Systemic epigallocatechin gallate protects against retinal degeneration and hepatic oxidative stress in the P23H-1 rat

Retinitis pigmentosa(RP) is a group of inherited retinal disorders that lead to photoreceptor loss.RP has been reported to be related to oxidative stress,autophagy,and inflammation.(-)-Epigallocatechin gallate(EGCG),the most abundant catechin-based flavonoid in green tea leaves,has significant antioxidant,anti-carcinogenic,antimicrobial,and neuroprotective properties.EGCG,given its low molecular weight and hydrophilic properties,can cross the blood-retinal barrier and is able to reach different ocular tissues such as the lens,cornea,and retina.EGCG has been shown to provide retinal protection against ischemia;sodium nitroprusside-,N-methyl-D-aspartate-,lipopolysaccharide-,light-,sodium iodate-,or H2 O2-induced damage and diabetic retinopathy.This suggests that systemic EGCG administration has the potential to protect against retinal degenerative or neurodegenerative diseases such as RP.The aim of this work was to investigate whether EGCG can protect against RP progression in the animal P23 H line 1,the model of RP.Albino P23 H rats were crossed with pigmented Long Evans rats to produce offspring exhibiting the clinical features of RP.Pigmented P23 H rats were treated via intraperitoneal injection with saline or EGCG at a dose of 25 mg/kg every week from P100 to P160 and then compared to wild-type Long Evans rats.Rats treated with EGCG showed better visual and retinal electrical function with increased contrast sensitivity and b-wave values compared with those observed in P23 H rats treated with vehicle.EGCG reduced lipid peroxidation and increased total antioxidant capacity and catalase and superoxide dismutase activities.No differences were observed in visual acuity,nitrate levels,nitrite levels or glutathione S-transferase activity.In conclusion,EGCG not only reduced the loss of visual function in P23 H rats but also improved the levels of antioxidant enzymes and reduced oxidative damage.This study was approved by the Institutional Animal Care and Use Committee(CEICA) from the University of Zaragoza under project license PI12/14 on July 11,2014.

Evaluation of patient visual comfort and repeatability of refractive values in non-presbyopic healthy eyes

AIMTo evaluate the intra-operator repeatability in healthy subjects using the WAM-5500 auto-kerato/refractometer and the iTrace aberrometer, to compare the refractive values and the subjective refraction obtained with both devices and to determine which of these three spherocylindrical corrections allows the subject to achieve the best visual comfort.METHODSForty-two non-presbyopic healthy eyes of 42 subjects were enrolled in this prospective study. Refractive values were compared, evaluating the repeatability, the relationship between the methods and the best visual comfort obtained.RESULTSSphere, cylinder and axis results showed good intraclass correlation coefficients (ICC); the highest ICC was obtained using the spherical refraction with the autorefractometer and the aberrometer, achieving levels of 0.999 and 0.998, respectively. The power vector (PV) was calculated for each refraction method, and the results indicated that there were no statistically significant differences between them (P>0.05). Direct comparison of PV measurements using the three methods showed that aberrometer refraction gave the highest values, followed by the subjective values; the autorefractometer gave the lowest values. The subjective method correction was most frequently chosen as the first selection. Equal values were found for the autorefractometer and the aberrometer as the second selection.CONCLUSIONThe iTrace aberrometer and the WAM-5500 auto-kerato/refractometer showed high levels of repeatability in healthy eyes. Refractive corrections with the aberrometer, the autorefractometer and subjective methods presented similar results, but spherocylindrical subjective correction was the most frequently selected option. These technologies can be used as complements in refractive evaluation, but they should not replace subjective refraction.