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| Year : 1962 | Volume
: 10
| Issue : 4 | Page : 107-112 |
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Ophthalmodynamometry and carotid compression
Lalit P Agarwal, Madan Mohan, SRK Malik, SS Gill
Department of Ophthalmology, All-India Institute of Medical Sciences, New Delhi, India
Correspondence Address:
Lalit P Agarwal
Department of Ophthalmology, All-India Institute of Medical Sciences, New Delhi
India
How to cite this article:
Agarwal LP, Mohan M, Malik S, Gill S S. Ophthalmodynamometry and carotid compression. Indian J Ophthalmol 1962;10:107-12 |
How to cite this URL:
Agarwal LP, Mohan M, Malik S, Gill S S. Ophthalmodynamometry and carotid compression. Indian J Ophthalmol [serial online] 1962 [cited 2013 May 23];10:107-12. Available from: http://www.ijo.in/text.asp?1962/10/4/107/39557 |
The occlusion of the carotid artery, clinically or experimentally, almost invariably causes a fall of pressure in ophthalmic and retinal circulation on the same side. The effect of percutaneous compression has been studied by Blodi and Van Allen (1957) recording an equal fall in systolic and diastolic values; and DeCarvalho et al (1960) showed more fall in systolic pressure. Hollenhorst et al (1951) laid stress on the diastolic figures. In view of this controversy between values of systolic and diastolic pressure we attempted this work.
 Material and Method | |  |
Twenty-five cases were selected for the study from the patients coming for refraction in the outpatient department. Ages varied between 12 and 62 years. The criteria for selection were:
i. Non-glaucomatous.
ii. No gross changes in fundus or media.
iii. No obvious history of any cardiovascular disease, neurological disease, or sudden black-outs.
iv. No marked obesity, lest it may render the carotid compression difficult and erratic.
v. Moderate or no refractive error.
The pupil was dilated with homatropine 2%. After retinoscope and fundus examination, the subject was put in supine recumbence. Cardiovascular system and neurological system were examined. Systolic and diastolic blood pressures were recorded in the right brachial artery. Intraocular tension was then recorded with Baillart's tonometer. Surface anaesthesia used in the series was Lignocaine 2%. The ophthalmodynamometric (ODM) readings were taken in the right eye first and then in the left eye. For this, the assistant separated the lids; the foot-piece of Baillart's ophthalmodynamometer was rested perpendicularly over the insertion of lateral rectus while the eye was slightly adducted by the patient. The optic disc was viewed through a direct ophthalmoscope. The pressure on the foot-piece was rapidly increased to get the diastolic (appearance of arterial pulsation) and the systolic readings (complete) disappearance of arterial pulsation). It took about 10 seconds to record the readings in each eye. Then after waiting for 20-25 minutes, the assistant applied firm digital compression over the right common carotid artery against the transverse process of 6th cervical vertebra till its pulsation disappeared. After 10 seconds of compression the patient was asked for any untoward effects (black-out, giddiness, etc.) he experienced. Now the second ODM reading was taken, first in the right then in the left eye. The compression was released.
The observer and the assistant were the same throughout the series.
| Observations | | |
1. ODM readings before carotid compression [Table - 1] :- The range of systolic pressure was 60 to 95 units or grams with an average figure of 72.0 units for right eye and 72.2 units for left eye. The diastolic range was between 30 and 45 units, averaging 36.8 for right and 36.6 units for left eye. The readings in two eyes were identical in a few patients; maximum difference was 5 units.
2. Relationship of ODM reading with brachial pressures before carotid compression [Table - 1]:-For the sake of simplicity the gram units on the dial of ophthalmodynamometer were taken as mm. of mercury (although very slight difference is stated in standard tables), The ratio was deduced as :
ODM systolic (or diastolic)
Brachial systolic (or diastolic)
x 100 = _______ %
The systolic ratio had an average of 55.4% in either eye (range : 51.1 -61.0%;) and diastolic ratio average was 44.7% right eye and 44.6% in left eye with a range of 40.0% - 47.9% in either eye.
3. ODM readings during right carotid compression [Table - 2]:- Both systolic and diastolic ODM pressures showed an invariable fall in right eye, while in left eye the figures were little affected. On the right side the systolic pressure showed an average of 58 units (range : 50-75 units) and diastolic average was 26.7 units (range : 20-38 units).
4. Relationship of ODM reading with brachial pressures during right carotid compression [Table - 2] :On the right side the maximum systolic ratio was 50.9% and minimum as 38.5% (average 44.6%). The diastolic ratio varied between 23.5 and 40.0% (average 32.9%).
The systolic and diastolic ratios on left side remained practically at a pre-compression level i.e. 56% and 44.3%.
5. Percentage fall in ODM values with carotid compression [Table - 3] :- For right eye the percentage fall of systolic pressure varied between 11.3% and 33.3% (average 19.4%) while diastolic fall was greater 12.5-50.0% (average 30.8%).
6. Effect of Age [Table - 4] :The brachial ODDS ratio, and average percentage fall was worked out according to the age group. The patients were divided into 5 groups i.e. 2nd decade, 3rd decade, 4th decade, 5th decade, and 6th decade or above. No consistent relationship of these figures with the age could be found out.
7. Effect of Sex [Table - 5] :Like age the figures were worked out for males and females separately. Sixteen were males and 9 females. All the figures were almost identical in either group.
8. Subjective symptoms on carotid compression. The subjective symptoms were complained of by three patients. They ranged from mild giddiness, perception of dark spots to complete black-out.
| Discussion | | |
Duke-Elder has pointed out that in ophthalmodynamometry we do not record the pressure in the central retinal artery, but the ophthalmic artery pressure (because of build up of back pressure). The ophthalmodynamometric readings are usually proportional to general blood pressure but may be modified by such factors as intraocular tension, patency of proximal arterial system like carotid artery, intracranial tension, direction of thrust of the instrument on the eye ball, the time taken to take the readings, and the scleral rigidity.
A definite relationship has been shown to exist between the ophthalmodynamometric pressures and the brachial blood pressure. The findings of our series are broadly comparable to others [Table - 6].
It is not proper to compare the compression of common carotid artery with the clinical entity of internal carotid insufficiency or thrombosis. Clinically nobody can lay one's hand on the exact process going on in the internal carotid, its distal vascular tree, and the efficiency of anastomosis. The main evident difference in percutaneous compression of common carotid is that both the internal as well as external carotid arteries share the crisis of blood flow, and whatever the anastomotic value be of the latter it is excluded. The evaluation under these circumstances, besides throwing light on internal carotid system, reflects the efficiency of other vascular anastomosis feeding the ophthalmic artery as well, or comparing the fall of ODM pressure after carotid compression with corresponding figures of clinical carotid occlusion worked out by various workers [Table - 7]. In our series the percentage fall in diastolic pressure is more than in systolic.
Of the three cases who exhibited some symptoms on carotid compression, two showed fall in ODM systolic and diastolic pressures but it was less than the average figures. In the third case, however, where there was complete black-out, the fall in ODM pressures registered was maximum in the series i.e. systolic 25 units (33.3%) and diastolic 20 units (50%) But another woman, who remained symptom free, also showed a considerable percentage fall of 15 units (21.4%) in systolic and 15 units (42.9%) in diastolic ODM. None of the 50 cases in the series of DeCarvalho et al got any untoward symptom on carotid compression. From this series it can be concluded that it is neither the absolute value nor the percentage fall of ophthalmic artery systolic or diastolic pressure which can explain the symptoms resulting from carotid compression, but it seems to be some factor of obscure nature.
No direct correlation between age and fall of ophthalmic pressure with compression could be found except that the symptoms occurred only in patients above the age of 40 years.
The sex did not have any bearing on any of the values.
| Summary | | |
1. The effect of percutaneous compression of common carotid on ophthalmodynamometric value has been studied in 25 normal individuals.
2. The fall of ophthalmic artery pressure is correlated with age, sex, and the symptoms experienced by the patient.
3. It has been pointed out that diastolic fall in pressure is of greater significance than the systolic fall in ophthalmic artery pressure.[9]
| References | | |
| 1. | Agarwal L. P., Chawla, S. R. and Saxena R. P. (1957) Amer. J. Obst. Gynae. 74, 521.  |
| 2. | Block F. C., and Van Allen M. W. (1957) Amer. J. Ophth. 43, 779. |
| 3. | Bailliart, P., (1928) Cliniopht. 15, 178. |
| 4. | DeCarvalho C. A., Caldeira, J, A. F. Berquo, L. and Filho, R. M. (1960) Amer. J. Ophth. 50 259. |
| 5. | Duke-Elder, S. `V, `Text book of Ophthalmology' Vol. 1942 (Henry Kimpton, London) p. ? |
| 6. | Hollenhorst, R. W., Willure, R. E., and S. Vien, H. J. (1957) Amer. J. Ophth. 43, 778. |
| 7. | Hollenhorst R. W. (1958) Amer. J. Ophth. 47, 753. |
| 8. | Smith, J. L. & Cogan, D. G. (1959) Amer. J . Ophth. 48, 735. |
| 9. | Spalter, H. F. (1959), Amer. J. Ophth. 47, 453. |
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7]
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