title: Effect of diabetic retinopathy and panretinal photocoagulation on retinal nerve fiber layer and optic nerve appearance.
abstract: OBJECTIVE
  To determine if panretinal photocoagulation (PRP) alters retinal nerve fiber layer (RNFL) thickness and optic nerve appearance.
  
  
  METHODS
  Patients with diabetes who did and did not undergo PRP and nondiabetic control subjects were enrolled in a prospective study. Participants underwent optical coherence tomography of the peripapillary retina and optic nerve. Stereoscopic optic nerve photographs were graded in a masked fashion.
  
  
  RESULTS
  Ninety-four eyes of 48 healthy individuals, 89 eyes of 55 diabetic patients who did not undergo PRP, and 37 eyes of 24 subjects with diabetes who underwent PRP were included in this study. Eyes that had been treated with PRP had thinner peripapillary RNFL compared with the other groups; this was statistically significantly different in the inferior (P = .004) and nasal (P = .003) regions. Optic nerve cupping did not increase with severity of disease classification, but the proportion of optic nerves graded as suspicious for glaucoma or as having nonglaucomatous optic neuropathy did (P = .008). These grading categories were associated with thinner RNFL measurements.
  
  
  CONCLUSIONS
  Diabetic eyes that have been treated with PRP have thinner RNFL than nondiabetic eyes. Optic nerves in eyes treated with PRP are more likely to be graded as abnormal, but their appearance is not necessarily glaucomatous and may be related to thinning of the RNFL.
authors: Department of Ophthalmology & Vision Science, University of California-Davis, 4860 Y St, Ste 2400, Sacramento, CA 95817, USA. michele.lim@ucdmc.ucdavis.edu
authors: Michele C
authors: MC
authors: Lim
authors: Suzana A
authors: SA
authors: Tanimoto
authors: Bruno A
authors: BA
authors: Furlani
authors: Brent
authors: B
authors: Lum
authors: Luciano M
authors: LM
authors: Pinto
authors: David
authors: D
authors: Eliason
authors: Tiago S
authors: TS
authors: Prata
authors: James D
authors: JD
authors: Brandt
authors: Lawrence S
authors: LS
authors: Morse
authors: Susanna S
authors: SS
authors: Park
authors: Luiz A S
authors: LA
authors: Melo
mesh_terms: D001369:Axons / Q000473:pathology*; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000601:surgery*; D005260:Female; D006801:Humans; D017075:Laser Coagulation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000209:etiology*; D011446:Prospective Studies; D012160:Retina / Q000601:surgery*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence