EyeWorld Asia-Pacific September 2017 Issue

Figure 1. The Extend absorbable plug increased the odds of improving the OSDI score after surgery by nearly six-fold (P<0.001). Figure 2. Punctal occlusion significantly influenced ocular surface quality (P=0.005), increasing the odds of improved corneal staining by approximately three-fold. Source (all): Eric Donnenfeld, MD occlusion resulted in a small (less than one line) but statistically sig- nificant improvement in the right eyes (P<0.001), although the change in the left eyes was not statistically significant. There was no impact on BCVA. This was not unexpected; dry eye-related changes in vision during the early postoperative period do not generally depress Snellen acuity. Most impressive, however, is the noticeably better quality of vi- sion that we see in the OSDI results. The OSDI questionnaire measures not just comfort but also quality of vision and the presence of visual fluctuations. At all postoperative time points, the mean change in OSDI resulted in a lower (better) OSDI score in the eyes with punc- tal occlusion, and a higher (worse) score in the eyes without plugs (Figure 1). The Extend absorbable plug increased the odds of improv- ing the OSDI score after surgery by nearly six-fold (P<0.001). Ocular surface quality, which was graded 0 to 4 according to the severity of corneal staining, was minimal (0 or 1) in all eyes prior to surgery. After LASIK, staining was unchanged or improved in the majority of eyes in the punctal oc- clusion group. In the control group, about half the eyes had worse staining in the first month after surgery (Figure 2). Insertion of the Extend absorbable plug significantly influenced ocular surface quality (P=0.005), increasing the odds of improved corneal staining by ap- proximately three-fold. Tear film osmolarity was in the normal range before LASIK and remained so postop, although punctal occlusion at the time of surgery did reduce tear film osmo- larity by 3.62 mOsmol/L (P=0.026). Punctal occlusion did not appear to have any effect on the presence of inflammation, as measured by MMP-9. In conclusion, this small study demonstrates that punctal plugs can play a role in promoting ocular surface health in patients under- going LASIK. The insertion of an absorbable plug may be the perfect short-term solution to the short- term problem of post-LASIK dry eye. EWAP Editors’ note: Dr. Donnenfeld has financial interests with Beaver-Visitec International. Contact information Donnenfeld: ericdonnenfeld@gmail.com LASIK patients – from page 47 High oxygen – from page 49 50 EWAP REFRACTIVE September 2017 Behndig said although the methods implemented in determining the endothelial cell count could vary somewhat, there were no significant discrepancies in the outcomes. The cell count in room air eyes went from 2,750 cells/mm 2 preopera- tively to just under 3,000 cells/mm 2 at 3 months. In high oxygen eyes, the cell count went from 3,000 cells/mm 2 preoperatively to around 2,800 cells/mm 2 at 3 months. The results of color coded and gray scale back scatter maps showed a much more pronounced effect in the high oxygen patients at 1 month, with further improvement by 3 months after treatment. “The corrective effect is much less in room air patients, which cor- responds to less corneal light back scatter,” Dr. Behndig said. “As we go down in the corneal stroma from 0 μm to 425 μm, back scatter chang- es. Looking at this in more detail, we see a characteristic demarcation ring in the periphery of the treat- ment zone of the high oxygen eyes at around 3 months after treatment, indicating that the treatment had a superior effect compared to room air treatment.” PiXL offers patients a noninvasive vision correction op- tion in a simple, safe, and effective procedure that does not involve tissue removal. Patients with a mild prescription can eliminate the high costs of glasses, contacts, or refractive surgery entirely. Compli- cations may include post-surgical dryness, an increased risk of infec- tion while the eye heals, or tempo- rary cloudiness of vision. “Epi-on PiXL in room air re- duces myopia about 0.25 D, which is not very much. In high oxygen, however, the effect averages 1.25 D. The method is safe from an en- dothelial perspective but requires fine tuning, both to increase the treatment effect and to reduce the variability of outcomes, which is evident sometimes even between two eyes of the same patient. PiXL is a promising new method for the treatment of low grade myopia. The long-term durability of the effect remains to be evaluated,” he said. EWAP References 1. Murphy C, et al. Refractive error and visual outcome after cataract extraction. J Cataract Refract Surg . 2002;28:62– 66. 2. Acar BT, et al. Can the effect of transepi- thelial corneal cross-linking be improved by increasing the duration of topical riboflavin application? An in vivo confocal microscopy study. Eye Contact Lens. 2014;40:207–12. Editors’ note: Dr. Behndig has no financial interests related to his com- ments. Contact information Behndig: anders.behndig@umu.se