Ophthalmodynamometry in toxemias of pregnancy

OPHTHALMODYNAMOMETRY IN TOXEMIAS OF PREGNANCY LALIT P. AGARWAL, M.B. (LucK.), D.O.M.S. (ENG.), D.O. (OxoN.), M.S. (OPHTH.), S. R. CHAWLA, D.O.M.S., AND R. P. SAXENA, M.S. (OPHTH.), KANPUR (U.P.), INDIA (From the Department of Ophthalmology, Medical College, Kanpur (U. P.}, India)

T HAS long been known that in the later stages of pregnancy theer may be a

sudden visual catastrophe often associated with a generalized body tissue Idamage. It has also come to be believed that the only remedy lies in prevention. With this realization much energy has been directed toward early diagnosis, even toward the recognition of a pretoxemic state. Recent work done by Bailliarts has raised the question of whether increased brachial pressure is usually the earliest manifestation of toxemia. Some cases of toxemia are seen with a normal brachial arterial pressure. It has been suggested that perhaps an increase in the arterial pressure of the small arterioles in the central nervous system is an earlier change. The arteriolar pressure in the central nervous system is well reflected in the arteriolar pressure of the retina. It was with the possibility of detecting very early signs of toxemia that these studies of retinal arterial pressures were undertaken. Work on ophthalmodynamometry comes mainly from Bailliart. 2 He was also the first to describe the relationship between retinal and brachial arterial pressures, the normal ratio being 0.45 :1 for the diastolic and 0.54:1 for the systolic pressure. He pointed out that in hypertensive conditions the retinal diastolic pressures rise in proportion to the rise in brachial diastolic pressures. The rise in retinal systolic pressure, however, is proportionately greater than the rise in brachial systolic pressure, the proportion being 0.7 to 0.8 :1. Bailliart was supported by Volhard,1 3 who further pointed. out that in essential hypertension a rise in the retinal pressure may be the earliest sign and that this is perhaps also true of the toxemias of pregnancy. Volhard's findings do not relate to the diastolic retinal pressures, for he believes that only the systolic pressure ratio between retinal and brachial pressures was altered. Bailliart, on the other hand, regarded a disproportionate rise in retinal diastolic pressure as an indication of high cerebrospinal vascular pressure. The values of retinal systolic and diastolic pressures as reported by different observers have varied over a wide range. Magitot and BailliarF found that in man the diastolic/systolic ratio varied from 25/50 to 30/70 mm. mercury. The assessment of ophthalmodynamometric data has been undertaken 521

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Am. }. Obst. & Gynec. September, 1957

by Gonzaby 5 and by Strei:ff, 12 who consider that the measurement of retinal pressures by this method is fairly accurate and the values obtained quite reliable for clinical purposes. Weigeli and associates 15 have pointed out the value of recording retinal arterial pressures to assess the state of intracranial cin:ulation and consider this procedure to uc of clinical significance. The diagnostic and prognostic significance of retinal diastolic pressures in general states of hypertension has been recently stressed by many authors1· 8 • 10 • 11 • 16 Kologolu 6 also assessed its importance in the prognosis of eclampsia. 'rho present study was conelud0d somewhat earlier than the appearance of Kologolu's report.

Technique of Recording Pressure Local anesthesia is applied to the eye and the intraocular tension recorded. The systemic blood pressure is measured in the usual way. The observer then sits in front of the patient as for direct ophthalmoscopy. He holds the ophthalmodynamometer in one hand and the self-illuminating ophthalmoscope in the other. The dynamometer is held like a pen with the first three fingers while the other two rest on tho temporal region. The instrument is placed upon the sclera about 7.5 mm. away from the corneoscleral junction to the temporal side. Rapid but gradual pressure is applied by the instrument directed perpendicularly to the eyeball. During compression the fundus is observed with the ophthalmoscopr and the large vessels at the disc are watched. At the appearance of the first tremor or fleeting pulsation in the artery the pressure is stopped without removal of the instrument. The pointer on the disc in the dial type of ophthalmodynamometer stops and the reading is recorded. The compression is then reapplied till the pulsations stop completely, the artery collapses, the disc becomes white, and vision is lost. The reading is noted and the pressure discontinued. The figures obtained can be converted into millimeters of mercury on the table provided with the instrument. The instrument is based on the same principle as the syphygmomanometer but instead of detecting the changes in the pulse, either by palpation or auscultation, the appearance and disappearance of the pulse in the large vascular trunks is directly observed at the disc. Duke-Elder• criticized this method as he feels that it records only pressures in the ophthalmic artery itself. Streiff 12 recently expressed the opinion that the method is clinically reliable and that an error of more than 1.5 mm. does not occur. We feel that the ophthalmodynamometer is comparatively accurate and is of practical clinical value. Clinical Material Thirty clinically normal women in various stages of pregnancy were examined for any abnormalities in the retinal and brachial pressures and for possible changes in the eye ground. Sixty women with evidence of preeclamptic or eclamptic toxemia were next examined. Retinal changes in these were also noted and arterial pressure in the brachial artery and retina recorded. Finally, 10 patients seen in the first trimester of pregnancy in whom the brachial arterial pressure and the retinal systolic pressure were within normal range but the retinal diastolic pressure was elevated have also been included in this study. All of these have been followed during pregnancy. The findings in all these cases have been correlated with eye ground changes according to gradations of Wagner 14 and Mylius. 9 The results m·e summarized in Tables I and II.

OPHTHALMODYNAMOMETRY IN TOXEMIAS OF PREGNANCY

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TABLE I.

During Pregnancy.-

523

SYSTOLIC RETINAL AND BRACHIAL A.RTERIAL PRESSURES

I

I

I

I

BRACHIAL EYE RETINAL NO. OF GROUND AVERAVERCASES GRADE AGE I MIN. MAX. AGE I MIN. __ I MAX.

Normal pregnancy First trimester Second trimester Third trimester Pre-eclampsia

Eclampsia

Potential toxemia

After Delivery.Normal preg'tWncy Pre-eclampsia Eclampsia

AVERAGE RATIO

10 10 10

0 0 0

58 !'}8 61

52 52 52

65 68 70

114 .109 115

102 90 102

125 120 125

0.51:1 0.53:1 0.52:1

10 20 10

0 1 2

77 86 100

60 65 86

95 105 110

125 138 155

110 128 140

140 158 180

0.61:1 0.62:1 0.64:1

2 6 8 4

0

1 2

3

95 84 104 104

95 80 88 95

95 88 112 112

140 154 163 167

140 150 155 160

140 158 180 175

0.68:1 0.53:1 0.64:1 0.59:1

10

0

60

54

70

115

102

128

0.54:1

30 30 10 8

0 0 1 0

62 60 72 85

52 52 60 70

70 65 95

114 115 124 130

102 105 100 110

125 128 155 165

0.54:1 0.54:1 0.58:1 0.60:1

0 1

70 84

62 65

85 100

128 140

107 120

142 150

0.55:1 0.60:1

90

In the Third 1'r·imester.Potential toxemia

3 7*

*Developed signs of toxemia. TABLE II.

--·······--·-

DIASTOLIC RETINAL AND BRACHIAL ARTERIAL PRESSURES

I NO. OF IGR~~~+VER·J CASES GRADES AGE

RETINAL MIN.

BRACHIAL lAVER MAX. AGE

I

MIN.

During Pregnancy.Normal pregnancy First trimester Second trimester Third trimester Pre-eclampsia

Eclampsia

Potential toxemia* ..f./!IAM

~J

(te-l

10 10 10

0 0 0

33 35 35

30 30 31

38 40 45

lll 20

1

0

45 4fi 5fi

70 70

I

MAX.

88

AVER· AGE RATIO

71

60 60 60

!l5

65 75

60 70 70

90 100 130

0.76:1

90

0.47:1 0.50:1 0.50;1

10

2

55 62 69

811

76 87 96

2 6

8 4

0 1 2 3

60 62 80 82

60 60 72 75

60 65 85 90

95 93 99 108

95 90 95 105

95 95 100 110

0.63:1 o.6n:1 0.81:1 0.76:1

10

0

45

36

54

74

60

88

0.62:1

0.70:1 0.71:1

n,J,.'"',,.."""'•

L'Vt--ltUtil9•-

Normal pregnaney

30

0

35

30

45

70

60

95

0.50:1

Pre-eclampsia

30

0

55

45 45

60

74

72

78

65 70

95 100

0.75:1 0.77:1

Eclampsia

10

1

8 12

0 1

68 74

60

65

80 85

90 95

so 85

105 110

0.76:1 0.80:1

0

56 60

40 44

60 70

75 87

60 70

85 98

. 0.70:1 0.71:1

57

In the Third Trimester.Potential toxemia

3 7t

1

*Cases showing high diastolic retinal pressure. tDeveloped signs of toxemia.

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Obst. & Gynec. September. 1917

Comment In normal pregnancy there is no alteration in the retinal and the brachial arterial pressures in the first trimester though later on there is a slight drop in both. The reason for this fall is not fully understood. In the cases of pre-eclampsia in our series, the eye ground changes varied from Grade 0 to Grade 2, and in eclampsia from Grade 1 to Grade 3. The ratio between retinal and brachial systolic pressures was found to be in the neighborhood of 0.63:1 in pre-eclampsia, and 0.65:1 in eclampsia. These figures are definitrly higher than those seen in normal individuals in the same month of preg-naney (0.53 :1). Although there is a rise in both the brachial and retinal arterial pressures, there is evidently a disproportionate rise in the retinal systolic prrssure. 'I'he disparity is more marked if we consider the diastolic pressures. The ratio between the retinal arterial diastolic and the brachial diastolic is in the neighborhood of 0.7:1 in the normal as compared with 0.5:1 in Grades 0 and 1 of retinopathy and 0.76 :1 in Grades 2 and 3 in eclampsia. In toxemia of pregnancy a comparatively greater rise of diastolic retinal pressure should always be looked upon with special concern, as it is in these cases that eclampsia may develop. During the follow-up of toxemia cases it has also been observed that the brachial pressure begins to fall much earlier than the retinal pressure. Similarly, in a few cases of normal pregnancy regarded by us as potentially toxemic, we have noted that there is an increase particularly in retinal diastolic pressure, and that a few of these cases have subsequently passed to toxemia, and even presented Grade 1 retinal changes. An increase in diastolic retinal pressure, even in normal pregnancy, calls for a careful and regular prenatal survey, and perhaps termination of pregnancy to prevent permanent vascular damage with detriment to maternal health. In the absence of eye ground changes, however, the pregnancy may be continued if kept under constant supervision. Eye ground changes alone do serve as a rough guide, but need not be looked upon with such grave concern as is common today, particularly if they are associated with only a moderate rise in retinal pressure. On the other hand, if there is present a disproportionate rise in retinal arterial pressure the continuation of pregnancy is highly dangerous. The presence of a disproportionately high retinal diastolic pressure in the absence of retinal changPs calls for a careful observation, but not for a hasty termination of pregnancy. The systolic pressure in the retinal artery shows an erratic trend and therefore we do not attach much importance to this change. It has been suggested that the retinal organic changes parallel a rise in brachial pressure, but this is not always true. On the other hand, we have observed that retinal organic change does parallel the retinal diastolic pressure. We therefore regard retinal diastolic pressure as a better indication of probable organic vascular changes.

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Retinal arteries are comparable to the arterioles of the central nervous system. Changes in these suggest a comparable change in the central nervous system. Similarly, pressure changes in the retinal arteries probably reflect the changes in the pressure in the arterioles of the central nervous system. This concept is suggested by Miller and Audoueineix 8 in relation to general hypertension. Perhaps the retinal arteries may also be compared with the arterioles of the kidney. Renal damage might then be anticipated, proportionate to the rise in retinal diastolic pressure. Hypertension of pregnaney is, of course, not to be regarded as a manifestation of primary kidney damage, but on the contrary it should be considered a sign of generalized vascular disorder. Sum~ary

1. Thirty eases of normal pregnancy have been studied for brachial and retinal pressures. It has been found that in the later months both are somewhat reduced. 2. In 10 cases of normal pregnancy which we regarded as potentially toxemic, a high retinal diastolic pressure was observed. A number of these patients became toxemic, suggesting that the retinal arterioles are the first to be affected, and indicating the importance of retinal diastolic pressures. 3. There is a disproportionate rise in the retinal diastolic pressure in pre-eclampsia and in eclampsia. The greater the disproportion, the graver is the prognosis. 4. The retinal changes in the form of retinopathy can be correlated more accurately with the retinal diastolic pressure than with brachial pressure. 5. Changes in the central nervous system and in the kidney arterioles probably occur simultaneously and perhaps can be gauged by the retinal damage. 6. Ophthalmodynomometry is recommended as a routine technique for investigation in pregnancy. References 1. Azcoga, .J. M.: Arch. Soc. oftal. hispano-am. 5: 519, 1945. 2. Bailliart, P.: Clin. opht. 15: 178, 1928.

3. Bailliart, P.: Vascular Affections of the Hetina, Paris, 1953, Gaston Doin & Cie. 4. Duke-Elder, S. W.: Text Book of Ophthalmology, London, 1940, Henry Kimpton, vol. 1. 5. Gonzaby, N. B.: Arch. Soc. oftal. hispano-am. 15: 262, 1955. 6. Kologolu, S.: Yeni Klin . .J. 1: 98, 1955. 7, Mal!"itot, A., and Bailliart, P.: Am . .T. Oohth. 5: 824. 1922. 8. Miller, H. A., and Audoueineix, E.: Trans. Ophth: Soc. U. Kingdom 75: 391, 1955. 9. Mylius, K.: Abhandl. a. d. Augenh. u. ihr. Grenzgeb. 1: 6, 1927. 10. Nigro, Lactitia: Riv. oto-neuro-oftal. 24: 409, 1949. 11. Pavia, .J. L.: Am ..J. Ophth. 41: 85, 1956. 12. Streiff, E. B., and Bischler, V.: Ophthalmologica 112: 19, 1946. 13. Volhard, I.: V erhandl. deutsch. Gesellsch. inn. Med. 33: 422, 1921. 14. Wagner, H. P.: .J. A.M. A. 101: 1381, 1933. 15. Weigeli, H., Althanes, H., Burhard, C., Reckmann 1 P.1 and Assendroff, J.; Docum. ophth. 7-8: 183, 1954. 16. Wilbrandt1 R.: Helvet. med. acta 18: 553, 1951.