Dr. Ron’s Research Review – March 16, 2016

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This week’s research review focuses on intraocular pressure.

A study published in Clinical and Experimental Optometry showed that corn silk aqueous extracts reduced intraocular pressure of systemic and non-systemic hypertensive subjects. Twenty systemic and 20 non-systemic hypertensive subjects received corn silk aqueous extract (60, 130, 192.5 and 260 mg/kg body weight) at two-week intervals. Intraocular pressure and blood pressure were measured at baseline and every hour for eight hours after administering water or a masked dose of corn silk aqueous extract. The results showed that the last three doses of corn silk aqueous extract gave a statistically significant reduction (p < 0.001) in mean intraocular pressure and blood pressure within eight hours of administration. The peak effect on intraocular pressure was observed after four hours and this was preceded by the peak effect on blood pressure, which occurred after three hours of administration. The hypotensive effect was dose-dependent in the two groups. Corn silk aqueous extract has a lowering effect on intraocular pressure in systemic and non-systemic hypertensive subjects. This may have resulted from the fall in blood pressure that is due to potassium-induced natriuresis and diuresis caused by the high potassium content in the high doses of the corn silk extract. (George and Idu, 2015)

A study published in the Journal of Ocular Pharmacology and Therapeutics examined the effects of a supplement containing forskolin, homotaurine, carnosine, folic acid, vitamins B1, B2, B6, and magnesium (2 tablets per day for 1 year) in 22 patients with primary open angle glaucoma (POAG) already in treatment and compensated by intraocular pressure (IOP)-lowering drugs, during a period of 12 months. Pattern Electroretinogram (PERG) amplitude, foveal sensitivity obtained with the visual field analyzer frequency doubling technology, and IOP were detected at enrollment (T0), 3 months (T1), 6 months (T2), 9 months (T3), and 12 months (T4).  The treated patients had a significant further decrease of IOP and an improvement of PERG amplitude at 6, 9, and 12 months, and foveal sensitivity at 12 months. All values remained substantially stable in control patients. (Mutolo et al., 2016)

Dr. Ron

Articles

Corn silk aqueous extracts and intraocular pressure of systemic and non-systemic hypertensive subjects.
            (George and Idu, 2015) Download
BACKGROUND:  Hypotensive properties have been attributed to the stigma/style of Zea mays L (corn silk). Although the effect of corn silk extract on blood pressure has been documented in animal studies, we are not aware of any study on its effect on human blood pressure and intraocular pressure. METHODS:  A randomised study was carried out on the effect of water only, masked doses of corn silk aqueous extract (60, 130, 192.5 and 260 mg/kg body weight) on intraocular pressure and blood pressure of 20 systemic and 20 non-systemic hypertensive subjects. Intraocular pressure and blood pressure were measured at baseline and every hour for eight hours after administering water or a masked dose of corn silk aqueous extract. Each dose was administered at two-week intervals to each subject in the two study groups. RESULTS:  The results showed that the last three doses of corn silk aqueous extract gave a statistically significant reduction (p < 0.001) in mean intraocular pressure and blood pressure within eight hours of administration. The peak effect on intraocular pressure was observed after four hours and this was preceded by the peak effect on blood pressure, which occurred after three hours of administration. The hypotensive effect was dose-dependent in the two groups. CONCLUSION:  Corn silk aqueous extract has a lowering effect on intraocular pressure in systemic and non-systemic hypertensive subjects. This may have resulted from the fall in blood pressure that is due to potassium-induced natriuresis and diuresis caused by the high potassium content in the high doses of the corn silk extract.

Oral Administration of Forskolin, Homotaurine, Carnosine, and Folic Acid in Patients with Primary Open Angle Glaucoma: Changes in Intraocular Pressure, Pattern Electroretinogram Amplitude, and Foveal Sensitivity.
            (Mutolo et al., 2016) Download
PURPOSE:  To evaluate the effects of a food supplement containing forskolin, homotaurine, carnosine, folic acid, vitamins B1, B2, B6, and magnesium in patients with primary open angle glaucoma (POAG) already in treatment and compensated by intraocular pressure (IOP)-lowering drugs, during a period of 12 months. METHODS:  Twenty-two patients (44 eyes) with POAG, with their IOP compensated by topical drugs, were enrolled and randomly assigned to the food supplement or control treatment group. The additional food supplement treatment consisted in 2 tablets per day (1 in the morning, 1 in the evening) given for 1 year of a balanced association of homotaurine, Coleus forskohlii root extract, l-carnosine, folic acid, vitamins B1, B2, B6, and magnesium. Pattern Electroretinogram (PERG) amplitude, foveal sensitivity obtained with the visual field analyzer frequency doubling technology, and IOP were detected at enrollment (T0), 3 months (T1), 6 months (T2), 9 months (T3), and 12 months (T4). RESULTS:  We observed in treated patients a significant further decrease of IOP and an improvement of PERG amplitude at 6, 9, and 12 months, and foveal sensitivity at 12 months. All values remained substantially stable in control patients. CONCLUSIONS:  The results of the present pilot study indicate that the components of the food supplement reach the eye in a detectable manner, as evidenced by the effects on the IOP. Moreover, they suggest a short-term neuroactive effect, as indicated by the improvement of PERG amplitude and foveal sensitivity in treated, but not in control patients.

 

 

References

George, GO and FK Idu (2015), ‘Corn silk aqueous extracts and intraocular pressure of systemic and non-systemic hypertensive subjects.’, Clin Exp Optom, 98 (2), 138-49. PubMed: 25727941
Mutolo, MG, et al. (2016), ‘Oral Administration of Forskolin, Homotaurine, Carnosine, and Folic Acid in Patients with Primary Open Angle Glaucoma: Changes in Intraocular Pressure, Pattern Electroretinogram Amplitude, and Foveal Sensitivity.’, J Ocul Pharmacol Ther, PubMed: 26771282