The electroretinogram in chronic renal failure.

Abstract

To evaluate functional changes of the retina in patients with chronic renal failure (CRF), we analyzed maximal combined response according to the recommendations of the International Society of Clinical Electrophysiology of Vision. Oscillatory potentials were extracted from maximal combined response by high pass filtering. Because most CRF patients suffer from hypertension, hypertensive patients were selected for the control group. Values recorded in CRF patients were compared with those recorded in hypertensive patients and in the normal control group. CRF patients underwent laboratory tests which included complete blood cell count and the determination of blood urea nitrogen, creatinine, natrium, and potassium levels. The parameters of electroretinograms obtained from CRF patients were compared with those obtained from the normal control group, in the former group all amplitudes were significantly lower and all implicit times except those of b-wave were significantly delayed (P < 0.05). In CRF patients, decreased b-amplitude of maximal combined response and delayed implicit time of oscillatory potentials 1, and 2 were significantly different from those in hypertensive patients (P < 0.05). CRF patients had anemia, and their blood urea nitrogen and creatinine levels appeared abnormal. There was, however, no clinical correlation between biochemical data and electroretinograms. Consequently, retinal function in CRF patients was severely damaged compared with control groups (i.e., normal and hypertensive patients). We suggest that these findings are result of anemia and uremia in addition to hypertensive retinal damage.