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Hepatic retinopathia. Changes in retinal function
A K Eckstein1, A Reichenbach, P Jacobi
1University Eye Hospital, Tübingen, Germany.
Vision Research
|June 1, 1997
Summary
Hepatic encephalopathy (HE) causes functional changes in the retina, detectable by electroretinogram (ERG). These retinal abnormalities correlate with HE severity, suggesting Müller cell damage.
Area of Science:
- Ophthalmology
- Neurology
- Hepatology
Background:
- Hepatic failure leads to brain changes (hepatic encephalopathy, HE), involving glial cells.
- Similar morphological changes occur in retinal Müller cells in HE patients.
- The functional impact of these Müller cell changes in HE remains unclear.
Purpose of the Study:
- To investigate functional deficits in the retina of patients with hepatic encephalopathy.
- To correlate retinal function abnormalities with the severity of hepatic encephalopathy.
Main Methods:
- Ophthalmological examination, color vision testing, and standard electroretinogram (ERG) recordings were performed on 11 patients with varying stages of HE.
- Patients were divided into two groups based on HE stage (0-1 and 2-3).
Main Results:
- Color vision tests showed increased confusions, particularly in the tritan axis, correlating with higher HE stages.
- Scotopic and photopic ERG showed decreased and delayed waves, especially in higher HE stages.
- Oscillatory potentials on ERG were most sensitive, with delayed latencies even in early HE stages and decreased amplitudes in advanced stages.
Conclusions:
- Patients with hepatic failure and HE exhibit functional retinal abnormalities.
- Electroretinogram (ERG) effectively demonstrates these abnormalities, which correlate with HE severity.
- Elevated ammonia levels may damage Müller cells, impairing retinal function through altered neurotransmission and glial-neuronal interaction.