title: Morphology of the HIV versus the diabetic cotton wool spot.
abstract: BACKGROUND
  Retinal cotton wool spots (CWS) have long been associated with many systemic diseases, including diabetes mellitus and infection with the human immunodeficiency virus (HIV). The pathogenesis of the diabetic CWS has been well established but is not clear in HIV disease. This study documents a morphological difference between cotton wool spots observed in diabetes mellitus and HIV infection.
  
  
  METHODS
  Electronic images of 47 diabetic CWS and 38 HIV CWS were compared in terms of eccentricity. Each CWS was enlarged, and its major and minor axes were determined. Eccentricity was determined by use of a simple ratio of major vs. minor axis. The eccentricity of these diabetic and HIV CWS were compared by use of the Mann-Whitney rank sum test to check for significance.
  
  
  RESULTS
  The HIV CWS was significantly more eccentric (p < or = 0.001), thus suggesting a different morphology than its diabetic counterpart.
  
  
  CONCLUSIONS
  There seems to be a significant difference in the morphology of the cotton wool spots observed in diabetes mellitus compared with those observed in HIV infection. This difference suggests that, at some level, the pathogeneses of these two CWS are not the same. Clinically, the practitioner should strongly suspect HIV disease in a patient with boomerang-shaped cotton wool spots.
authors.affiliation: Nova Southeastern University, College of Optometry, Ft. Lauderdale, Florida 33312, USA.
authors.forename: C
authors.initials: C
authors.lastname: Jaworski
mesh_terms: D003930:Diabetic Retinopathy / Q000473:pathology*; D005654:Fundus Oculi; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D012164:Retinal Diseases / Q000473:pathology* / Q000821:virology*; D012189:Retrospective Studies