Large drusen may influence retinal sensitivity and function.

Reports regarding the effect of all-trans-retinoic acid (RA) on the cell growth of retinal pigment epithelial cells (RPE) have been contradictory. The aims of this study are to clarify the in vitro effect of RA on RPE cells and to examine polyamine metabolism after RA stimulation. A 4-day incubation of fetal-calf-serum (FCS)-stimulated RPE cells with 10 or 25 µM RA significantly increased both cell number and [³H]thymidine incorporation. RPE cells grown over an extended period for 8 days also increased in number and reached full confluency. However, if the incubation was further extended to 12 days, no further increase in cell number was detected. RA treatment of FCS-stimulated RPE cells shifted the peak of ornithine decarboxylase (ODC) activity from 16 to 4 h. S-adenosylmethionine decarboxylase (SAMDC) activity and spermidine/spermine N¹-acetyltransferase (SAT) activity of RA-treated RPE cells were significantly greater until 8 and 16 h after incubation, respectively. The putrescine content was significantly increased in RA-treated RPE cells up until 24 h, while spermidine, spermine and N¹-acetylspermidine contents were significantly increased until 16 h. Our findings suggest that RA treatment increases the intracellular polyamine concentration of RPE cells via activation of ODC, SAMDC and SAT and that this results in the promotion of RPE cell growth until the cells reach full confluency.

MMP-2 played a role in laser-induced CNV development, and administration of BPHA reduced the experimental CNVs.

Scattered hypofluorescent spots seen in the posterior pole during the late-phase of ICG angiograms can apparently be due to aging of the fundus.