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The electroretinogram in chronic renal failure
1Department of Ophthalmology, School of Medicine, Kyungpook National University, Taegu, Korea.
Insights
Patients with chronic renal failure (CRF) exhibit significantly impaired retinal function, evidenced by lower electroretinogram amplitudes and delayed implicit times. These visual changes are linked to anemia and uremia, independent of hypertension.
Area of Science:
- Ophthalmology
- Nephrology
- Clinical Electrophysiology
Background:
- Chronic renal failure (CRF) affects multiple organ systems.
- Hypertension is a common comorbidity in CRF patients.
- Retinal function may be compromised in CRF.
Purpose of the Study:
- To evaluate functional changes in the retina of CRF patients.
- To compare retinal function in CRF patients with normal and hypertensive controls.
- To investigate potential correlations between biochemical markers and retinal function in CRF.
Main Methods:
- Maximal combined response (MCR) analysis using International Society of Clinical Electrophysiology of Vision recommendations.
- Extraction of oscillatory potentials (OPs) from MCR via high-pass filtering.
- Comparison of electroretinogram (ERG) parameters between CRF patients, hypertensive patients, and a normal control group.
Main Results:
- CRF patients showed significantly lower ERG amplitudes and delayed implicit times compared to normal controls.
- CRF patients exhibited decreased b-amplitude of MCR and delayed OP1 and OP2 implicit times compared to hypertensive patients.
- CRF patients presented with anemia and abnormal blood urea nitrogen and creatinine levels, but no direct correlation with ERG findings was observed.
Conclusions:
- Retinal function is severely damaged in CRF patients compared to both normal and hypertensive controls.
- Anemia and uremia are suggested as contributing factors to retinal dysfunction in CRF, alongside hypertensive damage.
- ERG analysis provides a valuable tool for assessing retinal function in CRF.
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.