Effect Of Astigmatism On Tear Film Stability In Age-related Cataract Patients

Objective: To observe the distribution of the corneal regularity and tear film stability of age-related cataract patients crowd before Phacoemulsification.To analysis their correlation and explore the concrete mechanisms of astigmatism on tear film stability.Methods: A prospective cross-sectional observational study,non-randomized clinical control is applied in this study.One hundred forty-four patients with age-related cataract(160 eyes)from the first affiliated hospital to Guangxi university of CM were collected according to the inclusion and exclusion criteria in this study.Corneal topography parameters,including corneal astigmatism axial?astigmatism?corneal regularity index(SRI)were extracted.And check the tear film stability in the patient the day before surgery.Using slit lamp photographic system dynamic record the location of first tear film break-up position,tear film break-up time(BUT).Grouped according to the degree of astigmatism,Group A: astigmatism<1D;Group B: 1D ? astigmatism<2D;Group C: 2D ? astigmatism.To investigate the correlation of corneal astigmatism,SRI,axial astigmatism with age and BUT,the relevance between topography astigmatism axis ± 30 °range and the first tear film break-up position of each group were also compared.The results were analyzed by SPSS 23.0.Results: 1.One hundred forty-four patients,Male 62,female 82,160 eyes,77 cases of right eye,83 cases of left eye.Patients aged between 44 to 88years,Mean age 69.7±8.9years,Overall average astigmatism1.3 ± 0.7D,BUT:7.5±2.4s,SRI0.47±0.36.Among them,40 to 50 years old 7 patients(7 eyes),The average astigmatism0.93 ± 0.69 D,the average SRI 0.1 ± 0.09,average BUT10.57 ± 3.14 s,51 to 60 years,20 patients(22 eyes),astigmatism average 1.11 ± 0.83 D,average SRI0.14 ± 0.22,the mean BUT 10.03 ± 1.96s;61 to 70 years in 30 patients(37 eyes),average astigmatism degree 1.21± 0.62 D,average SRI0.60 ± 0.37,average BUT8.50± 2.22s;71~-80 years in 74 patients(80 eyes),astigmatism average 1.30 ± 0.72 D,average SRI0.51 ± 0.34,average BUT6.50 ± 1.65s;81~88 years 13 patients(14 eyes),astigmatism average1.74 ± 0.78 D,average SRI0.61 ± 0.36,average BUT5.22±1.62 s.Correlation analysis: astigmatism was positively correlated with age(r=0.261,P=0.002<0.05);With age increased,tear film break-up time is shortened,tear film break-up time was negatively correlated with age(r=-0.633,P=0.000<0.05);astigmatism was negatively correlated with age tear film break-up time(r=-0.312,P=0.000<0.05).2.Group A: astigmatism <1D,68 eyes with average age 67.9±9.5y,average astigmatism 0.56±0.19 D,average SRI0.16±0.12,average BUT8.12±2.55s;Group B: 1D ? astigmatism<2D,60 eyes with average age70.4±8.5y,average astigmatism 1.51±0.24 D,average SRI0.57±0.23,average BUT7.43±2.16s;Group C: astigmatism?2D,32 eyes with average age 72.3±8.1y,average astigmatism2.31±0.41 D,average SRI0.5±0.29,average BUT6.4±2.47 s.Comparing mean BUT among three groups of astigmatism degrees,there is no statistically significant between A and B group(P=0.097),B and C group(P=0.079),but there is statistically significant between A and C group(P=0.002).Greater than the 1D case by the axial astigmatism group results as follows: 59 cases of astigmatism with the rule(WR),22 eyes of astigmatism against the rule group(AR),11 cases of oblique astigmatism group(OBL).61% cases astigmatism with the rule in the age group from 50,14% astigmatism against the rule,gradually drift to 40% astigmatism with the rule,30% astigmatism against the rule in 80-year-old group.3.Three degrees of astigmatism group first tear film break-up position comparison,the position of low astigmatism group at the four quadrants distribution : 23% at supertemporal quadrants ? 15% at infratemporal quadrants ?30% at inferonasal quadrants?32% at supernasal quadrants.32% first tear film break-up position in the range of ±30 ° astigmatic axis in group B.51% first tear film break-up position in the range of ±30 °astigmatic axis in group C,there is no statistically significant(P=0.006).WR group 47% of the first tear film break-up position in the rupture astigmatic axis ± 30 ° range,42% in AR group,51% in OBL group,each group was not statistically significant(P=0.442).Conclusions: 1.There is a significant corneal astigmatism in age-related cataract patients preoperative in Guangxi province.Significant correlations were found between the degree of corneal astigmatism and age,the older they are the higher the degree of astigmatism is,and the pattern of corneal astigmatism shifts from WR to AR.2.The tear film stability is poor in some cataract patients,it is related both with age and astigmatism.3.Corneal regularity is an important factor affecting the tear film stability.The higher the degree of astigmatism,the shorter the tear film break-up time,the more likelytear film firstbreak-up point in astigmatism axis area.But there was no significant difference in BUT among differentastigmatic axis groups.4.The slit lamp image analyzer dynamic recording of the tear film first break-up point can provide an objective basis?more intuitive clinic data.This method is convenient and practical for tear stability test in clinic.5.We should reduce surgically induced astigmatism according to topography during cataract surgery thereby reducing tear film instability caused by astigmatism.