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The vitreous humor is a transparent jelly
like structure which helps to maintain the
shape of the eyeball and optical function
.it has all the properties of the
hydrophilic gel, undergoing turgescence. It
contains a few cells and an obliterated
canal known as hyaloids canal it has no
blood vessels. Its surface is condensed to
form thin membrane called the hyaloids
membrane.
it is due to conversion of the
colloidal gel into a sol
Causes:
1)Senility
2)Degenerative myopia
3)Uveitis
4)Trauma-concussion or
intraocular foreign body
5)Treatment of retinal detachment
by diathermy or light coagulation
Clinical significance:
1)Development of retinal detachment
2)During lens extraction-posterior dislocation of
lens and vitreous loss may occur. That is why in
cases of degenerative myopia, planned
extracapsular lens extraction is indicated.
Subjectively they are seen entoptically as muscae
volitantes. Any opacity in the eye which casts a
shadow upon the sentient elements of the retina
(rods and cones) will appear as dark spot in the
field of vision. However, an opacity in the
retinal blood vessels (RBCs) will not produce
muscae
Causes:
1. Congenital remnants of the hyaloid
vascular system.
2. Endogenous opacities
A. Coagula of the colloid basis of the gelsenility, degenerative myopia.
B. Crystalline deposits- asteroid bodies,
synchisis scintillans.
3. Exogenous opacities
3. Exogenous opacities
A. Protein coagula- plasmoid vitreous as in
iridocyclitis and choroiditis.
B. Exudative cells.
C. Blood.
D. Tissue cells-epithelial cells, histocytes.
E. Tumors cells.
F. Pigment-melanin, haemosiderin .
Symptoms:
1. Muscae volitantes may appear in the form of
black dots, lines or cobwebs.
2. When many vitreous opacities are present there
may be haziness of vision. Vision is often best
in the morning before the vitreous has been
stirred up by movements of the eye.
3. In a myopia sudden increase in muscae volitantes
may herald the onset of retinal detachment.
Signs:
The opacities may be seen:
1. With the slit lamp.
2. As black opacities moving independently of the
movements of the eye by distant direct
ophthalmoscopy.
3. With an ophthalmoscope with a +10 D lens.
Treatment:
1. The patient should be
advised to ignore the
opacities as much as
possible.
2. Treatment of the underlying
cause –iridocyclitischoroiditis.
3. Vitrectomy in desperate
cases.
Asteroid bodies or
asteroid hyalitis
or Benson's disease
synchisis scintillans
1. Age 45-60 years.
1.age 45-60 years.
2. Unilateral.
2.Bilateral.
3. Appearance with
ophthalmoscope
looking like stars in the night
sky.
3.Flat angular crystalline
appearance- shower of golden
rain.
4. When the eye is moved the
bodies execute a lazy wave
like excursion and return to
their original location.
4.They may lie hidden at the
bottom of the vitreous: when the
globe is moved they leap into
sight and finally settle down.
5.Cholesterol crystals.
5. Chemical composition calcium
soaps.
6. Occurs in relatively healthy
6.Occurs in degenerated fluid
Vitreous.
Source:
1) Retinal blood vesselveins or arteries.
2) Vessels of the ciliary
body.
3) New vessels growing
into vitreous-retinitis
proliferans .
4) Spilling over of
hyphaema after cataract
extraction.
Causes:
1. Trauma.
2. Diabetes mellitus with
proliferative retinopathy.
3. Hypertension.
4. Eales’ disease.
5. Blood dyscrasias - anemia,
hemophilia, sickle cell disease.
 Small vitreous hemorrhage
may get absorbed but in
recurrent hemorrhages
retinitis proliferans may
develop.
Treatment:
1. Photocoagulation in cases
of diabetic retinopathy.
2. Vitrectomy.