The anatomy of the anterior chamber and the diagnosis as well as treatment of ACG

1. Ea Raksmey
First Year Resident
2014

2. Outline
Anatomy
IOP and Aqueous Humor Dynamics
Pathophysiology
Definition of Glaucoma
Classification
Diagnosis
Medical Management
Surgical Management

3. Anatomy
Ciliary Body:
6-7 mm wide
Has 2 parts:
○ Pars plana:
Avascular, smooth pigmented
4 mm wide
From ora serrata to ciliary process
○ Pars plicata:
Vascularized
Has around 70 radial folds (ciliary process)
Zonular fibers attachment

4. Anatomy
Lined by 2 layers of epithelial cells
○ Nonpigmented Epithelium (NPE)
○ Pigmented Epithelium (PE)
The apices of NPE and PE are fused
together by a system of junctions and
cellular interdigitations (Blood Aqueous
Barrier)

5. Anatomy

6. Anatomy
Anterior Chamber
Between Cornea (front) and Iris (back)
AC Angle lies at the corner of Cornea-Iris
junction, consists of:
○ Schwalbe Line
○ Schlemm Canal and TM
○ Scleral Spur
○ Ciliary Process
○ Iris

7. Anatomy

8. Anatomy
Schwalbe’s Line
Is the anatomical line found on the interior
surface of the cornea, and delineates the
outer limit of corneal endothelium layer.
It represents the termination of Descemet’s
membrane

9. Anatomy
Trabecular Meshwork
Is a circular spongework of connective
tissue lined by trabeculocytes, that have
contractile properties and may influence
outflow resistance
3 portions:
○ Uveal Portion
○ Corneoscleral Meshwork
○ Juxtacanalicular Tissue

10. Anatomy

11. Anatomy
Schlemm Canal
Circular tube resembling a lymphatic vessel
Contribute to the pressure-dependent
outflow of aqueous

12. IOP and Aqueous Dynamics
Aqueous Humor
Clear fluid that fills the PC and AC
Secreted by ciliary epithelium (NPE)
Flow rate 2-3 µL/mn
Functions:
○ Provide nutrients to avascular zones
○ Remove metabolic wastes
○ Maintain IOP
○ Clear medium for transmission of light

13. IOP and Aqueous Dynamics

14. IOP and Aqueous Dynamics
AH secretion into the PC result from:
Active Secretion: Na/K ATPase pump
Ultrafiltration: Hydrostatic/Oncotic pressure
Simple Diffusion: Different concentration

15. IOP and Aqueous Dynamics
Outflow: 0,22-0,30µL/mn/mmHg
Pressure-dependant:
○ Trabecular-Schlemm canal pathway
○ 80-95 % of outflow
Pressure-independent:
○ Non-trabecular or uveal pathway
○ 8-15 % of outflow

16. IOP and Aqueous Dynamics
Composition of AH
Inorganic Ions:
○ Na+, K+, Mg
○ Ca+
○ Cl-, HCO3-
○ Iron, copper, zinc
Organic Ions:
○ Lactate and Ascorbic Acid
Carbohydrates
Glutathione and Urea
Proteins
Enzymes

17. IOP and Aqueous Dynamics
IOP: 11-21mmHg
Balance between the aqueous inflow
and outflow
Fluctuation:
Higher in morning, lower in noon and
evening
Heart rate
Blood pressure
Respiration

18. Pathophysiology
Angle Closure
Refers to the occlusion of the TM by the
peripheral iris (Iridotrabecular Contact or
ITC)  Obstructing the aqueous outflow
Can be divided into two types:
○ Primary
○ Secondary

19. Pathophysiology
Primary Angle Closure Glaucoma
Risk Factors:
○ Race: Blacks 20-40 times higher than whites
○ Gender: Women are more likely to have
PACG than men due to shallower AC
○ Age: 55-65 years old
○ Refraction: Hyperopic
○ Inheritance: genetics

20. Pathophysiology
Secondary Angle Closure Glaucoma
caused by impairment of aqueous outflow
secondary to apposition between the
peripheral iris and the trabeculum
2 mechanisms:
○ “Pushing” of Iris from behind
Pupillary block, plateau iris syndrome, malignant
glaucoma, dislocated lens
○ “Pulling” of Iris forward
Iris incarceration after trauma, migration of corneal
endothelium, epithelium downgrowth

21. Definition
Glaucoma is a group of diseases
characterized by:
Optic neuropathy with CDR >0,5
Visual field loss
Color vision defect
+/- elevated IOP

22. Classification
Angle Closure Glaucoma
Primary Angle Closure Glaucoma
○ Acute Angle Closure
○ Subacute Angle Closure
○ Chronic Angle Closure
Secondary Angle Closure Glaucoma:
○ With Pupillary Block
○ Without Pupillary Block

23. Diagnosis
Primary Angle Closure Glaucoma
Acute Angle Closure
○ Definition: IOP rises rapidly as a result of
relatively sudden blockage of the TM by the
iris
○ Symptoms:
Ocular pain
Headache
Blurred vision
Rainbow-colored halos around lights
Nausea
Vomitting

24. Diagnosis
○ Signs:
VA 6/60-HM
High IOP
Congested episcleral and conjuctival blood vessels
Corneal edema
Shallow AC (aqueous flares and cells)
Iris bombé
Mid-dilated, sluggish and irregularly shaped pupil
Glaukomflecken

25. Diagnosis
Subacute or Intermittent Angle Closure
○ Blurred visions, halo
○ Mild pain by elevated IOP
○ IOP is normal between episodes
○ May  to chronic angle closure glaucoma or
acute attack if not resolve spontaneously

26. Diagnosis
Chronic Angle Closure
○ May develop after acute attack in which
synechial closure persists
○ Or after AC chamber close gradually or IOP
slowly rises (Creeping Angle)
○ Resembles open angle glaucoma due to:
Lack of symptoms
Modest IOP elevation
Optic nerve damage
Characteristic VF loss

27. Diagnosis
Clinical Evaluation:
History
Ocular Examination
Gonioscopy
Optic Nerve
Visual Field Test

28. Diagnosis
Ocular Examination
Complete ocular examination
AC:
○ Van Herick method:

29. Diagnosis
Gonioscopy

30. Diagnosis
Shaffer System: angle between TM and iris
○ Grade 4:
35-45 degrees
Wide open angle
Visible up to iris roots
○ Grade 3:
25-35 degrees
Visible up to scleral spurs
○ Grade 2:
20 degrees
Visible up to TM
○ Grade 1:
10 degrees
Visible up to Schwalbe line
○ Grade 0:
Angle completely closed

31. Diagnosis
Focal ischemic disc
Myopic disc with glaucoma
Senile sclerotic disc
Concentrically enlarging discs

32. Diagnosis
Baring of circumlinear blood vessels
Bayoneting
Collaterals
Loss of nasal NRR
Lamina dot sign
Disc hemorrhage
Sharpened edge

33. Diagnosis
Visual Field Test
Earliest step
Paracentral
Nasal step
Arcuate-shaped
Enlargement
Deepening
Ring scotoma
End stage

34. Diagnosis
Secondary Angle Closure Glaucoma
With Pupillary Block: Lens-Induced
○ Phacomorphic Glaucoma:

35. Diagnosis
Secondary Angle Closure Glaucoma
With Pupillary Block: Lens-Induced
○ Ectopia Lentis

36. Diagnosis
Secondary Angle Closure Glaucoma
Without Pupillary Block:
○ Neovascular Glaucoma
○ Iridocorneal Endothelial Syndrome
○ Tumours
○ Inflammation
○ Malignant glaucoma (aqueous misdirection)

37. Treatment
Goal of treatment:
Preserve visual function
Lowering IOP
Prevent VF loss
Neuroprotection

38. Treatment
Medical management
Decrease aqueous production:
○ Beta blockers
○ Alpha agonist
○ Carbonic anhydrase inhibitor
Increase uveoscleral outflow:
○ PG analogs
Increase TM outflow:
○ Parasympathomimetic
Induce intravascular osmolarity:
○ Hyperosmotic agents

39. Treatment

40. Treatment
Surgical treatment
Trabeculectomy
Artificial filtering shunt
Laser:
○ Argon laser trabeculoplasty
○ YAG laser iridotomy
○ Laser iridoplasty

41. FIN

42. References
Section 2, Fundamentals and Principles of Ophthalmology.
(2010-2011). Singapore, the American Association of
Ophthalmology
Section 10, Glaucoma. (2010-2011). Singapore, the
American Association of Ophthalmology
Kenski, J. Jack. MD, (2011). Clinical Ophthalmology: A
Systemic Approach, 7th Edition. Elsevier Saunders, UK.
Yanoff, M. and Duker, J. (2008). Yanoff & Duker:
Ophthalmology, 3rd Edition. Elsevier Saunders, UK.
Ehlers, Justis, P.; Shah, Chirag, P. (2008). Will’s Eye Manual,
The Office and Emergency Room Diagnosis and Treatment
of Eye Diseases, 5th Edition. Lippincott Williams & Wilkins