The document discusses the anatomy and physiology of aqueous humor dynamics. It describes the structures involved in aqueous humor formation, which occurs primarily through active transport by the non-pigmented ciliary epithelium. These include the iris, ciliary body, trabecular meshwork, Schlemm's canal, and collector channels. Aqueous humor is formed at a rate of around 2.3 μl/min through diffusion, ultrafiltration and secretion across the ciliary epithelium. Various factors influence aqueous humor production and outflow through the trabecular meshwork into episcleral veins.

1. AQUEOUS HUMOR DYNAMICS
BY DR. RAHUL
MODERATOR:DR. DHAMANKAR

2. ANATOMY
UVEAL TRACT CONSIST OF
IRIS
CILIARY BODY
CHOROID

3. IRIS
CILIARY ZONE
PUPILLARY ZONE
MICROSCOPIC
ANTERIOR LIMITING LAYER
STROMA
ANTERIOR PIGMENTED EPITHELIAL LAYER
POSTERIOR PIGMENTED EPITHELIAL LAYER

4. CILIARY BODY
FORWARD CONTINUATION OF CHOROID
ANTERIOR PART HAVING FINGER LIKE
CILIARY PROCESSES CALLED PARS PLICATA
POSTERIOR SMOOTH PART PARS PLANA

5. CILIARY PROCESSES
THESE ARE FINGER LIKE PROJECTIONS
70-80 IN NUMBER
2 MM LONG AND 0.5 MM IN D
WHITE IN COLOUR
EACH PROCESS LINED BY 2 LAYERS OF EPITHELIAL CELLS
IT CONTAINS BLOOD VESSELS AND LOOSE CONNECTIVE
TISSUSE
SITE OF AQUEOUS PRODUCTION

6. ANATOMY

7. Ciliary epithelium
Nonpigmented - inner layer, adjacent to aqueous in
the posterior chamber,
consisting of columnar cells (cuboidal in pars plana).
Intercellular tight junctions (zonulae occludens) form
major element of blood-aqueous barrier.
Tips or crests of nonpigmented ciliary epithelia are
site of active secretion,
hence numerous mitochondria, rough
endoplasmic reticulum, pinocytic

8. Angle of anterior chamber
Clinically angle structures can be visualized by
goniosciopic examination
Starting from posterior to anterior
1)Ciliary band
2)Scleral spur
3)Trabecular meshwork
4)Schwalbes line

9. . Shaffer’s system of grading the angle width
Grade Angle width Configuration Chances of closure Structures
visible on gonioscopy
IV 35-45o Wide open Nil SL, TM, SS, CBB
III 20-35o Open angle Nil SL, TM, SS
II 20o Moderately narrow Possible SL, TM
I 10o Very narrow High SL only
0 0o Closed Closed None of the angle structures visible
SL = Schwalbe’s line, TM = Trabecular meshwork, SS = Scleral spur,
CBB = Ciliary body band

10. Shaffer’s system of grading
the angle width

11. Shaffer’s system of grading
the angle width

14. AQUEOUS OUTFLOW SYSTEM
IT INCLUDES
TRABECULAR MESHWORK
SCHLEMMS CANAL
COLLECTOR CHANNLES
AQUEOUS VEINS
EPISCLERAL VEINS

19. TRABECULAR MESHWORK
IT IS SIEVE LIKE STRUCTURE THROUGH WHICH AQUEOUS
HUMOUR LEAVES EYE
CONSIST OF 3 PORTIONS
1)UVEAL MESHWORK
-Innermost part of TM, extends from iris root and ciliary body to
schwalbes line
-the arrangement of uveal trabecular bands create opening of 25 mu to
75 mu
-least resistance to flow

20. 2)CORNEOSCLERAL MESHWORK
-larger middle portion ,extends from scleral spur to
lateral wall of scleral sulcus
-opening 5 mu to 50 mu
Moderate resistance to flow

21. 3)JUXTACANLICULAR , ENDOTHELIAL
MESHWORK
It form outer most part
Lined on either side by endothelium
IT MAINLY OFFERS NORMAL RESISTANCE TO
AQUEOUS OUTFLOW

23. AQUEOUS DRAINAGE

24. SCHLEMMS CANAL
IT IS ENDOTHELIAL LINED OVAL CHANNEL PRESENT
CIRCUMFERENTIALLY IN SCLERAL SULCUS
THE ENDOTHELIAL CELLS OF ITS INNER WALL ARE
IRREGULAR, SPINDLE SHAPED AND CONTAIN GAINT
VACUOLES
THE OUTER WALL OF THE CANAL IS LINED BY
SMOOTH FLAT CELLS
CONTAINS OPENING OF COLLECTOR CHANNELS

25. COLLECTOR CHANNELS
ALSO CALLED INTRASCLERAL AQUEOUS VESSELS
ABOUT 25-35 IN NUMBER
LEAVES SCHLEMMS CANAL AT OBLIQUE ANGLES TO
TERMINATE INTO EPISCLERAL VEINS
NO VALVES ARE PRESENT IN COLLECTOR CHANNELS
THESE INTRASCLERAL AQUEOUS VESSELS CAN BE
DIVIDED INTO TWO SYSTEM

27. DIRECT SYSTEM
ON SLIT LAMP , THESE APPEAR AS CLEAR VESSELS WITH
AQUEOUS CALLED AS AQUEOUS VEINS BY ASCHER
AS THESE VESSELS TERMINATE INTO EPISCLERAL AND
CONJUNCTIVAL VEINS IN LAMINATED JUNCTIONS ,CALLED AS
LAMINATED VEIN OF GOLDMANN

28. EPISCLERAL VEINS
 MOST OF AQUEOUS VESSELS DRAIN INTO EPISCLERAL VEINS

29. Aqueous humor
 is a relatively cell free,protein free
 fluid formed by non pigmented ciliary epithelium
Slightly hypertonic
Acidic , PH IS 7.2
Marked excess of ascorbate
Marked deficit of proteins
Slight excess of chloride and lactic acid

30. PHYSICOCHEMICAL PROPERTIES
VOLUME
0.31 ML (0.25 ml in AC 0.06 ml in PC)
REFRACTIVE INDEX
1.336 SLIGHTLY LOWER THAN CORNEA
SLIGHT DIVERGENCE OF LIGHT AS IT PASS CORNEA -AQUEOUS
INTERFACE
DENSITY
SLIGHTLY GREATER THAN WATER

31. OSMOTICS PRESSURE
AQUEOUS IS SLIGHTLY HYPEROSMOTIC TO PLASMA BY 3 TO 5
MOSM/L
PH
ACDIC IN AC 7.2
RATE OF FORMATION
2.3 Ul/min

32. Formation of aqueous humour
Ciliary processes are site of aqueous production
The various constituents of aqueous humour have to
pass 3 tissue layers of cililary processes
1)capillary wall
2)stroma
3)two layers of epithelium

33. Formation processes involved
1)diffusion 10 %
2)Ultarafiltration 20%
3)secretion 70%

34. DIFFUSION
Diffusion - lipid-soluble substances are transported
through the lipid portions of the cell membrane
proportional to a concentration gradient across the membrane

35. ULTRAFILTRATION
Ultrafiltration - water and water-soluble substances,
limited by size and charge, flow through theoretical
micropores in the cell membrane in response to an
osmotic gradient or hydrostatic pressure; influenced
by
intraocular pressure,
blood pressure in the ciliary capillaries,
and plasma oncotic pressure

36. Diffusion and ultrafiltration are both passive
mechanisms, with lipid- and water-soluble substances
from the capillary core traversing the stroma and
passing between pigmented epithelial cells and
limited by the tight junctions of the non-pigmented
epithelial cells
c. Active transport (secretion) - water-soluble
substances

37. SECRETION
Active transport (secretion) - water-soluble substances
of larger size or greater charge are actively
transported across the cell membrane, requiring the
expenditure of energy; Na-K ATPase and glycolytic
enzymes are present in nonpigmented epithelial cells.
Active transport is decreased by hypoxia, hypothermia,
and any inhibitor of active metabolism.
 Active transport accounts for the majority of aqueous
production.
MEDIATED BY GLOBULAR PROTEINS IN MEMBRANE

38. STEPS OF AQUEOUS FORMATION

39. FORMATION OF STROMAL POOL

40. PASSIVE TRANSPORT ACROSS NON PIGMENTED
CILIARY EPITHELIUM
Active transport across non pigmented epithelium
result in osmotic and electical gradient
Sodium is primarily responsible for movement of
water into posterior chamber and its secretion is
major factor in formation of aqueous

41. ACTIVE TRANSPORT OF STROMAL FILTRATES
The tight junction between non pigmented epithelial
cells creat part of blood aqueous barrier
Substances actively transported are
1)NA
2)chloride
3)potassium
3)ascorbic acid
4)amino acid n bicarbonate

42. Control of aqueous formation
ADRENERGIC INNERVATION
CILIARY EPITHELIUM DOES NOT SHOW NERVE SUPPLY , BUT
VESSELS HAVE NERVE SUPPLY
MAJORITY OF RECEPTORS IN CILIARY BODY ARE α2 & β2
RECEPTORS
STIMULATION OF α 2 RECEPTOR LOWER AQUEOUS HUMOUR
PRODUCTION THROUGH INHIBITION OF ADENYLATE CYCLASE
STIMULATION OF β 2 RECEPTOR LEADS TO INCREASE IN
PRODUCTION BY STIMULATION OF ADENYLATE CYCLASE

43. α 2 AGONIST LIKE CLONIDINE AND β2
ANTAGONIST LIKE TIMOLOL DECREASES
AQUEOUS PRODUCTION

44. Functions
It serves the circulatory function for the avascular
tissues of the eye.
Brings essential nutrients such as oxygen glucose and
amino acids .
Removes harmful substances such as lactic acid and
CO2

45. Maintains the IOP and structural integrity of the eye.
Contains high concentrate of ascorbate which act to
scavenge free radicles and protects against effects of
radiation.
Facilitates cellular and humoral immunity in case
inflamation and infections

46. Conditions decreasing SECRETION
1.General conditions
 Age
Diurnal
Exercise

47. 2. Systemic conditions
Decrease BP
Reduction in internal carotid arterial blood flow
Diencephalic stimulation
Acidosis
General anaesthesia

48. 3.Local conditions
Increased IOP
Uveitis
Retinal detachment
Retrobulbar anaesthesia
Choroidal detachment

49. 4.Pharmacological agents
1)BETA BLOCKERS
DECREASE IN AQUEOUS PRODUCTION BY BETA 2 RECEPTOR
STIMULATION IN CILIARY PROCESSES
TIMOLOL ,
BETAXOLOL ,
LEVOBUNOLOL
CARTEOLOL

50. 2)PILOCARPINE
PILOCARPINE CONTRACTS LONGITUDINAL MUSCLE OF CILIARY
BODY AND OPENS SPACE IN T.M , SO MECHANICALLY
INCREASEING AQUEOUS OUTFLOW
3)CARBONIC ANHYDRASE INHIBITOR
BY DECREASING AQUEOUS SECRETION
DORZOLAMIDE
4) PROSTAGLANDINS
ACT BY INCREASING UVEO SCLERAL OUTFLOW OF AQUEOUS

51. ADRENERGIC DRUGS
-SELECTIVE ALPHA 2 ADRENERGIC AGONIST BY DECREASING
AQUEOUS PRODUCTION
-APRACLONIDINE
-BRIMONIDINE

52. CONDITIONS DECREASING SECRETION
5.Surgical conditions
Cyclodialysis
Cyclocryothermy
Cyclodiathermy
Cyclophoto coaguation.

54. THANK YOU