title: Optical coherence tomographic assessment of retinal nerve fiber layer thickness changes before and after glaucoma filtration surgery.
abstract: BACKGROUND
  Glaucomatous Optic Neuropathy (GON) is very common in the glaucoma patients, and impaired effect of glaucoma is measured by the Retinal Nerve Fiber Layer (RNFL) thickness.
  
  
  OBJECTIVE
  The study was conducted to find out the mean RNFL thickness, RNFL thickness in different quadrants, Intra-Ocular Pressure (IOP) changes, and visual field changes after filtration surgery in different ages and genders using Optical Coherence Tomography (OCT).
  
  
  METHODS
  The study was an interventional case-series conducted at the Glaucoma Clinic at the Regional Institute of Ophthalmology at Kolkata from March 2009 to August 2010. Fifty-one eyes of 43 open angle glaucoma patients had been selected for clinical and ophthalmologic evaluation. All the eyes of glaucoma patients who fulfilled the inclusion criteria were registered in the study population. The glaucoma filtration surgery was done in these patients. The RNFL thickness, IOP, visual field changes were measured before and after intervention of filtration surgery. Pre-operative OCT images of RNFL were obtained 0 to 120 days before surgery, and post-operative images were obtained from 60 to 120 days after surgery. Data collected in a standard data collection form included schedule.
  
  
  RESULTS
  Paired t-test was used. RNFL thickness was (pre-operative: 52.56 ± 17.40, post-operative: 58.48 ± 20.20, P < 0.0001) significantly increased after filtration surgery measured by OCT with significant reduction of IOP (r = - 0.38, P = 0.005) irrespective of age and gender.
  
  
  CONCLUSIONS
  An increase in RNFL thickness was observed after glaucoma filtration surgery that correlated with IOP reduction.
authors.affiliation: Department of Ophthalmology, Calcutta National Medical College, Kolkata, West Bengal, India.
authors.forename: Kumaresh Chandra
authors.initials: KC
authors.lastname: Sarkar
authors.affiliation: Department of Community Medicine, Midnapore Medical College, Paschim Medinipur, West Bengal, India.
authors.forename: Palash
authors.initials: P
authors.lastname: Das
authors.affiliation: Department of Community Medicine and Family Medicine, AIIMS, Jodhpur, India.
authors.forename: Ranabir
authors.initials: R
authors.lastname: Pal
authors.affiliation: Department of Ophthalmology, RIO, Medical College, Kolkata, West Bengal, India.
authors.forename: Chattaranjan
authors.initials: C
authors.lastname: Shaw
keywords: Glaucomatous optic neuropathy; optical coherence tomography; retinal nerve fiber layer thickness