Pycnogenol® improves retinal microcirculation and symptoms of optic nerve ischemic damage after sudden, reversible unilateral loss of vision: a pilot evaluation.

Background: The aim of this pilot registry study was to investigate the use of Pycnogenol^® (French maritime pine bark, standardized extract) in subjects 2 weeks after an episode of sudden loss of vision (SLV).

Methods: Visual acuity, retinal edema, vasospasms, distal retinal circulation and blood flow at the Zinn-Haller circle (distal optic nerve) were examined over 4 weeks. In addition, symptoms of neurological alterations (ION: ischemic optic neuritis) associated with retinal flow decrease were monitored. One registry group used only the standard management (SM, control group), a second group used SM+ 150 mg Pycnogenol^®/day (Pycno150) and another group used SM+100 mg Pycnogenol^® /day (Pycno100).

Results: Sixty subjects completed the study. 18 in the control group, 20 in the Pycno150 group and 22 subjects in the Pycno100 group. The registry groups were comparable at inclusion. No dropouts were observed in the two Pycnogenol^® groups whereas 2 dropouts occurred in the SM group (due to the occurrence of a new, minor visual loss episode). No side effects or tolerability problems were observed during the registry study. After 4 weeks, the visual acuity score of the affected eye was significantly higher in the Pycno150 group compared to the Pycno100 group and both Pycnogenol^® groups showed significantly higher acuity scores in comparison with controls using SM (P<0.05). In parallel, after 4 weeks, the retinal edema score was significantly lower in both Pycnogenol^® groups compared to controls (P<0.05 vs. SM patients) and even lower (P<0.05) with the 150 mg Pycnogenol^® dose compared to the 100 mg Pycnogenol^® dose. After 4 weeks, retinal systolic and diastolic blood flow velocities of the affected eye were significantly higher in the two Pycnogenol^® groups in comparison with controls using SM (P<0.05). The improvements in 150 mg Pycnogenol^® group were significantly higher compared to the low-dose 100 mg/Pycnogenol^® group (P<0.05). At the end of the study, blood flow velocity in the Zinn-Haller circle was significantly higher in both Pycnogenol^® groups compared to the control group (P<0.05) and was higher (P<0.05) with the 150 mg Pycnogenol^® dose compared to the 100 mg dose. ION symptoms (vision loss, visual field loss, loss of color vision, flashing lights) improved significantly in the Pycnogenol^® groups compared to controls (P<0.05), with better improvements in the Pycno150 group compared to the Pycno100 group (P<0.05).

Conclusions: The study showed a dose-dependent effect of Pycnogenol^® on blood flow velocity increase, reduction of retinal edema, ION symptoms and increase in visual acuity. Pycnogenol^® was shown to be effective and safe in improving retinal microcirculation after an episode of SLV.