Most people know that when a standard eye drop bottle is opened... the expiration date on the bottle becomes irrelevant and the bottle should be disposed in 30 days.  So how can eye drops with no preservatives last 3mth... 6mths...12mths after opening?!  It is logical to believe that eye drops with preservative last longer.  Why is this logic incorrect?

The answer to this trick drop question not the contents... it is the bottle.  Hi-tech bottles protect their contents from bacteria and fungus better than preservatives.   

Preservative free eye drops are regarded as healthier for the cornea... especially in compromised tissue situations.  These special bottles also extend the shelf life of an open bottle and ultimately saves the user money and wasted drops.  

Different companies use different bottle technologies to accomplish this feat.  Candorvision (HYLO) use a plunger and antimicrobial metal.  Thea (Thealoz DUO) uses a filter and I-MED (PUR) uses a valve and metal.

Bottom line  - non-preserved eye drops can sit on your desk or counter longer while being safer and more effective than standard, preserved, cheaper drops.

Almost all of our eye drops at mEYEspa are non-preserved.  I have found better clinic outcomes utilizing the great bottle tech.   Note - There are also some non-preserved drops available only in individual use containers (Thealoz DUO Gel) 

Dr Morris