2. INDEX
Anterior chamber
Angle of anterior chamber
Outflow of apparatus
Innervation of outflow apparatus
3. ANTERIOR CHAMBER:
Anterior chamber is an
angular space.
Anteriorly by the
posterior (inner)
surface of the cornea.
posteriorly by the lens
within the pupillary
aperture, anterior
surface of the iris and a
part of cilliary body.
4. Anterior chamber is 3 mm deep and it contains 0.25
ml of the aqueous humour.
Anterior chamber depth is shallower in the
hypermetropic eye than the myopic eye.
It is also shallower in children and in older people.
5. Volume: 220 µL.
Chamber Volume decreases by 0.11 µL/year life
Diameter: 11.3-12.4mm
Depth: 3.15mm (2.6- 4.4mm)
Chamber depth decreases by 0.01mm/year of life.
Chamber deepens by 0.06mm for each diopter of
myopia.
6. Chamber depth is slightly diminished during
accommodation, partly by increased lens curvature
& partly by forward translocation of the Lens.
Wide angle of anterior chamber denotes the eye in
which the angle between iris and surface of the
trabecular meshwork is between 20 to 45 degrees.
Angles less than 20 degrees are termed as narrow
angles
7.
8.
9. ANGLE OF ANTERIOR CHAMBER
It is the angle recess formed in between post. Surface of cornea
and ant. Surface of iris bounded from anterior to posteriorly by
Schwalbe’s line
Trabecular meshwork
Scleral spur
Anterior surface of cilliary body along with root of iris
10. DEVELOPMENT :
By 7th week , angle is occupied by mesenchymal
cells from neural crest cells to develop trabecular
meshwork.
In posterior aspect, iris is formed from advancing
bilayered optic cup.
Coreneal endothelium meets derivative of iris at
15th week to demarcate the angle.
Angle deeping continues even after birth.
11.
12. SCHWALBE’ S LINE
• Just anterior to the apical portion of the trabecular
meshwork is a smooth area called as zone S.
• Width-50 to150 μm
13. This anterior border of
this zone marks
transition from
1. trabecular to corneal
endothelium
2. termination of the
Descemet’s
membrane
3. Insertion of
trabecular
meshwork into
corneal stroma.
14. • The posterior border is demarcated by a
discontinuous elevation, called Schwalbe's line,
formed by the oblique insertion of uveal
trabeculae into limbal stroma.
• Clusters of secretory cells, called Schwalbe’s line
cells, produce a phospholipid material that
facilitates aqueous humor flow through the
canalicular system.
15. Trabecular meshwork:
Anterior to scleral spur and forms inner aspect of
schlemm’s canal.
pigmentation acquried with age.
16. SCLERAL SPUR:
wedge shaped circular ridge.
pale, translucent narrow strip of scleral tissue.
lies posterior to trabecular meshwork.
gives attachment to anteriorly to corneosceral
meshwork and posteriorly to cilliary muscle.
17. CILIARY BAND:
It marks the posterior most part of the angle.
Represents the anterior face of ciliary body
between its attachment to the scleral spur and
insertion of iris.
Width depends on the level of iris insertion
Wide in myopes and narrow in hypermetropes.
It appears as a grey/dark brown band
18. OUTFLOW OF APPARATUS
It consists of :-
Internal scleral sulcus
trabecular meshwork
schlemm’s canal
collector channels
episcleral veins
20. Limbus is the transition zone between the cornea &
sclera.
On the inner surface of the limbus, there is an
indentation or groove, which is known as the scleral
sulcus.
21. 1. SCLERAL SULCUS
This scleral sulcus has a sharp posterior margin-
the scleral spur & a sloping anterior wall which
extends to the peripheral cornea.
Bounded anteriorly by schwalbe’ s line and
posteriorly by scleral spur.
Accomodates schlemm’s canal and corneoscleral
meshwork
The portion of the spur which forms the post.
boundary of the sulcus is sometimes called scleral
roll.
22. 2. SCHWALBE’ S RING
Is the anterior border ring of the trabecular region
contians circularly arranged collagen fibres
intermixed with elastic fibres.
With age there are also patches of long spacing or
curly collagen.
This ring marks the transition between the corneal
endothelium and the trabecular cells and also the
termination of descement’s membrane.
23. 3. SCLERAL SPUR
Scleral spur is composed of a group of fibres known
as scleral roll.
Scleral roll is composed of 75-80% collagen + 5%
elastic tissue.
This circular structure prevents ciliary muscle from
causing Schlemm’s canal to collapse.
24. • Attached
anteriorly : trabecular meshwork
posteriorly : sclera and longitudinal fibers of ciliary
muscle.
• varicose axons characteristic of mechanoreceptor
nerve measure stress in the scleral spur due to
ciliary muscle contraction or changes in IOP.
25. TRABECULAR MESHWORK
Trabecular meshwork is a
spongy, sieve like tissue.
It is roughly a triangular
anteriorly by periphery of
the cornea and posteriorly
scleral spur and anterior
surface of the ciliary body.
Trabecular meshwork is
pale tan to dark-brown in
colour, varying with
pigmentation of the tissue,
which is darker posteriorly.
26. It is divided into three
portions:
(a) uveal meshwork,
(b) corneoscleral
meshwork, and
(c) juxtacanalicular tissue
27. UVEAL MESHWORK
• This inner most portion is
adjacent to the aqueous
humor in the anterior
chamber
• It is arranged in cord or
rope like trabeculae that
extend from the iris root to
the Schwalbe's line .
• The arrangement of the
trabecular bands creates
irregular openings that
vary in size from 25 to 75
μm.
28. CORNEOSCLERAL MESHWORK
• This portion extends
from the scleral spur to
the anterior wall of the
scleral sulcus
• It consists of 8-14
sheets of trabeculae
that are interconnected
via cytoplasmic
processes.
29. They are perforated by
elliptical openings which
become progressively
smaller as the trabecular
sheets approach
Schlemm's canal .
• These perforations are not aligned and have
a diameter ranging from 5 to 50 μm
30.
31. ULTRASTRUCTURE OF MESHWORK
• Both the uveal and corneoscleral trabecular bands or sheets are
composed of four concentric layers
1. An inner connective tissue core is composed of
collagen fibers, with 64nm periodicity. The central core
contains collagen types I and III and elastin.
2. Elastic fibers are arranged in a spiraling pattern with
periodicity of 100nm.
32. 3. Cortical zone also called as glassy membrane
4. An outer endothelial layer provides a continuous
covering over the trabeculae
33. TRABECULAR ENDOTHELIAL CELLS
Larger, more irregular and have less prominent
borders than corneal endothelium.
Joined by gap junction and desmosomes ,which
provide stability.
Two types of microfilaments:
1. Actin filaments:
cell periphery, around nucleus, in ctyoplasmc
processes.
cell contraction, phagocytosis, pinocytosis, and cell
adhesions
Regulating the shape and cytoskeletal organization.
34. 2. Intermediate filaments:
Numerous, composed of vimentin and desmin
Imparts the contractile n motility functions.
36. The outermost portion of
the meshwork (adjacent
to Schlemm's canal)
This structure has three
layers consisting of a
layer of connective tissue
lined on either side by
endothelium
The inner trabecular
endothelial layer is
continuous with the
endothelium of the
corneoscleral meshwork
37. The central connective tissue layer has variable
thickness and is unfenestrated with several layers of
parallel, spindle shaped cells loosely arranged in a
connective tissue ground substance.
The outermost portion of the trabecular meshwork is the
inner wall endothelium of Schlemm's canal.
This endothelial layer has significant morphologic
characteristics, which distinguish it from the rest of the
endothelium in both the trabecular meshwork and in
Schlemm's canal.
38. SCHLEMM'S CANAL
This 360-degree endothelial-lined channel
It is a single channel but occasionally branches
into a plexus-like system .
39. The endothelium of the outer
wall is a single cell layer that
is continuous with the inner
wall endothelium but has a
smoother surface with larger,
less numerous cells and no
pores .
The outer wall also differs in
having numerous, large outlet
channels
40. Lip-like thickenings are present around the openings of
the outlet channels and septa are noted to extend from
these openings to the inner wall of Schlemm's canal,
which help keep the canal open.
41.
42. Theory of transcellular aqueous transport in which a series of
pores and giant vacuoles opens (probably in response to
transendothelial hydrostatic pressure) on the connective tissue
side of the juxtacanalicular meshwork (2–4). Fusion of basal
and apical cell plasmalemma creates a temporary
transcellular channel (5) that allows bulk flow of aqueous into
Schlemm’s canal.
43. COLLECTOR CHANNELS
• Schlemm's canal is connected
to episcleral and conjunctival
veins by a complex system of
intrascleral channels.
• Two systems of intrascleral
channels have been identified:
(a) An indirect system of
numerous(15-20), finer
channels, which form an
intrascleral plexus
before eventually draining into
the episcleral venous system
and
44. (b) A direct system of large
caliber vessels, which run a
short intrascleral course
and drain directly into the
episcleral venous system,
they are about 6-8 in
number and also called as
aqueous vein.
since these aqueous vessels
terminate into the episcleral
and conjunctival veins in
laminated junction- laminated
vein of goldmann.
45. EPISCLERAL AND CONJUNCTIVAL VEINS
The aqueous vessels join the episcleral and conjunctival
venous systems by several routes.
Most aqueous vessels are directed posteriorly, with most
of these draining into episcleral veins, whereas a few
cross the subconjunctival tissue and drain into
conjunctival veins.
46. The episcleral veins drain into the cavernous sinus via
the anterior ciliary and superior ophthalmic veins,
while the conjunctival veins drain into superior ophthalmic
or facial veins via the palpebral and angular veins .
47. INNERVATION OF OUTFLOW APPARATUS
Derives from the supraciliary nerve plexus and the
ciliary plexus in the region of scleral spur
Both sympathetic adrenergic and parasympathetic
and sensory innervation present
Nerve endings contain mechanoreceptors which
are located in scleral spur.
1. act as proprioceptive tendon organs for the ciliary
muscle,who longitudinal fibres insert into scleral
spur.
2. contraction myofibroblast scleral spur cells.
3. baroreceptor function in response t change in
IOP.
48. REFERENCE:
Shields’ textbook of Glaucoma, 8th edition.
Wolff’ s Anatomy of the Eye and Orbit, Anthony J.
Bron, 8th edition.
Anatomy and Physilogy of Eye ,2nd edition, A K
Khuran and Indu khurana.
Editor's Notes
This portion of the tr abecular meshwork diff er s histologically from the other parts of the meshwo rk and has been given various names including juxtacanalicular connective tissue,
pore tissue,
cribriform layer,
and endothelial meshwork, depending on how o ne defines the anatomic limits of the tissue.
Connective tissue cells in human and rabbit trabecular meshwork contain co ated pits and coated vesicles in the plasma membr ane which are involved in receptor-mediated endocytosis
. Some aqueous vessels proceed anterio rly to the limbus,
with most o f these r unning a sho rt course parallel to t he limbus before turning posteriorly to conjunctival veins.
Other vessels make a sharp loo p to join conjunctival veins or
rarely extend a short distance into t he cornea before turning posteriorly (Fig. 1.14). Casting studies in rabbit and
do g eyes revealed a wide veno us plexus in the limbic region of the episcleral vasculatur e anastomosing with a small
arteriolar segment, the latter of which contains smooth muscle cells that may have a role in regulating aqueous
humor drainage by the episcler al venous plexus and subsequently influencing the IOP (217). In the r hesus monkey,
the conjunctival vessels receiving aqueous humor drainage have a diameter co nsistent with that of capillaries,
whereas most of the vessels in the episcler al plexus ar e the size of venules (218). Both types of vessels have
simple walls composed of endothelium and a discontinuous layer o f pericytes, through which tracer element (e.g.,
horseradish peroxidase), (and presumably aqueous humor) freely diffuse into subconjunctival and episcleral loose
connective tissue (218
Myelinated fibres- post attachment of trabecular sheet.
Nerve endings r more in pericanalicular zone. One thrid r adnergic