It has now widely been assumed that the kidney plays the most important role on pathogenesis of essential hypertension.
In the present studies, renal functions were estimated in 120 patients with essential hypertension by clearance methods and other renal function tests, and their retinal findings were compared with the data on clearance tests in these patients. In 15 of them, renal oxygen consumption was also measured by renal venous catheterization method.
As the result, reduction of RBF under the normal range was observed in about three fifths of 120 patients, but in the remainder (about two fifths of them), RBF was maintained within the normal range. Similarly, in regard to renal oxygen consumption, it was maintained within the normal range in the early stage of essential hypertension (in seven of fifteen cases), but gradually decreased in parallel with reduction of RBF.
Particular attention was given to the correlation between RBF and severity of retinal findings. The eyeground findings were graded I through IV following Keith-Wagener's classification.: It was observed that the higher the grade, the more strong was the reduction of RBF. Its correlation was statistically significant. In all patients with the retinal finding, IV grade RBF was reduced to belower than 40% of normal average value.