Fluorescein leakage of the optic disc: time course in primary open-angle glaucoma.

PURPOSE: To identify and quantify the time course of fluorescein leakage of the optic nerve head in primary open-angle glaucoma (POAG) and controls. METHODS: Twenty patients with POAG (aged 58 +/- 10 years) and 14 controls (aged 51 +/- 12 years, p = 0.07) were included in a prospective study. Fluorescein leakage of the optic disc was quantified using digital image analysis. A new leakage ratio (fluorescence of the optic disc divided by fluorescence of the surrounding retina) was defined and fluorescein leakage was quantified at 7-8, 9-10, 11-12, and 13-14 min after injection of 2.5 cc sodium fluorescein (10%). RESULTS: The fluorescein leakage exhibited a significantly different time course with higher leakage ratio values in POAG compared to controls (7-8 min: 1.24 +/- 0.32 vs 1.16 +/- 0.12; 9-10 min: 1.37 +/- 0.37 vs 1.19 +/- 0.1; 11-12 min: 1.38 +/- 0.36 vs 1.24 +/- 0.13; 13-14 min: 1.44 +/- 0.36 vs 1.27 +/- 0.13; p = 0.004). The change in optic disc fluorescence from 7-8 min to 9-10 min was significantly higher in POAG compared to controls (0.13 +/- 0.09 vs 0.03 +/- 0.07; p = 0.002). CONCLUSION: The time course of fluorescein leakage is significantly different in POAG compared to controls. This might reflect damage of the optic disc vasculature related to increased vascular permeability.

Dronabinol and retinal hemodynamics in humans.

PURPOSE: To investigate the effects of oral cannabinoids on retinal hemodynamics assessed by video fluorescein angiography in healthy subjects. DESIGN: Interventional study. METHODS: In a self-experiment, the cannabinoid dronabinol (delta-9-tetrahydrocannabinol [THC]) was administered orally to eight healthy medical doctors (7.5 mg Marinol; Unimed Pharmaceuticals, Chicago, Illinois, USA). At baseline and two hours after dronabinol intake, intraocular pressure (IOP) was measured and retinal hemodynamics were assessed by fluorescein angiography. The retinal arteriovenous passage time was determined on the basis of dye dilution curves by means of digital image analysis in a masked fashion. RESULTS: Dronabinol resulted in a significant IOP reduction from 13.2 +/- 1.9 mm Hg to 11.8 +/- 2.0 mm Hg (P = .038). The retinal arteriovenous passage time decreased from 1.77 +/- 0.35 seconds to 1.57 +/- 0.31 seconds (P = .028). Systemic blood pressure and heart rate were not statistically significantly altered. CONCLUSIONS: Cannabinoids, already known for their ability to reduce IOP, may result in increased retinal hemodynamics. This may be beneficial in ocular circulatory disorders, including glaucoma.