title: Impairment of visual acuity and reading performance and the relationship with cataract type and density.
abstract: OBJECTIVE
  To evaluate the association between the density of nuclear, cortical, and posterior subcapsular lens opacities and visual impairment in patients with cataract.
  
  
  METHODS
  In 80 patients, visual acuity and reading performance were evaluated 1 day before and 4 weeks after cataract surgery. Cataracts were categorized and graded according to the Lens Opacities Classification System (LOCS) III of nuclear color (NC), nuclear opalescence (NO), cortical (C), and posterior subcapsular cataract (P). A multiple linear regression analysis and partial correlation coefficients were calculated. Data were also checked for significant pre- and postoperative differences in visual performance related to cataract grading.
  
  
  RESULTS
  In the multiple linear regression analysis, significant associations were found between the improvement in visual acuity and reading performance after cataract surgery and the NC, NO, and P scores (P < 0.001); no significant association was found for the C score (P > 0.05). High partial correlation coefficients were found between the P score and the preoperative visual acuity (r = 0.6; P < 0.001), reading acuity (r = 0.74; P < 0.001), and maximum reading speed (MRS; r = -0.77; P < 0.001). Significant but lower partial correlation coefficients were found for the NO score. No significant partial correlation coefficients were found for the NC and C score. Significant pre- and postoperative differences in MRS were found in patients with P scores > or =3 or NO and NC scores > or =5, representing functionally relevant impairment.
  
  
  CONCLUSIONS
  A strong association was found between visual impairment in patients with cataract and the severity of posterior subcapsular cataract (PSC) and nuclear opacity. Particularly in patients with PSC, deficits in reading performance significantly increased. The functionally relevant deficits in patients with P scores > or =3 or NO and NC scores > or =5, should be carefully considered for planning cataract surgery or visual rehabilitation.
authors.affiliation: Department of Ophthalmology Medical University of Vienne, Austria. eva.stifter@meduniwien.ac.at
authors.forename: Eva
authors.initials: E
authors.lastname: Stifter
authors.forename: Stefan
authors.initials: S
authors.lastname: Sacu
authors.forename: Thomas
authors.initials: T
authors.lastname: Benesch
authors.forename: Herbert
authors.initials: H
authors.lastname: Weghaupt
mesh_terms: D000368:Aged; D002386:Cataract / Q000145:classification* / Q000503:physiopathology*; D002387:Cataract Extraction; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011932:Reading; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D019987:Persons with Visual Disabilities