Observations on the incidence and significance of linear irregularities in the course of major retinal blood vessels in the fundus of the rat.

The ophthalmoscopic examination of rats receiving drug administered by daily intravenous bolus injection for 6 months revealed an increase in the incidence and amplitude of linear irregularities in retinal blood vessels with a tendancy towards tortuosity which appeared to be related to treatment. Subsequent critical observation of groups of untreated rats, and rats dosed orally with a vasodilator suggest this phenomenum may be related to haemodynamic mechanisms; and that more attention should be given to the dose volume administered intravenously in this species to avoid the detection of such ocular artefacts.