People suffering from chronic dry eye disease are likely to have a slow reading rate, according to researchers.

The chronic dry eye is a common disease in which natural tears fail to adequately lubricate the eyes, thus drastically affecting its functioning. The study found that the condition can slow a person's reading speed by as much as 10 per cent and can make it difficult to read for more than an average of 30 minutes.

Those with clinically significant dry eye could read fewer words per minute -- 32 words per minute less -- than those without the condition, who read at the same rate of 272 words per minute. "We suspected that people with dry eye were mostly unable to sustain good reading performance because their tears cannot re-lubricate their eye surfaces fast enough," said Esen Akpek, from the Johns Hopkins Wilmer Eye Institute in the US. 

For the study, published in the journal Optometry and Vision Science, the team included 186 adults aged 50 or older. The participants had not used prescription or over the counter eyedrops in the 24 hours before testing. Importantly, all participants responded to eye discomfort vision quality and environmental contributors to eye complaints, such as wind or smoke. People who experience frequent dry eye symptoms such as stinging, fluctuating vision and dryness can try over the counter eyedrops, but will do best if they undergo professional testing and diagnosis, said Akpek.