Eyeworld

61 EW REFRACTIVE June 2017 eters in all eyes. In the treatment group, Extend punctal plugs (Bea- ver-Visitec International, Waltham, Massachusetts) were placed in the lower punctum of each eye at the conclusion of surgery. These syn- thetic plugs swell to comfortably fit the canalicular system without foreign body sensation or irritation. They are absorbable, fully dissolving within about 3 months, around the time when we would expect corneal sensation and dry eye symptoms to improve in the post-LASIK eye. The same postoperative medications were prescribed in all eyes. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), fluorescein staining, tear production (Schirmer score), matrix metalloproteinase 9 (MMP-9) de- tection, tear osmolarity, and Ocular Surface Disease Index (OSDI) scoring were evaluated at 1 week and 1 and 3 months and compared to the same measures preoperatively. Staining was used to grade the ocular surface quality. In addition to standard pre- and post-LASIK visual acuity assess- ments, patients underwent slit lamp biomicroscopy with fluorescein staining, which was used to grade the ocular surface quality (0 to 4); Schirmer basic secretion test with topical anesthetic; and MMP-9 and osmolarity testing of the tear film. All subjects also completed OSDI questionnaires at each visit. Results are reported at baseline (preop), and at 1 week, 1 month, and 3 months. Data were analyzed for left and right eyes separately, using either para- metric or non-parametric methods, depending on the nature of the re- sponse. Results for right and left eyes were very consistent; data for right eyes is presented here, except where noted below. Results Preoperative characteristics are shown in Table 1. There were no statistically significant differences between the treatment and control groups in age, sex, median OSDI scores, or visual acuity at baseline. Ocular surface testing also revealed that the two groups were quite sim- ilar preoperatively. The only statis- tically significant difference was in the presence of a positive test for the cytokine MMP-9. Three eyes in the control group were MMP-9 positive versus none in the plug group. How- ever, this did not correspond to any meaningful differences in staining or OSDI score. Overall, these were not patients with significant ocular surface problems prior to surgery; all were deemed to be good candidates for corneal refractive surgery. Punctal occlusion had a modest effect on Schirmer scores. When both eyes were evaluated, patients who received plugs had higher Schirmer scores by 1.03 mm, on continued on page 63

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