ANETRIOR CHAMBER AND AQUEOUS HMOR DRAINAGE SYSTEM

1. AC & AQUEOUS
HUMOR DYNAMICS
ANIK DINGAL(2ND YEAR )
VIDYASAGAR COLLEGE OF OPTOMETRY & VISION SCIENCE

2. The aqueous humor is involved with all portions of the eye , although principle
ocular structures concerned with it are:
 Ciliary body
 Posterior Chamber
 Anterior Chamber
 Angle Of the Anterior Chamber
 Aqueous out-flow system
ANATOMICAL CONSIDERATIONS OF
AQUEOUS HUMOR:

3.  It is the forward continuation of the choroid at ora serrata.
 Triangular cut section, anterior side of its forms the part of angle of ant.
and post. chamber. In middle attached to the iris . The outer side of its
lies against the sclera with suprachoroidal space in b/w.
 The inner side of the triangle is divided into two .
a) Pars Plicata(2-2.5mm): anterior part having finger-like ciliary
processes(corona ciliaris).
b) Pars Plana(5mm temporally & 3mm nasally): Posterior
smooth part is called orbicularis oculi
CILIARY BODY:

4. MICROSCOPIC STRUCTURE OF CILIARY
BODY:
It consists of following five layer:
I. Supraciliary lamina: • Outermost part of stroma and consists of collagen.
• Posteriorly ,it is a continuation of the suprachoroidal lamina and ant. It
continue with the anterior limiting membrane.
2. Stroma: • It consists of connective tissue of collagen and fibroblasts.
3. Layer of pigmented epithelium: • It is forward continuation of retinal pigmented epithelium . Anteriorly
, it continuation with the anterior pigmented epithelium.
4. Layer of Non-pigmented
epithelium:
• It forward continuation of sensory retina which stops at the ora serreta.
5. Internal limiting membrane: • It lines the nonpigmented epithelium and forward continuation of the
internal limiting membrane of the retina.
Ref : Anatomy and Physiology of Eye, A.K.KHURANA , pg- 66-67

5. STRUCTURE OF CILIARY
BODY

6. CILIARY MUSCLE:
• It is a non-straited muscle .Mainly 3 parts –
a) Longitudinal or meridional fibres - helps in aqueous outflow
b) Circular fibres- helps in accommodation
c) Radial fibres - helps in aqueous outflow
 CILIARY PROCESSES:
• The network capillaries consists of a thin endothelium with false pores which is lined by basement membrane.
• Stroma of a ciliary processes is thin and separated from the epithelial layer.It consists of ground substances,
collagen.
• The outer pigmented epithelium contains melanin granules . The inner non-pigmented epithelium is consist of
mitochondria , zonula occludentes
Ref : Anatomy and Physiology of Eye, A.K.KHURANA , pg- 67-68
Wolf Anatomy Of the Eye and Orbit, pg – 336-337

7. • Containing about 0.6 ml of aqueous humor.
• It is bounded by –
a) Anteriorly , by the posterior surface of the iris and
part of the ciliary body
b) Posteriorly , by the crystalline lens and its zonules
c) Laterally by the ciliary body
POSTERIOR CHAMBER:

8.  COMPARTMENTS OF POSTERIOR
CHAMBER:
1. PREZONULAR COMPARTMENT: • It lies b/w the posterior surface of the iris and anterior
surface of the zonular fibres.
2. ZONULAR
COMPARTMENT(CIRCUMLENTAL
SPACE):
• Centrally – equator of lens
• Peripherally – ciliary processes
• Anteriorly – posterior surface of anterior zonular fibres
• Posteriorly – anteriorly surface of posterior zonular
fibres
3. RETROZONULAR SPACE: • It lies b/w the posterior surface of zonules and
peripheral part of anterior vitreous face
Ref: Anatomy and Physiology of Eye, A.K.KHURANA , pg- 72
Wolf Anatomy Of the Eye and Orbit, pg – 335-336

9. • Anterior chamber volume is in the region of 220 μI,
• the average depth is 3.15 (range 2.6-4.4) mm.
• Chamber diameter varies from 11.3 to 12.4 mm
• It contains about 0.25ml aqueous humor
• Anteriorly by the inner surface of the cornea, except at its far
periphery where it is related to trabecular meshwork.
• Posteriorly it is bounded by the lens within the pupillary
aperture, by the anterior surface of the iris
• peripherally by the anterior face of the ciliary body.
ANTERIOR CHAMBER:

10. ANGLE RECESS IS FORMED BY -
1. CILIARY BAND : • In the angle recess, the most posterior landmark is
the dark ciliary band, which represents the anterior
face of the ciliary body including the insertion of
the ciliary muscle into the scleral spur. This lies at
the apex of the chamber angle.
2. SCLERAL SPUR: • The scleral spur is a pale, translucent narrow strip
of scleral tissue which is located anterior to the
ciliary band and marks the posterior boundary of
the corneosceral meshwork, as a white line in
gonioscopy.
3. TRABECULAR MESHWORK : • It is seen as a band just anterior to the scleral spur.
ANGLE OFANTERIOR CHAMBER:

11. 4. SCHWALBE’S LINE : • The anterior limit of the drainage angle
is termed Schwalbe's ring or line.
• It is formed by the prominent end of
Decement’s membrane of the cornea.
Ref: Wolf Anatomy Of the Eye and Orbit, pg – 279-
283

12.  DEVELOPMENT :
• By approximately 7 weeks of gestation (embryo 22-24 mm), the angle of the anterior chamber is
occupied by a nest of loosely organized undifferentiated mesenchymal cells that are destined to
develop into the trabecular meshwork.
• The posterior aspect of the angle is defined by mesodermal cells that are developing into the
vascular channels of the pupillary membrane.
• the 15th week of gestation, these cells meet the anterior surface of the developing iris, thus
demarcating the angle of the anterior chamber.
• By 7 months gestation the deepest part of the angle has receded to the level of Schlemm's canal
Ref: Wolf Anatomy Of the Eye and Orbit, pg – 633 -634

13.  HYPHAEMA :
• A traumatic hyphaema associated with IOP elevation due
to trabecular blockage by red blood cell.
• Blood clot in AC.
Ref – KANSKI,CLINICAL OPHTHALMOLOGY, PG - 379
ABNORMALITIES IN AC:

14.  HYPOPYON :
• Pus in AC
• Usually for inflammation(Uveitis etc).
 CELLS:
• Appear as small particles floating in aqueous.
• May be WBCs , RBCs or pigment cells.
 FLARE:
• Appears as hazy cloudy aqueous because severe fibrin ,protein exudate
• Usually found in uveitis , trauma , keratitis etc.
Ref – KANSKI,CLINICAL OPHTHALMOLOGY, PG - 379
HYPOPYON
CELLS AND FLARE

15. PHYSIOCHEMICAL PROPERTIES:
• Volume – 0.31ml(0.25ml anterior chamber & 0.06ml posterior chamber)
• Refractive index – 1.336
• Viscosity – 1.025-1.040
• Osmotic pressure – 3 to 5 mOsm/l(hyperosmotic to plasma)
• pH – 7.2(anterior chamber , slightly acidic)
• Rate of formation – 2.3 μl/min
PHYSIOLOGY OF AQUEOUS HUMOR :

16.  FUNCTION OF AQUEOUS HUMOR:
• MAINTENANCE OF INTRAOCULAR PRESSURE
• MATABOLIC ROLE
• OPTICAL FUNCTION
• CLEARING FUNCTION
 BIOCHEMICAL COMPOSITION OF AH:
 Water – 99.9%
 Proteins – 5to16mg/100(IgG and IgM present)
 Amino acids
 Non-colloidal constituents
 Insulin and steroid
 Prostaglandins
 Cyclic-Amp
Ref : Anatomy and Physiology of Eye, A.K.KHURANA , pg -76-78

17.  BLOOD-RETINAL BARRIER:
• The inner blood-retinal barrier composed of the tight junction of
retinal capillaries , endothelial cells
• The outer barrier consists of tight junctional complex(zonula
occludens and zonula adherans)which are located b/w RPE cells.
 BLOOD-AQUEOUS BARRIER :
• It is formed by the tight junction b/w the cells of the inner non-
pigmented epithelium of the ciliary body and the non-fenestrated
endothelium of the iris capillaries.
Ref : Anatomy and Physiology of Eye, A.K.KHURANA ,pg - 79
BLOOD-OCULAR BARRIER:

18. • The ciliary processes are the site of aqueous production . The aqueous humour is primarily derived
from the plasma within the capillary network of the ciliary processes.
Three main mechanism:
• Diffusion – 10%
• Ultrafiltration – 20%
• Active transfer(secretion) – 70%
FORMATION OF AQUEOUS HUMOR :

19.  DIALYSIS:
• When a solution of protein and salt is separated from plain water and a less concentrated
salt solution by a membrane permeable to salt and water and not in protein.
 ULTRAFILTRATION:
• It refers to occurrence of dialysis under hydrostatic pressure or osmotic gradient.
 Lead to formation of stromal pool . By ultrafiltration , most substances pass easily from
the capillaries of the ciliary processes, across the stroma and b/w the pigmented epithelium
cells before accumulating behind the tight junctions of the non-pigmented epithelium.
ULTRAFILTRATION:

20. • It is an active process that selectively
transport some substances across the
cell membrane .
• Energy is required . In aqueous
formation , water-soluble substances
of larger size or greater charge are
actively transported across cell
membrane.
SECRETION(ACTIVE TRANSFER):

21. • In this process ,there occurs a net flux of the particles from areas of high
concentration to areas of low concentration.
• Diffusion also occurs across a semipermeable membrane.
• Fick’s law of diffusion :
Rate of movement = K(C1 – C2);
Where, C1 = Concentration of substance on side with higher concentration
C2 = Concentration of substance on side with lower concentration
K = Constant which depends on nature and permeability of membrane,
temparature .
Ref: Anatomy and Physiology of Eye, A.K.KHURANA , pg -80 - 84
DIFFUSION:

22. Methods of
measurement
Perilimbal
suction cup
perfusion
Radioactive
labelled
isotopes
IV PAH or
fluorescein
Fluorescein
techniques
Class 1 method Class 2 method
Tonography
Ref: Anatomy and Physiology of Eye, A.K.KHURANA , pg -84

23. TRABECULAR MESHWORK:
• the trabecular meshwork is a spongework of connective tissue beams which are arranged
as superimposed perforated sheets.It bridge the scleral sulcus and converts it into tube.
MICROSCOPIC STRUCTURE:
UVEAL MESHWORK:
• The inner uveal meshwork (1-2 layers) are cord-like trabecule . The innermost trabeculae
may pass from the ciliary muscle almost to the region of Schwalbe's ring.
AQUEOUS OUTFLOW SYSTEM:

24.  CORNEOASCLERAL MESHWORK :
• It forms middle portion and extends from
scleral spur to the lateral wall of the scleral
sulcus . It consists of flat sheets of trabeculae.
 JUXTACANALICULAR(ENDOTHELIA
L)MESHWORK:
• It forms the outermost portion of the
trabecular meshwork . It is part of the
trabecular meshwork mainly offers the
normal resistance to aqueous outflow

25.  SCHLEMM’S CANAL:
• The canal of Schlemm is a narrow circular tube some 36 mm in circumference, which is lined by
endothelium . It lies in the outer portion of the internal scleral sulcus and contain giant vacuoles.
• The endothelial cells lining the outer wall of the Schlemm’s canal openings are smooth and flat . It contains
numerous opening of collector channels.
 COLLECTOR CHANNELS:
• It also called intrascleral aqueous vessels . The collector channels are lined by vascular endothelium .
• Direct system – It is formed by eight larger vessels which run a short intrascleral course and terminate
directly into the episcleral veins . They appear as clear vessels with aqueous and have been called aqueous
veins.
• Indirect system – It is constituted by three interconnecting venous plexus – the deep intrascleral plexus, mid-
intrascleral plexus and episcleral plexus
 EPISCLERAL VEINS:
• Most aqueous vessels drain into the episcleral veins.the episcleral veins drain into the cavernous sinus via
the anterior ciliary and superior ophthalmic veins.
Anatomy and Physiology of Eye, A.K.KHURANA , pg -76-78
Wolf Anatomy Of the Eye and Orbit, pg – 285 - 295

26. AQUEOUS HUMOR DRAINAGE:

27. Aqueous production
(Ciliary process)
Posterior Chamber
Trabecular
Meshwork
Anterior Chamber
Ciliary body
Venous circulation
of ciliary body,
sclera, orbit
Suprachoroidal
Space
Systemic
circulation
Episcleral veins
Collector Channels
Schlemm’s Canal
AQUEOUS HUMOR
DRAINAGE
Trabecular
(conventiona
l)outflow(90
%)
Uveoscleral
outflow(10%
)

28. GLAUCOMA
(When a IOP is elevated to
damage vision)
Primary Open-Angle
Glaucoma
(the elevation in IOP is caused by
increased resistance in drainage
channels)
Angle-Closure Glaucoma
(the obstruction to aqueous
outflow is caused by closure of
the chamber of angle by the
peripheral iris)
DISORDER:
Ref : Kanski Clinical Ophthalmology , page - 182

29. PROSTAGLANDIN DERVATIVES:
• The major mode of prostaglandin action is the enhancement of uveoscleral aqueous
outflow , also increased trabecular outflow facility.
• E.g – Latanoprost , Travoprost etc.
BETA-BLOCKERS:
• Beta-blockers reduce IOP by decreasing aqueous production , mediated by an effect on
ciliary epithelium.
• E.g – Timolol, Betaxolol , Metipranolol etc.
ANTIGLAUCOMA DRUGS:

30.  ALPHA-2-AGONISTS:
• Alpha-2 receptors stimulation decreases aqueous synthesis via an effect on the
ciliary epithelium and increases uveoscleral outflow
• E.g – Brimonidine etc.
 TOPICAL CARBONIC ANHYDRASE INHIBITORS :
• The carbonic anhydrase inhibitors are related to sulfonamide antibiotics. They
lower IOP by inhibiting aqueous secretion.
• E.g – Dorzolamide , Brinzolamide etc.
 MIOTICS:
• Miotics are cholinergic agonists that are used in treatment of angle closure
glaucoma.
• E.g – Pilocarpine etc.
Ref : Kanski Clinical Ophthalmology , page – 330-333