Sunday, 1 December 2013

Muscae Volitantes (Floater) - The Symptoms and Causes

Muscae volitantes or Floater is defined as a condition of pathol moving black specks or threads seen before the eyes, as results of opaque fragments floating in the vitreous humour or a lens defect due to degeneration of the vitreous humour.  Floater as it suspends in the vitreous humour, it tends to drift  and follows the rapid motions of the eye as a result of damage of the eye that causes material to enter the vitreous humour.

II. Symptoms
1. Seeing a spot or spots, other shapes such as black or gray dots, squiggly lines, threadlike strands, ring shaped, etc. before the eyes    
2.  Movement of the spots or shapes that parallels eye movement.
3. Etc.

A, Causes
There are many causes of floater, including
1.  Eyes diseases
Eye diseases can cause damage to the eye of that can lead to muscae volitantes.
2. Vitreous cyst
Vitreous cyst is associated to the cause of floater, although it is rare. The etiology has been theorized to be both congenital and acquired. Acquired cysts may be due to trauma or other forms of intraocular inflammation. Pigmented cysts are believed to originate from the pars ciliaris and nonpigmented cysts are likely to be derived from the remnants of the hyaloidal artery system. The appearances of the cysts are striking and are often seen as clear spherical bodies in the vitreous with interesting interlacing surface patterns. The cysts are benign and are of little significance, except when they encroach on the visual axis and produce visual disturbances (usually floater symptoms)(1).

3.  Vitreous syneresis
vitreous normally will undergo liquefaction and changed from jellylike material to fluid like material in a process called syneresis of vitreous and this will cause the collage fibers within the vitreous to form strands. With each eye movements, those strands will also move, causing eye floaters(2).

4. Posterior vitreous detachments (PVD)
Posterior vitreous detachments can cause uscae volitantes. It is a condition of the eye in which the vitreous humor separates from the retina due to aging as the condition is common in older adults and over 75% of those over the age of 65 develop it(3).

5. Retinal detachment
Retinal detachment associated to the causes of floater, is a eye disorder in which the retina peels away from its underlying layer of support tissue(4) and affected mostly in middle-aged or older population.

6. Hyaloid remnant
A rare condition in which there remain some parts of the hyaloid artery. Posteriorly there may be a vascular loop or the thread of an obliterated vessel running forward from the optic disc and floating freely in the vitreous. Anteriorly there may be some fibrous remnants attached to the posterior lens capsule and others sometimes floating in the vitreous. The anterior attachment of the hyaloid artery to the lens may also remain throughout life as a black dot, called Mittendorf's dot, and can be seen within the pupil by direct ophthalmoscopy (it appears as a white dot with the biomicroscope). There is rarely any visual interference although patients may sometimes report seeing muscae volitantes(5).

7.  Other causes of Muscae volitantes
a. Patient with oily tears and inpissated meibomian glands may also accumulate debris within the tear layer, which can be reported as floaters.
b. Patients with ocular allergies may also be prime candidates for this phenomenon, since the eye produces excess mucus in order to soothe the eye from the allergic assault.
c. Vitreous haemorrhage. A PVD that encounters an area of vitreoretinal adhesion can cause a tractional tear in the retina. If a retinal blood vessel is involved, subsequent leakage into the vitreous cavity and retrohyaloid space will occur.
d. A relatively common vitreous anomaly that occasionally causes floaters is asteroid hyalosis. Asteroid bodies are calcium soaps that attach to the vitreous framework(6).

8. Etc.

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