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Abstract

Background: Diabetic retinopathy is a vascular disorder affecting the microvasculature of retina. 
It is caused by changes in the blood vessels of retina. If untreated, it may lead to blindness which is 
usually preventable if retinopathy is diagnosed early and treated promptly. In ophthalmology, color 
Doppler imaging is a new method that enables us to assess the orbital vasculature. It allows for 
simultaneous two dimensional anatomical and Doppler evaluations of hemodynamic 
characteristics of retinal artery. Objective: To observe the difference between Doppler flow 
velocity indices (peak systolic velocity, end diastolic velocity and resistive index) of retinal artery 
in type 2 diabetic subjects without retinopathy and those of normal controls. Materials and 
Methods: This case-control study was carried out in the department of Radiology and Imaging, 
Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic 
Disorders (BIRDEM) in collaboration with Ophthalmology Outpatient Department, BIRDEM, 
Dhaka from July 2011 to June 2013. Eighty diabetic patients without retinopathy aged 27–68 years 
were enrolled as cases and age and sex matched 80 healthy subjects were selected as controls. 
Type 1 diabetic patients, type 2 diabetics with retinopathy, hypertensive and dyslipidemic subjects 
were excluded from the study. All the selected subjects underwent duplex Doppler ultrasonography 
of both eyes using 5 to 7.5 MHZ linear phase transducer. Duplex color Doppler findings including 
spectral analysis (PSV, EDV and RI) were recorded. Unpaired t test was done to compare blood 
flow velocity indices of retinal artery in type 2 diabetic patients without retinopathy and that of 
healthy control subjects. p value <0.05 was considered as significant. Results: Majority (42.5% 
and 47.5%) of subjects were in 4th decade of life in both groups with predominance of males. The 
mean duration of diabetes was 4.56 ± 2.1 years. Mean peak systolic velocity (PSV) in 80 diabetic 
patients without retinopathy was 10.70 ± 1.50 cm/sec ranging 5.30 –16.10 cm/sec and that of 80 
healthy subjects was 11.27 ± 0.98 cm/sec ranging 9.0 –13.10 cm/sec. Mean end diastolic velocity 
(EDV) in 80 diabetic patients without retinopathy was 2.58 ± 0.67 cm/sec ranging 1.00 –5.10 
cm/sec and that of 80 healthy subjects was 4.11 ± 2.7 cm/sec ranging 3.00–4.60 cm/sec. Mean 
resistive index (RI) in 80 diabetic patients without retinopathy was 0.75 ± 0.04 ranging 0.66 –0.81 
and that of 80 healthy subjects was 0.64 ± 0.02 ranging 0.60 –0.70. Mean difference of retinal 
arterial RI of diabetic subjects without retinopathy and healthy control eyes was statistically 
significant (p<0.001). Conclusion: From the present study it can be concluded that, there is 
statistically significant difference between retinal arterial RI of type 2 diabetic patients without 
retinopathy and that of healthy control adult subjects.
Key words: Retinopathy; Ultrasonography; Type 2 DM; Duplex color Doppler

J Enam Med Col 2014; 4(3): 168--173

 

 

168

Duplex Color Doppler Evaluation of Retinal Arterial Blood Flow in
Type 2 Diabetic Subjects without Retinopathy 

1.  Assistant Professor, Department of Radiology and Imaging, Enam Medical College & Hospital, Savar, Dhaka 
2.  Junior Consultant, Department of Radiology and Imaging, Bangladesh Institute of Research and Rehabilitation 
     in Diabetes, Endocrine and Metabolic Disorders (BIRDEM), Dhaka
3.  Medical Officer, Department of Radiology and Imaging, BIRDEM, Dhaka
4.  Assistant Professor, Department of Radiology and Imaging, Enam Medical College & Hospital, Savar, Dhaka 
5.  Assistant Professor, Department of Radiology and Imaging, North East Medical College & Hospital, Sylhet
6.  Senior Consultant, Department of Radiology and Imaging, BIRDEM, Dhaka
Correspondence Mashah Binte Amin, Email: mashah.amin@gmail.com 

Original Article

Mashah Binte Amin1, Farzana Shegufta2, Md. Towhidur Rahman3, Tarana Yasmin4,
Khaleda Parvin Rekha5, A. S. Mohiuddin6

Received: May 24, 2014  Accepted: June 20, 2014

Journal of Enam Medical College
Vol 4 No 3 September 2014



Diabetes mellitus is one of the most common non-
communicable diseases globally. The prevalence of 
diabetes for all age groups worldwide has been 
estimated to be 6.4%, affecting 285 million adults in 
2010.1 Bangladesh is a developing country that has 
been facing a high prevalence of diabetes mellitus. In 
2011, 8.4 million of people with diabetes have been 
estimated in our country with prevalence of 8.1% in 
urban and 2.3% in rural areas.2-3

As the prevalence of diabetes is rising, the systemic 
complications that include retinopathy, nephropathy and 
neuropathy and involvement of cardiovascular system 
are also increasing.4 Diabetic retinopathy is a vascular 
disorder affecting the microvasculature of retina. It is 
caused by changes in the blood vessels of retina. If 
untreated, it may lead to blindness. Therefore, if 
diagnosed and treated promptly, blindness is usually 
preventable.5-7

In ophthalmology, color Doppler imaging is a new 
method that enables us to assess the orbital vasculature. 
It allows for simultaneous two dimensional anatomical 
and Doppler evaluations of hemodynamic characte-
ristics of retinal artery.8-13 Standard ophthalmoscopy 
can detect retinal abnormalities, but after the 
development of retinopathy and it is very much 
observer dependent.14-16 On the other hand, slit-lamp 
biomicroscopy can assess retinal changes, but it is very 
much time consuming and needs pupillary dilatation 
which causes discomfort to patient.17-18 Retinal arterial 
hemodynamic changes can also be assessed by the gold 
standard fluorescein dye-dilution technique, but 
accurate measurement of staining after intravenous 
injection of fluorescein is difficult at retinal arterial 
level. Therefore, duplex color Doppler ultrasonography 
is the investigation of choice for qualitative and 
quantitative assessment of retinal arterial blood flow 
velocities very quickly without any invasive 
procedure.19-21

Diabetic retinopathy is the leading cause of blindness. 
As the prevalence of diabetes is rising, the  incidence of 
retinopathy is increasing day by day. For diagnosis of 
early changes in retinal blood flow in DM without 
retinopathy duplex color Doppler ultrasonography is the 
investigation of choice to assess the problem very 

quickly without any invasive procedures. Thus, this 
would be a beneficial tool for the ophthalmologist to 
assess and make quick decision about patient with 
impaired blood flow and to take necessary actions. 
Therefore, we designed this study in our population to 
assess the different Doppler flow velocity indices of 
retinal arteries.

Materials and Methods
This case-control study was conducted on both eyes of 
160 subjects aged 27–68 years in the department of 
Radiology and Imaging, Bangladesh Institute of 
Research and Rehabilitation in Diabetes, Endocrine and 
Metabolic Disorders (BIRDEM) from July 2011 to June 
2013. Patients with type 2 diabetes without retinopathy 
(normal findings in slit lamp biomicroscopy) were 
referred from Ophthalmology OPD, BIRDEM to the 
department of Radiology and Imaging for duplex color 
Doppler study of eyes. Among them 80 diabetic patients 
without retinopathy were enrolled as cases and age and 
sex matched 80 healthy subjects with normal 
ophthalmology examination findings were taken as 
controls. Patients with hypertension and dyslipidemia 
were excluded. The objective of the study was 
discussed in details with the patients before enrollment. 
Demographic information was recorded and 
substantiated by means of inspection of medical record. 
Information included the subject’s age, sex, medical and 
surgical history, clinical history of diabetes, followed by 
duplex color Doppler study with spectral analysis. The 
color Doppler study was performed first by the 
investigator herself and subsequently confirmed by a 
radiologist of the department of Radiology and 
Imaging, BIRDEM who was not informed of the 
subject’s condition to eliminate bias. Peak systolic 
velocity (PSV), end diastolic velocity (EDV) and 
resistive index (RI) of retinal arteries were recorded 
from both right and left eyes. Duplex color Doppler 
sonography of retinal arteries was also carried out in 
control group after informing them about the purpose of 
the study. PSV, EDV and RI were also measured in both 
eyes in control group. PSV, EDV and RI values of 
retinal artery of both groups were compared. 

All the relevant collected data were compiled on a 
master chart first, then organized by using scientific 
calculator and standard statistical formulas. Percentage 
was calculated to find out the proportion of the findings. 

Introduction

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J Enam Med Col  Vol 4  No 3 September 2014



Further statistical analysis of the results was 
done by SPSS version 17.0. Comparison 
between the velocity indices in diabetic 
patients without retinopathy and normal 
control individuals was done by the unpaired 
student t test. p value <0.05 was considered 
significant. 

Results 
Mean age of the diabetic patients was 46.05 ± 
9.78 years with range from 27–68 years. 
Among them 58.7% were male and 41.3% 
were female. Most of the patients (42.5%) 
were found in 4th decade. On the other hand, 
the mean age of healthy control subjects was 
42.78 ± 7.31 years with range from 30–59 
years. Among them 53.7% were male and 
46.3% were female. Majority (47.5%) were 
found in 4th decade. The mean duration of 
diabetes was 4.56 ± 2.1 years. The study also 
reveals that there was no significant difference 
(p>0.05) in retinal arterial mean PSV, mean 
EDV and mean RI between right and left eyes 
of diabetic patients without retinopathy and 
also in control subjects.

In the current study, it was found that the mean 
PSV in diabetic patients without retinopathy 
was 10.70 ± 1.50 cm/sec ranging 5.30 –16.10 
cm/sec and the mean PSV measured in healthy 
subjects was 11.27 ± 0.98 cm/sec ranging 
9.00–13.10 cm/sec (Table I).

In the present study, it was also found that the 
mean EDV in diabetic patients without 
retinopathy was 2.58 ± 0.67 cm/sec ranging 
1.00–5.10 cm/sec and the mean EDV measured 
in healthy subjects was 4.11 ± 2.7 cm/sec 
ranging 3.00–4.60 cm/sec (Table II).

In this study the mean differences of retinal 
arterial PSV and EDV in diabetic eyes without 
retinopathy and healthy control eyes was 
statistically significant (p<0.01). 

In the current study, it was found that the mean 
RI in 80 diabetic patients without retinopathy 
was 0.75 ± 0.04 ranging 0.66 –0.81. And the 

mean RI value measured in 80 healthy subjects was 0.64 ± 0.02 
ranging 0.60 – 0.70. The mean difference was statistically 
significant (p<0.001) between two groups  (Table III).

Spectral Doppler flow patterns of retinal arteries of both eyes in 
a normal control subject and a type 2 diabetic subject are shown 
in Figures 1, 2, 3 and 4.

Table I: Comparison between mean peak systolic velocity of 
retinal artery of 160 control eyes and 160 diabetic 
patients’ eyes without retinopathy (n=320)

 Groups Mean (cm/sec) Range (cm/sec) t value p value

 Control group 11.27 ± 0.98 9.00–13.10
     (n=160) 78.45 <0.01

 Diabetic group 10.70 ± 1.50 5.30–16.10 
     (n=160)

p value was achieved from unpaired t test 

Table II: Comparison between mean end diastolic velocity of 
retinal arteries of 160 control eyes and 160 diabetic 
patients’ eyes without retinopathy (n=320)

  Groups   Mean (cm/sec) Range (cm/sec) t value p value

  Control group  4.11 ± 2.7 3.00–4.60
     (n=160) 71.76 <0.01

  Diabetic group  2.58 ± 0.67 1.00–5.10
     (n=160)

p value was achieved from unpaired t test

Table III: Comparison of retinal arterial mean resistive index 
(RI) between 160 control eyes and 160 diabetic 
patients’ eyes without retinopathy (n=320)   

 

  Groups Mean ± SD Range t value p value

  Control group 0.64 ± 0.02 0.60–0.70
      (n=160) 13.41 <0.001

  Diabetic group 0.75 ± 0.04 0.66–0.81
      (n=160)

p value was achieved from unpaired t test 

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Discussion
As the prevalence of diabetes is rising, the systemic 
complications that include retinopathy, nephropathy, 
neuropathy and involvement of cardiovascular system 
are also increasing. Diabetic retinopathy is the leading 
cause of blindness in the world. Prevention of 
retinopathy needs early diagnosis.22 Despite the 
improvement in ophthalmoscopic examination in 
outpatient department (OPD) in Ophthalmology, in 
order to diagnose early changes in retinal arterial flow 
velocity, a newer imaging modality may be used for 
diagnosis of early changes in retinal artery before 
clinical manifestation of retinopathy.

Color Doppler imaging is the most promising modality 
that produces conventional gray-scale ultrasound 

images along with information regarding the direction 
and velocity of blood flow.23 The present study was 
attempted to evaluate clinically diagnosed diabetic 
patients without retinopathy by measuring the retinal 
arterial RI and compare the result with normal healthy 
controls by duplex color Doppler study.

In this study the age of the patients ranged from 27 to 
68 years with the maximum number of cases found in 
the 40 – 49 years age group. Observation reveals no 
statistically significant difference regarding mean age 
between cases and controls (p>0.05). A similar study 
done by Kawagishi et al24 showed no significant 
difference between the two groups with respect of age.

In this study the mean difference of retinal arterial PSV 
in diabetic eyes without retinopathy and control eyes 

 

 

Fig 1.  Spectral Doppler flow patterns of retinal artery of 
           right eye in a normal control subject

Fig 2. Spectral Doppler flow patterns of retinal artery of
          right eye in a type 2 diabetic subject

Fig 3. Spectral Doppler flow patterns of retinal  artery of
          left eye in a normal control subject

Fig 4. Spectral Doppler flow patterns of retinal artery of
          left eye in a type 2 diabetic subject

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was statistically significant (p<0.01). One investigator 
Guthoff et al25 who compared the mean PSV of retinal 
artery in diabetic patients without retinopathy and 
healthy subjects also found significant difference in 
retinal arterial PSV between cases and controls. 

The mean EDV of 160 diabetic eyes without 
retinopathy and 160 control eyes was statistically 
significant (p<0.01). This observation is supported by 
the study done by Jack et al15 who has compared the 
mean EDV of diabetic patients and control group and 
discovered that there was statistically significant 
difference of mean retinal arterial EDV between cases 
and control groups.

In this study mean RI in 160 eyes of 80 diabetic patients 
without retinopathy was found 0.75 ± 0.04 (0.66 – 0.81). 
Kawagishi et al24 found the mean RI value 0.70 ± 
0.005. Mean RI value measured in 160 eyes of 80 
healthy subjects was 0.64 ± 0.02 (0.60 – 0.70) in this 
study and Kawagishi et al24 found the mean RI value 
0.65 ± 0.05 in healthy subjects. So, the result of present 
study is consistent with the study done by Kawagishi et 
al.24 

From the results of the present study it can be 
concluded that there is statistically significant 
difference between retinal arterial RI of type 2 diabetic 
patients without retinopathy and that of healthy control 
adult subjects included in this study. Higher RI in type 2 
diabetics may predict the early hemodynamic changes 
in the retinal artery of these patients before the clinical 
onset of retinopathy. However, further studies including 
large number of study subjects are recommended.

References

1.  Ahmed KR, Karim MN, Bhowmik B, Habib SH, Ali L. 
Incidence of diabetic retinopathy. J Diabetes 2012; 4:                
386–391. 

2.   Shaw JE, Sieree RA, Zimmet PZ. Global estimates of the 
prevalence of diabetes. Diabetes Res Clin Prac 2010; 87(1): 
4–14.

3. IDF Diabetes Atlas. Available at: http//www. 
idf.org/diabetesatlas/5e/the global burden. Accessed 
November 2012.

4.   Yau JW, Rogers SL, Kawasaki R, Lamourese EL, Bek T. 
Global prevalence and major risk factors of diabetic 
retinopathy. Diabetes Care 2012; 35(3): 556–564.

5.  Sandeman DD, Shore AC, Tooke JE. Relation of skin 
capillary pressure in patients with insulin-dependent 

diabetes to complications and metabolic control. N Engl J 
Med 1992; 327: 760–764.

6.    Dandona R, Dandona L. Socioeconomic status and blindness. 
Br J Ophthalmol 2001; 85: 1484–1488.

7.   Dandona R, Dandona L. Review findings from the Andhra 
Pradesh eye disease study. Indian J Ophthalmol 2001; 49: 
215–234.

8.  Mackinnon JR, McKillop G, Brien O, Butt Z, Nelson P. 
Colour Doppler imaging of the ocular circulation in diabetic 
retinopathy. Acta Ophthalmol 2000; 78: 386–389.

9.    Mendivil A, Cuartero V, Mendivil MP. Ocular flow velocities 
in patients with proliferative diabetic retinopathy and 
healthy volunteers. B J of Ophthalmology 1995; 79:           
413–416.

10.  Dimitrova G. Colour Doppler imaging of ocular and orbital 
blood vessels in retinal diseases. European Ophthalmic 
Review 2011; 5: 16–19.

11. Fielding JA. Ultrasound imaging of the eye through the 
closed lid using a non dedicated scanner. Clin Radiol 1987; 
38: 131–135.

12.  Guthoff RF, Berger RW, Winkler P, Helmke K, Chumbley 
LC. Doppler ultrasonography of the ophthalmic and central 
retinal vessels. Arch Ophthalmol 1991; 109: 532–536.

13.  Goebal W, Leib H, Sergott RC, Farhoumand R, Grehn F. 
Colour Doppler imaging: a new technique to assess orbital 
blood flow in patients with diabetic retinopathy. Invest 
Ophthalmol Vis C 1995; 36: 864–870. 

14.  Tamaki Y, Nagahara M, Yamashita H, Kikuchi M. Blood 
velocity in the ophthalmic artery determined by colour 
Doppler imaging in normal subjects and diabetics. Jpn J 
Ophthalmol 1993; 37: 385–392.

15. Jack PH. Colour Doppler ultrasonographic imaging of 
central retinal artery. Available at: http://www.res-
medical.com/endocrine-glands/58571. Accessed April 2012.

16. Little HL. The role of abnormal hemodynamic in the 
pathogenesis of diabetic retinopathy. Trans Am Ophthalmol 
Soc 1976; 74: 573–636.

17.  Eliash ZB, Nelsol DA, Barak A, Bartal O. Reduced retinal 
blood flow velocity in diabetes retinopathy. Retina 2010; 
10: 1–11.

18. Nagaoka A, Sato E, Takahashi A,Yokota H, Sogawa K, 
Yoshida A.  Impaired retinal circulation in patients with 
type 2 diabetes mellitus: retinal laser Doppler velocimetry 
study. Invest Ophthalmol Vis Sci 2010; 51: 6729–6734.

19.  Zawinka C, Dornar GT, Polska E, Frank B. Calculation of 
the diameter of the central retinal artery from non invasive 
measurements in human. Current Eye Research 2002; 25: 
341–345.

 

 

172

J Enam Med Col  Vol 4  No 3 September 2014



     

20.  Polska E, Kircher K, Ehrlich P, Vecsei PV, Schmetterer L. 
RI in central retinal artery as assessed by CDI does not 
correspond to retinal vascular resistance. Am J Physiol 
Heart Circ Physiol 2001; 280(4): 1442–1447.

21.  Dimitrova G. Colour Doppler imaging of ocular and orbital 
blood vessels in retinal diseases. European Ophthalmic 
Review 2011; 5: 16–19.

22.  Prahs P, Helbig H. Diabetic eye disease. Ther Umsch 2009; 
66: 183–188.

23.  Benden CJ, Abbitt PL, Beadless KA. Colour Doppler US of 
the orbit. Radio Graphic 1995; 15: 589–608.

24.  Kawagishi T, Nishizawa Y, Emoto M, Konishi T, Maekawa 
K, Hagiwara S et al. Impaired retinal artery blood flow in 
IDDM patients before clinical manifestations of diabetic 
retinopathy. Diabetes Care 1995; 18: 1544–1549.

25.  Guthoff RF, Berger RW, Winkler P, Helmke K, Chumbley 
LC. Doppler ultrasonography of the ophthalmic and central 
retinal vessels. Arch Ophthalmol 1991; 109: 532–536.

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