title: Variation of lamina cribrosa depth following trabeculectomy.
abstract: OBJECTIVE
  To investigate the long-term changes in lamina cribrosa (LC) depth following trabeculectomy.
  
  
  METHODS
  Serial horizontal B-scan images of the optic nerve head were obtained using spectral-domain optical coherence tomography from 28 primary open-angle glaucoma patients who underwent trabeculectomy and were followed up for at least 2 years. Approximately 65 B-scans covering the optic discs were obtained before surgery and at 6 months and ≥2 years postoperatively. The pre- and postoperative LC depth (the distance from the opening plane of Bruch's membrane to the level of the anterior LC surface) was determined on seven selected B-scan images from each eye and averaged (mean LC depth).
  
  
  RESULTS
  The intraocular pressure (IOP) decreased from 27.4 ± 9.0 (mean ± SD) to 9.7 ± 3.1 mm Hg at postoperative 6 months (P < 0.001) and subsequently increased to 12.7 ± 5.1 mm Hg at a mean final follow-up of 27.1 ± 3.3 months (P = 0.001). The mean LC depth was reduced from 625.6 ± 186.3 to 499.6 ± 140.6 μm at postoperative 6 months (P < 0.001). A subsequent slight, but nonsignificant, increase in the LC depth was noted at final follow-up. The degree of LC depth increase after 6 months was significantly associated with younger age, higher IOP at final follow-up, greater IOP fluctuation, and higher mean follow-up IOP from 6 months to final follow-up (all P < 0.05).
  
  
  CONCLUSIONS
  The postoperative reduction in the LC depth that was observed 6 months after surgery was not maintained in some eyes. The redisplacement of the LC after postoperative 6 months appeared more likely to occur in patients who were younger and who had higher IOP and IOP fluctuation during the postoperative follow-up.
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Lee
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Kim
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D003238:Connective Tissue / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000473:pathology*; D011184:Postoperative Period; D015203:Reproducibility of Results; D013997:Time Factors; D041623:Tomography, Optical Coherence; D014130:Trabeculectomy; D055815:Young Adult
keywords: intraocular pressure lowering; lamina cribrosa; primary open angle glaucoma; spectral domain optical coherence tomography