title: Changes in visual acuity, axial length, and refraction after removal of intraocular silicone oil following retinal reattachment surgery in Chinese patients: An open-label, prospective study.
abstract: BACKGROUND
  As a vitreous substitute for long-term tamponade, silicone oil is widely used in vitreoretinal surgery to treat retinal detachment with proliferative vitreoretinopathy and some internal reconstruction after globe trauma.
  
  
  OBJECTIVE
  The aim of this study was to compare the changes in visual acuity, axial length, and refraction in eyes before and after removal of intraocular silicone oil of 2 different viscosities after retinal reattachment surgery. The difference in the final anatomic success (stable retinal reattachment) rate was also assessed.
  
  
  METHODS
  Patients with surgically reattached retinas were enrolled in this open-label, prospective, nonrandomized study. All patients underwent pars plana vitrecto-my, lensectomy, scleral buckling or encircling, and epiretinal membrane dissection; silicone oil was removed after stable retinal reattachment was achieved. Refraction, axial length, final visual acuity, and stable retinal reattachment were assessed ≤2 days prior to surgery (baseline) and ≤1 month after silicone oil removal. Refraction was measured using an autorefractometer, and axial length was measured using A-scan ultrasonography, while visual acuity was assessed using a standard Snellen chart.
  
  
  RESULTS
  Of the 96 eyes assessed for inclusion, 89 eyes of 89 Chinese patients (mean [SD] age, 36.8 [4.3] years) were included in the study. Forty-two eyes (47.2%) were filled with 3700-centistoke (cS) silicone oil and 47 (52.8%) were filled with 5000-cS silicone oil. The mean interval between instillation and removal of the silicone oil was similar between the 3700-cS and 5000-cS groups (5.37 vs 5.10 months, respectively). The mean changes in visual acuity from before surgery to after removal of the silicone oil in the 3700-cS and 5000-cS groups were not significantly different (13/100 vs 15/100). The mean increase in axial length was also not significantly different in the 3700-cS group compared with the 5000-cS group (11.92 [1.97] vs 12.33 [1.28] mm). Mean decrease in refraction was significantly lower in the 3700-cS group compared with the 5000-cS group (5.80 [1.51] vs 6.88 [2.31] diopters; t = 2.57, P < 0.05). The anatomic success rate was 92.9% (39/42 patients) in the 3700-cS group and 91.5% (43/47) in the 5000-cS group.
  
  
  CONCLUSIONS
  A statistically significant decrease in refraction from baseline was found in the 3700-cS group compared with the 5000-cS group in these Chinese patients who underwent instillation and removal of silicone oil after retinal reattachment surgery. There were no other statistically significant differences between the 2 groups.
authors.affiliation: Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: An-Huai
authors.initials: AH
authors.lastname: Yang
authors.affiliation: Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jin
authors.affiliation: Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Yi-Qiao
authors.initials: YQ
authors.lastname: Xing
keywords: axial length; refraction; silicone oil; viscosity