症(branch retinal vein occlusion,以下BRVO)の1例を経験したので報告する.症例は51歳女性,乳癌の術後1日量20mgのタモキシフェンによるアジュバント療法を受けていた.2年後に左眼の黄斑円孔が発見され硝子体 …
NAID 110009866507

Membrane tissue on the optic disc may cause macular schisis associated with a glaucomatous optic disc without optic disc pits

Takashina Saori,Saito Wataru,Noda Kousuke,Katai Maki,Ishida Susumu
Clinical Ophthalmology 7, 883-887, 2013-05-13
… Posterior vitreous detachment was observed intraoperatively. … The changes in OCT findings described here suggest an etiology for macular schisis without optic disc pits in an eye with a glaucomatous optic disc with posterior vitreous detachment. …
NAID 120005372291

Related Pictures

Floaters & Flashes Lexington | Retinal Tears Louisville | Retina Associates Posterior Vitreous Detachment Griffin | Takle Eye Group Flashes or Floaters: Does you have a retinal tear? - Metrolina Eye Associates Posterior Vitreous Detachment: Signs, Causes, Treatment | EYExan.com Posterior-Vitreous-Detachment - evrs - YouTube