Why should I avoid preservatives, other products have them?

Many eye products contain a preservative called benzalkonium chloride (BAC). Used long term this preservative can have a negative effect on the ocular surface and the epithelium. Equally an unpreserved product is open to contamination and the possibility of infection within the bottle.
The ideal system is one that protects the solution in the bottle and on contact with the eye,  biodegrades into naturally occurring physiological elements causing no irritation or reaction to the eye.
Oxyd™ is a preservative offering protection in the bottle whilst being non toxic to the eye, as it converts into physiological salt and oxygen.
The DEWS report states in its section on preservatives “the ideal lubricant would come in a multidose, easy to use bottle that contains a preservative that completely dissipates before reaching the tear film, or is completely non toxic and non irritating and maintains absolute sterility with frequent use.”