title: Photophobia measurement in intermittent exotropia using the contrast sensitivity test.
abstract: BACKGROUND
  To assess the presence and extent of photophobia in children with intermittent exotropia (X[T]) using the contrast sensitivity test.
  
  
  METHODS
  Fifty-eight children with X(T) and 34 normal controls were studied with the functional acuity contrast test. Each participant viewed the stimuli of contrast monocularly and binocularly under photopic and mesopic conditions, performed with and without glare. Photophobia was defined as a reduction of contrast sensitivity caused by glare light. We compared the photophobia of children with X(T) to that of normal controls, and to the photophobia 3 months after muscle surgery.
  
  
  RESULTS
  With stimuli of glare, the contrast sensitivity of children with X(T) was suppressed at intermediate spatial frequencies under mesopic condition (p = 0.006 for 6 cycles per degree [cpd], p = 0.027 for 12 cpd), whereas that of normal controls showed no difference. It occurred when X(T) patients viewed targets binocularly, and significantly improved after strabismus surgery (p = 0.003 at 6 cpd). The measured photophobia of X(T) was strongly correlated to the photophobia symptoms reported by parents (p = 0.002).
  
  
  CONCLUSIONS
  The mesopic contrast sensitivity with glare can represent the photophobia of children with X(T). Contrast sensitivity may be a useful measure for monitoring symptoms related to X(T).
authors.affiliation: Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seung Ah
authors.initials: SA
authors.lastname: Chung
authors.forename: Soolienah
authors.initials: S
authors.lastname: Rhiu
authors.forename: Seung Han
authors.initials: SH
authors.lastname: Han
authors.forename: Jong Bok
authors.initials: JB
authors.lastname: Lee
mesh_terms: D002648:Child; D015350:Contrast Sensitivity / Q000502:physiology*; D005099:Exotropia / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D019466:Glare; D006801:Humans; D008027:Light; D008297:Male; D055255:Mesopic Vision / Q000502:physiology; D009801:Oculomotor Muscles / Q000601:surgery; D013508:Ophthalmologic Surgical Procedures; D020795:Photophobia / Q000503:physiopathology*; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology