title: Objective Assessment of Nuclear and Cortical Cataracts through Scheimpflug Images: Agreement with the LOCS III Scale.
abstract: OBJECTIVE
  To assess nuclear and cortical opacities through the objective analysis of Scheimpflug images, and to check the correlation with the Lens Opacity Classification System III (LOCS III).
  
  
  METHODS
  Nuclear and cortical opacities were graded according to the LOCS III rules after pupil dilation. The maximum and average pixel intensity values along an elliptical mask within the lens nucleus were taken to analyse nuclear cataracts. A new metric based on the percentage of opaque pixels within a region of interest was used to analyse cortical cataracts. The percentage of opaque pixels was also calculated for half, third and quarter areas from the region of interest's periphery.
  
  
  RESULTS
  The maximum and average intensity values along the nucleus were directly proportional to the LOCS III grade: The larger the LOCS III value, the larger maximum and average intensity ones. These metrics showed a positive and significant correlation with the LOCS grade: The larger the LOCS grade, the higher was percentage of opaque pixels along the cortex within the same mask's size. This metric showed a significant correlation to the LOCS grade.
  
  
  CONCLUSIONS
  The metrics used to assess nuclear opacities showed good correlation with the LOCS III. The percentage of opaque pixels showed to be a useful metric to measure objectively the severity of the cortical opacity. These metrics could be implemented in an algorithm to detect and grade lens opacities automatically and objectively.
authors.affiliation: Optometry Research Group, Department of Optics and Optometry and Vision Science, University of Valencia, Burjasot, Comunidad Valenciana, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Domínguez-Vicent
authors.affiliation: Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.|St. Erik Eye Hospital, Stockholm, Sweden.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Birkeldh
authors.forename: Carl-Gustaf
authors.initials: CG
authors.lastname: Laurell
authors.affiliation: Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.|St. Erik Eye Hospital, Stockholm, Sweden.
authors.forename: Laurell
authors.initials: L
authors.lastname: Carl-Gustaf
authors.affiliation: Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Nilson
authors.affiliation: Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Rune
authors.initials: R
authors.lastname: Brautaset
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002386:Cataract / Q000175:diagnosis* / Q000473:pathology; D003952:Diagnostic Imaging / Q000379:methods*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007904:Lens Cortex, Crystalline / Q000473:pathology*; D007907:Lens Nucleus, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D055815:Young Adult