Grape Seed Extract Improves Eye Health

Waxy deposits in the retina, called hard exudates, are made from lipid material leaking from blood vessels in the retina. As one of the outcomes of retinal neuropathy, it may seem like this condition couldn’t be reversed. But grape seed extract may provide a potential answer.

In a one-year, multi-center, double-blind clinical trial, patients were given either a placebo, calcium dobesilate (often used for retinopathy or other vein-related conditions), or supplemented with 150 mg of grape seed extract daily. By the end of the study, grape seed extract showed the best effects, improving hard exudates significantly versus the calcium dobesilate.

In some ways, this shouldn’t be too surprising. After all, compounds in grape seeds, called oligomeric proanthocyanidins (OPCs) are well known for helping preserve blood vessels, normalize blood pressure, stop blood clots from forming (without thinning the blood), and shield arteries from oxidative damage.

Even though grape seed extracts have shown remarkable benefits over the years, one of the ways to ensure that grape seed extract works best is by finding one that is standardized to be tannin-free. That’s because not all OPCs are absorbable by the body – and tannins, as OPCs, are some of them. However, low-molecular weight OPCs are small and can be easily absorbed to begin protecting delicate structures like blood vessels in the eyes.


Moon SW, Shin YU, Cho H, Bae SH, Kim HK; and for the Mogen Study Group. Effect of grape seed proanthocyanidin extract on hard exudates in patients with non-proliferative diabetic retinopathy. Medicine (Baltimore). 2019;98(21):e15515.


To evaluate the efficacy and safety of orally administered grape seed proanthocyanidin extract (GSPE) in patients with non-proliferative diabetic retinopathy (NPDR).


In this randomized (1:2:2), multicentre, double-blind trial, patients (n = 124; age: 40-78 years) were administered placebo, calcium dobesilate (CD; 750 mg/d), or GSPE (150 mg/d) orally for up to 12 months. All patients had retinal thickening with hard exudates (HEs) that met predefined criteria; the median best-corrected visual acuity was 0.8, as assessed using the Snellen visual acuity card. The main outcome measure was an improvement in HEs by at least 1 grade on a 10-grade severity scale. This was evaluated using fundus photography over 1 year.


The rate of improvement in the HE severity was higher in the GSPE group than in the CD group. No statistically significant difference existed among the study groups in optical coherence tomography parameters, such as central subfield macular thickness and total macular volume (TMV). However, in the GSPE group, TMV after 9 months of treatment was significantly decreased compared with that at baseline. The GSPE group showed a significantly greater improvement in HE severity than did the placebo or CD group. Four cases in the GSPE group and 2 in the CD group were determined to have developed potential treatment-related adverse reactions, which were all gastrointestinal in nature.


Oral GSPE therapy for 1 year improved HEs in patients with NPDR. The efficacy of GSPE for HEs was higher than that of oral CD in the study patients.

Click here for a link to the complete article: Effect of grape seed proanthocyanidin extract on hard exudates in patients with non-proliferative diabetic retinopathy