Abstract: IntraLase, flap position & dry eye

Hm.

So where was the OSDI at 12 months? Any interesting outliers? Define "mild". How about the bottom line: Were there any patients in serious pain a year later?

I thought the flap position thing was put to bed in the last several dozen studies. Don't we have more interesting things to study about dry eye and LASIK than proving or disproving whether flap position matters? Or demonstrating yet again, to the consternation of all those in our online communities who had femtosecond laser flaps, that persistent dry eye Does Not Happen, and therefore presumably Did Not Happen to them?

Dry eyes and corneal sensation after laser in situ keratomileusis with femtosecond laser flap creation Effect of hinge position, hinge angle, and flap thickness.
J Cataract Refract Surg. 2009 Dec;35(12):2092-8.
Mian SI, Li AY, Dutta S, Musch DC, Shtein RM.
Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan 48105, USA. smian@umich.edu

PURPOSE: To determine whether corneal sensation and dry-eye signs and symptoms after myopic laser in situ keratomileusis (LASIK) surgery with a femtosecond laser are affected by varying hinge position, hinge angle, or flap thickness. SETTING: University-based academic practice, Ann Arbor, Michigan, USA.

METHODS: This prospective randomized contralateral-eye study evaluated eyes after bilateral myopic LASIK with a femtosecond laser (IntraLase). Superior and temporal hinge positions, 45-degree and 90-degree hinge angles, and 100 microm and 130 microm corneal flap thicknesses were compared. Postoperative follow-up at 1 week and 1, 3, 6, and 12 months included central Cochet-Bonnet esthesiometry, the Ocular Surface Disease Index questionnaire, a Schirmer test with anesthesia, tear breakup time (TBUT), corneal fluorescein staining, and conjunctival lissamine green staining.

RESULTS: The study evaluated 190 consecutive eyes (95 patients). Corneal sensation was reduced at all postoperative visits, with improvement over 12 months (P<.001). There was no difference in corneal sensation between the different hinge positions, angles, or flap thicknesses at any time point. The overall ocular surface disease index score was increased at 1 week, 1 month, and 3 months (P<.0001, P<.0001, and P = .046, respectively). The percentage of patients with a TBUT longer than 10 seconds was significantly lower at 1 week and 1 month (P<.0001).

CONCLUSIONS: Dry-eye syndrome after myopic LASIK with a femtosecond laser was mild and improved after 3 months. Corneal flap hinge position, hinge angle, and thickness had no effect on corneal sensation or dry-eye syndrome.