title: Neovascular glaucoma after central retinal vein occlusion in pre-existing glaucoma.
abstract: BACKGROUND
  To determine the outcome of central retinal vein occlusion (CRVO) in pre-existing glaucoma and the predisposing factors of developing neovascular glaucoma (NVG).
  
  
  METHODS
  We retrospectively assessed a pre-existing glaucoma CRVO group and a non-glaucoma CRVO group to elucidate the demographics, clinical course and ocular parameters of these two cohorts. Among the pre-existing glaucoma cases, the predisposing factors for the development of NVG were monitored, including the retinal capillary non-perfusion status, intraocular pressure (IOP) and best-corrected visual acuity (BCVA) at presentation.
  
  
  RESULTS
  Of 642 CRVO patients reviewed in this 10-year cohort study, 60 (9.3%) had pre-existing glaucoma at a mean follow-up of 30.8 months, including 28 (4.4%) primary open angle glaucoma (POAG), 27 (4.2%) primary angle closure glaucoma (PACG), and 5 (0.8%) normal tension glaucoma (NTG) cases. Although the presence of glaucoma in the CRVO eyes was not significantly associated with the risk of developing NVG, the incidence of developing NVG in pre-existing glaucoma eyes was significantly higher in the group with IOP greater than 20 mmHg at CRVO presentation (P = 0.02, Chi-square test) as well as in the ischemic CRVO group compared to the non-ischemic patients (P = 0.005, Fisher's exact test). Overall, 20% of pre-existing glaucoma patients needed glaucoma surgery after a CRVO event, including 11.7% of patients who developed iris neovascularisation (INV) and 8.3% of patients who developed a high IOP without INV.
  
  
  CONCLUSIONS
  Both the retinal non-perfusion status and uncontrolled IOP contribute to NVG in patients with pre-existing glaucoma after CRVO. Following CRVO, glaucoma surgery is necessary for pre-existing glaucoma cases with intractable elevated IOP with or without INV.
authors.forename: Hsi-Fu
authors.initials: HF
authors.lastname: Chen
authors.forename: Min-Chi
authors.initials: MC
authors.lastname: Chen
authors.forename: Chi-Chun
authors.initials: CC
authors.lastname: Lai
authors.forename: Ling
authors.initials: L
authors.lastname: Yeung
authors.forename: Nan-Kai
authors.initials: NK
authors.lastname: Wang
authors.forename: Henry Shen-Lih
authors.initials: HS
authors.lastname: Chen
authors.forename: Wan-Chen
authors.initials: WC
authors.lastname: Ku
authors.forename: Shiu-Chen
authors.initials: SC
authors.lastname: Wu
authors.forename: Shirley H L
authors.initials: SH
authors.lastname: Chang
authors.affiliation: Department of Ophthalmology, Chang Gung Memorial Hospital, 222 Mai-Chin Rd, Keelung 204, Taiwan. c571019@cgmh.org.tw.
authors.forename: Lan-Hsin
authors.initials: LH
authors.lastname: Chuang
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D018463:Filtering Surgery; D015812:Glaucoma, Angle-Closure / Q000150:complications*; D015355:Glaucoma, Neovascular / Q000209:etiology* / Q000601:surgery; D005902:Glaucoma, Open-Angle / Q000150:complications*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D017075:Laser Coagulation; D057066:Low Tension Glaucoma / Q000150:complications*; D008297:Male; D008875:Middle Aged; D064266:Preexisting Condition Coverage; D012170:Retinal Vein Occlusion / Q000150:complications*; D012189:Retrospective Studies; D012307:Risk Factors; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology