Uptake and distribution of gadolinium in the ocular lens.

The lens of the eye has no blood vessels. Although necessary for transparency, this feature of the ocular lens implies that any circulation in the lens tissue must be avascular. A range of previous studies attests to the metabolic activity of the fiber cells that make up the body of the lens. It is also established that the continuing transparency of the lens depends upon this metabolic activity. When metabolism is disturbed, cataracts (lens opacities) result. It has been proposed that metabolism occurs throughout the lens, enabled by an intercellular micro-circulation system driven by ion pumps and cell volume-regulation mechanisms. The present study attempted directly to trace micro-circulation in the ocular lens on a spatially coarse scale. High field strength magnetic resonance imaging was used to record the movement of gadolinium into the lens and the global distribution patterns that result. Our data lend new support to previous attempts at documenting, by other techniques, differential micro-circulation mechanisms in the ocular lens.