The Complete Approach To Glaucoma Evaluation, glaucoma, POAG, PAC, PACS, PACG

1. EVALUATION OF A
GLAUCOMA
PATIENT
Dr. ANKITH NAIR

2. DEFINITION
Glaucoma is a Chronic Optic Neuropathy with typical structural
damage in the optic disc, usually accompanied by or leading to
corresponding functional changes in the visual field

3. Causes and risk factors
• No identifiable cause for Primary glaucoma
• Secondary Glaucoma has underlying causes likeTumor, diabetes, hypothyroidism,
advanced cataract or inflammation
• R/f forGlaucoma include :
o Age
o Black race
o Diabetes
o Family history
o Eye injury or previous surgery
o Severe myopia
o Corticosteroid use, especially topical
o High blood pressure
o Genetic factors (CongenitalGlaucoma)

4. TYPES OF GLAUCOMA
Open-angle glaucoma.
Angle-closure glaucoma
Congenital glaucoma
Secondary glaucoma

5. SYMPTOMS OF GLAUCOMA
CLOSED ANGLE OPEN ANGLE GLAUCOMA
Symptoms develop slowly, and a
person may not notice them until the
later stages.
They include:
• Gradual loss of peripheral vision,
usually in both eyes and
• Tunnel vision

6. HISTORY

7. ▪ Visual Complaints
▪ Ocular symptoms
▪ Medical history
▪ Current topical medications
▪ Family history
▪ Allergies to medications
▪ Systemic medications
▪ Trauma/Surgical history
History

8. Components of a Comprehensive
Eye Examination

9. VisualAcuity and
Refraction
External
examination and
assessment of
ocular motility
Examination of
pupil
Slit Lamp
Biomicroscopy
IOP measurement
Gonioscopy
Dilated Fundus
Examiantion
Visual Fields

10. Visual Acuity and Refraction
▪Myopes at higher risk for
POAG and
▪Hyperopes at higher risk for
PACD

11. External Examination
▪ To detect subtle hemangioma or
dilated episcleral
veins indicating Secodary cause
▪ CiliaryConjuctival Congestion -->
Serious intraocular pathology (Acute
Angle Closure)

12. Ocular Motility
▪ Patient having Amblyopia or
Extropia may change the
management plan

13. Pupil Examination
▪ Glaucoma is usually an
asymmetric disease, and
demonstration of a relative
afferent pupillary defect is an
important diagnostic clue
▪ A dilated pupil may be a sign
of angle closure

14. Slit-Lamp Examination
▪ For signs of
pseudoexfoliation (PXF),
pigment dispersion, uveitis,
or trauma
▪ Pigment liberation following
dilatation – Highly suggest
PXF

15. Intraocular Pressure
Measurement
▪ Measured at every visit
▪ Desirable to obtain multiple readings throughout
the day
▪ Current gold standard --> Goldmann applanation
tonometer
▪ Corneal edema detected --> Underestimated IOP
▪ Central CornealThickness – Affect IOP reading --
>CCT Correction done
▪ 22mmhg is the cut off for Indian population
▪ Water drinking test to predict peak IOP and IOP
fluctuations

16. GONIOSCOPY

17. • POAG is a diagnosis of exclusion
• Demonstration of open angle especially
important in regions where PACD
common
• Gonioscopy is used to examine the Angle
of the anterior chamber
• Best performed with
Indentation Gonioscope and 4 mirror
type

18. • Testing conditions critical in determining
Whether angle open or closed
o Many angles open in bright room and
long slit beam (image)
• Ideal testing conditions :
•Dim room illumination
•Minimal intensity of slit lamp
illumination
Low slit beam height
No pressure on eye with gonioscope
Wait 30-45s for pupil to dilate before
deciding if angle open

19. If under these conditions, PosteriorTrabecular Meshwork
(PTM) not seen --> Pt. asked to look toward mirror to
obtain “Over the hill view” of the angle
o If >180 degree seen with such view, angle
considered open
o If not seen > Pt considered a PACS
o Next > increase illumination and slit height to
constrict pupil > Perform indentation with
gonioscope> Look for other signs of pathology in
the angle (Peripheral ant synechiae, signs of PXF,
trauma, old hemmorhage, inflammation, new
vessels)
o If other signs absent, and angles open under
conditions described above, then, in prescence of
disc of field changes > diagnosis of POAG

20. Role of Van Herrick tests and Angle
Imaging
▪ Suggested as a screening test for Angle
closure
▪ Negative test does not rule it out and positive
test still requires gonioscopy
▪ VH positive and raised IOP in combination is
highly specific
▪ Angle imaging techniques like the US
biomicroscope and ASOCT have not yet
replaced gonioscopy and therefore not
necessary for clinical use

21. OPTIC DISC AND NERVE
FIBRE LAYER
EXAMINAITON

22. • Ideal – Magnified stereoscopic
examination of disc – 60-90D lens or
contact lens with Slit Lamp
• Stereo Photographs - Current gold
standard
• Document disc findings with drawing or
imaging for future comparison

23. STRUCTURAL
CHANGES OF THE OPTIC
DISC IN GLAUCOMA

24. Increased cup to disc ratio
▪ Arbitrary statistical cut off of 0.7:1 - suspicious
– Even more suspicious if vertically oriented
▪ CDR --> Fallacious as disc size is not accounted for
▪ Size of disc estimated with a 60D lens.
– Magnification factor for 90D lens is 1.41
▪ “Normal” sized disc in India –Vertical diameter of 2.0mm
▪ Get a feel of whether the disc is Small, Medium or Large
– Ask “Is this disc physiologically allowed to have this sort of cup?”
▪ CDR difference of 0.2 is suspicious
▪ Increase in CDR over time is pathognomic for Glaucoma
▪ Also can document the Rim to disc ratio in Superior, Supertemporal, Inferotemporal,
Inferior and Nasal areas of disc
– Rim : Disc <0.1:1 considered pathology until proven otherwise

25. Changes in NRR
▪ NRR thickness follows the ISNT rule - (80%)
▪ Change in this pattern is suspicious
▪ Inferior rim thinner than temporal is highly suspicious
▪ If the rim extends to edge for one clock hour – Notch
▪ Notch is characteristic of glaucoma and produces a
functional field defect too
▪ Hemmorhage that touches NRR is specific but not
sensitive
▪ Peripapillary choroidal atrophy is a soft sign of
glaucomatous damage
▪ Significant if associated with other signs or if it
increases in size

27. Nerve Fibre Layer Defect
▪ Gold standard for examination – Red free
photography
▪ Examined clinically using green filter on slit lamp or
ophthalmoscope
▪ The Inferior arcuate NFL - larger area and more clearly
seen consistent with NRR thickness
▪ Localized NFLD - Dark wedge that follows the pattern
of NFL and increases width toward periphery
– Strong predictive value for future functional changes
▪ Hemmorhage that touches NRR is specific but not
sensitive
▪ High specificity but low sensitivity.
▪ Definite sign of pathology, but can occur in other
diseases too.

28. So, the diagnosis of glaucomatous changes in the ON is usually based on
a combination of the above signs
NOTCH NFLD
Rule in
Glaucoma
Disc
Hemmorhage
Rim
Thinning
Rule in
Glaucoma

29. IMAGING TECHNIQUES
FOR EXAMINING THE
OPTIC DISC
• These instruments lack specificity and sensitivity for
routine clinical use
• Provide valuable clinical information

30. VISUAL FIELD

31. • Integral part of a full ophthalmic evaluation
•Available techniques
oTo test the full field (including confrontation, tangent screen, Goldmann perimetry and automated
perimetry),
oTo assess just the central field of vision, such as the Amsler Grid , BjerrumTangent screen
•Manual and/or automated visual field testing is subjective
•Abnormalities in the visual field - sign of damage anywhere in the visual system
o Assess whether or not a visual field defect matches the appearance of the disc and retina, or fits
with other clinical signs
• Test each eye separately -Non-congruous defects in each eye could be missed as the normal areas of
field in one eye overlap the defects in the other eye

32. • Early glaucomatous visual field defects are subtle and
easily missed
 Even with modern automated and sensitive visual field
analysers, not evident until at least 30% of the retinal
ganglion cell axons that make up the optic nerve are lost
• Two major types of perimetry
o Kinetic perimetry - detection of moving targets
o Static perimetry - detection of a stationary target
• Static testing > Kinetic perimetry
• To detect glaucomatous field loss, important to test for differences in
the superior and inferior hemi-fields and hunt for defects such as a
nasal step
• Emerging technologies in visual field testing include:
 Short-wavelength (blue–yellow) automated
perimetry (SWAP)
 Frequency doubling technology (FDT) perimetry
 Motion displacement perimetry (MDP)

33. Features of Glaucomatous Visual Field
Defects
▪ Relatively specific glaucomatous visual field defects

34. CONFRONTATION TESTING
Position
Have the patient
cover one eye
Hold a target in
the central
visual field
Move the target
from periphery
to center
Patient
indicates when
they see it
witch occluder
to cover the
opposite eye
Record Findings

35. AMSLER CHART TESTING
▪ Can be used to detect subtle central defects as well as
paracentral defects
▪ Patients hold chart at comfortable reading distance
from their uncovered eye and stare at the central spot
of the grid
• Ask them to identify and then point out any
areas where the grid is missing or distorted
• Missing areas may suggest paracentral
glaucomatous visual field loss, whereas distortion
is more common with macular disorders

36. STANDARD AUTOMATED PERIMETRY
▪ Constant size stimulus against a constant background illumination
presented in varied light intensities at particular points according to
testing strategy and minimum intensity necessary for detection of
stimulus recorded as threshold of that particular point
▪ May be performed as a threshold or suprathreshold analysis
– With suprathreshold analysis, the intensity of the stimulus target is not reduced
to the level of detection/non-detection.
– A threshold analysis is more sensitive, but takes longer and is more susceptible
to detecting artefacts

37. GOLDMANN PERIMETRY
• Enables kinetic visual field testing, and generates a permanent record of
the visual field, making it more sensitive, reproducible, and better for
detecting change overtime
• Consists of an illuminated hemispheric bowl upon which target spots of
light are shone
o Moved from non-seeing regions to seeing regions
• Kinetic testing
o Examiner moves the target where they choose throughout a test,
o Observe that the patient's eye is fixating on the fixation spot,
o Communicate with the patient and document isopters between
seeing and non-seeing regions to produce an exact drawing of visual
fields
• For static testing, the test target can be projected statically at a single
location and the brightness increased until the patient responds that the
target has been seen

38. THRESHOLD VS SUPRATHRESHOLD TESTING
SUPRATHRESHOLD
▪ Definition: Presents stimuli
well above expected thresholds
▪ Application: Quick assessment
for screening purposes
THRESHOLD
▪ Definition: Determines the
lowest intensity stimuli
detectable.
▪ Application: Quantifies and
characterizes visual field
defects
▪ More sensitive, but takes
longer and more susceptible to
detecting artefacts

39. SAP Analysis provides the following:
1. Patient data and reliability indices
2. Pictorial grey-scale plot of the visual field
3. Plot of raw data sensitivities for each test spot
4. Global indices (in dB) indicating how the height and
shape of
5. Patient's hill of vision deviates from normal.
• Mean deviation gives the average difference between the
patient's overall visual field sensitivity compared to a normal
• Pattern standard deviation gives the standard deviation of the
tested spot deviations from normal
6. Total deviation plot, with a probability map
• (indicating the likelihood for each missed point that it is
abnormal)
7. Pattern standard deviation plot, together with its
probability map
8. Analyses of change in visual field sensitivity with time

41. • The key feature of a glaucomatous visual field defect is an
abnormality on the Pattern Standard Deviation plot, which
also shows on the total deviation plot
o A field defect on theTDP, in the absence of a defect on the PSDP, can
be due to glaucoma , but is more likely to be due to media opacity
o Field defect more extensive on theTDP than on the PSDP may
indicate co-morbidity (e.g. cataract and glaucoma)

42. CONCLUSION
▪ Diagnosis of established glaucoma at a stage where
treatment can prevent blindness involves the strategy of
case detection.This requires comprehensive eye
examination, including slit lamp, IOP, gonioscopy, and
detailed disc and retinal examination on all patients.
Automated Perimetry should be obtained for all suspects

43. REFERENCES
▪ Evaluation of a Glaucoma patient – RaviThomas et al
– https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038503/
▪ Visual field testing. A practical guide - Pubmed
– https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3588129/

44. THANK YOU