I would assume you are referring to lubricating eyedrops. If so, you are right to say that some eyedrops are not suitable for use after LASIK. Very often, lubricating eyedrops contain preservatives. One of the common preservatives used is benzalkonium chloride (BAK).
BAK was initially used to prevent microbial contamination in the bottle, and was thought to help the active ingredient reach its desired effect. However, studies have shown that BAK can cause inflammation, cell damage, and instability of the tear film.
One common early post-operative side effect of LASIK is dry eye, which tends to improve gradually after surgery. There can also be mild inflammation during the period of recovery. Hence, it is best to use non-preservative based eyedrops during the initial healing stage to avoid the harmful effects of BAK preservative based lubricants as mentioned above.
Dr David Chan
