I am blogging from our largest annual international professional conference, the annual meeting of American Society of Cataract and Surgery held this year in San Diego. Over 10,000 ophthalmologists from all over the world are attending. Today, I heard an interesting study presented by Julie Schallhorn, MD, MS, who is Assistant Professor of Ophthalmology at UC San Francisco Medical School (the medical school I attended).
Studying Common Myths About LASIK Laser Vision Correction and Dry Eye:
Dr. Shallhorn’s study aimed to scientifically examine several myths about LASIK laser vision correction and dry eye. Dr. Shallhorn said that two very common myths about LASIK and dry eye are:
- Any degree of dry eye a patient already has before LASIK will be made worse by LASIK laser eye surgery.
- Women are more likely to get severe dry eyes after LASIK compared to men.
In science, the larger the study, the more dependable the conclusions. Dr. Schallhorn’s study was excellent in this respect in that it included over 24,000 cases from over 12,000 patients over a broad range of age, giving strong statistically validity to her study. Slightly more women then men were included in the study.
Pre-operative Dry Eye Findings Before LASIK Laser Eye Surgery:
The first interesting finding of the study was that even before surgery, 41.5% of all patients undergoing LASIK laser eye surgery had dry eye symptoms, ranging from mild to even severe. This shows that dry eye per se was not a contraindication to ultmiately having surgery. In practical terms, many of these patients’ dry eyes could be successfully treated prior to surgery, allowing them to continue on to surgery. Also before surgery, women were more likely to have dry eye than men, with 23% more women reporting dry eye symptoms prior to surgery. Contact lens wearers were 45% more likely to report dry eye symptoms than patients wearing glasses before surgery. Of course, this does not mean contact lens wearers actually had drier eyes, rather it means their contacts likely were producing the dry eye symptoms. Interestingly, pre-operative age, degree of severity of correction, and season of surgery were not correlated to any increase or decrease in dry eye symptoms.
Post-operative Dry Eye Findings After LASIK Laser Eye Surgery:
Dr. Schallhorn’s study did find that some patient who never had dry eye symptoms before surgery did develop them after LASIK. However, the important finding of her study was that patients who reported dry eye symptoms before surgery actually tended to get less dry eye after their LASIK surgery. This surprising finding of improvement in dry eye symptoms after LASIK was found across the entire spectrum of severity of pre-operative dry eye, from mild to severe, but those with the most severe dry eye pre-operatively demonstrated the greatest improvement after laser eye surgery. In Dr. Shallhorn’s words, “What our study shows is that dry eye before surgery does not necessarily equal dry eye after surgery.”
In terms of the impact of being female on dry eye and LASIK, Dr. Schallhorn’s study showed that before surgery, women tended to have a higher incidence of dry eye than men accross all severity ranges of dry eye, from mild to severe. However, being female had only a minimal impact on whether LASIK would increase dry eye above its pre-operative levels. Age did not affect either men or women in terms of increasing the odds of developoing post-operative dry eye after LASIK laser eye surgery.
Explanation of LASIK Study Results:
Dr. Schallhorn felt that the perhaps surprising result of this large study showing that dry eye actually improved after LASIK compared to before LASIK was due to two factors. The first was simply removing patients from their contact lenses. Contact lenses certainly can cause dry eye symptoms of redness, irritation, eye fatigue, and a feeling that something is in the eye (“foreign body sensation”). More importantly though, Dr. Schallhorn emphasized that patients coming in for LASIK laser eye surgery often have untreated dry eye and there are several excellent treatments that can help dry eye treat their dry eye. A thorough LASIK surgeon would treat pre-operative dry eye and also treat post-operative dry eye symptoms as well. Treatment options include nutritional supplements, including omega 3 and certain omega 6 products. Eyelid cleaning with specialized wipes can help dry eye. There are prescription anti-dry eye drops, including Restasis, Xiidra, and Klarity-C which can optimize the eye and get it ready for LASIK surgery and these drops can be used after surgery as well. Punctal plugs can be inserted into the tear drain in the lids to increase tear volume by slowing the escape of natural tears from the eye, causing them to back up and better coat the surface. Many of these patients who came for LASIK with dry eyes would have had one or more of these treatments before continuing on to surgery, so the improvement in dry eye seen after LASIK likely isn’t necessarily an effect of LASIK eye surgery per se, but rather an effect of the whole process of optimizing the eye to get it ready for surgery. Nonetheless, these patients emerge fromt he process with excellent vision and a reduction in dry eye, making them very happy!