Download Blood velocity in the ophthalmic artery in normal subjects and

Reporrs
No. 9
1919
Investigative Ophthalmology & Visual Science. V o l . 3 1 , No. 9. September 1990
Copyright © Association for Research in Vision and Ophthalmology
Blood Velocity in the Ophthalmic Artery in Normal Subjects and Patients
with Endophthalmitis
Georg Michelson,* Kornelio Gierrh,* Rolf Priem,-|- and Rudolf Laumerf
Some ocular diseases lead to temporary changes in the ocular blood circulation. This study was undertaken to evaluate
changes in the blood-flow velocity of the ophthalmic artery
in patients with endophthalmitis. With pulsed Dopplcr sonography the blood velocity of the ophthalmic artery was
measured in 50 normal subjects and in ten patients with
bacterial endophthalmitis. In normal subjects blood velocity decreased with increasing age, and the average systolic/
diastolic blood velocity in cm/sec were 38.8 ± 6.3/11.6
± 4.7 in the 18-50-ycar-old age group and 28.3 ± 4.6/6.7
± 3 . 3 in the 51-88-ycar-old age group. Endophthalmitis
produced increased systolic/diastolic blood velocity in the
ophthalmic artery in the affected eyes in cm/sec (99.7
± 15.5/26.6 ± 10.5 in the 16-50-year-old age group; 60.4
±8.8/16.6 ± 4 . 8 in the 51-83-year-old age group). Some
patients showed similar changes in the unaffected fellow
eyes. The noted elevation of the blood velocity in unaffected
eyes may be due to the bilaterally projected parasympathetic fibers of the oculomotor nerve. Invest Ophthalmol
Vis Sci 31:1919-1923, 1990
Many ocular diseases are associated with altered
blood flow in the ophthalmic artery. We know less
about temporary changes of ocular circulation in
states of severe ocular inflammation. Endophthalmitis may produce ocular hyperemia with increased
blood flow to the affected eye. We determined if patients with endophthalmitis develop an increased
blood velocity in the ophthalmic artery detectable by
pulsed ultrasound Doppler sonography.1"8
Materials and Methods. The Doppler principle
describes the frequency shift of received wave energy
caused by a moving reflector (in our case, moving
blood). The frequency shift f depends on the velocity
v of the red cells and on the angle a between the vessel
and the insonation beam: f = 2 f0 v cosine a/c; where
fo = 2 MHz and c = 1540 m/sec (c = propagation
velocity of ultrasound through tissues). By rearranging the equation, the velocity component, v*, which
causes the frequency shift, f, can be calculated: v*
= 39 f. The measured blood velocity, v*. is related
to the real blood velocity, v, by the cosine of the
angle, a, between the axis of the ultrasound beam
and the vessel. Due to this function the trigonometric
velocity error (TVE) depends on the angle a: TVE(%)
= (1 - cosine a) 100 with TVE(%) = (v - v*) 100/v
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and v* = v cosine a. Within an insonation angle a of
40° (-20°-+20°), the TVE is therefore maximally
8%. All further data are based on the measured velocity, v*.
Pulsed Doppler sonography measures blood velocity of orbital vessels at given spatial intervals from a
reference point (temporal upper lid), with a sample
length of 4 mm, parallel to the ultrasound beam.
With the direction of insonation from the upper lid to
the optic foramen and an orbital measuring depth of
39 ± 4 mm the identification of the ophthalmic artery
just after entering the orbit was achieved (Figs. 1, 2).
After visual and acoustic optimization of the pulse
curve (monitor and headphones) by varying the angle
a with the hand-held transducer, 12 pulse curves of
each eye were stored. The arithmetic means of the
systolic (vsys), diastolic (vdia), and mean velocity are
used in further data.
With a pulsed ultrasound Doppler sonograph (4
MHz; EME, Uberlingen, West Germany), the ophthalmic arteries of 50 normal subjects (average age.
38.7 ± 18; range, 18-80 yr) and often patients (range,
16-83 yr) with bacterial endophthalmitis were examined. Bacterial endophthalmitis was caused by perforating injury in four patients and by complicated
cataract extraction in six patients. We compared the
v
sys, vdia, and vascular resistance—Pourcelot index
[PI] = (vsys - vdia)/vsys—in the ophthalmic arteries of
the two groups.
Informed consent was obtained from all patients
and subjects before of the investigation.
Results. In normal subjects both the vsys and vdia in
the ophthalmic artery decreased significantly with increasing age (vsys: linear correlation coefficient r
= -0.56, P < 0.001; vdia: r = 0.52, P < 0.0001).
Average vs>s/vdia in cm/sec were 38.8 ± 6.3/11.6 ± 4.7
in the 18-50-yr-old age group and 28.3 ± 4.6/6.7
± 3.3 in the 51-80-yr-old age group (Figs. 3. 4). Vascular resistance of normal subjects also increased
with increasing age (linear correlation coefficient r
= 0.275; P < 0.05) (Fig. 5).
All ten patients with endophthalmitis showed significantly increased blood velocity in the affected eye
up to an average of 99.7 ± 14.5 cm/sec in the 16-50yr-old age group (P = 0.0001, Mann-Whitney-Wilcoxon test) and 60.4 ± 8.8 cm/sec in the 51-83-yr-old
1920
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE / Seprember 1990
Vol. 31
Pulsed Doppler
Sonograph
Fig. 1. Schematic picture of the
pulsed 4 MHz transducer examining the ophthalmic artery.
Ophthalmic Artery
Sample Volume
Ophthalmic
Fig. 2. Normal pulse
curve of the ophthalmic artery measured by a pulsed
ultrasound Doppler sonograph (4 MHz) in 39 mm
orbital depth from the temporal upper lid.
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Fig. 3. Systolic blood velocities in the ophthalmic
artery of 50 normal subjects
(right eyes, OD; left eyes,
OS) and in 10 patients with
cndophthalmitis (affected
eyes, unaffected fellow eyes)
with increasing age. Note
the linear regression line of
normal right eyes (linear
correlation coefficient r
= -0.56. /J = 0.001) with 2
standard deviation (SD)
range. Seven of ten patients
with
cndophthalmitis
showed also increased velocities in the unaffected fellow eyes outside of the ±2
SD range.
1921
Reporrs
No. 9
* Affected
eye
SYSTOLIC BLOOD UELOCITY
IN ENDOPHTHALMITIS
12B
° Unaffecte
d fellow
eye
IBB
* Normal
eye OD
.E 88
- Norma1
eye OS
14B
U
CD
E
u
>-
68 +
(J
o
"o
_
_•
o
c
2SD
48
_J"
u
>
28
--—2SD
8
-H
18
28
38
48
58
1
68
\—
78
1
1
88
98
— L inear
Regress io
n Line OD
- +- 2 SD
Range
AGE in years
age group (P = 0.0001, Mann-Whitney-Wilcoxon
test) during systole in comparison with normal subjects. In seven often patients elevated vsys outside the
range of two standard deviations was noted also in
the unaffected fellow eye (Fig. 3).
Eight often patients had significantly increased vdia
blood velocities in the affected eye (18-50-yr-old age
group: vdia 26.6 ± 10.5, control 11.6 ± 4.7 cm/sec, P
< 0.001 Mann-Whitney-Wilcoxon test; 51-83-yr-old
age group: vdia 16.6 ± 4.8, control 6.7 ± 3.3 cm/sec, P
< 0.001 Mann-Whitney-Wilcoxon test) (Fig. 4). The
PI of the affected eyes and of the unaffected fellow
60
Fig. 4. Diastolic blood velocities in the ophthalmic
artery of 50 normal subjects
(right eyes OD, left eyes OS)
and in 10 patients with cndophthalmitis (affected
eyes, unaffected fellow eyes)
with increasing age. Note
linear regression line of normal right eyes (linear correlation r = -0.52. P< 0.001)
with ±2 SD range.
eyes did not differ significantly from normal subjects
(Fig. 5).
Systemic features like blood pressure, erythrocyte
sedimentation rate, and leukocyte count were normal. In patient LA, 69 yr of age, the blood velocities
were observed for 60 days after complicated extracapsular cataract extraction/intraocular lens implantation with postoperative endophthalmitis. In this patient the blood velocity normalized after 60 days in
both eyes (Fig. 6).
Discussion. We observed three phenomena: (1) in
normal subjects we found a decrease of vsys and vdia in
* Affected
eye
DIASTOLIC BLOOD UELOCITY
IN ENDOPHTHALMITIS
T
° Unaffected
fe1 low eye
O 50QJ
E
' Normal eye
OD
40
o
- Normal eye
OS
30
o
20
— L inear
regress ion
1 ine
normal eye
OD
.
10
- +- 2 SD
Range
18
28
30
40
50
60
AGE in years
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70
88
98
1922
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE / Seprember 1990
l
X
LJ
Q
Z
* Affected
eye
POURCELOT-INDEX P . I .
IN ENDOPHTHALMITIS
P.I. =(Usys-UdiaVUsys
1,1-
o Unaffected
fe1 low eye
- •
8,9
- Norma1 eye
OD
+2SD
8,8 •
" Normal eye
OS
8,7
Ld
O
o
— Linear
Regress ion
Line
Norma1 eye
OD
8,6
-2SD
8,5
Vol. 31
8,4-
— + - 2 SD
Range
Fig. 5. Pourcclot Index
(index for vascular resistance, P.I. = (Vsys
- Vdias)/Vsys) of 50 normal subjects and of 10 patients with endophthalmitis
(affected eye, unaffected fellow eye) with increasing age.
Note linear regression line (r
= 0.275, P < 0.05) with ±2
SD range of normal right
eyes. Both the affected eyes
and the unaffected fellow
eyes showed values inside
the ±2 SD range.
8,3
18
28
38
48
58
68
78
88
98
AGE in years
the ophthalmic artery and an increase of the vascular
resistance with increasing age; (2) in patients with
endophthalmitis we measured increased blood velocities in the affected eyes; and (3) in some patients
there were also increases in the unaffected fellow eyes.
The cause of these observations is unknown. The
age-related decrease of the blood velocity and the increased vascular resistance in the ophthalmic artery
may depend on diminished perfusion pressure caused
by age-related arteriosclerosis. The phenomenon of
age-related decrease of the blood velocity is already
known in cerebral arteries.9"13
The significant elevation of the blood velocity in
the ophthalmic artery in affected eyes may be due to a
secondary hyperemia in the choroid and/or to a secondary vasospasm of the ophthalmic artery. The release of prostaglandins in affected eyes may stimulate
trigeminal sensory nerves, producing choroidal vasodilation through parasympathetic fibers of the oculomotor nerve.14"16 The associated blood velocity elevation in the unaffected fellow eyes may contribute to
bilaterally projected sympathetic fibers with vasospasm of the ophthalmic artery in the unaffected fellow eyes. The normal vascular resistance in eyes with
Time course
Patient L.A., 69 years
•"•• a f f e c t e d
eye
°- unaffecte
d
fel low
eye
-
normal
range
69 years
- + 2 SD
-
days
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-
2 SD
Fig. 6. Time course of the
systolic blood velocity after
complicated ECCE/IOL
with endophthalmitis (L.A.,
69 years) in comparison to
normal systolic blood velocity with ±2 SD range.
Reporrs
No. 9
endophthalmitis can be an argument for the hypothesis that the increase in blood velocity is due partially
to a vasospasm of the ophthalmic artery.
Key words: pulsed Doppler sonography, blood velocity,
ophthalmic artery, normal subjects, endophthalmitis
From the Departments of "Ophthalmology and fNcurosurgery,
University Erlangen, Niirnberg, West Germany. Reprint requests:
Gcorg Michclson, Augenklinik mit Poliklinik, Universitat Erlangcn-Nurnbcrg, Schwabachanlagc 6, D-8520 Erlangen, West Germany.
References
1. Canning CR and Restori M: Doppler ultrasound studies of the
ophthalmic artery. Eye 2:92, 1988.
2. Cellini M, Profazio V, Barbaresi E, and Scarpellini I: Doppler
measuring in induced ocular hypertony. Ann Ottalmol Clin
Ocul 111,6:491, 1985.
3. Evans DH, Barric WW, Asher MJ, et al: The relationship between ultrasonic pulsatility index and proximal arterial stenosis in canine model. Circ Res 46:470, 1980.
4. Fcdorov SN, Ivashina AI, Mikhaylova GD, and Niketin YM:
Possibilities for investigation of hemodynamics of the eye with
the help of ultrasonic apparatus Dopscan. Oftalmol Zh 3:169,
1986.
5. Nilsson SFE, Lindner J. and Bill A: Characteristics of uveal
vasodilatation produced by facial nerve stimulation in monkeys, cats and rabbits. Exp Eye Res 40:841, 1985.
6. Rein A, Sigal R, and Hamard H: Ophthalmic a: v r y and pulsed
doppler. J FrOphtalmol 8, 4:341, 1985.
1923
7. Rittgers SE, Thornhill BM, and Barnes RW: Quantitative
analysis of carotid artery Doppler spectral waveforms: Diagnostic value of parameters. Ultrasound Med Biol 9:255, 1983.
8. The Doppler standards and nomenclature committee of the
American Society of Echocardiography 1986, Recommendations for terminology and display for Doppler echocardiography. In Basic Doppler Echography, Kisslo J, Adams D, Mark
DB, editors. New York, Churchill Livingstone,.
9. Woodcock JP, Gosling RG, and Fitzgerald DE: A new noninvasivc technique for assessment of superficial femoral artery
obstruction. Br J Surg 59:226, 1972.
10. Meyer CHA, Lowe D, Meyer M, Richardson PL, and NeilDwyer G: Progressive change in cerebral blood flow during the
first three weeks after subarachnoid hemorrhage. Neurosurgery 12:58, 1983.
11. Naratomi H, Meyer JS, Yamaguchi F, and Shaw T: Effects of
advancing age on regional cerebral blood flow. Arch Ncurol
36:410, 1979.
12. Aim A, Stjcrnschantz J, and Bill A: Effects on oculomotor
nerve stimulation on ocular blood flow in rabbits after sympathetic denervation. Exp Eye Res 23:609, 1976.
13. Bill A: Circulation in the eye. In Handbook of Physiology. The
Cardiovascular System, Vol IV. The American Physiological
Society, 1984, pp. 1001-1034.
14. Bill A, Lindner M, and Lindner J: The protective role of ocular
sympathetic vasomotor nerves in acute arterial hypertension.
Bibl Anat 16:30, 1977.
15. Mandahl A: Release of Substance P and its Role in the Acute
Inflammatory Response in the Rabbit Eye. Thesis. Acta Univ.
Upsaliensis, 1983, pp. 1-29.
16. Nilsson SFE and Bill A: Vasoactive intestinal polypcptidc
(VIP): Effects in the eye and on regional blood flow. Acta
PhysiolScand 121:385, 1984.
Investigative Ophthalmology & Visual Science, Vol. 31. No. 9, September 1990
Copyright © Association Tor Research in Vision and Ophthalmology
Human Presaccadic Spike Potentials
Of Cenrrol or Peripheral Origin?
Avinoom Nariv,* Joel M. Weinsrein.j- and Rodolfo Rosas-Ramos*
Electroencephalographic (EEG) activity associated with
voluntary and spontaneous saccades were analyzed in 12
normal subjects to determine the influence of volition upon
the presaccadic spike potentials (SPs). In addition, two different electrode configurations, of a temporal and a parietal
derivation, and two different filter bandwidths were simultaneously analyzed to clarify issues regarding the structure,
function, and origin of SPs. An off-line averaging of the preand postsaccadic EEG epochs showed distinct spike potentials associated with spontaneous saccades in both the temporal and the parietal locations. Subsequent statistical analyses indicated that the amplitude of the SPs associated with
spontaneous saccades was not significantly different from
the respective amplitude of SPs preceding voluntary saccades. Independent effects of filter bandwidth and electrode
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derivation are suggestive of a complex late presaccadic
EEG activity. Invest Ophthalmol Vis Sci 31:1923-1928,
1990
Earlier work in our laboratory1 suggested that spike
potentials (SPs, "cortical potentials" preceding eye
movements by 10-15 msec) were associated with voluntary, but not with spontaneous, eye movements.
Although scalp-recorded SPs initially suggested a posterior parietal origin for this potential,12 later work3
with dipole mapping, showed that the origin of SPs
was in the orbital region, most probably derived from
extraocular muscle activity. A different suggestion