title: Changes in choroidal thickness after intraocular pressure reduction following trabeculectomy.
abstract: OBJECTIVE
  To evaluate the changes of peripapillary and subfoveal choroidal thickness (CT) after trabeculectomy.
  
  
  METHODS
  Prospective longitudinal study included 37 eyes with open-angle glaucoma. The subfoveal and peripapillary CT was measured using enhanced depth imaging spectral domain optical coherence tomography before trabeculectomy and 1 week, 3 and 6 months postoperatively. The associations between changes in the CT, intraocular pressure (IOP) and axial length were analysed.
  
  
  RESULTS
  The medium subfoveal CT (IQR) increased from 182 (97) μm at baseline to 267 (107) μm 1 week, 213 (97) μm 3 months and 207 (91) μm 6 months postoperatively (p < 0.001). The peripapillary CT increased in all four quadrants at all follow-ups (p < 0.05). The subfoveal and peripapillary choroidal thickening correlated with the magnitude of IOP reduction (p < 0.05) and axial length shortening (p < 0.01) during whole follow-up period. There was a peripapillary CT increase of 2.9 μm per mmHg of IOP reduction (p < 0.001, CI 1.5-4.4) and 4.8 μm per mm of baseline axial length (p = 0.049, CI 0.03-9.6) 1 week postoperatively after adjustment for baseline IOP. Six months postoperatively, the decrease in axial length was the only factor associated with peripapillary choroidal thickening (p = 0.031; regression coefficient: 73.29 μm/mm, CI 7.1-139.5).
  
  
  CONCLUSIONS
  Intraocular pressure (IOP) reduction after trabeculectomy caused the increase in subfoveal and peripapillary CT for at least 6 months postoperatively correlating with greater IOP reduction and axial length shortening. In the long term, the decrease in axial eye length, but not IOP, was the only factor to be associated with peripapillary choroidal thickening.
authors.affiliation: Faculty of Medicine, Vilnius University, Vilnius, Lithuania.|Centre of Eye Diseases, Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania.
authors.forename: Aiste
authors.initials: A
authors.lastname: Kadziauskiene
authors.affiliation: Faculty of Medicine, Vilnius University, Vilnius, Lithuania.|Centre of Eye Diseases, Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kuoliene
authors.affiliation: Faculty of Medicine, Vilnius University, Vilnius, Lithuania.|Centre of Eye Diseases, Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania.
authors.forename: Rimvydas
authors.initials: R
authors.lastname: Asoklis
authors.affiliation: Faculty of Medicine, Vilnius University, Vilnius, Lithuania.|Centre of Ear, Nose and Throat, Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania.
authors.forename: Eugenijus
authors.initials: E
authors.lastname: Lesinskas
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.|Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
authors.forename: Leopold
authors.initials: L
authors.lastname: Schmetterer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058452:Axial Length, Eye / Q000473:pathology; D002829:Choroid / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011446:Prospective Studies; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular; D014130:Trabeculectomy
keywords: choroid; choroidal thickness; intraocular pressure; trabeculectomy