By Dr. Michael Lawless

Everyone knows that LASIK decreases tear production.  It is related to the fact that LASIK (even all laser LASIK, which is the best way to do it) cuts through corneal nerves and they regenerate slowly over weeks to months.  The nerve supply is in a very complex way linked to tear volume.  After LASIK one of the things you can guarantee is that your tear production will be decreased probably by about 25%.  Most people have a good tear reserve so that they may be aware of mild dry eye, or sometimes nothing at all.

It can become a problem though if the tear volume or quality is compromised ahead of refractive surgery.  It is important to recognise this by looking at the quality of the tear film break-up time and analysing the tear volume, but there are no perfect tests to determine this and it is in some ways a subjective assessment by the surgeon.

Without making the issue too confusing, there is an element of tear production that is not just the amount of tears you produce, but the quality of tears, which  is important and can be disturbed by a poor blink response if you are sitting in front of the computer for long periods and compounded by air conditioning or heating.  It can also be impacted by inflammation in the lids oil glands that produce oil for the tears, and this is something to recognise ahead of surgery and deal with.

In the last twelve months, I’ve started to more aggressively target the tear film peri-operatively.  Simply it comes down to recognising that there is a problem and deciding whether it is due to low tear volume or whether it is a tear film disturbance for other reasons.  I deal with it by using weak topical corticosteroids (FML or Fluoromethalone drops) for a few days before LASIK, sometimes using punctal plugs, either temporary or permanent at the time of LASIK. What has made a great difference is getting prospective patients to take oral flaxseed oil 2000mg per day for a week before and about a month after LASIK.  Flaxseed oil is one of the few things known to increase tear volume and quality.  It is a very safe thing to take and is available from health food stores.

The combination of these things has led to not just more comfortable patients, but there is a link between tear volume and quality and the accuracy of corneal refractive surgery.  A good tear quality film will help you see well.  The tear film is not just a wetting agent coating the surface; it is linked to how the eye behaves optically, so for a whole range of reasons attention to the tear film is just as important as getting the laser accurately calibrated and the surgery performed well.  It makes a difference.