title: Optical coherence tomography in paediatric glaucoma: time domain versus spectral domain.
abstract: OBJECTIVE
  Spectral-domain (SD)- Optical Coherence Tomography (OCT) can track eye movements, has faster acquisition time and higher resolution than time-domain(TD)-OCT. The aim of the study was to assess the utility of SD-OCT in paediatric glaucoma and determine its agreement with TD-OCT.
  
  
  METHODS
  Children who had SD-OCT(Spectralis, Heidelberg-Engineering,Germany) were retrospectively and prospectively identified from Duke paediatric glaucoma clinic. The peripapillary retinal nerve fibre layer (RNFL) and macular thickness and volume (MV) were compared amongst four groups: normal eyes, eyes with physiologic cupping (C:D >0.5 and <0.8, IOP <21), mild glaucomatous eyes (C:D <0.5, intra-ocular pressure (IOP) >21) and severe glaucoma (C:D>0.5, IOP>21). SD-OCT values were compared to TD-OCT(OCT-3, Carl-Zeiss-Meditec, Dublin, CA) values in a subset of subjects who had same day scans using both instruments. Children with neurologic disorders, refractive error >±5D, pseudophakia and prematurity were excluded.
  
  
  RESULTS
  Included were 83 eyes of 83 children, mean age 11.9 ± 4.2 years. SD-OCT measurements of average RNFL thickness and MV differed among normals(n=24), physiologically cupped (n=31), mild (n=15) versus severe glaucoma (n=13): (RNFL:104 ± 9, 99 ± 6, 98 ± 9 vs 62 ± 18 µm, respectively, p<0.05; MV: 8.7 ± 0.3, 8.6 ± 0.3, 8.8 ± 0.4 vs 8.0 ± 0.6 mm³;, respectively, p<0.05). Same-day SD-OCT and TD-OCT measures in 53 eyes correlated linearly (RNFL r(2)=0.88; MVr(2)=0.58). SD-OCT measured lower RNFL and higher macular thickness than TD-OCT. Among eyes with severe glaucoma, 4 of 13 (30%) had unreliable TD-OCT but reliable SD-OCT.
  
  
  CONCLUSIONS
  SD-OCT was easier to obtain than TD-OCT in children. SD-OCT and TD-OCT measurements correlated, but values were not interchangeable.
authors.affiliation: Department of Ophthalmology, Duke Eye Center, Durham, North Carolina 27710, USA.
authors.forename: Fatema F
authors.initials: FF
authors.lastname: Ghasia
authors.forename: Sharon F
authors.initials: SF
authors.lastname: Freedman
authors.forename: Anand
authors.initials: A
authors.lastname: Rajani
authors.forename: Sandra
authors.initials: S
authors.lastname: Holgado
authors.forename: Sanjay
authors.initials: S
authors.lastname: Asrani
authors.forename: Mays
authors.initials: M
authors.lastname: El-Dairi
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D009412:Nerve Fibers / Q000473:pathology*; D009798:Ocular Hypertension / Q000175:diagnosis; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence / Q000295:instrumentation; D014065:Tonometry, Ocular; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult
keywords: Glaucoma; Imaging