The finding, by researchers from the London School of Hygiene and Tropical Medicine, is likely to reawaken fears about the effects of exposure to pesticides on the developing foetus. The use of pesticides in farming has increased sharply in recent decades and the researchers say the possible link needs further investigation.
Dr Helen Dolk and colleagues from the environmental epidemiology unit were commissioned by the government in 1993 to investigate the eye abnormality after clusters of cases were reported in different parts of the country. The reports said the abnormality might be caused by exposure to the pesticide benomyl.
The investigation examined every case of the abnormality, called anophthalmia (born with no eyes) and microphthalmia (born with very small eyes), between 1988 and 1994. It identified 444 cases, a rate of one in 10,000 births, but found no evidence of clustering, which might have pointed to a local environmental cause such as heavy exposure to pesticides.
However, the study found the abnormality was 80 per cent more common among children from rural areas and that severe cases were almost 140 per cent more common.
The researchers say that an infection caught by the mother, as yet unidentified, is the most likely cause of the abnormality and the evidence of a causal link with pesticides is "currently weak". More specific research is needed "to prevent this condition in future generations".