title: Effect of light-emitting diode colour temperature on magnifier reading performance of the visually impaired.
abstract: BACKGROUND
  As light-emitting diodes become more common as the light source for low vision aids, the effect of illumination colour temperature on magnifier reading performance was investigated.
  
  
  METHODS
  Reading ability (maximum reading speed, critical print size, threshold near visual acuity) using Radner charts and subjective preference was assessed for 107 participants with visual impairment using three stand magnifiers with light emitting diode illumination colour temperatures of 2,700 K, 4,500 K and 6,000 K. The results were compared with distance visual acuity, prescribed magnification, age and the primary cause of visual impairment.
  
  
  RESULTS
  Reading speed, critical print size and near visual acuity were unaffected by illumination colour temperature (p > 0.05). Reading metrics decreased with worsening acuity and higher levels of prescribed magnification but acuity was unaffected by age. Each colour temperature was preferred and disliked by a similar number of patients and was unrelated to distance visual acuity, prescribed magnification and age (p > 0.05). Patients had better near acuity (p = 0.002), critical print size (p = 0.034) and maximum reading speed (p < 0.001), and the improvement in near from distance acuity was greater (p = 0.004) with their preferred rather than least-liked colour temperature illumination.
  
  
  CONCLUSIONS
  A range of colour temperature illuminations should be offered to all visually impaired individuals prescribed with an optical magnifier for near tasks to optimise subjective and objective benefits.
authors.affiliation: Aston University, Life and Health Sciences, Ophthalmic Research Group, Birmingham, United Kingdom. j.s.w.wolffsohn@aston.ac.uk
authors.forename: James S
authors.initials: JS
authors.lastname: Wolffsohn
authors.forename: Eshmael
authors.initials: E
authors.lastname: Palmer
authors.forename: Martin
authors.initials: M
authors.lastname: Rubinstein
authors.forename: Frank
authors.initials: F
authors.lastname: Eperjesi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003116:Color; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D011932:Reading; D013696:Temperature; D015354:Vision, Low / Q000534:rehabilitation*; D014792:Visual Acuity