1. History
  2. Exam
  3. Photos
  4. Diagnosis
  5. Teaching Points
  6. Comments

Case 60 Teaching Points

  • Cone-rod dystrophy: electroretinogram testing demonstrates cone-isolated waveform is worse than the rod-isolated signal
  • Both are abnormal
  • Heterogeneous group of disorders with autosomal dominant, recessive and x-linked inheritance patterns
  • Cone-rod dystrophy characterized by early loss of visual acuity, color vision defects, night blindness, photophobia, sometimes nystagmus
  • Fundus can appear normal or include bone-spicule hyperpigmentation and atrophy in the macula and periphery, can have bull’s eye macular atrophy
  • Histological studies have shown regional photoreceptor loss, regional loss of retinal pigment epithelium, accumulation of lipofuscin
  • Tendency for visual field defects to begin in pericentral region 5-30° from fixation
  • Many non-retinal conditions can be seen in these patients including optic nerve head atrophy and telangectasia, high myopia, macular coloboma
  • Early disease may show an isolated cone dystrophy

References

Ryan S. Retina. St. Louis:Mosby – 2001.

Szlyk JP et al. Clinical subtypes of cone-rod dystrophy. Archives of Ophthalmology 1993:(3) 781-788.

Retina and Vitreous, Section 12, Basic and Clinical Science Course, American Academy of Ophthalmology, 2005-2006: 203-224.

Last Modified: Friday, 27-Jun-2008 12:44:21 EDT