The Study Of Correlation Between Ocular Surface And Cytokines After LASIK By Different Corneal Flaps Creating

Objective1To analyze the main characteristics of ocular surface symptoms and signs after LASIK whose flap creation with a femtosecond laser and a mechanical microkeratome, and to study the differences of the symptoms and signs.2To analyze the changes of tear cytokines after LASIK whose flap creation with a femtosecond laser or a mechanical microkeratome and the differences of the two groups.According to the results, TNF-α and GRO-α are analyzed to find the correlation between the two cytokines and ocular symptoms and signs after LASIK with different flaps creating.Methods1A non-randamized controlled prospective study was proceeded with patients who accepted LASIK in Tianjin Medical University Eye Center from December2010to July2012.According to the patients’choices,the patients were divided into two groups:the femtosecond laser group,25persons(50eyes) and the mechanical microkeratome group35persons(70eyes).The main parameters were dry eye questionnaire, corneal sensation, the anterior segment with slit lamp examination, tear film break-up time,fluorescein staining and Schirmer Ⅰ test preoperatively and1day,1and3months postoperatively.2Ten cases of preoperative patients,ten cases of postoperative patients with the femtosecond laser flap creating and ten cases of postoperative patients with the mechanical microkeratome flap creating were randomly selected to analyze the tear cytokines by cytokine antibody array. We measured TNF-α and GRO-α concentrations in tears from another15cases of the two groups using ELISA.Results1The incidence of7and9symptoms post LASIK at1week postoperatively in the femtosecond laser group and the mechanical microkeratome group respectively was significant ly higher than that of preoperative symptoms,(p<0.05).At1month postoperatively, there are3and4symptoms, compared with the preoperative symptoms,whose incidence have a statistical difference(p<0.05). At3month postoperatively,the incidence of all the symptoms went back the preoperative level.2Corneal sensation returned to the preoperative level at3month postoperatively in the femtosecond laser group,but corneal sensation was still under the preoperative level in the the mechanical microkeratome group, there was a statistically significant difference(p<0.05).3The change of TBUT in the femtosecond laser group was minimal,there was a statistical difference between tow groups at any observation time(p<0.05).4FL staining score was significantly lower in the mechanical microkeratome group at1week postoperatively.There was no significantly difference at1and3month postoperatively (P>0.05)5There was no significantly difference at1day,1and3month postoperatively (P>0.05) on Schirmer I test.But at3month postoperatively,Schirmer I score was higher in the femtosecond laser group.6We found post-LASIK4cytokines up-regulated and1cytokine down-regulated in the mechanical microkeratome group,5cytokines up-regulated and1cytokine down-regulated in the femtosecond laser group by cytokine antibody array.7There was no significantly difference at1day,1and3month postoperatively between the two groups on TNF-α by ELISA,though the concentration of TNF-a elevated at1week postoperatively,and returned to the preoperative level at3month postoperatively (P>0.05). The concentration of GRO-a in two groups decreased at1week postoperatively,but GRO-a in the femtosecond laser group is significantly higher than another group(p<0.05),there was no difference in other observation time.Conclusion1The symptoms and signs after LASIK in the femtosecond laser group are less severe than those in mechanical microkeratome group. The symptoms and signs after LASIK return to the preopetative level3month postoperaively in the femtosecond laser group,but not in mechanical microkeratome group.2The concentration of GRO-a in mechanical microkeratome group is significantly lower than that in the femtosecond laser group,which may correlation with slighter damage on the cornea caused by femtosecond laser group.On the other hand, the higher concentration of GRO-a in the femtosecond laser group accelerates the corneal wound healing.3The function of TNF-α and GRO-a were a reticular network and they influenced each other,they also related with the changes of tear film, tear secretion and corneal sensation.