title: Visual function in human ocular toxoplasmosis.
abstract: OBJECTIVE
  To assess functional impairment in terms of visual acuity reduction and visual field defects in inactive ocular toxoplasmosis.
  
  
  METHODS
  61 patients with known ocular toxoplasmosis in a quiescent state were included in this prospective, cross-sectional study. A complete ophthalmic examination, retinal photodocumentation and standard automated perimetry (Octopus perimeter, program G2) were performed. Visual acuity was classified on the basis of the World Health Organization definition of visual impairment and blindness: normal (> or =20/25), mild (20/25 to 20/60), moderate (20/60 to 20/400) and severe (<20/400). Visual field damage was correspondingly graded as mild (mean defect <4 dB), moderate (mean defect 4-12 dB) or severe (mean defect >12 dB).
  
  
  RESULTS
  8 (13%) patients presented with bilateral ocular toxoplasmosis. Thus, a total of 69 eyes was evaluated. Visual field damage was encountered in 65 (94%) eyes, whereas only 28 (41%) eyes had reduced visual acuity, showing perimetric findings to be more sensitive in detecting chorioretinal damage (p<0.001). Correlation with the clinical localisation of chorioretinal scars was better for visual field (in 70% of the instances) than for visual acuity (33%). Moderate to severe functional impairment was registered in 65.2% for visual field, and in 27.5% for visual acuity.
  
  
  CONCLUSIONS
  In its quiescent stage, ocular toxoplasmosis was associated with permanent visual field defects in >94% of the eyes studied. Hence, standard automated perimetry may better reflect the functional damage encountered by ocular toxoplasmosis than visual acuity.
authors.affiliation: Department of Ophthalmology, University of Bern, Bern, Switzerland.
authors.forename: Janine
authors.initials: J
authors.lastname: Scherrer
authors.forename: Milko E
authors.initials: ME
authors.lastname: Iliev
authors.forename: Markus
authors.initials: M
authors.lastname: Halberstadt
authors.forename: Laurent
authors.initials: L
authors.lastname: Kodjikian
authors.forename: Justus G
authors.initials: JG
authors.lastname: Garweg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D014126:Toxoplasmosis, Ocular / Q000150:complications* / Q000503:physiopathology*; D014786:Vision Disorders / Q000175:diagnosis / Q000469:parasitology* / Q000503:physiopathology; D014792:Visual Acuity; D058609:Visual Field Tests / Q000379:methods; D014794:Visual Fields