title: Influence of cataract on optical coherence tomography image quality and retinal thickness.
abstract: BACKGROUND
  As optical coherence tomography (OCT) is widely used for diagnosis and monitoring of ocular pathology, especially in the elderly people, the influence of cataract on image quality and macular retinal thickness was studied.
  
  
  METHODS
  In 29 patients scheduled for cataract surgery, preoperative and postoperative OCT scans were obtained. Cataracts were categorised as nuclear, posterior or cortical. Parameters for image quality (signal-to-noise ratio (SNR)) and signal strength and macular thickness were compared. A three-level expert grading scale was used to evaluate the discriminative abilities of SNR and signal strength.
  
  
  RESULTS
  Nuclear cataracts (n = 12) provided better preoperative scans (higher SNR/signal strength) than posterior (n = 7) and cortical (n = 10) cataracts (p<0.004). Postoperatively SNR and signal strength increased significantly in all patients (p<0.001). The SNR was better at discriminating poor from acceptable and good scans than signal strength (area under the receiver operating curve: 0.879 and 0.810, respectively). Postoperative macular thickness overall showed a significant increase (p = 0.005), most evident in patients with posterior cataracts (p = 0.028).
  
  
  CONCLUSIONS
  OCT imaging is influenced by cataract; image quality is reduced preoperatively and macular thickness measurements are slightly increased postoperatively. In individual patients, OCT scans remain reliable for gross clinical interpretation, even in the presence of cataract.
authors.affiliation: Department of Ophthalmology, Academic Medical Centre, Meibergdreef 9, Amsterdam, The Netherlands. m.e.vanvelthoven@amc.uva.nl
authors.forename: M E J
authors.initials: ME
authors.lastname: van Velthoven
authors.forename: M H
authors.initials: MH
authors.lastname: van der Linden
authors.forename: M D
authors.initials: MD
authors.lastname: de Smet
authors.forename: D J
authors.initials: DJ
authors.lastname: Faber
authors.forename: F D
authors.initials: FD
authors.lastname: Verbraak
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000473:pathology* / Q000503:physiopathology; D002387:Cataract Extraction; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008875:Middle Aged; D011182:Postoperative Care; D011300:Preoperative Care; D041623:Tomography, Optical Coherence; D014792:Visual Acuity