Special Techniques Used in Ophthalmology

Abstract

Fundus fluorescein angiography is used to demonstrate abnormalities in the vascular architecture of the fundus before retinal photocoagulation is performed. A sodium fluorescein solution is injected intravenously and its circulation through the fundus recorded with a fundus camera. Normal retinal blood vessel walls are impermeable to sodium fluorescein and retain the dye within the vessels. In diabetic retinopathy the new vessels leak dye through their walls due to breakdown of the blood-retinal barrier. In addition retinal ischaemia due to capillary closure shows up as dark underperfused areas on the angiogram.