Approximately 1 in 100,000 babies are born with anophthalmia (no eyes) worldwide. Microphthalmia (small eyes) occurs in around 1 in 10,000 births. About two thirds of the cases are believed to be genetic. The rest are believed to be caused by environmental factors--for example, exposure to an environmental toxin such as Benlate--or viral infections.

Currently, at least ten children and their families have brought legal action against DuPont, the manufacturer of Benlate, claiming exposure to the product caused their eye defects; one in Florida, one in West Virginia, and eight in Delaware.

All, except for the Florida case, involve foreign plaintiffs. This is because fungicides are far more widely used in European countries than in the United States due to the damp climate. Fungus, and not insects, is the main crop killer there.

Further, Benlate was freely available over the counter for home use in Britain. DuPont claimed that they removed the product from shelves in January of 1998 because it was becoming less effective, not because it was dangerous.

What causes these eye defects?

Normal development of the eye is an extremely complex process that relies on a precisely arranged sequence of developmental steps. These steps are governed by control genes that are switched on and off at particular times of development. Most of the important development of eye structures in a developing fetus is programmed to take place in the first three months of pregnancy. However, after this there are still some refinements that occur. F

ailure of any of the early eye development stages may cause anophthalmia and/or microphthalmia. Later events in pregnancy such as infections or exposure to chemicals such as Benlate may also cause microphthalmia, but usually not anophthalmia. In most cases the cause of these problems is not known.

True anophthalmia occurs in around 1 in 100,000 births worldwide. Microphthalmia occurs in around 1 in 10,000 births. Around two thirds of these cases are believed to be genetic. The remaining are thought to be caused by environmental factors such as drugs, pesticides--such as Benlate, radiation, toxins, or viral causes. Some of the viruses that have been linked to these conditions are toxiplasmosis, rubella, and certain strains of the flu virus. Research into the cause or causes of these distressing conditions has intensified over the past few years.

What does science say about a link between eye defects in a fetus and chemical exposure during pregnancy?

Adverse effects such as eye birth defects occur after exposing experimental animals to high doses of pesticide. In 1997, DuPont funded a scientific study by an independent laboratory in Yorkshire. The internal report, details of which emerged in 2002, indicated that in rat studies a high proportion of benomyl, the active ingredient of the product, was drawn to the eyes. The report showed that after two hours, a third of the benomyl was concentrated in the eyes, rising to two-thirds after 24 hours. After 10 days, 80% of the benomyl was pooled around the eyes.

In 1991, scientists at the University of California discovered that more than 40% of pregnant rats fed high levels of benomyl produced fetuses with severe eye defects. When the dosage of benomyl was administered to rats given a protein-deficient diet, almost two out of three pregnant animals gave birth to babies without eyes.

The study was designed to show the impact of the chemical on those with a poor diet. Further, it has been pointed out that if the active substance of Benlate is inhaled or absorbed through the skin, it bypasses the liver and is therefore detoxified far more slowly. It will then remain in the mother's system for far longer, with potentially devastating effects on the developing fetus.