Long-term changes in corneal structure and tear inflammatory mediators after orthokeratology and LASIK.
OBJECTIVE
To monitor changes in corneal structure and level of inflammatory mediators in tears of myopic patients following orthokeratology (OK) and laser in situ keratomileusis (LASIK).


METHODS
Sixty-two myopic subjects were analyzed in this prospective study. Thirty-two had worn Paragon CRT contact lenses and 30 underwent standard LASIK. Thirty-two control subjects were also recruited. Pachometry and corneal topography were performed 12 months after both interventions. Tears were collected and assayed using ELISA for IL-6, IL-8, matrix metalloproteinase-9 (MMP-9), and epidermal growth factor (EGF).


RESULTS
Corneal power decreased in the central area and increased in the paracentral area. Simultaneously, there was a central corneal thinning with mid-peripheral thickening for OK. No changes were observed for LASIK. In comparison with controls, IL-6, IL-8, MMP-9, and EGF levels were increased significantly for OK (P < 0.01). Only MMP-9 (P < 0.01) and EGF (P < 0.01) were increased for LASIK. Pro-inflammatory response was found to be associated with the degree of myopia in the OK group. The MMP-9 and EGF upregulation was linked to the presence of iron deposition in both groups, whereas increased levels of EGF were connected with the presence of myopic regression after LASIK.


CONCLUSIONS
Both interventions involved important tissue reshaping. The physical presence of a reverse geometry contact lens caused certain markers to change significantly in comparison with no lens wear or LASIK in the long-term response. MMP-9 was significantly higher in tears of subjects presenting iron deposition after OK or LASIK, and EGF levels seemed to play an important role in postoperative refractive outcomes after LASIK.
Ocular Surface and Contact Lens Research Group, Universidade de Santiago de Compostela, A Coruña, Spain. javier.gonzalez@usc.es
Javier
J
González-Pérez
César
C
Villa-Collar
José Manuel
JM
González-Méijome
Nery García
NG
Porta
Manuel Ángel
MÁ
Parafita
D000328:Adult; D015415:Biomarkers / Q000378:metabolism*; D016022:Case-Control Studies; D003315:Cornea / Q000378:metabolism / Q000473:pathology*; D003316:Corneal Diseases / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D004815:Epidermal Growth Factor / Q000378:metabolism; D005260:Female; D006801:Humans; D007378:Interleukins / Q000378:metabolism; D020731:Keratomileusis, Laser In Situ; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009216:Myopia / Q000378:metabolism / Q000473:pathology*; D011446:Prospective Studies; D013666:Tears / Q000737:chemistry*
D015415:Biomarkers; D007378:Interleukins; D004815:Epidermal Growth Factor; D020780:Matrix Metalloproteinase 9