1. COLOUR DOPPLER VELOCIMETRY OF
CENTRAL RETINAL ARTERY IN
GLAUCOMATOUS AND NORMAL
SUBJECTS
Dr. Harmeet Singh Waraich
Dr. K.P. Chaudhary M.D. Dr. P.C. Negi D.M.
(Prof. & Head , Ophthalmology) ( Prof. & Head, Cardiology)
Deptt.of Ophthalmolgy
I.G.M.C. SHIMLA

2. Glaucoma can be defined as a multifactorial
optic neuropathy with a characteristic loss of
optic nerve fibres presenting as :-
Classical optic nerve head features.
Visual field changes.
May or may not be associated with elevated IOP and
angle anomalies in the presence or absence of any cause
for the disease.
Role of IOP in the current definition is only one of the
multiple factors responsible for the disease.

3. IOP and Glaucoma in the present context
Considering the intraocular pressure as a primary
variable, glaucoma can be classified as :-
1) High Tension Glaucoma-POAG (IOP> 21mm of Hg )
2) Normal Tension Glaucoma-NTG(IOP < 21mm of Hg )
3) Ocular Hypertension-OHT

4. Pathogenesis of Glaucomatous optic nerve damage
Two main mechanisms have been proposed
1) One suggests, mechanical damage directly to the
axons or small vessels by structural alterations at the
lamina cribrosa. – MECHANICAL THEORY
2) The other suggests, primary problem in the blood flow
of the optic nerve as a result of localised organic
change with or without a low perfusion pressure or
vasospasm. – VASCULAR THEORY

5. Evidence in support of Vascular
Theory.
1) In NTG patients, despite the IOP <21mm of Hg , there is
progressive damage of optic nerve head suggesting that
vascular factors have predominant role in NTG.
2) In OHT , IOP> 21 mm of Hg does not cause glaucomatous
damage , which supports that IOP alone is not sufficient to
cause optic nerve damage.
3) NTG is associated with various vascular disorders like
hypotension, migraine, Raynaud’s phenomenon which
suggests that same pathophysiological mechanism is
causing ONH damage.

6. VASCULAR COMPROMISE – NTG
Patients of NTG may suffer from ocular blood flow deficits.
Increased choroidal filling time.
Increased vascular downstream resistance in CRA & SPCA.
Increased areas of ICG hypofluorescence in peripapillary
region.
Diffuse cerebral ischemia.

7. Role of perfusion pressure & vascular
resistance of retrobulbar vessels.
Blood flow of optic nerve head = Perfusion pressure
Resistance
Blood flow has direct relation with perfusion pressure and inverse
relation with resistance of vessels.
Perfusion pressure = Mean arterial pressure – IOP
Fall in perfusion pressure due to decreased mean arterial pressure or
increased IOP results in decreased perfusion of ONH.
Increased resistance of retrobulbar vessels also decreases ONH
perfusion and thus accelerates glaucomatous damage.

8. Measurement of ONH Perfusion
 Colour Doppler imaging is an ultrasound technique that
combines B scan gray scale imaging of tissue structure ,
coloured representation of blood flow based on Doppler
shifted frequencies and pulsed Doppler measurement of
blood flow velocities.
 With the advent of colour Doppler it has become possible to
visualize retrobulbar vessels and to calculate the blood flow
velocities in these vessels.

9. ATL HDI – 3000 COLOR DOPPLER

10. BLOOD SUPPLY OF THE OPTIC NERVE HEAD

11. COLOR DOPPLER SCAN
 SPCA
CRA
OA
OA (Reverse flow)

12. COLOUR DOPPLER VELOCIMETRY OF CENTRAL RETINAL
ARTERY IN GLAUCOMATOUS AND NORMAL SUBJECTS.
STUDY CONDUCTED IN THE DEPTT. OF
OPHTHALMOLOGY I.G.M.C. SHIMLA
AIM OF STUDY
To assess the blood flow velocities ( Peak Systolic Velocity
and End Diastolic Velocity ) and Resistive Index in
Central Retinal Artery in patients with chronic open angle
glaucoma in comparison with non-glaucomatous control
population.

13. REVIEW OF LITERATURE
 In 1989, Ericson – first to describe qualitative appearance of CDI
in normal orbits
 Quantitative estimation – done by Lieb et al (1991),
Guthoff et al (1991) and Williamson et al( 1993).
 In 1995, Rankin et al– found positive correlation of visual
field changes with retro bulbar hemodynamic parameters.
 In 2000, Schumann et al suggested that eyes with progressive
visual field defects in pts with NTG had statistically significant
lower blood flow velocities and higher resistive indices in CRA
than with practically stable visual field defects.

14. Material & Methods
Group I.
30 patients of chronic open angle glaucoma fulfilling the selection
criteria.
Group II
30 normal age and sex matched healthy volunteers.
Criteria for selection of patients of Gr. I .Patients fulfilling 2 out
of 3 undermentioned selection criteria
IOP consistently above 21+1 mm of Hg.
Reproducible visual field defects.
 Glaucomatous optic disc changes.

15. Exclusion criteria
Patients having history of
 Intraocular surgery
Cardiovascular disease
Systemic hypertension or hypotension
Diabetes mellitus
Migraine
Active ocular infection or inflammation

16. Pre procedure evaluation
 Written informed consent was obtained after explaining the
procedure.
 Detailed history
 Visual acuity
 IOP recording – Goldmann applanation tonometer
 Slit lamp Biomicroscopy – 78 D lens
 Gonioscopy – Goldmann 3 Mirror Goniolens
 PS Evaluation – Indirect ophthalmoscope
 Visual field analysis- Humphrey visual field analyzer

17. Technique of Colour Doppler Imaging of Central
Retinal Artery
An ATL ( Advanced Technologies Limited) HDI 3000 Colour
Doppler with 7.5 MHz linear phased transducer was used for
colour Doppler imaging of Central Retinal Artery.
All the examinations were done with patients in supine position.
To examine the Central Retinal Artery the B scan image of the
optic nerve was used to localize the area of anterior optic nerve.
The sample volume was placed with the centre about 3mm
behind the surface of the disk.

18. Colour Doppler in application

19. SPECTRAL WAVEFORMS OF CRA

20. From the spectral waveform of Central Retinal Artery, Peak
Systolic Velocity (PSV) and End Diastolic Velocity ( EDV)
were measured.
Resistive Index was calculated using the formula
PSV-EDV/ PSV
Resistive index is a ratio and is Doppler angle independent.

21. RESULTS
Std. Std. Error Significance
GROUP N Mean Deviation Mean (2-tailed)
AGE glaucoma 60 61.92 10.496 1.344 0.131
normal 60 59.60 5.428 .701
PSV glaucoma 60 9.48 3.348 .429 0.869
normal 60 9.57 2.554 .330
EDV glaucoma 60 2.89 1.066 .137 0.000
normal 60 3.93 1.219 .157
RI glaucoma 60 0.69 .062 .008 0.000
normal 60 0.59 .062 .008

22. RESULTS
Std. Std. Error Significance
GROUP N Mean Deviation of Mean (2-tailed)
IOP glaucoma 60 18.00 7.057 .904 0.039
normal 60 16.00 2.314 .299
SBP glaucoma 60 123.80 8.546 1.094 0.350
normal 60 122.67 3.909 .505
DBP glaucoma 60 80.82 6.136 .786 0.312
normal 60 79.93 2.875 .371
MEAN glaucoma 60 95.10 6.833 .875 0.374
normal 60 94.27 2.357 .304
PP glaucoma 60 77.16 6.778 .868 0.413
normal 60 77.93 2.603 .336

23. NORMAL 59.6
GLAUCOMA 61.92
0 20 40 60 80 100
GLAUCOMA NORMAL
Series1 61.92 59.6
Series1
Comparison of Age group of Normal & Glaucoma patients
( P value = 0.131)

24. NORMAL 16
IOP
GLAUCOMA
18
15 16 17 18 19
Series1
Comparison of IOP of Normal and Glaucoma patients ( P value=0.039)

25. NORMAL 77.93
PP
GLAUCOMA
77.16
76.6 76.8 77 77.2 77.4 77.6 77.8 78
Series1
Comparison of Perfusion pressure of Normal & Glaucoma patients
( P value = 0.413)

26. NORMAL 9.57
PSV
GLAUCOMA
9.48
9.4 9.45 9.5 9.55 9.6
Series1
Comparison of PSV of Normal & Glaucoma patients (P value = 0.869)

27. NORMAL 3.93
EDV
GLAUCOMA
2.89
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Series1
Comparison of EDV in Normal & Glaucoma patients ( P value =0.000)

28. NORMAL 0.59
RI
GLAUCOMA
0.69
0.54 0.56 0.58 0.6 0.62 0.64 0.66 0.68 0.7
Series1
Comparison of RI of Normal & Glaucoma patients ( P value = 0.000)

29. DISCUSSION
Color Doppler Imaging and spectral analysis are attractive tools
for noninvasive vascular investigation of retrobulbar vessels.
Central retinal artery can be easily identified by its position within
the optic nerve head and its characteristic waveform.
Measurements from central retinal artery are most reproducible.
This study shows that there is significant decrease in mean End
Diastolic Velocity (EDV) and increase in Resistive Index (RI) in
glaucoma patients as compared to normal subjects substantiating
vascular theory of glaucoma.
Perfusion pressure was found to be lower in Glaucoma patients as
compared to normals but the difference was not significant.

30. DISCUSSION
A decrease in EDV is a sensitive indicator of downstream
resistance which leads to decreased perfusion.
Changes in resistance affect the diastolic flow velocity more
than systolic velocity.
Resistive Index represents a quantification of end organ
resistance, the formula is suited to low resistance vascular
beds typical of the cerebrovascular region.
Resistive index can be used to assess the effectiveness of various
pharmacological interventions directed at increasing the

31. SUMMARY AND
CONCLUSIONS
 There is no doubt that vascular compromise plays an
important role in the pathogenesis of Glaucoma especially
NTG.
 Colour Doppler can be used in investigating cases of POAG
& NTG on regular basis to assess the retrobulbar
haemodynamic variables . It can prove to be a promising
investigation to assess vascular compromise in these patients.
 We can evaluate the severity of the disease, its progression
and efficacy of treatment in glaucoma patients with the help
of CDI which is a wonderful investigation to assess
retrobulbar haemodynamic profile.

32. Thank you