Slaked lime is an alkali compound widely used as a binding agent, along with betel nut and other ingredients, to make paan in the Indian subcontinent. A new study has found that chuna is a major cause for ocular burns among children, along with household chemicals and fireworks.
The study paper was published in the July 2023 edition of the Indian Journal of Ophthalmology. It was conducted by researchers at the L.V. Prasad Eye Institute, Hyderabad, and Narayana Nethralaya, Bengaluru.
Loosely sold in plastic packets, the quicklime can puff out of the packet on to a child’s eyes. The alkali then burns the ocular surface and can result in eye injury.
Ocular burns due to household chemicals are wholly avoidable. They are a tragic cause of ocular morbidity, even vision loss, especially among children.
What is chuna and what are its risks?
Indian paan has slaked lime, or chuna (sunnam in Telugu; sunna in Kannada; sunnaampu in Tamil), smeared onto a betel leaf and is chewed along with areca nut. Tobacco is also added to the paan and the alkali quickens its absorption. Paan consumption, especially in South and South East Asia, has been reported from prehistoric times.
Chuna is often sold in loose and poorly sealed packets across the region.
An exploding packet of chuna can deliver the alkali straight into a person’s eye, with the chemical lodging itself inside the eyelid and coating the cornea, the outer transparent layer of the eye. Here, the alkali chemically burns through the delicate tissue, causing extensive damage.
The rim of the cornea, called the corneal limbus, is home to specialised stem cells that replenish the cornea. Chemical burns can destroy the limbus, in turn compromising the cornea’s ability to repair itself.
The risk of chemical injury to the eye is not limited to slaked lime. Household cleaning agents like toilet cleaners and other acids, as well as fireworks and even super-glue in tubes, are all liable to cause ocular injury.
Chemical burns to the eye results in ocular burns or, in worse cases, severe loss of vision. They may require extensive surgical intervention, including stem-cell transplantation and corneal grafts, and will need lifelong management. Alkali burns can have a poor prognosis and interventions often restore sight only to a limited extent.
Who is at risk?
Children with access to household chemicals like chuna, adults who work with such agents without protective eye glasses, and individuals of both age-groups when they play with firecrackers are at risk of ocular burns.
Many small studies and reports have flagged chuna-related ocular burns, especially in children. The new study – one of the largest of its kind in India – offers insights into who is at risk and the primary causes of ocular burns.
For the study, researchers obtained the clinical profiles of 271 children (338 eyes) and 1,300 adults (1,809 eyes) who presented to the L.V. Prasad Eye Institute and the Narayana Nethralaya hospitals with acute ocular burns (AOB).
“Both the hospitals in this study are tertiary referral centres, so they are not the first stop for patients with ocular burns,” Swapna Shanbhag, consultant ophthalmologist at the Institute and one of the corresponding authors of the study paper, said. “For this study, we defined patients who presented to these centres within one month of injury as ‘acute’.”
“Patients who present later are ‘chronic’, and their outcomes are even poorer,” she added.
Chuna most common alkali agent
The researchers found that a majority of people with AOB were male (over 80% among adults and over 60% among children), and that alkalis accounted for 38% of all ocular burns – and as much as 45% of all burns in children.
While the study found that the physical or chemical agents responsible for the burns varied between children and adults, chuna was the most common alkali agent in both groups, causing 32% of all alkali burns among children and 7% among adults. Some 17% of children presented with thermal burns (due to fireworks) and another 14% had squirted superglue into their eyes. Acids, like toilet-cleaning or surfacing-cleaning liquids, also caused burns in both children and adults.
More than 60% of the children had low-grade burns and benefited from medical therapy. At the same time, sadly, the fraction of individuals with greater injury, chronic complications, and poorer visual outcomes was higher among children.
What preventive measures are needed?
All these injuries can be avoided if the substance causing them is stored safely, away from the reach of children. Adults who are at risk of workplace injuries – since lime is also present in whitewash, for example – will benefit from protective eye glasses.
The study also underscores the need to improve the packet integrity of chuna sold over the counter. Better quality plastic and sealing and clear warning messages on the packet may help reduce the risks to children. People should only purchase adequately sealed packets of alkalis and acids, and insist on using them with protective glasses.
Firecrackers are a known risk for burns, and people should be made aware of the risk of ocular injury as well. All the usual safety measures – sourcing good-quality firecrackers, using them in open areas where bystanders, especially children, are at a safe distance – apply.
Finally, a key finding of this study is that close to 60% of all patients with ocular burns did not present to a hospital within 24 hours. It also found that more than 20% of the patients did not receive any eye wash when they reached, or before reaching, emergency care.
It is imperative that the burnt eye is immediately washed off the chemical as soon as the injury happens. When the patient visits a hospital, the eye must also be thoroughly irrigated to remove any substances that may be lodged in the eye.
Tejah Balantrapu is the associate director of Science, Health Data, and Story-telling at the L.V. Prasad Eye Institute.
