The ingredients contained in e-cigarettes can include formaldehyde, a carcinogen which has been shown to irritate the eyes, nose and throat in studies, while propylene glycol can also cause eye and respiratory irritation.
Prolonged exposure to propylene glycol can also affect the nervous system and spleen.
"Although e-cigarette research is still in early stages and the long term effects are yet to be established, there are early indications that some types can cause irritation to the eyes in the form of dry eye," Nigel Best, Specsavers' clinical spokesperson, said.
There are also concerns that older e-cigarette users can develop age-related macular degeneration (AMD), which can cause sufferers to lose central vision, usually in both eyes, Best added.
But if you've switched to e-cigarettes for health reasons, worry not: tobacco smokers are still the most at risk, with double the chance of developing AMD, and a definitive link between vaping and eye damage has yet to be proven.
"Age-related macular degeneration affects around 600,000 people in the UK alone and smokers are more likely to from this eye condition than non-smokers. The condition is most common in people over the age of 50," Dr Best added.