4. AQUEOUS HUMOR FORMATION
Aqueous humor is produced from pars plicata
along the crests of the ciliary processes.
Aqueous humor is derived from plasma within the
capillary network of the ciliary processes.
Volume of aqueous humour is about 0.31 ml.
Normal aqueous production rate is 2.0-2.5µl/min.
5. BIOCHEMISTRY OF AQUEOUS HUMOUR
Three physiologic processes contribute to the
formation and chemical composition of the
aqueous humor:
Diffusion.
Ultrafiltration.
Active secretion.
6.
7. AQUEOUS HUMOR OUTFLOW
TRABECULAR OUTFLOW
• The aqueous humor leaves the eye at the anterior chamber
angle through trabecular meshwork, the Schlemm’s canal,
intrascleral channels, and episcleral and conjunctival veins.
• This pathway is referred to as the conventional or
trabecular outflow.
UVEOSCLERAL OUTFLOW
• In the unconventional or uveoscleral outflow, aqueous
humor exits through the root of iris, between the ciliary
muscle bundles, then through the suprachoroidal –
scleral tissues.
• Trabecular outflow accounts for 70% to 95% of the aqueous
outflow .
• And remaining 5% to 30% by uveoscleral outflow.
8.
9. GLAUCOMA
The glaucomas are a group of progressive optic
neuropathies characterized by degeneration of
retinal ganglion cells and resulting changes in the
optic nerve head.
These are central nervous system neurons that
have their cell bodies in the inner retina and axons
in the optic nerve.
Glaucoma affects more than 70 million people
worldwide with approximately 10% Being
bilaterally blind, making it the leading cause of
irreversible blindness in the world.
Untreated of glaucoma leads to permanent
damage of the optic nerve and resultant visual
field loss, which can progress to blindness.
10. Family history of glaucoma
Ageing
Ocular hypertension
Severe myopia
Eye trauma
Ocular surgery
Black race
Prolonged use of corticosteroids
Diabetes
11. Glaucoma can be classified into several
different and unique types:
Primary Open Angle Glaucoma (POAG)
Angle – closure Glaucoma (Acute Glaucoma)
Congenital Glaucoma
Secondary Glaucoma
Pigmentary Glaucoma
Normal – tension Glaucoma (NTG)
12. PRIMARY OPEN-ANGLE GLAUCOMA
In patients with open-angle glaucoma, there is
increased resistance to aqueous outflow through the
trabecular meshwork.Firstly,primitery vision is lost
gradually being lost towards the center of the eye.
ANGLE-CLOSURE GLAUCOMA
The access to the drainage pathways is obstructed
typically by their iris in patients with angle-closure
glaucoma.
The normal drainage system of the eye
becomes suddenly blocked,causing pressure build
up at a rapid rate,leading to complete blindness
within 3 to 5 days.
13. CONGENITAL GLAUCOMA: Children born with
condition such as abnormal development of
anterior chamber angles prohibiting normal
drainage system of the eye.
SECONDARY GAUCOMA: It is caused usually due
result of the trauma(physical injury) to the eye.
PIGMENTARY GLAUCOMA: It develops due to the
result of small pieces of iris breaking off, causing
obstruction in the normal drainage canals of the
eye.
NORMAL TENSION GLAUCOMA:It occurs when
there is a damage in the optic nerve though
observed to have normal intra-ocular pressure.
14.
15. IOP is more than normal (above 25mm Hg).
Intraocular pressure–induced stress and strain may
result in compression, deformation, and
remodeling of the lamina cribrosa with consequent
mechanical axonal damage and disruption of
axonal transport that interrupts retrograde delivery
of essential trophic factors to retinal ganglion cells
from their brainstem target.
16.
17.
18. GLAUCOMA TESTS:
SLIT LAMP: A special microscope called a slit lamp
is used to examine the structures of the eye.
GONIOSCOPY: A gonioscopy lens may be used to
view the drainage angle.
TONOMETRY: Eye pressure is measured with an
instrument called a tonometer.
OPHTHALMOSCOPY/FUNDUSCOPY: A fundus
camera or retinal camera is a specialized low
power microscope with an attached camera
designed to photograph the interior surface of the
eye, including the retina, retinal vasculature, optic
disc, macula, and posterior pole (i.e. the fundus).