This document provides information about glaucoma including its definition, epidemiology, classification, anatomy of the anterior chamber, physiology of the anterior chamber, measurement of intraocular pressure, optic disc examination, visual field testing, and the diagnosis of glaucoma. Glaucoma is a condition associated with elevated intraocular pressure that can cause damage to the optic nerve and vision loss. It is a leading cause of irreversible blindness worldwide.

1. Dr. Md. Almas Hossain
Associate Professor & Head
Department of Ophthalmology
Sylhet MAG Osmani Medical College.
Almas Eye Care
& Phaco Centre
Glaucoma

2. Definition Of Glaucoma
Glaucoma is a clinical condition of eye that is
often associated with elevated intraocular
pressure in which damage to the optic nerve &
impaired of vision even blindness.
Glaucoma is the leading cause of irreversible
blindness in the world.

3. EPIDEMIOLOGY
In the world glaucoma is the second leading
cause of blindness.
An estimated 13.5 million people may have
glaucoma & 5.2 million of those may be blind.
POAG is most common form of glaucoma
(75%).
Female are more affected than male.

4. Four Key Facts About Glaucoma
Glaucoma is a leading cause of blindness
Glaucoma can cause blindness if it is left untreated.
There is no cure (yet) for glaucoma
Glaucoma is not curable, and vision lost cannot be regained. With medication and/or
surgery, it is possible to halt further loss of vision. Since glaucoma is a chronic
condition, it must be monitored for life time.
Everyone is at risk for glaucoma
Everyone is at risk for glaucoma from babies to senior citizens. Older people are at a
higher risk for glaucoma but babies can be born with glaucoma.
There may be no symptoms to warn you
With open angle glaucoma, the most common form, there are virtually no symptoms.
Usually, no pain is associated with increased eye pressure.

5. Classification Of Glaucoma
Congenital or Developmental
Primary - due to primary developmental anomaly at the
angle
Secondary - associated with other ocular or systemic
disorder
Acquired
Primary
Angle closer glaucoma (PACG)
Open angle glaucoma (POAG)
Secondary - associated with some ocular or systemic

7. Anterior Chamber Anatomy
Anterior chamber is an angular space.
Anteriorly by the posterior surface of the cornea.
Posteriorly by the lens within the pupillary aperture,
anterior surface of the iris and a part of ciliary body.
Anterior chamber is 3 mm deep and it contains 0.25 ml of the
aqueous humor.
Chamber Volume decreases by 0.11 µL/year.
Diameter: 11.3-12.4mm.
Depth: 3.15mm (2.6- 4.4mm).
If AC depth <2.5mm is at risk for ACG.

8. Anterior Chamber Anatomy cont.
AC angle: extends from Schwalbe’s line (the
termination of Descemet’s membrane on the peripheral
cornea) posteriorly to the trabecular meshwork, scleral
spur, and, in some cases, ciliary body where an acute
angle is formed with the peripheral iris.
Trabecular meshwork: this is a reticulated band of fibro
cellular sheets, with a triangular cross-section, base
towards the scleral spur
Scleral spur: firm fibrous projection from the sclera.
From Anterior To Posterior

9. Anterior Chamber Anatomy cont.
Schlemm’s canal: circumferential septate drain, with an
inner wall of endothelium containing giant vacuoles
and an outer wall obliquely punctuated by collector
channels that drain into the episcleral veins.
Ciliary body: comprises the ciliary muscle and ciliary
epithelium, arranged anatomically as the pars plana and
pars plicata (containing the ciliary processes).
Contraction of the ciliary muscle permits
accommodation and increases trabecular outflow.

11. Physiology Of Anterior Chamber
1. Aqueous production
Aqueous humor is a colorless, plasma-like fluid produced by
the ciliary epithelium of the ciliary body.
It is a structurally supportive medium, providing nutrients to
the lens and cornea.
It differs from plasma in having lower glucose (80% of plasma
levels), low protein (assuming an intact blood aqueous
barrier), and high ascorbate.
It is formed at about 2.5 𝝻𝝸/min by a combination of active
secretion (70%), ultrafiltration (20%), and osmosis (10%).

12. 2. Aqueous outflow
Trabecular (conventional) route -
(About 70 % of outflow)
Most aqueous humor leaves the eye by this passive
pressure-sensitive route - then transported via collector
channels to the episcleral veins and on to the general
venous circulation.
Uveoscleral (unconventional) route -
(About 30% of outflow)
The aqueous passes across the iris root and ciliary
body into the supraciliary and suprachoroidal
spaces, from where it escapes via the choroidal
Physiology Of Anterior Chamber cont.

13. Angular Grade Width (in degrees) Grade
Clinical
Interpretation
Wide Open 35-45 4
Angle closure
impossible
Open 20-35 3
Angle closure
impossible
Moderate Narrow 10-20 2
Angle closure
possible
Extreme Narrow 10 or less 1
Angle closure
imminent
Closed 0 0 Closure present
Grading Of The Angle (Schaffer’s) (Gonioscopy)

14. Grade 4 (35-45 )
• Ciliary body easily visible.
Grade 3 (25-35 )
• At least scleral spur visible.
Grade 2 (20 )
• Only trabeculum visible.
• Angle closure possible but
unlikely.
Grade 1 (10 )
• Only Schwalbe line and
perhaps top of trabeculum
visible.
• High risk of angle closure.
Grade 0 ( 0 )
• Iridocorneal contact present.
• Apex of corneal wedge not
visible.
Shaffer grading of angel width

15. Optic Disc/ON Head
The optic disc or optic nerve head is the point
of exit for ganglion cell axons leaving the eye.
As there are no rods or cones overlying
the optic disc, it corresponds to a small blind
spot in each eye.
The ganglion cell axons form the optic nerve
after they leave the eye.

16. Optic Disc cont.
Cup Disc Ratio
• The cup-to-disc ratio (CDR) is a measurement used
in ophthalmology and optometry
• If it fills 7/10 of the disc, the ratio is 0.7.
• The normal cup-to-disc ratio is 0.3.
• A large cup-to-disc ratio may imply glaucoma or
other pathology.
• However, cupping by itself is not indicative of
glaucoma.

17. Cup Disc Ratio (CDR)

19. Visual Field
The visual field refers to the total area in which objects can
be seen in the side vision as focus of eye on a central point.
Usually done by
 Confrontation visual field exam:
 Automated perimetry
Visual field extension
A normal visual field is an island of vision measuring
90 ̊ temporally to central fixation, 50 ̊ superiorly, 50 ̊
nasally & 60 ̊ inferiorly.

20. HVFA Analyzer

21. Intraocular Pressure (IOP)
It is the fluid pressure inside the eye.
Normal IOP ranges between 10-21 mm of Hg
Two main factors concerned with the maintenance of
IOP
• Rate of secretion &
• Outflow of the aqueous humor.
In normal condition the rate of aqueous
production is relatively constant but outflow
may vary due to the resistance of the exit

22. Factors Modifying IOP
Physiological variations
Normally fluctuates 2-5 mm Hg through out the
day.
 Tendency to higher in the morning & lower in the
afternoon & evening.
 With the venous pressure – the Valsalva maneuver
temporarily ↑ IOP.
 With the arterial pressure – with the ↑ of BP
causing transient ↑ of IOP.

23. Local mechanical factors
Dilatation of the pupil - ↑ IOP if AC shallow.
Intumescent cataract – rapid ↑ size of the lens - ↑ IOP.
Pressure from outside of the eye – forceful blepharospasm causing ↑
IOP.
Pharmacological factors
Pilocarpine – reliving the pupillary block & open the drainage
channel in acute closed angle glaucoma - ↓ IOP.
𝛽-Blockers - ↑ aqueous outflow - ↓ IOP.
Acetazolamide – reduction of aqueous production - ↓ IOP.
Epinephrine - reduction of aqueous production & ↑ outflow- ↓ IOP.
Factors Modifying IOP cont.

24. Instrumental tonometry –
Contact tonometer
Indentation tonometer
Schiotz tonometer
Applanation tonometer (AT)
Goldman AT (slit lamp
mounted)
Parkin’s hand held AT
Non contact tonometer
Air puff non contact
tonometer
Others –
Tonopen
Measurement Of IOP (Tonometry)
Digital Tonometry – roughly assessed by digital palpation by the
two index fingers through the upper lid above the tarsal plate.

25. Schiotz
Tonometer

26. Goldman Applanation Tonometer

27. Parkin’s hand held

28. Air Puff Non Contact

29. Tonopen

30. Measuring IOP with Tonopen

31. Ocular Hypertension (OHT)
 OHT describes an IOP >21 mmHg in the
presence of a healthy OD and normal VF.
 5–7% of those aged >40 having an IOP
>21mmHg.
 In the absence of glaucomatous damage, it is
difficult to differentiate those in whom such an
IOP is physiological from those in whom it is
pathological.

32. Risk Factors For Ocular Hypertension
• Older age.
• Higher IOP.
• Larger C/D ratio.
• Greater pattern SD.
• Thinner CCT: Normal CCT 540 microns.

33. When Needed To Treat OHT ?
There is considerable variation in practice.
• Isolated OHT: if IOP >27mmHg.
• OHT and suspicious disc: if IOP >21mmHg.
• OHT and thin cornea: if IOP >21mmHg.
• OHT and only eye.
• OHT and CRVO or AION in either eye.
• OHT and FH of glaucoma (especially of blinding
disease).

34. Normotensive glaucoma (NTG)
Also known as low tension or normal pressure
glaucoma, is a form of glaucoma in which damage
occurs to the optic nerve without eye pressure exceeding
the normal range.
In general, a "normal" pressure range is between 12-21
mmHg.
Generally believed to occur either because of an
unusually fragile optic nerve that can be damaged
despite of normal IOP.

35. Normotensive glaucoma (NTG) cont.
Risk factors
Age – more common elderly but up to 1/3rd may be < 50
yrs.
Ethnicity – more common in Japan.
Sex – female predominance.
Clinical Features
Usually asymptomatic.
OD change – as POAG.
Visual field – as POG.
Differential diagnosis
POAG, Migraine,

36. A. Raised IOP
• >21mmHg
B. Abnormal disc
• C/D ratio asymmetry
• Large C/D ratio for disc
size
• NRR notch/thinning
• Disc haemorrhage
• Vessel bayoneting/nasally
displaced
C. VF defect
• Nasal step
• Paracentral scotoma
• Arcuate scotoma
• Altitudinal scotoma
• Residual temporal or
central island of vision
Glaucoma Triad

37. Diagnosis Of Glaucoma
Is based upon
 Intraocular pressure ( IOP ) and its
measurement. (tonometry)
 Optic disc examination (CFP)
 Visual Field examination ( Perimetry )
 Angle structure study (Gonioscopy)
 Central corneal thickness (CCT)

38. THANKSALL
To be continued