Role of local factors in hypertensive retinopathy

SK Lal; IS Jain; SD Gupta; PL Wahi

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Year : 1974 | Volume : 22 | Issue : 2 | Page : 1-5

Role of local factors in hypertensive retinopathy

SK Lal, IS Jain, SD Gupta, PL Wahi
Department of Ophthalmology, Post-Graduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
S K Lal
Department of Ophthalmology, Post-Graduate Institute of Medical Education and Research, Chandigarh
India

Source of Support: None, Conflict of Interest: None

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PMID: 4461687

How to cite this article:
Lal S K, Jain I S, Gupta S D, Wahi P L. Role of local factors in hypertensive retinopathy. Indian J Ophthalmol 1974;22:1-5

How to cite this URL:
Lal S K, Jain I S, Gupta S D, Wahi P L. Role of local factors in hypertensive retinopathy. Indian J Ophthalmol [serial online] 1974 [cited 2021 Jun 21];22:1-5. Available from: https://www.ijo.in/text.asp?1974/22/2/1/31374

Table 3

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Table 2

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Table 1

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In systemic hypertension, eye involvement does occur in due course of time, which manifests as retinal changes. Retinal changes do not occur in every case of systemic hypertension. Moreover there seems to be no direct relationship between the retinal changes and the magnitude of systemic hypertension. Various factors have been blamed for the disproportionate retinal changes in systemic hypertension.

This study was carried out to know the effect of retinal artery pressure, intraocular pressure and various refractive errors on the development and severity of hypertensive changes in the ocular fundus.

Material and Methods

One hundred cases of hypertension, irrespective of their aetiology attending the medical and eye outpatient departments of the Nehru Hospital attached to the Postgraduate institute of medical education and research, Chandigarh, were taken for this study. Cases having persistently high blood pressure (blood pressure over 150/90 mm Hg) were considered as hypertensive for this study. Fifty patients having normal blood pressure were studied as control.

Eash case was processed as under

(i) A detailed history was taken, visual acuity was recorded and refraction was done.

(ii) A thorough fundus examination was carried out after dilating the pupil with phenylephrine 10%.

On the basis of fundus findings following groups were made :

a) Group I: Cases without fundus changes.

b) Group II: Increased hypertonus of arterioles with or without increased arterial reflex.

c) Group III: Generalised and focal narrowing of arterioles with or without A. V. crossing changes.

d) Group IV: Generalised and focal narrowing of arterioles with haemorrhages and exudates.

e) Group V: Haemorrhages, exudates, narrowing of arteries and papilloedema.

f) Group VI: Arteriosclerotic changes (incresed arterial reflex, A. V. crossing changes, copper wiring and silver wiring).

g) Group VII: Mixed picture of hypertensive and arteriosclerotic changes.

(iii) Intraocular pressure was recorded with Schiotz's tonometer (5.5 and 10 gms weights). The pressure was calculated by using Friedenwald nomogram (1955).

(iv) Ophthalmodynamometry was performed with Bailliart's ophthalmodynamometer.

(v) Examination of chest, abdomen, and central nervous system was made and blood pressure and electrocardiography findings were recorded to know the effect of hypertension on body.

(vi) Blood urea and blood sugar estimation were done.

Observations

Out of the hundred cases of systemic hypertension 64 were males and 36 were females. Hypertension was of less than one year duration in 58 cases between one to five years in 28 cases and more than five years duration in 14 cases.

Seventy eight percent of the cases who showed hypertensive changes, were between 31 and 60 years of age while fifteen percent were below 30 years and seven percent were over 60 years of age.

No fundus changes were seen in 14.5% cases. Thirty six percent eyes showed increased hypertonus, 24.5% eyes had generalised and focal narrowing of the arterioles, 14% denoted haemorrhages, exudates and papilloedema and 11% had only arteriosclerotic changes.

In 50 normotensive cases, mean systolic blood pressure was 125 mm Hg., mean systolic retinal arterial pressure was 82 mm Hg. and retinobrachial systolic ratio was 0.64. On the other hand, mean diastolic blood pressure was 84 mm Hg., diastolic retinal artery pressure was 42.5 mm Hg, and retinobrachial diastolic ratio was 0.50. The mean retinal artery pressure, blood pressure and retinobrachial ratio in hypertensive cases is shown in [Table - 1].

There was statistically significant difference (p<0.01) between group II and group I, in retinal diastolic and systolic pressures and also in retinobrachial ratios. Group III indicated a highly significant (p<0.01) retinal arterial diastolic pressure and also significant rise of retinobrachial ratio (p<0.05) when it was compared with group II. Although there was no significant difference in pressures between the groups III and IV, the difference in the diastolic retinobrachial ratio becomes highly significant as one passes from grade 1V to V. Rise in systolic retinal pressure is relatively less. Group VI showed a significant difference (p<0.05) in retinal diastolic and systolic pressures and retinobrachial ratios when compared to normotensive cases. Similarly, group VII showed still higher levels of difference (p<0.05) in retinal diastolic and systolic pressures as compared to Group VI but retinobrachial ratios did not differ so significantly.

Five patients, who showed generalised and focal narrowing in one eye and haemorrhages and exudates in other eye, did not indicate any significant difference in retinal pressures and retinobrachial ratios on two sides.

The retinal pressures and retinobrachial ratios were same in both eyes in a patient having retinal branch vein occlusion in only one eye; whereas another patient showed high diastolic retinal artery pressure as compared to the eye having branch vein occlusion.

There was no difference in retinal pressures in a patient having increased hypertonus of vessels in one eye and generalised narrowing of arterioles in the other and in a case having normal fundus in one eye and increased hypertonus in the other eye.

Normal mean intraocular pressure was 15.79 mm Hg (SD+3.63). The relationship of intraocular pressure with various fundus findings in hypertensive patient is shown in [Table - 2]. The average intraocular pressure in hypertensive without fundus changes was 17.48 mm Hg. There was a gradual fall in intraocular pressure with an increasing severity of hypertensive changes in the fundus. The intraocular pressure in cases with purely arteriosclerotic changes was 15.54 mm Hg. Mean intraocular pressure in cases showing retinopathy when compared with control eyes showed significantly a lower pressure (p<0.05).

From [Table - 3], it is evident that the eyes showing various retinal changes had no refractive error in 48% cases; 28.5% cases had hypermetropia and 23.5% cases had myopia. Only 2 eyes had hypermetropia more than +4.00 D and 2 eyes had myopia more than -6.00 D. The number of eyes with high myopia and hypermetropia was too small for statistical analysis.

Discussion

Direct ophthalmoscopy offers an important diagnostic aid in the assement of the severity of systemic hypertension. It is well known that 11 to 35.3% cases of hypertension have no changes in retinal vessels^[4] Aggarwal et al^[2] pointed out that in one third of the cases of hypertension, there were no retinal changes.

In our series 14.5% of eyes did not indicate any fundus pathology in the cases of hypertension.

In our series, normal mean diastolic retinal artery pressure was 42.50 mm of Hg and mean systolic retinal artery pressure was 82 mm of Hg.

In hypertensive cases of this series, it was found that, with increasing severity of the changes in the retinal grounds, there was a proportionate rise in the retinal artery pressure particularly diastolic pressure. This strongly supports the hypothesis put forward by Aggarwal et al^[2] that retinal diastolic pressure was a better indication of a probable systemic and the retinal changes. Ophthalmodynamometry combined with fundoscopy is more satisfactory investigation in the cases of systemic hypertension.

Baillart^[3] gave figures for normal diastolic retinobrachial ratio as 0.45 and for systolic as 0.54. Perry and Rose^[12] reported that retinal arterial diastolic and systolic pressures were 50% and 70% of brachial pressures respectively. Our findings in controls were similar to those of Perry and Rose. The hypertensive groups in our series showed significantly (p<0.01) high levels of retinobrachial ratios. Rise of retinal artery pressure was more prominently visible than brachial artery pressure. As the severity of fundus findings increased, there was a progressive rise in diastolic and systolic retinobrachial ratios. The diastolic retinobrachial ratio was more significant. These observations strongly support the earlier observations made by Kock^[9] Further, more or less a parallel rise of diastolic blood pressure with an increasing severity of retinal changes in our series evidently existed which is smaller to the findings of earlier workers 2%.

In our series a gradual fall in intraocular pressure was seen with an increasing severity of hypertensive changes except in purely arteriosclerotic group. The cases showing retinal haemorrhages and exudates had significantly (p.<005) lower levels of intraocular pressure as compared to hypertensives without any retinopathy. These findings had close resemblance to the observation made by Jain et al^[8] that higher intraocular pressure had a beneficial effect on diabetic retinopathy.

Jain et al^[8] , showed that myopia more than 5.00 D had a beneficial effect on diabetic retinopathy. In our series, an incidence of myopia and hypermetropia was about equal and there existed only two high myopes, so a significant relationship between high myopia and hypertensive retinopathy could not be established though both eyes had minimal changes in the fundus.

Summary

One hundred cases of systemic hypertension were examined to study the effect of retinal artery pressure, intraocular pressure and the refractive error on the production and severity of hypertensive retinopathy.

Following conclusions have been drawn from the study :

i) Retinal diastolic arterial pressure rises before the retinal changes appear.

ii) The rise in diastolic retinal arterial pressure has a close direct correlation with the severity of hypertensive retinopathy. In severe grades of retinopathy, there exists a disproportionate rise in diastolic retinobrachial ratio.

iii) A gradual fall is noticed in intraocular pressure with an increasing severity of hypertensive changes in retina.

iv) Refractive errors have got no effect on the production of hypertensive changes in the retina.

References

1.	Aggarwal, L.P. : 1963, Text Book of Eye Diseases. Ist Ed. P. 256. Kitab Mahal, Allahabad.
2.	Aggarwal, L. P. Patnaik, B. Batta, R. K. and Gupta, A. K. : 1965, Orient Arch. Ophthal. 3 : 238.
3.	Bailart, P and Magitol, A. P. : 1922 Amer J. Ophthal. 5 : 777.
4.	Backgaard, Porsaa and Vogelius : 1950, Brit. J. Ophthal. 34: 409.
5.	Becker, B; Brenik, G; Chevrette, L; Kokkar, A. E.; Oakes, M. C. and Cibis, A. : 1966, Arch. Ophthal. 76 : 477.
6.	Breslin, D. J. and Gifford, R. W. : 1966, J. Amer. Med. 195. 355.
7.	Fraut, R. and Green, J. : 1950, Arch. Int. Med. 85 : 727.
8.	Jain, 1. S. and Luthra, C. L.: 1967, Arch. Ophthal. 78, 198.
9.	Jain, I. S.; Luthra, C. L. and Dass : 1967, Arch. Ophthal, 78, 198.
10.	Kock, F. L. P. : 1941 Arch. Ophthal. 26 : 565.
11.	Minsky, H. : 1954, Arch. Ophthal, 51 : 863.
12.	Perry, B. R. and Rose, C. J., 1958, Circulation, 18 : 864.