B-mode Ultrasound Measurement Of Axial Length Of The Clinical Studies

Objective: To discuss the value of measure of ocular axial length with type B ultrasound.Methods: According to the axial length, 140 eyes of 70 cases with cataract/combined retinopathy were divided into three groups ,that is,number 1 group:the axial length was <24mm;number 2 group: the axial length was between 24mm and 26mm ; number 3 group: > 26mm.The axial length was measured with type A and B ultrasoundrespectively. Refractive degree of the intraocular lens during surgery was based on the axial length that type A ultrasound measured. The standard dioptre of intraocular lens were equal to the sum that between 1.25 time postoperative refractive error and the dioptre of implanted intraocular lens, the average of the axial lengths in every group were analyzed with the t-test ; the dioptre of intraocular lens that based on type A and type B ultrasound was analyzed with the t-test; the dioptre of intraocular lens that based on type A,B ultrasound and the normal dioptre of lens was analyzed with the t-test respectively.Results: In 87 eyes of number 1 group, the axial lengths measuring with two kinds of method were 22.43±0.80mm and 22.43±0.81mm respectively, there being no statistically significant difference (P>0.05).In 13 eyes of number 2 group, the axial lengths were 24.32±0.56mm and 24.50±0.36mm respectively, there being no statistically significant difference (P>0.05) .In 40 eyes of number 3 group, the axial lengths were 27.28±2.0mm and 26.73±1.1mm respectively, there being statistically significant difference(P<0.05). In number 1 and 2 groups the dioptre of intraocular lens that based on type A and type B ultrasound were 22.01±0.68D and 22.03±0.71 D, there being no statistically significant difference (P>0.05) ; in number 3 groups the dioptre of intraocular lens that based on type A and type B ultrasound were 9.93±0.51D and 11.23±0.43D, there being statistically significant difference (P>0.05);there were statistically significant difference (P<0.05) between the dioptre of intraocular lens that based on type A ultrasound and the normal dioptre of intraocular lens in number 3 groups; there were no statistically significant difference (P>0.05) between the dioptre of intraocular lens that based on type B ultrasound and the normal dioptre of intraocular lens in number 3 groups.Conclusion: It is accurate and easy to measure ocular axial length with type B ultrasound, especially in the eye with high myopia and vitreoretinopathy, so type B ultrasound is superior to type A.