Influence of posterior vitreous detachment and type of intraocular lens on lipid peroxidation in the human vitreous

PURPOSE: The aim of this study was to evaluate the relationship between oxidative stress and human vitreous degeneration, using the presence of an evident posterior vitreous detachment (PVD) as a clinical sign and thiobarbituric acid-reactive substances (TBARS) and nitrite as oxidative biomarkers. METHODS: We collected 42 vitreous samples from patients undergoing pars plana vitrectomy for two groups of vitreoretinal diseases (macular holes and epimacular membranes). TBARS and nitrite were assessed spectrophotometrically and compared to the presence of an evident PVD, considering other clinical features potentially related to the oxidative stress in the vitreous: diabetes, plasma fibrinogen, type of intraocular lens (IOL), and the vitreoretinal disease requiring the surgery. RESULTS: Vitreous TBARS levels were significantly higher in patients with artificial IOLs compared to those with natural lenses and cataracts (1.39±0.64 versus 0.75±0.45; p=0.003). Furthermore, patients with PVD had a significant increase in vitreous TBARS compared to those without PVD (1.45±0.54 versus 0.53±0.38; p=0.001). The plasma fibrinogen levels explained 17% of the TBARS variance, with a significant correlation between these two markers (p=0.011). No significant differences were observed when nitrites were used as biomarkers. CONCLUSIONS: Current IOLs, even with ultraviolet (UV) absorber, do not ensure the same photoprotection offered by natural lenses affected by corticonuclear cataracts. Furthermore, we observed a relevant correlation between the increased presence of peroxidation products in the vitreous and an evident PVD, but the nature of this relationship requires further study.