title: [How can the success of a glaucoma operation be predicted?].
abstract: OBJECTIVE
  The effect of glaucoma surgery can simply be measured in terms of intraocular pressure (IOP) reduction. However, IOP reduction is not the final goal of glaucoma surgery, but rather long-term visual field preservation. Visual field preservation, on the other hand, can only be judged many years after surgery. Therefore, a formula that could be used to define the success of a pressure-lowering operation soon after surgery should take account of IOP reduction, but the correlation between "successful IOP reduction" and "long-term visual field preservation" should be as high as possible.
  
  
  METHODS
  In an attempt to find such a formula, we examined the long-term course with reference to both IOP and visual field in 108 patients (mean follow-up 7.9 years). Several criteria were tested for their ability to predict the long-term visual field preservation.
  
  
  RESULTS
  The best correlation was obtained by a combined criterion specifying both an absolute upper limit and a relative IOP decrease (i.e. IOP postoperatively < 0.8*IOP preoperatively and IOP postoperatively < 21 mmHg).
  
  
  CONCLUSIONS
  We recommend use of this criterion whenever the effect of a pressure-lowering operation has to be estimated shortly after surgery.
authors.affiliation: Universitäts-Augenklinik, Freiburg.
authors.forename: J
authors.initials: J
authors.lastname: Funk
authors.forename: A
authors.initials: A
authors.lastname: Frank
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005901:Glaucoma / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology*; D011379:Prognosis; D014130:Trabeculectomy; D016896:Treatment Outcome; D014794:Visual Fields / Q000502:physiology*