title: Intraocular pressure elevation after uncomplicated pars plana vitrectomy: results of the Pan American Collaborative Retina Study Group.
abstract: OBJECTIVE
  To compare the incident rates of sustained elevation of intraocular pressure (IOP) after uncomplicated pars plana vitrectomy for idiopathic epiretinal membrane and the unoperated fellow eye.
  
  
  METHODS
  Retrospective multicenter study of 198 patients who underwent pars plana vitrectomy for an idiopathic epiretinal membrane that was followed for at least 12 months. The diagnosis of sustained IOP elevation was defined as an elevation of IOP ≥ 24 mmHg or an increase of ≥ 5 mmHg in the IOP from baseline on 2 separate visits that warranted the initiation of ocular hypotensive therapy. The main outcome measured was the development of sustained IOP elevation as defined above.
  
  
  RESULTS
  Patients were followed for an average of 47.3 ± 24 months (range, 12-106 months). In the vitrectomized eyes, 38 of the 198 (19.2%) patients developed elevated IOP compared with 9 of the 198 (4.5%) unoperated fellow eyes (P < 0.0001, Fisher exact test; odds ratio, 4.988). Possible risk factors include a family history of open-angle glaucoma (P = 0.0004 Fisher exact test; odds ratio, 7.206) and cataract surgery (P = 0.0270 Fisher exact test; odds ratio, 2.506).
  
  
  CONCLUSIONS
  Uncomplicated PPV seems to increase the IOP, particularly in those who are pseudophakic and have a family history of open-angle glaucoma. This increase in IOP may lead to glaucomatous damage if not managed appropriately. Patients with a previous PPV need to be followed by an ophthalmologist to monitor the IOP in the vitrectomized eye.
authors.affiliation: *Instituto de Cirugia Ocular, San José, Costa Rica; †Universidad de Puerto Rico, San Juan, Puerto Rico; ‡Fundación Oftalmológica Nacional, Universidad del Rosario, Bogotá, Colombia; §Vitreoretinal Surgery Unit, Brazilian Institute of Fighting Against Blindness, Assis/Presidente Prudente, Sao Paulo, Brazil; ¶Vitreoretinal Surgery, Universidade Federal de Sao Paulo, Sao Paulo, Brazil; **Asociación Para Evitar La Ceguera, Hospital Luis Sanchez Bulnes, Mexico, Mexico; ††Hospital Universitario Ramón y Cajal, Departamento de Retina, and VISSUM Madrid Mirasierra de Oftalmología Integral, Madrid, Spain; ‡‡Clinica Oftalmologica Centro Caracas, Caracas, Venezuela; §§Clínica Ricardo Palma, Lima, Peru; ¶¶The King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia; and ***Wilmer Eye Institute, The Johns Hopkins University, Baltimore, Maryland.
authors.forename: Lihteh
authors.initials: L
authors.lastname: Wu
authors.forename: Maria H
authors.initials: MH
authors.lastname: Berrocal
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Rodriguez
authors.forename: Mauricio
authors.initials: M
authors.lastname: Maia
authors.forename: Virgilio
authors.initials: V
authors.lastname: Morales-Canton
authors.forename: Marta
authors.initials: M
authors.lastname: Figueroa
authors.forename: Martín
authors.initials: M
authors.lastname: Serrano
authors.forename: José A
authors.initials: JA
authors.lastname: Roca
authors.forename: J Fernando
authors.initials: JF
authors.lastname: Arévalo
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Navarro
authors.forename: Hector
authors.initials: H
authors.lastname: Hernández
authors.forename: Samantha
authors.initials: S
authors.lastname: Salinas
authors.forename: Rafael
authors.initials: R
authors.lastname: Romero
authors.forename: Natalia
authors.initials: N
authors.lastname: Alpizar-Alvarez
authors.forename: Giovanna
authors.initials: G
authors.lastname: Chico
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019773:Epiretinal Membrane / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis / Q000209:etiology*; D009885:Ophthalmology / Q000458:organization & administration; D010175:Pan American Health Organization / Q000458:organization & administration; D011183:Postoperative Complications; D012189:Retrospective Studies; D012307:Risk Factors; D014821:Vitrectomy; D055815:Young Adult