Most of us have heard the term "artificial tears". Many of us know someone who is using these products regularly. However, for most products that identify themselves as artificial tears, it is a misnomer because they do not actually mimic the composition of human tears. Most function as lubricants, although some more recent formulations do mimic the electrolyte composition of human tears (e.g. TheraTears® [Advanced Vision Research, Woburn, MA]).
Many of the ocular lubricants presently available are not based on clinical efficacy. The description of any given product often specifies permitted active ingredients (eg, emulsifiers, surfactants, and viscosity agents) and concentrations, but may give only limited guidance on inactive additives and solution parameters. Certain inactive ingredients that are used in artificial tears sold over the counter (eg, castor oil in Endura and guar in Systane) are not listed in the product description. It can thus be difficult to prove that any given ingredient in an ocular lubricant acts as the active agent.
Although certain artificial tears have demonstrated more success than others in reducing symptoms of irritation, or in reducing ocular surface dye staining, in head-to-head comparisons, there have been no large scale, masked, comparative clinical trials to evaluate the wide variety of ocular lubricants.That said, the main objectives in caring for patients with dry eye disease are to improve the patients ocular comfort and quality of life, and to return the ocular surface and tear film to the normal homeostatic state.
Whilst symptoms can rarely be eliminated, they can often be improved, leading to an improvement in the quality of life. It is more difficult to demonstrate that topical lubricants improve the ocular surface and the tear film abnormalities associated with dry eye. Until agents are developed that can restore the ocular surface and tear film to their normal homeostatic state, the symptoms and signs of dry eye disease will continue.
Ocular lubricants are characterized by hypotonic or isotonic buffered solutions containing electrolytes, surfactants, and various types of viscosity agents. In theory, the ideal artificial lubricant should be preservative-free, contain potassium, bicarbonate, and other electrolytes and have a polymeric system to increase its retention time.
Some helpful tips
- Use lubricants regularly. Once or twice aday may not be helpful in the long term.
- If you are using lubricants more than 4-6 times per day, you may benefit from preservative free drops. Although more expensive, the preservatives in ubricants may accumulate and worsen your dry eyes, hence the use of preservative free drops.
- Preservative free drops maybe used with contact lens related dry eye.
- When in air conditioned premises, remember to use more lubricants as air conditioning by definition causes evaporation of the tear film.
- When using computers, use the tips outlined in computer vision syndrome.
- Use dietary changes to help your eye condition.