title: Intraocular pressure lowering effect of orbital decompression is related to increased venous outflow in Graves orbitopathy.
abstract: OBJECTIVE
  To investigate the effects of combined orbital bone and fat decompression on intraocular pressure (IOP) and superior ophthalmic vein blood flow velocity (SOV-BFV), and their association with the clinical features of Graves orbitopathy (GO).
  
  
  METHODS
  During the 2002-2008 period, 72 eyes of 36 GO cases demonstrating moderate to severe orbitopathy were evaluated according to their clinical features as: cases with or without dysthyroid optic neuropathy (DON), and underwent orbital decompression. A control group comprised 40 eyes of 20 healthy subjects. In both groups, a full ophthalmic examination including IOP and Hertel measurements was performed, and SOV-BFV was analyzed with color Doppler imaging. Examinations were repeated after orbital decompression in GO patients.
  
  
  RESULTS
  All the cases demonstrated clinical features of inactive disease. Among the patients 24 of 72 eyes (33.3%) showed clinical features of DON. After surgery, the mean decrease in Hertel values was 6.2 ± 1.8 mm (p = 0.001). The mean decrease in IOP was 3.0 ± 1.7 mmHg (from 17.3 ± 2.7 to 14.3 ± 2.0 mmHg) after orbital decompression where the post-operative values were comparable with the control group (12.9 ± 1.4 mmHg, p = 0.36). The mean increase in SOV-BFV achieved with decompression was 1.2 ± 0.6 cm/s (from 4.8 ± 1.7 to 6.0 ± 1.8 cm/s) and post-operative SOV-BFV values were also comparable with the control group (6.6 ± 1.3 cm/s, p = 0.26). The increase in SOV-BFV in cases with DON did not differ from cases without DON (p = 0.32), however, post-operative SOV-BFV of cases with DON was stil lower than cases without DON (p = 0.035).
  
  
  CONCLUSIONS
  Combined orbital bone and fat decompression significantly reduced the IOP levels and increased the SOV-BFV in GO. This could be the confirmative finding of prediction that elevated IOP in GO is associated with increased episcleral venous pressure. The post-operative changes in IOP and SOV-BFV show differences regarding the clinical features of disease.
authors: Department of Ophthalmology, Kırıkkale University School of Medicine , Kırıkkale , Turkey .
authors: Zafer
authors: Z
authors: Onaran
authors: Onur
authors: O
authors: Konuk
authors: Suna Özhan
authors: SÖ
authors: Oktar
authors: Cem
authors: C
authors: Yücel
authors: Mehmet
authors: M
authors: Unal
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D049970:Graves Ophthalmopathy / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D009915:Orbit / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000601:surgery; D012039:Regional Blood Flow / Q000502:physiology*; D012189:Retrospective Studies; D014065:Tonometry, Ocular; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color
keywords: Dysthyroid optic neuropathy; Graves orbitopathy; intraocular pressure; orbital decompression; superior ophthalmic vein