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Electrophysiological assessment of visual function in IDDM patients
V Parisi1, L Uccioli, G Monticone
1Cattedra di Clinica Oculistica, Università di Roma Tor Vergata, Italy. vparisi@mbox.vol.it
Electroencephalography and Clinical Neurophysiology
|March 1, 1997
Summary
Electrophysiological abnormalities in the visual system appear early in insulin-dependent diabetes mellitus (IDDM) patients, even before retinopathy is visible. These functional deficits progress over time, affecting retinal and visual pathway functions.
Area of Science:
- Ophthalmology
- Neuroscience
- Diabetology
Background:
- Insulin-dependent diabetes mellitus (IDDM) can affect the visual system.
- Electrophysiological tests are used to detect visual system abnormalities.
- Early detection of visual impairment in IDDM is crucial.
Purpose of the Study:
- To assess the appearance and progression of electrophysiological abnormalities in the visual system of IDDM patients.
- To evaluate retinal, macular, and visual pathway functions in IDDM patients without clinical retinopathy.
- To correlate electrophysiological findings with disease duration in IDDM.
Main Methods:
- A comprehensive neurophysiological protocol was used, including flash-electroretinogram (ERG), oscillatory potentials (OPs), pattern-electroretinogram (PERG), and visual evoked potentials (VEPs).
- Tests were performed on 12 control subjects and 42 IDDM patients without retinopathy (DR-), divided into four groups based on disease duration (1-5, 6-10, 11-15, 16-20 years).
- An additional group of 12 IDDM patients with background retinopathy (DR+) was also evaluated.
Main Results:
- All IDDM patients without retinopathy (DR-) showed significantly impaired PERG and VEP.
- IDDM patients with longer disease duration (11-15 and 16-20 years) also displayed impaired OPs.
- Electrophysiological parameters were further compromised in IDDM patients with retinopathy (DR+).
Conclusions:
- Visual pathway functions are impaired early in IDDM patients, even without clinical retinopathy.
- Electrophysiological deficits progress with increasing disease duration, affecting retinal and macular functions.
- The study highlights a sequential impairment starting in visual pathway conduction, followed by inner retinal layers, macula, and finally middle/outer retinal layers.