Experiences with fluorophotometry

Fluorophotometry using the Metricon Model 120 slit-lamp fluorophotometer showed, at an anterior focus, two peaks which corresponded to the cornea and ciliary region--the latter predominantly due to the ciliary body but contributed to by the lens--and following this, at a posterior focus, a mid-vitreous minimum and a chorioretinal peak. Tracings made both before and after fluorescein injection were similar but the levels were higher post-injection, with increasing age and with non-pigmented irides. The change in fluorescein distribution with time after injection is described. Abnormally high fluorescein levels were found in the normal fellow eye in retinal vein occlusion, in diabetes, in senile macular degeneration with neovascular membrane, in active central serious retinopathy and in acute optic neuritis. It is of use in the differentiation of primary choroidal melanoma from naevus and metastases. There was no correlation between isolated measurements of the haemoglobin A1C level and leakage; plasma and ultrafiltrate fluorescein levels in diabetics did not differ from normal.