| Objective: The lens is a very important part of the eye refractive system,its lesions will seriously damage vision,cataract and lens subluxation are two most common lens diseases.The observation and diagnosis on lens and lens diseases have mainly depended on slit lamp after dilation in the past.In recent years,with the rapid development of anterior segment imaging technology,especially the appearance of ultrasound biomicroscopy(UBM),it provided an objective method to study lens and lens-related diseases.25 MHz panoramic UBM is a new kind of high frequency ultrasound diagnostic equipment,its probe frequency is between conventional 50 MHz UBM and general ophthalmic B scan,and the ultrasonic focus is on lens.To the best of our knowledge,information regarding this kind of UBM is scarce.The objective of this study is to discuss and evaluate the application scope and value of 25 MHz UBM on anterior segment diseases,especially on lens disease.At the same time,using 25 MHz UBM to classify age-related cataract,quantitatively evaluate the degree of lens opacity in order to guide the setting of energy parameters preoperative phacoemulsification.In addition,to investigate the accuracy and reliability of 25 MHz ultrasound biomicroscopy in subluxated lens,so as to assistant clinical diagnosis and treatment.Methods: 1.Comparative study on imaging of cataract and its related diseases using 25 MHz and 50 MHz ultrasound biomicroscopy A total of 303 patients(456 eyes)with normal and anterior segment diseases were included in this study from November 2014 to March 2015.Patient ages ranged from 5 to 89 years(mean±SD: 61.0±17.7years).Different cross-sectional images of anterior segment and the lens were collected to compare and analyze the image characteristics and anterior segment parameters: central corneal thickness(CCT),anterior chamber depth(ACD),and lens thickness(LT)using 25 MHz and 50 MHz UBM in axial and longitudinal scanning modes,respectively.SPSS 19.0 for Windows and paired t-tests were used for data analysis and a value of P<0.05 was considered statistically significant.2.Feasibility study of 25 MHz UBM classification and grading on age-related cataract.A total of 277 age-related cataract patients(294eyes)were included in this study from February 2015 to June 2016.Patient ages ranged from 45 to 91 years(mean±SD: 68.0±10.9 years).Preoperative,each patient underwent slit lamp photo,Scheimpflug imaging(Pentacam)and 25 MHz UBMexaminations after dilation.Lens thickness(LT)was measured using 25 MHz UBM,cumulative dissipated energy(C.D.E)values were recorded during phacoemulsification.According to the image features of slit lamp and 25 MHz UBM,classified and graded age-related cataract.Pentacam Nucleus Staging(PNS)was automatically recorded by Pentacam.Comparing the consistency and difference among the grading scores of 25 MHz UBM,the slit lamp photos and PNS.Correlation among C.D.E values and scores of 25 MHz UBM,the slit lamp photos and PNS were analysised.Comparing the difference of LT and C.D.E value between different types of age-related cataract.SPSS 19.0 for Windows and ANOVA,independed t-test,Pearson correlation were used for data analysis,and a value of P<0.05 was considered statistically significant.Bland-Altman method was used for consistency analysis,kappa coefficient closed to 1was considered to be consistent.3.Role of 25 MHz ultrasound biomicroscopy in subluxation of lens A total of 20 normal subjects(40 eyes)and 45 suspected patients(49 eyes)were included in this retrospective study from February 2015 to May 2016.Patient ages ranged from 21 to 85 years(mean ± SD: 51.4±14.4 years).Different cross-sectional images of the subluxated lens were collected to compare and analyze the image characteristics,the distance between lens equator and ciliary process,testing time and the rate of detection using 25 MHz and 50 MHz UBM in axial and longitudinal scanning modes,respectively.SPSS 19.0 for Windows,paired t-test,independent t-test and chi-square tests were used for data analysis,and a value of P<0.05 was considered statistically significant.Result: 1.Comparative study on imaging of cataract and its related diseases using 25 MHz and 50 MHz ultrasound biomicroscopy The 25 MHz UBM images displayed the lens shape,lens zonule and most lens related diseases more clearly than 50 MHz UBM images in axial section of 9mm tissue penatration.Particularly for cataracts,the whole opacity of the lens was shown and the types of cataract could be classified by 25 MHz UBM,but 50 MHz UBM only showed part of the lens and could not classify the types of cataract.While the images of anterior segments before lens anterior capsule were displayed low resolution by 25 MHz UBM.In longitudinal section,the image resolution of 25 MHz UBM was lower than 50 MHz UBM.The means of the anterior segment parameters obtained using 25 MHz and 50 MHz UBM were as follows: CCT: 0.55±0.03 mm and 0.51±0.04 mm,respectively;ACD: 2.48±0.54 mm and 2.56±0.56 mm,respectively;and LT: 4.26±0.62 mm and 4.15±0.56 mm,respectively.A statistically significant difference was found between the results obtained with 25 MHz UBM and those obtained with 50 MHz UBM(P<0.05).2.Feasibility study of ultrasonic classification and grading on age-related cataract using 25 MHz UBM.In all 294 eyes with age-related cataract,according to slit lamp photos,188 eyes were cortical cataract,84 eyes were nuclear cataract,14 eyes were posterior subcapsular cataract and 8 eyes were mixed cataract.According to the ultrasonic image features in 25 MHz UBM,69 eyes were capsular cataract;26 eyes were cortical intumescent cataract;93 eyes were concentric circles cataract.84 eyes was simple thick lens cataracts,14 eyes were posterior subcapsular cataract and 8 eyes were mixed cataract.Compared to the slit lamp photos,the first three types of cataract classified by 25 MHz UBM were the ultrasonic image performance of cortical cataract,the simple thick lens cataract was the ultrasonic image performance of nuclear cataract,and the latter two were ultrasonic image performance of posterior subcapsular and mixed cataract.The grading scores of 25 MHz UBM,LOCS? in different types of cataract were as follows: capsular cataract: 3.70±1.22 and 3.85±1.27,respectively;cortical intumescent cataract: cortical opacity score: 4.80±0.63and4.80±0.63,nuclear opacity score: 3.40±1.84 and 3.70±1.64,respectively;concentric circles cataract: cortical opacity score: 3.45±1.14 and 3.37±1.17,nuclear opacity score: 3.20±1.17 and 3.33±1.23,respectively;simple thick lens cataract: 2.28±1.59 and 3.28±1.46,respectively;posterior subcapsular cataract: 4.22±0.83 and 4.56±0.73,respectively.Pentacam could not classify the types of cataract definitely.The grading scores of PNS in different types of cataract were as follows: capsular cataract: 0.60±0.88;cortical intumescent cataract: 2.50±1.78;concentric circles cataract: 0.65±0.86;simple thick lens cataract: 0.84±0.94;posterior subcapsular cataract: 0.22±0.44.The C.D.E values of different types of cataract were as follows respectively: capsular cataract: 2.99±2.46;cortical intumescent cataract: 21.45±18.50;concentric circles cataract: 12.51±8.68;simple thick lens cataract: 12.75±8.42;posterior subcapsular cataract: 3.34±2.26.Different types of cataract LTs were as follows respectively: capsular cataract: 4.12±0.42;cortical intumescent cataract: 5.40±0.45;concentric circles cataract: 4.10±0.46;simple thick lens cataract: 4.62±0.50;posterior subcapsular cataract: 3.70±0.61.The grading scores comparison among 25 MHz UBM,LOCS? and PNS in different types of cataract,the former two had good consistency(kappa>0.60),there was no statistically significant difference(P>0.05)between these two methods except in simple thick lens cataract(kappa=-0.01,P<0.05)).There were no consistency between PNS and the other two methods(kappa<0.01),and there was statistically significant difference between PNS and the other two methods(P<0.05).There was no correlation between C.D.E values and cortical grading scores(P>0.05),but there was good correlation between C.D.E values and nuclear grading scores except in simple thick lens cataract graded by 25 MHz UBM.There was no correlation between C.D.E values and PNS(P>0.05).There was statistically significant difference between different types of cataract in C.D.E value(P<0.05)except capsular and posterior subcapsular cataract,concentric circles cataract and nuclear cataract.There was statistically significant difference between different types of cataract in LT(P<0.05)except capsular and concentric circles cataract.3.Role of 25 MHz ultrasound biomicroscopy in subluxation of lens Determining the position of lens using UBM was mainly based on the distance between lens equator and ciliary process in every direction.25 MHz UBM showed the position of the lens more intuitively and clearly than 50 MHz UBM in axial section.The means of the normal and subluxated subjects parameters obtained using 25 MHz and 50 MHz UBM were as follows: the distance between lens equator and ciliary process means in the normal subjects were 1.01±0.20 mm and 0.83±0.20 mm,respectively.In the subluxaed subjects,the maximum distance were 2.00±0.84 mm and 1.64±0.91 mm,respectively;the minimum distance were 0.42±0.41 mm and 0.59±0.52 mm,respectively;D-Value of maximum and minimum were 1.54±0.78 mm and 1.02±0.74 mm,respectively;the testing time were 2.05±0.34 min and 7.48±2.53 min,respectively;diagnosed eyes were 46 eyes and 35 eyes,respectively;the diagnostic accuracy were 93.9% and 71.4%, respectively.A statistically significant difference was found between the results obtained with 25 MHz UBM and those obtained with 50 MHz UBM(P<0.05).There were 15 eyes misdiagnosis because of slight subluxated lens in all patients,among them,8 eyes were age-related cataract,3 eyes were posteroperative glaucoma,4 eyes were traumatic cataract.Conclusion: 1.25 MHz UBM can display the whole morphology of lens,it can be used to diagnose the abnormal shape and position of the lens.2.25 MHz UBM can measure the lens parameters.3.25 MHz UBM has an ability to identify the type of age-related cataract.4.25 MHz UBM can quantitatively evaluate the degree of lens opacity in cortical and posterior subcapsular cataract.5.25 MHz UBM can semiquantitatively evaluate the degree of lens nuclear opacity.6.25 MHz UBM has a great and accurate diagnostic value on subluxated lens.7.25 MHz UBM can both qualitively and qunantitatively diagnoses in lens subluxation. |
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