title: Comparison of silicon oil removal with various viscosities after complex retinal detachment surgery.
abstract: BACKGROUND
  Despite the progress in vitreoretinal surgery and the importance of silicone oil as an adjunct for the treatment of complex forms of retinal detachment, controversy still surrounds the issue of selecting the proper oil viscosity for clinical use. Herein, we evaluate the outcomes of retinal detachment (RD) surgery after removing silicone oils of different viscosities.
  
  
  METHODS
  In this retrospective cohort study, eighty-two eyes with surgically re-attached retinas, of which 53 were filled with 5000 cs silicone oil and 29 with 1000 cs silicone oil were enrolled. We evaluated the outcomes and complications following silicone oil removal. Final anatomic success (stable re-attachment), final visual acuity (VA) and intraocular pressure (IOP)were recorded and analysed.
  
  
  RESULTS
  Of 82 eyes, 41 had proliferative vitreoretinopathy (PVR), 24 were associated with intraocular foreign bodies, 10 had endophthalmitis and 7 had proliferative diabetic retinopathy with tractional retinal detachment. Prior to silicone oil removal, the retina was attached in all eyes, 29% had VA > or = 6/120 and 52% had IOP > or = 21 mmHg. After silicone oil removal, the retina remained attached in 59(72%) of the eyes, 34% had VA > or = 6/120 and 9% had IOP > or = 21 mmHg. Comparing 1000 cs and 5000 cs silicone oil filled eyes, redetachment occurred more frequently in the latter group especially in cases with associated PVR. Final VA worse than 6/120 was associated with initial VA < 6/120 (OR = 32.2 95%CI 7.4-140.2) and use of 5000 cs silicone oil (OR = 7.9 95%CI 1.9-32.2). No factor was significantly associated with final IOP > or = 21 mmHg.
  
  
  CONCLUSIONS
  In complicated retinal detachment surgery, use of 5000 cs silicone oil may be associated with a poorer anatomic and visual outcome compared with 1000 cs silicone oil. However there was no difference between the two viscosities in IOP elevation. A randomized controlled study is necessary to further evaluate such a possibility.
authors.affiliation: Ophthalmology Department and Ophthalmic Research Center Labbafinejad Medical Center, Shaheed Beheshti University of Medical Sciences, Tehran, 16666, Iran. masoud_soheilian@yahoo.com
authors.forename: Masoud
authors.initials: M
authors.lastname: Soheilian
authors.forename: Mohammad
authors.initials: M
authors.lastname: Mazareei
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Mohammadpour
authors.forename: Bahram
authors.initials: B
authors.lastname: Rahmani
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D011184:Postoperative Period; D012160:Retina / Q000473:pathology; D012163:Retinal Detachment / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D012189:Retrospective Studies; D012827:Silicone Oils / Q000008:administration & dosage* / Q000737:chemistry* / Q000627:therapeutic use; D016896:Treatment Outcome; D014783:Viscosity; D014792:Visual Acuity
chemical_list: D012827:Silicone Oils