| Purpose: To analyse the accuracy of ocular biometry parameters after instilling artificial tear drop.Methods:From June to September 2019,38 subjects(76 eyes)with dry eyes and without dry eyes recruited by Shenyang He Eye Hospital were selected.Before instilling artificial tear drop(0.1% sodium hyaluronate eye drops without preservatives),a subject was measured with oculus Keratograph 5M,and themeasured indicators were non-invasive tear break-up time(NITBUT)and meniscus tear height(MTH).NITBUT divided the subjects into dry eye groups and non dry eye groups.Dry eye group: age 43.66 ± 19.61 years old,male to female ratio 11:27(eye count);Age of non dry eye group 32.53 ± 16.89 years old,male to female ratio of11:27(eye count).Three biological measurements by using the IOL Master 500,were taken before the artificial tear drop and one minute and three minutes after the artificial tear drop.The indicators measured were baseline flat meridian of the anterior corneal surface(K1),steep meridian of the anterior corneal surface(K2),axial length(AL),anterior chamber depth(ACD),lens thickness(LT),intraocular lens(IOL)power calculation was measured.Finally,the measured values are analyzed.Results: The change of AL measured in the non dry eye group(p=0.004,P<0.05)and the dry eye group(p<0.001,P<0.05)was statistically significant at one minute after the application of artificial tear drop,ACD,LT and Mean K showed not statistical difference at one minute and three minutes are the application of artificial tear drop.Although,one minute after the application of artificial tear drop when the non dry eye group(P = 0.93,P>0.05)and dry eye group(P = 0.932,P>0.05)of the average of K1 did not statistical difference,and the non dry eye group(P = 0.41,P>0.05)and dry eye group(P = 0.416,P>0.05)of the averageof K2 did not statistical difference,but in the non dry eye group,the K1 value of 23% of the subjects and the K2 value of 31% of the subjects changed by 0.25 D.The dry eye group: 36% of the subjects K1 value and K2 value of 39% of subjects were 0.25 D.Three minutes after the application of artificial tear drop,the average values of K1 in the non dry eye group(P = 0.93,P>0.05)and dry eye group(P = 0.937,P>0.05)were not statistical difference,and the non dry eye group(P = 0.1,P>0.05)and dry eye group(P = 0.101,P>0.05)The K2 average were not statistical difference,but in the non dry eye group:K1 values in 8% of subjects and K2 values in 18% of subjects changed by 0.25 D,and in the dry eye group: 28.20% of subjects.And 18% of subjects had a K2 value of 0.25 D.Similarly,in the non dry eye group(P=0.22,P>0.05),one minute after the application of artificial tear drop,the SRK / T formula did not statistical difference,but the calculated IOL power of 40% of the subjects changed by 0.5D.Three minutesafter the application of artificial tear drop,the SRK / T formula was still not statistical difference,but the calculated IOL degree change of 0.5D accounted for 26% of the subjects.In the dry eye group,there was no statistical difference in the SRK / T formula at one minute and three minutes after the application of artificial tear drop,but the proportion of subjects with a calculated change of 0.5D in IOL power was40% and 29%,respectively.Conclusions:Overall,ocular biometry and IOL power calculation,before and after artificial tear drop application in non dry eye and dry eye group did not demonstrate statistically significant difference.However,in further analysis,a minute(23% to 39%)of subjects experienced a 0.25 D change in corneal curvature measurement at one minute after the application of artificial tear drop,and the IOL power calculation results of 40% of subjects There is a 0.5D change.Three minutes after the application of artificial tear drop,8% to 28% of the subjects' corneal curvature measurements changed by 0.25 D,and 26% to 29% of the subjects' IOL power calculations had 0.5D changes.Therefore,the use of artificial tear drop before biological measurement will affect the measurement data,and then affect the refractive effect after refractive surgery. |
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