Speaking during the Refractive Original Papers session, Edward Manche, MD, and Kevin Ma, MD, delivered results of a one-year study comparing changes in corneal sensitivity and self-reported dry eye in eyes that had undergone wavefront-guided femtosecond LASIK and SMILE. In this randomized, contralateral, prospective study, the authors measured the Ocular Surface Disease Index (OSDI) for each eye at one month, three months, six months, and 12 months.
The question was whether there would be a difference after the treatments, given that SMILE is a less invasive surgery, typically employing a 4-mm incision, compared with LASIK, which generally uses an approximately 20-mm incision.
Eighty eyes of 40 patients underwent SMILE surgery in one eye and LASIK in the fellow eye. Corneal sensitivity was measured preoperatively and at each postop visit using Cochet-Bonnet esthesiometry. And for dry eye, patients completed the OSDI validated questionnaire preoperatively and at each postop visit. “Most patients can darn well tell you which eye is better,” said Dr. Manche.
Significant differences in corneal sensitivity were found in the first six months. “We measured a more profound decrease in corneal sensitivity in LASIK eyes during the first six months,” than in the SMILE eyes, said Dr. Manche. Measures at one month were a mean of 2.1 cm for LASIK and 3.6 cm for SMILE; at three months, 3.5 vs. 5.4 cm; and at six months, 4.7 vs. 5.7 cm, respectively. Overall, there was a marked decrease in corneal sensitivity in both groups after surgery.
After 12 months, no significant differences in corneal sensitivity were found between LASIK and SMILE. Both groups of eyes had returned to baseline sensitivity, 5.9 cm, at 12 months.
Significant improvement in dry eye at 12 months was seen in both eyes. Surprisingly, when comparing the OSDI at baseline to the OSDI 12 months after surgery, the researchers noted a significant improvement in both LASIK and SMILE eyes. Mean OSDI scores changed from within the mild range at baseline to within the normal range: from 15.3 to 8.6 for LASIK eyes and from 15.1 to 9.4 for SMILE eyes. While several patients fell into the severe range preoperatively, none did at 12 months postoperatively. “Given that dry eye symptoms are ultimately what drives patient satisfaction, patient-reported OSDI is arguably even more important” than corneal sensitivity, said Dr. Manche.
No difference was found in dry eye between SMILE and LASIK eyes. OSDI showed no significant difference at any point in self-reported dry eye.
Dr. Manche summed up by saying, “there was marked improvement in dry eye in both groups with no difference between them.” And while there was a marked decrease in corneal sensitivity in LASIK eyes during the first six months compared with SMILE eyes, that difference disappeared after 12 months.
—Kathleen E. Erickson
Financial Disclosures:Dr. Manche: Alcon Laboratories, Inc.: S; Allergan: S; Avedro: C,S; Best Doctors, Inc.: C; Carl Zeiss Inc: C,S; Guidepoint: C; Johnson & Johnson Vision: C,S; KKR: C; Novartis Pharma AG: S; Placid0: PS,SO; Presbia, Inc.: S; RxSight: US; VacuSite: P,PS. Dr. Ma: None.
Disclosure key:C = Consultant/Advisor; E = Employee; EE = Employee, executive role; EO = Owner of company; I = Independent contractor; L = Lecture fees/Speakers bureau; P = Patents/Royalty; PS = Equity/Stock holder, private corporation; S = Grant support; SO = Stock options, public or private corporation; US = Equity/Stock holder, public corporation For definitions of each category, see aao.org/eyenet/disclosures.
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