Abstract
Abstract: :
Purpose: Decreased optic nerve circulation has been previously reported in glaucoma. The purpose of this investigation was to assess whether decreased optic nerve head circulatory parameters are associated with subsequent progression of visual field damage. Methods: This study included 29 eyes of 23 patients with open angle glaucoma that had typical glaucomatous visual field defects and nueroretinal rim loss. Laser Doppler flowmetry (Oculix) was used to measure relative optic nerve blood volume (Vol), velocity (Vel) and flow in three regions of the optic nerve: the superior temporal (ST) and inferior temporal (IT) neuroretinal rim and the cup. After blood flow measurements, patients were followed for 6 to 62 months (Mean 33±17 months) and 2 to 11 Humphrey visual fields (4.7±2.6 fields) were obtained. Progression of visual field loss was assessed by the slope of the Corrected Pattern Standard Deviation (CPSD) change in time, which was calculated manually for each eye using regression analysis. Results: A significant negative correlation was observed between Vol in the IT rim and the CPSD slope (R=-0.562, p=0.002); patients with lower Vol tended to show more progression of glaucomatous field damage than those with higher Vol. When the eyes were arbitrarily divided into two groups according to lower or higher Vol, those with lower Vol (0.32±0.06 Arbitrary Units, AU, N=15) had significantly worse CPSD slopes than those with higher Vol (0.49±0.06 AU, N=14; non-paired t-test, p=0.009). These results were still significant when patients with follow up of less than 4 visual fields were excluded. No other significant relationships were observed. Conclusions: In the IT rim, the area most prone to develop glaucomatous field damage, lower Vol is associated with more progression of the disease. These measurements suggest that circulatory abnormalities may play an important role in the development of glaucoma and may help identify patients at risk for future progression of visual field damage.
Keywords: 499 optic flow • 498 optic disc • 331 blood supply