The limitations of serological assessment in toxoplasma
infection of the eye are well recognised, but the predictive value of clinical examination is not defined. We undertook a prospective investigation into the role of clinical examination and of serological findings in cases of suspected toxoplasma
infection of the eye by means of the
dye test and multiple
IgM assays. Seventy-four cases of
retinal disease and 202 control patients were studied. Patients with
retinal disease had a significantly higher incidence of toxoplasma seropositivity than the control group. This was because some patients with
retinal disease had acquired the
infection congenitally. Half the patients investigated for
toxoplasmosis were seronegative. Possible explanations for these findings included misdiagnosis, clinical uncertainty, or, the use of serology testing in the confirmation of other diseases. An excess of
IgM reactivity among the
retinal disease group may indicate low level
immunoglobulin-M production associated with an acute exacerbation of
ocular toxoplasmosis. There is a need to consider invasive procedures in cases of
ocular infection and for novel techniques to aid the diagnosis of toxoplasma retinochoroiditis.