Study: Pre-operative risk factors for post LASIK dry eye

To those of you with post LASIK dry eye, your initial response will probably be "Well, duh! Dry before surgery = drier / higher risk afterwards. Oh and by the way, why didn't they run those tests on ME before surgery?" Fair enough, it's not exactly a newsworthy study. However, there are one or two points of interest. Check out the one I highlighted in the abstract, for example....

On the other hand, what I really want to know is, why didn't they do an anesthetized schirmer - or if they did, why not report on it? (Hard to believe it's because it correlated with nothing at all.) LASIK surgeons do not normally relish operating on the likes of Sjogrens patients, and most of us lasikees were not seriously aqueous deficient before lasik. MGD red flags is what we had.

Oh - and another point of mild interest. Those of you who gripe about being told repeatedly that you're still healing may be interested to note that these authors consider dry at 9 months to be "chronic" dryness. Sounds discouraging on the face of it but when you put this in the context of all the other studies showing nerve regrowth for far longer periods, I would not take it too seriously.

Preoperative characteristics and a potential mechanism of chronic dry eye after LASIK.
Konomi K, Chen LL, Tarko RS, Scally A, Schaumberg DA, Azar D, Dartt DA
Invest Ophthalmol Vis Sci. 2008 Jan;49(1):168-74

PURPOSE: To determine whether measurable preoperative characteristics predispose patients to chronic dry eye after laser in situ keratomileusis (LASIK).

METHODS: The study consisted of 24 eyes of 24 patients who underwent LASIK. Tear breakup time, Schirmer testing with and without anesthesia, rose bengal staining, central corneal sensitivity, nucleus-to-cytoplasmic ratio, and goblet cell density were evaluated 2 weeks before and 1 week, 3 months, and 9 months after surgery. Patients were classified into two outcome groups, the nondry-eye group (NDEG) and the chronic dry-eye group (CDEG), on the basis of dry eye status 9 months after surgery. The authors tested whether preoperative values of each parameter were associated with the development of chronic dry eye.

RESULTS: All parameters, except rose bengal staining, deteriorated significantly after surgery but returned to preoperative levels within 3 to 9 months. The CDEG had significantly lower preoperative Schirmer test values with and without anesthesia and were delayed in recovery after surgery in goblet cell density, rose bengal staining, Schirmer test values without anesthesia, and tear breakup time. Results of preoperative Schirmer tests without anesthesia positively correlated with tear breakup time 9 months after surgery.

CONCLUSIONS: Preoperative tear volume may affect recovery of the ocular surface after LASIK and may increase the risk for chronic dry eye