Wound Healing, Inflammation, and Corneal Ultrastructure After SMILE and Femtosecond Laser–Assisted LASIK: A Human Ex Vivo Study
Abstract
PURPOSE:
To assess the wound healing, inflammation, and tissue ultrastructure in the human corneal stroma after small incision lenticule extraction (SMILE) and femtosecond laser–assisted LASIK (FS-LASIK).
METHODS:
Sixteen corneoscleral discs of 16 human donors unsuitable for corneal transplantation were obtained from an eye bank. Eight eyes underwent SMILE with −5.00 diopters (D) of myopic correction; in 3 of them the lenticule was not extracted. Further 5 donor corneas were subjected to FS-LASIK with −5.00 D ablation, and 3 eyes served as the control group without surgical intervention. Postoperatively, specimens were incubated in organ culture medium for 72 hours before being subjected to immunofluorescence staining for CD11b, Ki67, fibronectin, terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay, and high-magnification scanning electron microscopy.
RESULTS:
Keratocyte apoptosis, keratocyte proliferation, and infiltration of immune cells were generally mild and comparable between FS-LASIK and SMILE (irrespective of surgical lenticule extraction). By staining for fibronectin, we observed a trend toward milder fibrotic response in the corneal stroma after SMILE than after FS-LASIK. On the contrary, scanning electron microscopy analysis revealed a smoother, more regular ultrastructural appearance of the residual corneal bed after FS-LASIK.
CONCLUSIONS:
Corneal stromal wound healing after SMILE and FS-LASIK was virtually identical with respect to keratocyte proliferation and apoptosis in the human donor eye model. Although reactive fibrosis adjacent to the laser application site appeared less marked after SMILE, the stromal bed after LASIK exhibited a smoother surface texture.
[J Refract Surg. 2018;34(6):393–399.]
- 1.Leonardi A, Tavolato M, Curnow SJ, Fregona IA, Violato D, Alio JL. Cytokine and chemokine levels in tears and in corneal fibroblast cultures before and after excimer laser treatment. J Cataract Refract Surg. 2009; 35:240–247.
10.1016/j.jcrs.2008.10.030 Crossref Medline, Google Scholar - 2.Riau AK, Angunawela RI, Chaurasia SS, Lee WS, Tan DT, Mehta JS. Early corneal wound healing and inflammatory responses after refractive lenticule extraction (ReLEx). Invest Ophthalmol Vis Sci. 2011; 52:6213–6221.
10.1167/iovs.11-7439 Crossref Medline, Google Scholar - 3.Mastropasqua L, Calienno R, Curcio C, In vivo and ex vivo evaluation of inflammation and apoptosis induced after SMILE procedures for different refractive error range. Curr Eye Res. 2017; 42:701–707.
10.1080/02713683.2016.1231324 Crossref Medline, Google Scholar - 4.Dong Z, Zhou X, Wu J, Small incision lenticule extraction (SMILE) and femtosecond laser LASIK: comparison of corneal wound healing and inflammation. Br J Ophthalmol. 2014; 98:263–269.
10.1136/bjophthalmol-2013-303415 Crossref Medline, Google Scholar - 5.Liu YC, Ang HP, Teo EP, Lwin NC, Yam GH, Mehta JS. Wound healing profiles of hyperopic-small incision lenticule extraction (SMILE). Sci Rep. 2016; 6:29802.
10.1038/srep29802 Crossref Medline, Google Scholar - 6.Shah R, Shah S, Sengupta S. Results of small incision lenticule extraction: all-in-one femtosecond laser refractive surgery. J Cataract Refract Surg. 2011; 37:127–137.
10.1016/j.jcrs.2010.07.033 Crossref Medline, Google Scholar - 7.Liu YC, Teo EP, Lwin NC, Yam GH, Mehta JS. Early corneal wound healing and inflammatory responses after SMILE: comparison of the effects of different refractive corrections and surgical experiences. J Refract Surg. 2016; 32:346–353.
10.3928/1081597X-20160217-05 Link, Google Scholar - 8.Nishida T. The role of fibronectin in corneal wound healing explored by a physician-scientist. Jpn J Ophthalmol. 2012; 56:417–431.
10.1007/s10384-012-0165-0 Crossref Medline, Google Scholar - 9.Tervo K, van Setten GB, Beuerman RW, Virtanen I, Tarkkanen A, Tervo T. Expression of tenascin and cellular fibronectin in the rabbit cornea after anterior keratectomy: immunohistochemical study of wound healing dynamics. Invest Ophthalmol Vis Sci. 1991; 32:2912–2918. Medline, Google Scholar
- 10.Zhao Y, Li M, Sun L, Zhao J, Chen Y, Zhou X. Lenticule quality after continuous curvilinear lenticulerrhexis in SMILE evaluated with scanning electron microscopy. J Refract Surg. 2015; 31:732–735.
10.3928/1081597X-20151029-01 Link, Google Scholar - 11.Ziebarth NM, Lorenzo MA, Chow J, Surface quality of human corneal lenticules after SMILE assessed using environmental scanning electron microscopy. J Refract Surg. 2014; 30:388–393.
10.3928/1081597X-20140513-01 Link, Google Scholar - 12.Ang M, Chaurasia SS, Angunawela RI, Femtosecond lenticule extraction (FLEx): clinical results, interface evaluation, and intraocular pressure variation. Invest Ophthalmol Vis Sci. 2012; 53:1414–1421.
10.1167/iovs.11-8808 Crossref Medline, Google Scholar - 13.Liu YC, Pujara T, Mehta JS. New instruments for lenticule extraction in small incision lenticule extraction (SMILE). PLoS One. 2014; 9:e113774.
10.1371/journal.pone.0113774 Crossref Medline, Google Scholar - 14.Heichel J, Blum M, Duncker GI, Sietmann R, Kunert KS. Surface quality of porcine corneal lenticules after femtosecond lenticule extraction. Ophthalmic Res. 2011; 46:107–112.
10.1159/000323814 Crossref Medline, Google Scholar - 15.Netto MV, Mohan RR, Ambrósio R, Hutcheon AE, Zieske JD, Wilson SE. Wound healing in the cornea: a review of refractive surgery complications and new prospects for therapy. Cornea. 2005; 24:509–522.
10.1097/01.ico.0000151544.23360.17 Crossref Medline, Google Scholar
