Efficacy of Green Tea Extract for Treatment of Dry Eye and Meibomian Gland Dysfunction; A Double-blind Randomized Controlled Clinical Trial Study

Abstract

IntrOductIOnWith an incidence rate of 9%, dry eye syndrome is a common condition that causes different amounts of discomfort and disability, especially in patients over 40 years of age. It can result in visual disturbance and instability in the tear film, due to the increase of tear film osmolarity and inflammation of ocular surface, or the overall lack of an appropriate and stable tear film [1,2].A well-formed tear film is required for nourishing, lubricating, and protecting the ocular surface. Tear film instability may be caused by the dysfunction of any lachrymal or meibomian gland: eyelids, cornea, conjunctiva, or the connecting neural reflex circles.Dry eye has been divided into two distinct etiological groups: Aqueous Tear Deficiency (ATD) and evaporative dry eye. The first group is further divided into Sjögren's syndrome and non-Sjögren causes of lachrymal gland dysfunction. The second group includes intrinsic MGD and extrinsic causes (contact lens wear or ocular surface diseases, such as allergy) [1,2].

Effects of intranasal administration of violet oil in dry eye disease

“…However, the comparison of the groups after the four‐week intervention revealed that the VAO group did not improve significantly compared with the other groups (p > 0.05). These results are in agreement with the results obtained in a recent study conducted by Nejabat et al, where the rate of improvement between the treatment and control groups was negligible . Note that the corneal epithelium turnover is approximately 10 days .…”

“…These results are supported by previous studies that have demonstrated that anti‐inflammatory agents can improve the signs and symptoms of DED . However, in contrast to the present study, Nejabat et al did not show any significant differences in the Schirmer's test scores between the groups treated with a topical green tea extract (a natural anti‐inflammatory agent) and the placebo, perhaps due to an unsuitable dosing schedule or the time and frequency of drug administration.…”

“…Therefore, in recent years, there has been an increasing tendency to use complementary and alternative medicine, such as acupuncture and herbal medicine, for the treatment of DED . Regarding the key role of inflammation in DED pathogenesis, it has already been shown that oral or topical (intraocular) administration of natural anti‐inflammatory and anti‐oxidant compounds extracted from medicinal herbs has a significant effect on the improvement of signs and symptoms of DED …”

The Role of Nutrition and Nutritional Supplements in Ocular Surface Diseases

“…A randomized controlled trial evaluated the efficacy of green tea extract in 60 patients with DED secondary to meibomian gland dysfunction. The improvement of symptoms, break-up time and meibum quality was significantly higher in the green tea group compared to the control group [111].…”

A Randomized, Placebo-Controlled Study on the Safety and Efficacy of Daily Ingestion of Green Tea (Camellia sinensis L.) cv. “Yabukita” and “Sunrouge” on Eyestrain and Blood Pressure in Healthy Adults

“…Green tea contains many functional ingredients such as catechins, caffeine, flavonols, vitamins, and dietary fiber. It has been reported to have various bioregulatory functions, such as anti-carcinogenic and anti-metastatic [ 4 ], anti-obesity [ 5 ], anti-diabetes [ 6 ], anti-hypercholesterolemic [ 7 , 8 ], antioxidative [ 9 ], anti-cardiovascular [ 10 ], anti-allergic [ 11 ], and anti-dry-eye activities [ 12 ], and it is known to improve the intestinal flora. The tea cultivars (cv.)…”