Trace elements iron, copper and zinc in vitreous of patients with various vitreoretinal diseases.

PURPOSE: To measure the concentrations of iron, copper and zinc in human vitreous and to interpret their levels with various vitreoretinal diseases like proliferative diabetic retinopathy, retinal detachment, intraocular foreign body, Eales' disease and macular hole.
METHODS: Undiluted vitreous fluid collected during pars plana vitrectomy was used to measure trace elements using an atomic absorption spectrophotometer.
RESULTS: The level of vitreous iron increased threefold in Eales' disease (1.85 +/- 0.36 pg/ml), 2.5-fold in proliferative diabetic retinopathy (1.534 +/- 0.17 pg/ml) and 2.3-fold in eyes with intraocular foreign body (1.341 +/- 0.25 pg/ml) when compared with macular hole (0.588 +/- 0.16 pg/ml). This was statistically significant (P < 0.05). Zinc was found to be low in Eales' disease (0.57 +/- 0.22 pg/ ml) when compared with other groups, though the difference was not statistically significant.
CONCLUSION: The increased level of iron with decreased zinc content in Eales' disease confirms the earlier reported oxidative stress mechanism for the disease. In proliferative diabetic retinopathy and intraocular foreign body the level of iron increases. This is undesirable as iron can augment glycoxidation, which can lead to increased susceptibility to oxidative damage, in turn causing vitreous liquefaction, posterior vitreous detachment and ultimately retinal detachment and vision loss.