Article: Journal of Cataract and Refractive Surgery; September 2005

Di Pascuale MA, Liu TS, Trattler W, Tseng SC.
J Cataract Refract Surg. 2005 Sep;31(9):1741-9.

Purpose
To determine whether lipid tear deficiency is a significant pathogenic factor in persistent dry eyes after laser in situ keratomileusis (LASIK).

Setting
Ocular Surface Center, Miami, Florida, USA.

Methods
Thirty-four eyes of 17 patients (mean 46.35 years ± 11 [SD]) complaining of persistent dryness more than 12 months after LASIK were prospectively studied by symptom scoring and kinetic analysis of tear interference image, tear breakup time, and fluorescein clearance test. Once patients had been clear of inflammation and treated for aqueous tear deficiency, lipid tear deficiency was further confirmed and treated with Eyefeel (Kao, Inc.), an eye-warming device, 4 times daily for 4 weeks.

Results
Sixteen patients were asymptomatic before LASIK but dryness persisted for 41 ± 19.3 months. Delayed tear clearance was observed in 15 patients (88.2%) and floppy lids in 12 patients (70.5%). Aqueous tear deficiency was reconfirmed in 16 eyes (53.3%). After Eyefeel treatment, there was a subjective improvement of ocular surface diseases index from 60.6 ± 10.6 to 25.8 ± 18.5 (P = .0007). Tear breakup time was improved from 2.4 ± 3.9 seconds to 7.9 ± 3.6 seconds (P = .004). There was a tear interference pattern change from a vertical lipid tear deficiency to a horizontal normal in 7 eyes. There was a mean lipid spread time improvement from 1.3 ± 0.4 sec to 0.8 ± 0.4 sec (P = .001), and there was a mean lipid thickness improvement from 63.5 ± 23 nm to 79.5 ± 27 nm (P = .04).

Conclusion
Persistent nature of dry eye after LASIK is attributed to in part to delayed tear clearance, undercorrected aqueous tear deficiency, and nonrecognized lipid tear deficiency.