title: Multifocal electroretinograms in cases of central areolar choroidal dystrophy.
abstract: OBJECTIVE
  To study multifocal electroretinograms (mfERG) in patients with early-stage central alveolar choroidal dystrophy (CACD) with well-demarcated atrophic areas.
  
  
  METHODS
  Eight eyes of eight patients with CACD (ages, 47-67 years) and 20 normal control subjects were examined. The first- and second-order kernels (K1 and K2) were extracted from the responses elicited by 61 standard hexagonal elements of a visual response imaging system. The amplitudes and peak times of the focal responses at various retinal eccentricities were studied.
  
  
  RESULTS
  The amplitudes of K1 were reduced in the visibly atrophic areas, and they were also decreased in areas with no visible atrophy. The peak time was slightly delayed in many loci, but the delay was not as long as that in congenital stationary night blindness or diabetic retinopathy. The amplitude of K2 was very small in the central and peripheral areas, but the K2/K1 ratio in both areas was not significantly reduced, compared with that in normal subjects.
  
  
  CONCLUSIONS
  Although the atrophic area was ophthalmoscopically well demarcated in patients with CACD, the abnormality of retinal function extended beyond the borders of the ophthalmoscopic and angiographic lesions. The retinal dysfunction outside the atrophic areas suggests a centrifugal progression of the disease, and abnormal K2 and K1 with preserved K2/K1 ratio are consistent with a presynaptic mechanism for the retinal dysfunction in this disease.
authors.affiliation: Department of Ophthalmology, Nippon University School of Medicine, Tokyo, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Nagasaka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Horiguchi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Shimada
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Yuzawa
mesh_terms: D000328:Adult; D000368:Aged; D015862:Choroid Diseases / Q000503:physiopathology*; D004596:Electroretinography; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000502:physiology*