A recent study has brought to our attention the significant role that ‘Chuna’, or slaked lime, plays in ocular burns amongst children in the Indian subcontinent. It’s revealing that adult males and child populations remain highly vulnerable, with ocular burn victims predominantly male – over 80% among adults and 60% among children.
Understanding Slaked Lime
Slaked lime (Ca(OH)2), is a product of quicklime (calcium oxide) mixed with water. The resulting chemical reaction produces calcium hydroxide. This process, known as “slaking,” is highly exothermic, meaning it gives off substantial amounts of heat. Having a high pH value positions slaked lime as highly alkaline and caustic.
For better understanding, an alkali can be characterized as a base that dissolves in water. Bases refer to chemical substances with high pH values, usually more than seven on the pH scale. They are recognized for their ability to neutralize acids, thus producing salts and water. Some common examples of alkalis include sodium hydroxide (NaOH) and potassium hydroxide (KOH).
In contrast, an acid is a chemical substance with low pH values, generally lower than seven on the pH scale. Acids can release hydrogen ions (H+) in a solution and can react with metals, carbonates, and bases to form salts and water. Hydrochloric acid (HCl) and sulfuric acid (H2SO4) are regular examples of acids.
Applications of Slaked Lime
Historically, slaked lime has found use in various capacities including construction, agriculture, and even culinary applications. Traditionally, it also serves as a binding agent, or chuna, in the preparation of paan – a chewable mixture popular in South and Southeast Asia.
The Looming Issue
One of the major concerns arises from the presence of loosely packaged and poorly sealed packets of chuna. The explosion of such packets can allow alkali to come into contact with an individual’s eyes, causing chemical burns to the ocular surface and potentially inflicting severe damage.
In particular, chemical burns to the corneal limbus (a specialized stem cell-rich area of the cornea) can impair the cornea’s self-repair ability, leading to long-term vision complications.
Children, a Vulnerable Group
Alkalis are accountable for 38% of all ocular burns. Chuna emerges as the most common alkali agent, responsible for 32% of all alkali burns in children. Its prevalence amongst children is largely due to their exposure to chuna in households and when handling fireworks.
It’s important to explain, ocular burns refer to injuries caused by exposing the eye to damaging substances like acids, alkalis, solvents or even high-energy sources like welding arcs or lasers. These exposures result in damage to either the eye’s surface or internal structures.