The relationship between impaired retinal vascular reactivity and renal function in patients with degenerative vascular disease.

In hypertension and diabetes retinal vascular changes which are evident on fundiscopic examination are usually accompanied by renal vascular changes which are evident on microscopic examination. It has been found that the retinal vessels of most patients with hypertension or diabetes fail to constrict normally when the blood oxygen tension is elevated. This investigation evaluates the clinical significance of decreased retinal vascular reactivity in patients with degenerative vascular disease by relating it to kidney function as measured by common clinical tests. The results of the study show that impairment of retinal arterial reactivity usually occurs in the course of degenera-tive vascular disease, particularly in hypertension, in advance of clinical evidence of altered kidney function. When clinical tests of renal function demonstrate renal damage, loss of retinal arterial and venous reactivity is marked. IN HYPERTENSION and diabetes, pathological changes often occur in both retinal and renal vessels.'-' Retinal vascular changes which are advanced enough to be evident on fundiscopic examination are usually accompanied by renal vascular changes which are evident on microscopic examination. Recently it has been found that the retinal vessels of most persons with hypertension and many with diabetes fail to constrict normally when the blood oxygen tension is raised.6 This loss of vascular reactivity is thought to result from degenerative changes in the vessel wall and may be found in arteries and veins which show little or no change on ophthalmoscopic examination. When the vessels have become definitely abnormal in appearance, reactivity is almost always markedly diminished. Decreased reactivity to increased arterial oxygen tension, therefore, appears to be a sensitive index of degenerative changes in the retinal vessels. Impairment of retinal vascular reactivity has been significantly correlated with a decrease in cerebral blood flow and cerebral vascular reactivity in arteriosclerotic patients.7 The purpose of the present study was to investigate further the clinical significance of retinal vessel reactivity by relating it to the state of the kidneys, as determined by common clinical tests, in normal individuals and patients with degenerative vascular disease. METHODS Observations were made in 97 hospital patients ranging in age from 12 to 76 years. This group includes 29 patients (the "control" group) without known renal disease, vascular disease or diabetes mellitus. The remaining patients had hypertension, diabetes, glomerulonephritis or pyelonephritis. The group did not include patients with congestive failure or prerenal azotemia which might cause transient changes in the tests by which the state …