2. Glaucoma: What do I want to know
The aim of today’s lecture is to:
1.Know what glaucoma is
2.Be able to identify a patient with glaucoma
3.Know what the basic work up is
4.Have some familiarity with visual fields
5.Have some familiarity with ONH imaging
6.Have a basic understanding of medical rx
7.Have some familiarity with surgical and laser Rx
3. Glaucoma: What we will cover
1.Definition of glaucoma
1.Definition
2.Risk factors
3.Epidemiology
2.Diagnosis of glaucoma
1.IOP
2.Gonioscopy
3.ONH appearance
4.HVF appearance
5.ONH Imaging
4. Glaucoma: What we will cover
3.Different types of glaucoma
1.Open Angle Glaucoma
Primary
Secondary:
Pseudoexfoliation
Pigment dispersion
Steroid induced
Uveitis induced
Ghost cell glaucoma
Raised EVP
Lens induced
Trauma induced
5. Glaucoma: What we will cover
2.Angle Closure Glaucoma
Primary
Secondary
Neovascular glaucoma
Lens induced
Tumor induced
ICE
6. Glaucoma: What we will cover
4.Treatment of glaucoma
Medical
Surgical
Laser
Incisional
7. Glaucoma: Definition
Glaucoma represents a diverse group of eye
conditions that share either the common
feature of progressive optic neuropathy (open
angle variant) or the common feature of
occludable drainage angles in the anterior
chamber (closed angle varient).
8. Glaucoma: Definition
Risk Factors
Elevated intraocular pressure is the most important
risk factor for glaucoma.
Other risk factors include:
-Increasing age
-Family history
-Race
-Myopia
-Diabetes Mellitus?
-Hypertension?
10. Glaucoma: What we will cover
1.Definition of glaucoma
2.Diagnosis of glaucoma
1.IOP
2.Gonioscopy
3.ONH appearance
4.HVF appearance
5.ONH imaging
11. Glaucoma: Diagnosis- IOP
Intraocular pressure (IOP):
-Normal range between 9-21mmHg, but no absolute
cut off
-Methods of checking IOP:
1.Goldmann (gold standard)
2.Tonopen
3.Schiotz tonometer
4.Puff tonometer
13. Glaucoma: Diagnosis- IOP
Intraocular pressure (IOP):
Goldmann (gold standard): The tonometer is a biprism
mounted on a standard slit-lamp, which is used to
applanate (flatten) the cornea. The IOP calculation is
based on the Imbert - Fick principle, whereby an
external force (exerted by the tonometer) against a
sphere (the eye) equals the pressure within the
sphere times the area flattened by the force (3.06 sq.
mm of the cornea).
14. Glaucoma: Diagnosis- IOP
Intraocular pressure (IOP):
Unusually thick or thin corneas or irregular corneas can generate
errors in IOP readings.
CCT (microns)Adjustment for Measured IOP mmHg
445+7 515+2 585-3
455+6 525+1 595-4
465+6 535+1 605-4
475+5 545-0 615-5
485+4 555-1 625-6
495+4 565-1 635-6
505+3 575-2 645-7
18. Glaucoma: Diagnosis- IOP
Methods of checking IOP:
1.Goldman
2.Tonopen:
The Tonopen is also an applanation device with a very
small “footprint” on the cornea, which makes it easier
to use with corneal abnormalities. Since the patient
can be done lying or sitting, it is also useful when the
patient cannot sit positioned properly at the slit lamp.
21. Glaucoma: Diagnosis-IOP
Methods of checking IOP:
1.Goldman
2.Tonopen:
3.Schiotz:
A form of indentation tonometry, a preset weight is placed on
the tonometer which is placed on the anaesthetized cornea.
The amount that the plunger sinks into the eye is measured
off the scale, and the reading converted to mm Hg reading a
conversion table. The further the weight sinks in (the
greater the scale reading) the softer the eye (lower IOP).
This method is frequently used in emergency departments
where applanation tonometry is not available
24. Glaucoma: Diagnosis- IOP
Methods of checking IOP:
1.Goldman
2.Tonopen:
3.Schiotz:
4.Puff tonometry:
Noncontact (or air-puff) tonometry does not touch
your eye but uses a puff of air to flatten your
cornea. This type of tonometry is the least
accurate way to measure intraocular pressure.
26. Glaucoma: What we will cover
1.Definition of glaucoma
2.Diagnosis of glaucoma
1.IOP
2.Gonioscopy
3.ONH appearance
4.HVF appearance
5.ONH imaging
27. Glaucoma: Diagnosis-Gonioscopy
Gonioscopy:
A method of viewing the anterior chamber angle.
The angle cannot be directly viewed due to total
internal reflection
A contact lens is required to neutralize the corneal
refractive power and see the angle structures.
34. Glaucoma: What we will cover
1.Definition of glaucoma
2.Diagnosis of glaucoma
1.IOP
2.Gonioscopy
3.ONH appearance
4.HVF appearance
5.ONH imaging
35. Glaucoma: Diagnosis-
ONH appearance
The optic nerve is the collection of the axons of
the retinal ganglion cells.
The optic nerve consists of 700k-1.2million
ganglion cell axons
From each RGC, a single axon extends into the
RNFL
The outer rim of the optic nerve consists of
these RGC axons. The more axons there are
the thicker the rim.
37. Glaucoma: Diagnosis-
ONH appearance
At the ONH all the axon fiber bundles turn to exit the
eyeball thru the posterior scleral foramen.
In the posterior scleral canal the ON received
collagenous extensions from the surrounding sclera
that forms the lamina cribrosa
38. Glaucoma: Diagnosis-
ONH appearance
The optic nerve consists of an outer rim of retinal ganglion cell
axons
inner cup: cup to disc ratio is approximately 0.3 (range of 0.1-
0.4).
The shape of the rim depends on:
1.The size of the ON
2.Direction of ON as it enters the eye
3.The number of RGC fibers
Thus the fewer the RGC axons, the thinner the rim
39. Glaucoma: Diagnosis-
ONH appearance
The average cup to disc ratio is approximately 0.3,
with a normal range of 0.1-0.4.
Rim width greatest
inferiorly>superiorly>nasally>temporally (ISNT)
40. Glaucoma: Diagnosis-
ONH appearance
Signs of glaucomatous optic nerve changes:
1.Concetric cup enlargement
2.Temporal cup enlargement
3.Focal cup enlargement (notch)
4.ONH asymmetry
5.Disc homorrhages
46. Glaucoma: What we will cover
1.Definition of glaucoma
2.Diagnosis of glaucoma
1.IOP
2.Gonioscopy
3.ONH appearance
4.HVF appearance
5.ONH imaging
47. Glaucoma: Diagnosis-
HVF appearance
The visual field is an assessment of the patients
peripheral vision.
It can be assessed in several ways:
1.Static perimetry----------- Humphrey visual field
2.Kinetic perimetry----------Goldmann
48. Glaucoma: Diagnosis-
HVF appearance
Humphrey visual field:
- The most commonly used technique
- Sita (Swedish interactive threshold algorithm) is the gold
standard.
57. Glaucoma: Diagnosis-
ONH imaging
ONH imaging
-Stereo photographs
Photographs of the
optic nerve taken
several degrees off
angle and viewed
through a stereo
viewer.
58. Glaucoma: Diagnosis-
ONH imaging
ONH imaging
-Optical Coherence Tomography/RNFL:
“RNFL thickness” measures the thickness around the
optic nerve head along three high density (256
Ascans/line) circular scans of 3.4mm in diameter,
acquired one at a time.
It measures the thickness by assessing the degree of
interference of a given illuminating light. The
thicker the tissue the greater the interference.
61. Glaucoma: Diagnosis-
ONH imaging
ONH imaging
-Heidelberg Retinal Tomograph (HRT):
The HRT uses a diode laser to sequentially scan the
retinal surface in a 15x15 degree field, up to 64
optical sections. It then uses confocal scanning
principals to measure the amount of light relfected
form each scanned point, and thus creates a
topographic image.
63. Glaucoma: Diagnosis-
ONH imaging
-Heidelberg Retinal Tomograph
Topography image Reflection image
Horiz and vert height Mean height contour
profiles graph
Stereometric analysis MRA graphed results
64. Glaucoma: Diagnosis-
ONH imaging
ONH imaging
-GDx (Scanning laser polarimetry):
An optical imaging technique based on the birefringence
of the RNFL. Laser polarized light is refracted by the
RNFL, resulting in two refracted rays. One of the rays
travels with the same velocity along the optical axis of
the tissue while the other ray travels with a velocity that
is dependant on the propagation direction within the
tissue. The distance of separation between the two
rays increases with increasing tissue thickness.
67. Glaucoma: What we will cover
1.Definition of glaucoma
1.Definition
2.Risk factors
3.Epidemiology
2.Diagnosis of glaucoma
1.IOP
2.Gonioscopy
3.ONH appearance
4.HVF appearance
5.ONH Imaging
68. Glaucoma: What we will cover
3.Different types of glaucoma
1.Open Angle Glaucoma
Primary
Secondary:
Pseudoexfoliation
Pigment dispersion
Steroid induced
Uveitis induced
Ghost cell glaucoma
Raised EVP
Lens induced
Trauma induced
69. Glaucoma: What we will cover
2.Angle Closure Glaucoma
Primary
Secondary
Neovascular glaucoma
Lens induced
Tumor induced
ICE
72. Glaucoma: What we will cover
3.Different types of glaucoma
1.Open Angle Glaucoma
Primary
Secondary:
Pseudoexfoliation
Pigment dispersion
Steroid induced
Uveitis induced
Ghost cell glaucoma
Raised EVP
Lens induced
Trauma induced
73. Glaucoma: Classification-POAG
POAG:
Definition: open angle with no secondary cause
On Gonioscopy:wide open angle with no gross pathology
Cupping of ONH
Thinning of retinal NFL
Visual Field:
-Typical changes:
Arcuate
nasal step
paracentral scotoma
temporal wedge
75. Glaucoma: Classification-POAG
Normal Tension Glaucoma
Same anatomical findings as POAG
associated with thin cornea
Disc hemorrhages more common
HVF: loss close to fixation
= paracentral scotoma
83. Glaucoma: Classification-
Pigment Dispersion Syndrome
Epidemiology:
20-50yo
Males>Females, Males get glaucoma at younger age
Myopic (Moderate)
30-50%of pts with PDS go on to develop glaucoma
84. Glaucoma: Classification-
Pigment Dispersion Syndrome
Anatomical / Clinical Features:
Wide swings in IOP leading to halos, blurring of
acuity esp with exercise or pupil dilatation
Cornea: Krukenberg spindle
Iris: mid-peripheral TID
Gonioscopy: Posterior (concave) bowing of iris, 360
degree band of pigment in TM
85. Glaucoma: Classification-
Pigment Dispersion Syndrome
Mechanism:
Posterior bowing of the iris
Pigment granules being rubbed by zonules
Pigment harmful to epith of TM leading to their death
Beams then clogged with pigment that blocks
openings. (Campbell)
94. Glaucoma: Classification-
Steroid induced
Epidemiology:
Response to dexamethasone 0.1% topically 4x/day
for 6 weeks:
50% of general population will respond:
95% of glaucoma patients are steroid responders
5% of general population IOP rise of --- 15mmHg
30% --------------------------------------------- 5-14mmHg
65% -----------------------------------------------5mmHg
Increased incidence of glaucoma responders in
glaucoma relatives, diabetics, high myopia
95. Glaucoma: Classification-
Steroid induced
Anatomical/Clinical Features:
Usually after at least two weeks of steroid treatment.
May be seen after a very short duration of treatment.
May be associated with topical, depot, or systemic steroids.
Also seen with periocular skin ointments.
Weaker steroids cause less of a response than stronger ones
May mimic NTG because is ‘burnt out’ high pressure glaucoma
Anatomically identical to POAG
96. Glaucoma: Classification-
Uveitis induced
Iritis may either lower or raise IOP.
HSV associated iritis usually raises IOP
Important to balance uveitis control with steroid
response.
Subtypes of uveitis induced:
Posner Schlossman
Fuchs
97. Glaucoma: Classification-
Uveitis Induced
Posner Schlossman:
Anatomical / Clinical Features:
Symptoms of slight ocular discomfort, blurred vision, halos lasting
Several hours to weeks. Usually self limited attacks.
Some pts go on to OAG and VF loss even in fellow eye
Minimal physical findings
Conj: Mild ciliary flush
Cornea: Mild corneal epithelial edema with few fine KPs
Iris: Early segmental iris ischemia
Anterior chamber: Occasional faint flare
Gonioscopy: Open angle with no PS
IOP: 40-60mmHg coinciding with duration of uveitis with return to
normal between attacks
Mechanism unclear with either inflammation of TM or elevated aqueous
production secondary to elevated aqueous levels of prostaglandins
98. Glaucoma: Classification-
Uveitis Induced
Fuchs Heterochromic Iridocyclitis
Onset in third or fourth decade
Male = Female
87% Unilateral, glaucoma develops in 13% of u/l cases and 33%
of b/l
Cornea: Colorless, stellate KPs throughout cornea
Iris: Heterochromia (lighter iris on side with Fuchs)
Gonioscopy: Blood vessels in angle (cause bleed during CE and
paracentesis)
Mild iritis, minimally responsive to steroids
Cataract
High percentage with Choriretinal scars
102. Glaucoma: Classification-
Ghost Cell Glaucoma
Three months post vitreous hemorrhage
(trauma, DM, other etiology)
Usually history of surgery establishing a
connection between anterior and posterior
chambers
103. Glaucoma: Classification-
Raised Episcleral Venous Pressure
Associated pathology:
CCF
Sturge Weber syndrome (sporadic, no known inheritance)
Retrobulbar tumors
Thyroid ophthalmopathy
Orbital varices
Important history:
Trauma?
Thyroid disease
Sturge Weber (may be masked cosmetically or with laser)
112. Glaucoma: Classification-
Lens Induced
Lens particle glaucoma:
break in capsule (cataract surgery trauma)
cortical/inflammatory cells clogging TM.
Degree of inflammation is between that of
phacolytic and phacoanaphylactic
Associated with PS, PAS, inflammatory
membranes
Rise in IOP ----shortly after the inciting
event
114. Glaucoma: Classification-
Lens Induced
Phacoanaphylaxis (rare):
following penetrating trauma/surgery
sensitization to own lens proteins resulting in
granulomatous uveitis.
Usually associated with lens material
(nucleus) in the vitreous.
chronic, relentless, granulomatous uveitis.
latent period between inciting event and
rise in IOP
115. Glaucoma: What we will cover
3.Different types of glaucoma
1.Open Angle Glaucoma
Primary
Secondary:
Pseudoexfoliation
Pigment dispersion
Steroid induced
Uveitis induced
Ghost cell glaucoma
Raised EVP
Lens induced
Trauma induced
116. Glaucoma: Classification-
Trauma induced
Mechanisms:
4-9% of those with angle recession greater that 180 degrees
Related to angle recession scarring of the TM
Significant percent with angle recession glaucoma will develop
bilateral disease
Elevated IOP may be seen without other obvious damage
associated iritis, hyphema, dislocated lens,
