Lithium effects on ophthalmological-electrophysiological parameters in young healthy volunteers

The effects of lithium on the visual system in man have been tested. Ten healthy volunteers followed a 10-day lithium regimen. Lithium plasma levels in the range of 0.6-0.8 mmol/l were obtained. Clinically used ophthalmological-electrophysiological tests were performed. Most of the tests showed no significant change during the lithium treatment. The lithium regimen resulted in a strong reduction of the slow phase. Also the "Arden-ratio", measured by electrooculogram (EOG), was influenced by lithium. The "Arden-ratio" reflects the corneo-fundal potential in retinal illumination and dark adaptation and is influenced by the state of adaptation. All the demonstrated effects were fully reversible at the end of lithium administration. Possible mechanisms of the action of lithium are discussed (for example Ca2+-fluxes, c-AMP, cGMP). These lithium-induced effects on the visual system in man may give some hint of the individual responsiveness to lithium.