title: Chromatic and luminance contrast sensitivities in asymptomatic carriers from a large Brazilian pedigree of 11778 Leber hereditary optic neuropathy.
abstract: OBJECTIVE
  To determine whether asymptomatic 11778 LHON carriers demonstrated impairments in (1) chromatic red/green (R/G) and blue/yellow (B/Y) contrast sensitivity functions (CSF) and in (2) luminance contrast sensitivity functions in the spatial CSF (SCSF) and temporal CSF (TCSF) domains.
  
  
  METHODS
  Twenty-five carriers (8 male, 17 female; 34.1 +/- 15.1 years of age) of homoplasmic 11778 LHON from the same well-described family and 30 age-matched controls (17 male, 13 female; 29.2 +/- 7.1 years of age) were tested in one eye, randomly selected. Of the 25 eyes tested, 18 had normal fundus, 5 had swelling and microangiopathy, and 2 had temporal pallor. The R/G and B/Y CSFs were obtained after equiluminance correction with bichromatic horizontal sinusoidal gratings at 0.3, 0.7, and 2 cycles per degree (cpd); the SCSFs were obtained with achromatic gratings at 0.3, 2, 6, and 12 cpd; and the TCSFs were obtained at 2, 10, 20, and 33 Hz with sinusoidal modulation of a 2.7 degrees field with a superimposed spatial Gabor function.
  
  
  RESULTS
  Differences between carriers and controls were statistically significant for all spatial frequencies of chromatic and luminance SCSFs, but not for the TCSFs. R/G equiluminance settings of carriers differed from those of controls (P < 0.001), requiring higher luminance in the green; B/Y equiluminance settings were not statistically different in carriers and controls. Fundus findings did not correlate with CS results.
  
  
  CONCLUSIONS
  Luminance and chromatic spatial CS losses that affected all tested spatial frequencies, are reported in LHON asymptomatic carriers with the mtDNA 11778 mutation. No losses were found in the temporal CSF. An intriguing finding is that the blue system is substantially spared in this LHON family. These represent subclinical visual impairments in otherwise asymptomatic LHON carriers.
authors.affiliation: Department of Experimental Psychology, University of São Paulo, São Paulo, Brazil. dventura@usp.br
authors.forename: Dora Fix
authors.initials: DF
authors.lastname: Ventura
authors.forename: Peter
authors.initials: P
authors.lastname: Quiros
authors.forename: Valerio
authors.initials: V
authors.lastname: Carelli
authors.forename: Solange R
authors.initials: SR
authors.lastname: Salomão
authors.forename: Mirella
authors.initials: M
authors.lastname: Gualtieri
authors.forename: André G F
authors.initials: AG
authors.lastname: Oliveira
authors.forename: Marcelo F
authors.initials: MF
authors.lastname: Costa
authors.forename: Adriana
authors.initials: A
authors.lastname: Berezovsky
authors.forename: Federico
authors.initials: F
authors.lastname: Sadun
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: de Negri
authors.forename: Alfredo A
authors.initials: AA
authors.lastname: Sadun
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D005425:Flicker Fusion; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D029242:Optic Atrophy, Hereditary, Leber / Q000208:ethnology / Q000235:genetics* / Q000503:physiopathology*; D010375:Pedigree; D013028:Space Perception; D014792:Visual Acuity
chemical_list: D004272:DNA, Mitochondrial