Year : 1970 | Volume
: 18 | Issue : 4 | Page : 155--161
Comparative histopathological study of arteriosclerosis of the retina, the brain and the circle of willis
JR Patwardhan, RK Gadgil, Y.K.C Pandit, BB Velankar
Department of Pathology and Ophthalmology, Grant Medical College, Bombay, India
J R Patwardhan
Department of Pathology and Ophthalmology, Grant Medical College, Bombay
|How to cite this article:|
Patwardhan J R, Gadgil R K, Pandit Y, Velankar B B. Comparative histopathological study of arteriosclerosis of the retina, the brain and the circle of willis.Indian J Ophthalmol 1970;18:155-161
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Patwardhan J R, Gadgil R K, Pandit Y, Velankar B B. Comparative histopathological study of arteriosclerosis of the retina, the brain and the circle of willis. Indian J Ophthalmol [serial online] 1970 [cited 2019 Jul 19 ];18:155-161
Available from: http://www.ijo.in/text.asp?1970/18/4/155/35632
This study was undertaken to assess the prevalence and the degree of arteriosclerosis of the retinal and the choroidal blood vessels in an unselected autopsy population from Bombay. No such studies have been reported from this geographical area. This study formed part of a survey of the incidence and severity of atherosclerosis of different blood vessels of the body carried out at this department. (Nair  ; Joshi; Jhala and Gadgil  ; Patwardhan Man sukhani; Joshi and Gadgil  ) Many studies on the problem of retinal arteriosclerosis have been published in the Western literature (Hogan and Zimmerman; Alpers; Forster and Herbut: 1948; Duke-Elder and Wybar  Friedenwald and in the Japanese Tamura, 1967; Iizuka, 1962) literature. Correlation of arteriosclerosis of the retinal and the choroidal blood vessels with those of the brain and of the circle of Willis was attempted.
Materials and Methods
The material was collected from 48 unselected consecutive clinical autopsies at the pathology department. Grant Medical College, Bombay. As it was not possible to remove the entire eyeball, only the posterior half of the globe was removed. It was impossible to avoid some collapse of the eye-ball and some detachment of the retina. The tissue was immediately fixed in 10% formalin. The circle of Willis was dissected and collected as previously described (Patwardhan  et al). Histologic sections of the brain were taken from the frontal, the parietal and the occipital cortex and the basal ganglia. All tissues were processed in the usual manner and stained with hematoxylin and eosin. and Verhoff-Van Gieson stain for connective and elastic tissue. The incidence and severity of atherosclerosis of the arteries of the circle of Willis were studied by previously described methods (Patwardhan  et al).
The grading of atherosclerosis of the arteries of the circle of Willis was done according to the W.H.O. scheme (1958) . The segments of stenosis were recorded as:
a) No stenosis (N).
b) Moderate stenosis (M) - More than half the diameter of the lumen preserved.
c) Severe stenosis (S) - Less than half the diameter of the lumen preserved.
d) Occlusion (Q) - Complete occlusion of the lumen.
The grading of atherosclerosis of the arteries of the retina, the choroid, and the brain was also done into these four groups.
There were 32 males and 16 females. The causes of death included injuries. acute and chronic infectious diseases and neoplasms. No clinical opththalmic disease was present in any case. There was no case of hypertension or other disease associated with arteriosclerosis. The recorded blood pressure in all cases «gas within normal limits for the age.
Results and Discussion
It is seen from [Table 1] that arteriosclerosis has first appeared in the circle of Willis in the third decade (at 28 years) whereas in the brain it has appeared in the fourth decade (at 39 years) and in the retina in the fifth decade (at 43 years).
It is seen from [Table 2] that the severity of narrowing is more in the circle of Willis than in the retina and the brain the severity is almost the same. In each group of arteries, the severity has increased with age. Complete occlusion was not seen in any group in any artery.
[Table 3] shows the percentage of cases of arteriosclerosis according to the age at the different sites. The involvement is in diminishing order from the circle of Willis to the retina upto the sixth decade. After that, there is one hundred per cent involvement in all the groups of arteries. There is a parallel correlation between arteriosclerosis of the retina and the brain. In each case where the retina and the brain showed arteriosclerosis, the circle of Willis was always affected.
Retinal arteriosclerosis is commonly stated by many authors (Hogan and Zimmerman  ; Duke-Elder and Wybar  ; Walsh  ). But the earliest age at which it appears has not been definitely stated, when hypertension is absent. Tamura  found it in a 41-year-old male with hypertension. Izuka  in a clinical (fundoscopic) study stated that the narrowing of vascular lumen had a highest occurrence at 40 years with a rapid increase after that.
It is generally agreed that the blood vessels in the retina are arterioles and cannot properly be called arteries as they do not have a muscular coat (navies and Davies  ; Hogan and Zimmerman  : Duke-Elder and Wybar  Walsh  ). Therefore in this study the term arteriosclerosis is used rather than the specific term, atherosclerosis. As far as the arteries of the circle of Willis are concerned, the term atherosclerosis is proper. The term arteriolosclerosis is not used as it connotes an association with hypertension.
The histological features of retinal arteriosclerosis were fibrosis and hyalinization. The fibrosis manifested either as subendothelial fibrous plaques or more commonly as diffuse fibrous thickening of the vessel wall producing narrowing of the lumen. [Figure 1]. The changes were similar in the arteries of the choroid [Figure 2], and those of the cerebral cortex and basal ganglia [Figure 3].[Figure 4]. Typical atheromatous plaques were not found in the retinal arterioles although Friedenwald  has demonstrated them. Arteriosclerotic changes associated with hypertension like intimal hyalinization, medial hypertrophy and endothelial hyperplasia were not seen as there was no case of hypertension in this study. Calcification of the arterioles was not seen in any case.
Arteriosclerosis was seen much more commonly in the choroid than in the retina. According to Hogan and Zimmerman, this change makes its appearance in the fifth decade and increases progressively thereafter. The findings in this study are similar.
In this study, arteriosclerosis of the retina and choroid showed a parallel correlation with arteriosclerosis of the frontal, parietal and occipital cortex and the basal ganglia of the brain. Similar observations were made by Tamura  . Arteriosclerosis of the above two groups of arteries also showed parallel correlation with atherosclerosis of the arteries of the circle of Willis. Tamura also came to the same conclusion. The observations in this study agree with those of Alpers who stated that the presence of retinal arteriosclerosis indicated the possibility of cerebral arteriosclerosis, involving the basilar artery. But the observations in this study, do not agree with the further observations of Alpers, Forster and Herbut  , that retinal arteriosclerosis Gives no indication of the state of the arteries and arterioles of the cerebral cortex, meninges and basal ganglia.
This study has shown that retinal and choroidal arteriosclerosis is common in an unselected autopsy population from Bombay, after the age of 40. This increases in incidence and severity with the age, and shows a parallel correlation with arteriosclerosis of the cerebral cortex and of the circle of Willis.
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