Multivariate Analysis Of Central Corneal Thickness In Patients With Myopia Who Had Receiving Excimer Laser Corneal Refractive Surgery

Purpose Objective To retrospectively analyze the main correlative factors of central corneal thickness in myopiawho had receivedExcimer laser corneal refractive surgery and the influence of soft contact lens on the measurement of central corneal thickness.Methods Screening of 1214 myonic patientswho had receivedExcimer laser corneal refractive surgeryin the department of Ophthalmology and Optometry center of the second affiliated hospital of University of South China during August 2015 toAugust 2017.To study the correlation between the measured corneal central thickness andsex,age,Fellow eyes,the dominant eye,naked vision,diopter of spherical powers,diopter of cylindrical power,astigmatism type,average corneal curvature,intraocular pressure,wearing soft contact lens time and Stopping soft contact lens time.The results obtained were statistically analyzed to investigate the main correlative factors of central corneal thickness measurements and the influence of the history of wearing softcontact lenses on the measurement of central corneal thickness.Results 1.The average thickness of central cornea of myonic patients who had received Excimer laser corneal refractive surgerymeasured535.63 ± 28.93μm;The central corneal thickness of myonic patients who had receiving Excimer laser corneal refractive surgery and Sex(R=-0.022,P=0.288),Age(R= 0.013,P= 0.538),Fellow eyes(R= 0.019,P= 0.354),Thedominant eye(R=-0.011,P= 0.602),Naked vision(R=-0.014,P=0.500)was not relevant.The central corneal thickness of Patients who were divided into groups according to Sex,Fellow eyes or Thedominant eyehad no significant difference(P> 0.05).2.Therewere no correlations between central corneal thickness of myopic patientswho had received Excimer laser corneal refractive surgery and diopter of spherical powers,diopter of cylindrical power,astigmatism type,average corneal curvature(∣r∣ < 0.1).The central corneal thickness of Patients who were divided into groups according to diopter of spherical powers and diopter of cylindrical powerhad no significant difference(P> 0.05).The characteristics of central corneal thickness of myopic patientswho had received Excimer laser corneal refractivesurgeryon Astigmatismtype:with-the-rule(WI’R)astigmatism>without astigmatism> against-the-rule(ATR)astigmatism>Oblique axis astigmatism group,but the difference was not statistically significant(P>0.05).3.There was a positive correlation between central corneal thickness and intraocular pressure(R = 0.408,P = 0.000).With the increase of intraocular pressure,central corneal thickness tended to thicken.There was significant difference in central corneal thickness between groups(P<0.05),the difference between any two groups was statistically significant(P<0.05).4.the differences in the central thickness of cornea according to the history of wearing soft contact lenses:Groupsdivided by the removing time of soft contact lens,the central corneal thickness of each group was statistically different(P < 0.05).The central corneal thickness in the group of less than one week was significantly lower than that in the group of more than one week and the group without the history of wearing soft contact lens if comparing every two groups(P<0.05).corneal central thickness between the the removing time of soft contact lens more than one weekgroup and no wearing history group was no significant difference(P> 0.05).The central corneal thickness of the(1 year ≤wearing time of soft contact lens <5 years,stopping wearing time of soft contact lens≤ 1week)group was significantly thinner than(1 year ≤wearing time of soft contact lens <5 years,stopping wearing time of soft contact lens> 1 week)group,the difference was statistically significant(P<0.05).There was no significant difference in the restless than 1 year group and morethan 5 year group(P>0.05).The central corneal thicknessof the(wearing time of soft contact lens ≥ 5 years,stopping wearing time of soft contact lens> 1 week)Group was significantly thinner than the(1year ≤ wear soft contact lens time <5 years,stop wearing> 1 week)group,the differences were statistically significant(P<0.05),the difference between anyrest two groups hadno significant(P>0.05).Conclusion 1.There was a positive correlation between central corneal thickness of myopic patientswho had received Excimer laser corneal refractive surgeryand intraocular pressure;Therewere no correlations between central corneal thickness of myopic patientswho had received Excimer laser corneal refractive surgery and Sex,Age Fellow eyes,Thedominant eye,Naked vision,diopter of spherical powers,diopter of cylindrical power,astigmatism type,and average corneal curvature.2.The impact of soft lens contact lens on the central corneal thickness:wearing time of soft contact lens less than 1 year has little effect on the measurement of the central corneal thickness;wearing time of soft contact lens within 5 years when stopped wearing within 1 week The central corneal thickness measurement was lower than the actual value,abut the central corneal thickness will recovere after stopping wearing soft contact lens of 1 week.Long-term wearing of the soft contact lens(≥5 years)will cause irreversible loss of central corneal thickness,and the measured central corneal thickness was less than the measured within one-week rest.and there is no obvious recovery of the loss after stoppingfor one week.