CHOROIDAL HEMODYNAMICS IN GLAUCOMA

Aim-Quantification of haemodynamics of the peripapillary choroid in an d the assessment of possible differences between normal subjects (N), ocular hypertensive (OHT), primary open angle (POAG), and normal press ure glaucoma (NPG) patients. Methods-Video fluorescein angiograms (Rod enstock SLO 101) were made in 22 N subjects, 12 OHT, 48 POAG, and 46 N PG patients. The angiographically derived dye build up curves were des cribed by means of an exponential model. One of the model parameters i s the time constant tau theoretically reflecting local blood refreshme nt time; the blood refreshment time tau is the time needed to replace the blood volume in the choriocapillaris, inversely proportional to th e local choroidal blood flow. Other variables are maximal fluorescence (F-dt) and time of first fluorescence (t(o)). Mean variable values we re calculated for disc area and circular areas around the disc. Result s-F-dt of the disc was significantly lower in the POAG and NPG patient s. There was no statistical difference in t(o) between the study group s. The choroidal blood refreshment time was significantly longer in NP G patients and to a lesser extent in the POAG patients compared with t he normal controls. The slowest choroidal blood refreshment can be fou nd in the NPG group. The median choroidal Netherlands blood refreshmen t times (25th-75th percentile) in the controls, OHT, POAG, and NPG pat ients were 4.1 (3.7-4.5), 4.4 (3.7-6.4), 5.8 (4.3-6.8), and 7.1 (5.5-9 .3) seconds respectively. Conclusions-With the help of parametrisation of dye curves, using a one compartmental model, choroidal haemodynami cs can be quantified. The blood refreshment time of the peripapillary choriocapillaris was found to be significantly prolonged especially in NPG patients; this may indicate slower choroidal haemodynamics in NPG patients.