title: [Clinical results of ultrasound biometry in silicone oil-filled eye].
abstract: OBJECTIVE
  To evaluate a method of ultrasound biometry in silicone oil-filled eye and its clinical results.
  
  
  METHODS
  This was a series case study. According to the principle of measuring a distance with ultrasound, we compared the measured distance between a space filed with balanced salt solution and silicone oil at same height, to calculate a conversion factor (0.674) between them. A formula for corrective axial length in silicone oil-filled eye was established. The formula = ab + 0.674 x bc (a, b and c standing for the apex of the cornea, the posterior pole of the lens or the center of the capsular membrane and the anterior surface of the macular, respectively). The axial lengths of 150 silicone oil-filled eyes in 150 cases were then measured before and after silicone oil removal with Vivid 7 Dimension ultrasound. According to the axial length, they were divided into two groups, namely group 1 (the length < 25 mm) and group 2 (the length > or = 25 mm). In 76/150 eyes, before combined silicone oil removal and intraocular lens (IOL) implantation, the SRKT formula was used for intraocular lens calculation; the post-operative actual refraction was compared with the pre-operative predicted refraction and statistics analysis was made.
  
  
  RESULTS
  The retinal condition of 150 silicone oil-filled eyes in 150 cases after 3 months' follow-up was stable after surgery. The results of the biometry were as follows. In the first group, the mean corrective axial lengths of 111 silicone oil-filled eyes before silicone oil removal was (22.77 +/- 1.00) mm (ranging from 21.10 to 24.90 mm); the mean axial lengths after silicone oil removal was (22.76 +/- 0.99) mm (ranging from 21.00 to 24.70 mm). The difference between them was not statistically significant (t = 0.518, P > 0.05). The vitreous cavity depth before and after silicone oil removal was (26.57 +/- 2.14) mm and (17.90 +/- 1.38) mm, respectively. The ratio of the latter to the former was 0.673 78. In the second group, the mean corrective axial lengths of 39 silicone oil-filled eyes before silicone oil removal was (26.52 +/- 1.31) mm (ranging from 25.00 to 30.58 mm); the mean axial lengths after silicone oil removal was (26.53 +/- 1.29) mm (ranging from 25.00 to 30.59 mm). The difference between them was not statistically significant (t = 0.109, P > 0.05). The vitreous cavity depth before and after silicone oil removal was (32.01 +/- 2.90) mm and (21.57 +/- 2.04) mm, respectively. The ratio of the latter to the former was 0.673 95. In 76 eyes with IOL, the post-operative actual refraction after at least 3 months follow-up was compared with the pre-operative predicted refraction (-1.50 DS) in both groups. The differences between them were not statistically significant (t(1) = 0.253, P(1) > 0.05; t(2) = 0.209, P(2) > 0.05) in each group.
  
  
  CONCLUSIONS
  Ultrasound biometry in silicone oil-filled eye is accurate and simple, and has good results in clinical measurement.
authors.affiliation: Eye Center, Qingdao Hiserve Medical Center & Affiliated Hiserve Hospital, Medical College of Qingdao University, Qingdao 266033, China. liugj777@163.com
authors.forename: Guo-jun
authors.initials: GJ
authors.lastname: Liu
authors.forename: Bao-lian
authors.initials: BL
authors.lastname: Shen
authors.forename: Yi-jie
authors.initials: YJ
authors.lastname: Qiu
authors.forename: Zhan
authors.initials: Z
authors.lastname: Yu
authors.forename: Hu-shan
authors.initials: HS
authors.lastname: Cui
authors.forename: Hai-cun
authors.initials: HC
authors.lastname: Wang
authors.forename: Wei-qiang
authors.initials: WQ
authors.lastname: Kang
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001699:Biometry / Q000379:methods*; D002648:Child; D005123:Eye / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D012827:Silicone Oils; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D012827:Silicone Oils