A woman suffered chemical injuries to her eye after she mistook a bottle containing e-cigarette liquid for eye drops. 

The Scottish woman, who is in her mid-50s, had been prescribed antibiotic eye drops to treat a case of pink eye. 

But she stored the antibiotic drops beside the e-cigarette refill liquid in her bathroom cupboard and accidentally picked the wrong bottle. 

She then squirted the e-cigarette (EC) liquid into her eye instead of the medication, according to a report, published as a letter in the journal JAMA Ophthalmology. 

The woman suffered an ocular chemical injury by "inadvertent administration" of the liquid, resulting in "instant ocular pain, redness, and blurred vision". 

Medical experts have now warned about the dangers of bringing the liquid into contact with the eye . 

Health care providers at Gartnavel General Hospital in Glasgow, who treated the woman, wrote in their report of her case: "We would like to raise awareness of this potential hazard that can result in an ocular chemical injury. 

"We would recommend that manufacturers of EC fluid consider carrying advice to irrigate and seek prompt medical attention if the fluid comes into contact with the eyes, as is standard practice with other ocular chemical injuries. 

"There is a paucity of data in the literature regarding the potential harm from EC use, and EC liquid has already been shown to cause increased inflammation in human airway epithelial cells. 

"To our knowledge there are no published studies looking at the effect on corneal and conjunctival epithelial cells." 

They added: "Because ECs are not viewed as a conventional medical product, we propose that EC sellers recommend storage away from other medical bottles, such as eyedrops to minimise the potential confusion." 

The liquid used in e-cigarettes usually contains nicotine and chemicals such as propylene glycol, glycerin and, in some cases, flavorings. 

Electronic cigarettes heat this liquid into a vapor that users inhale, and refills of the liquid are often sold in small bottles. 

The woman quickly washed out her eye with water and went to an emergency eye clinic with the bottle of the e-cigarette liquid. 

She told the doctors that she had stored the e-cigarette refill liquid in her medicine cabinet beside the antibiotic eye drops. 

The doctors tested both the pH of the e-cig liquid and the pH of the woman's eye. 

The liquid had a pH of 6, making it slightly acidic. 

Though acidic chemicals can cause damage to the eye, they are actually less damaging than alkaline chemicals. 

In a study from August 2016 in the same journal, researchers noted that acidic compounds cause proteins to build up in the eye, creating a barrier that can prevent further damage. 

In contrast, alkaline substances break down cell membranes, and can burn into the cornea, the transparent outer covering of the eye. 

The doctors found that the woman's eye had a pH of 7, which is within the normal range for the eye. 

The woman had some superficial damage to her cornea, but the EC liquid did not cause any serious defects, the doctors wrote. 

They noted in their letter that the EC liquid bottle contained no warnings about what should be done if someone got the liquid in their eye. 

Although the liquid that the woman used was only mildly acidic, the doctors wrote that these liquids can have a wide range of pH levels, from 4.7 (acidic) to 9.6 (alkaline). 

The safety guidance listed on the E-cigarette liquid bottle is as follows: "Store locked up and out of the reach of children and pets. 

"Only for use in electric cigarettes. Seek medical attention if swallowed. May contain traces of nuts. this product contains nicontine which is a highly addictive substance." 

Tom Pruen, Chief Scientific Officer with the Electronic Cigarette Industry Trade Association (ECITA) said there had been a number of such incidents reported. 

He said: "While, on the face of it, confusing a refill for a safer alternative to smoking with eye-drops seems unlikely, there have now been a few incidents reported. 

"Due to this, we recently advised our members to include a warning to consumers to help to avoid this kind of accident. 

"Many things come in small dropper bottles, such as glues, cosmetics, and indeed e-liquid. 

"These should not be stored with medical products, particularly those intended for application to sensitive areas, in order to minimise the chance of confusion. 

"While the damage was temporary and minor e-liquid is irritating to the eyes and contact should be avoided. 

"Hopefully, this incident, combined with improved warnings, will raise awareness of the potential for accidents and consumers will be able store their products in a way that reduces any risk of inappropriate application."