The ocular manifestations of congenital infection: a study of the early effect and long-term outcome of maternally transmitted rubella and toxoplasmosis.

PURPOSE: To study the spectrum of adverse ocular effects which result from maternally transmitted rubella and toxoplasma infection; further, to record the long-term visual and neurodevelopmental outcomes of these 2 major causes of fetal infection.

STUDY DESIGN AND PATIENTS: A series of 55 patients with congenital infection have been studied prospectively on a long-term basis. The study group included a cohort of 34 cases with congenital rubella syndrome demonstrated by virus isolation, and 21 cases with a clinical diagnosis of congenital toxoplasmosis and serologic confirmation. All patients had specific disease-related ocular defects. Rubella patients were first identified during or following the last major rubella epidemic in 1963-1964, and some have been followed serially since that time. A separate study group of representative toxoplasmosis patients presented for examination and diagnosis at varying time periods between 1967 and 1991.

OBSERVATIONS AND RESULTS: This study confirms that a broad spectrum of fetal injury may result from intrauterine infection and that both persistent and delayed-onset effects may continue or occur as late as 30 years after original infection. Many factors contribute to the varied outcome of prenatal infection, the 2 most important being the presence of maternal immunity during early gestation and the stage of gestation during which fetal exposure occurs in a nonimmune mother. RUBELLA: As a criteria of inclusion, all 34 rubella patients in this study exhibited one or more ocular defects at the time of birth or in the immediate neonatal period. Cataracts were present in 29 (85%) of the 34, of which 21 (63%) were bilateral. Microphthalmia, the next most frequent defect, was present in 28 (82%) of the 34 infants and was bilateral in 22 (65%). Glaucoma was recorded in 11 cases (29%) and presented either as a transient occurrence with early cloudy cornea in microphthalmic eyes (4 patients), as the infantile type with progressive buphthalmos (1 patient), or as a later-onset, aphakic glaucoma many months or years following cataract aspiration in 11 eyes of 6 patients. Rubella retinopathy was present in the majority of patients, although an accurate estimate of its incidence or laterality was not possible because of the frequency of cataracts and nystagmus and the difficulty in obtaining adequate fundus examination. TOXOPLASMOSIS: Twenty-one patients with congenital toxoplasmosis have been examined and followed for varying time periods, 7 for 20 years or more. The major reason for initial examination was parental awareness of an ocular deviation. Twelve children (57%) presented between the ages of 3 months and 4 years with an initial diagnosis of strabismus, 9 of whom had minor complaints or were diagnosed as part of routine examinations. All cases in this study have had evidence of retinochoroiditis, the primary ocular pathology of congenital toxoplasmosis. Two patients had chronic and recurrent inflammation with progressive vitreal traction bands, retinal detachments, and bilateral blindness. Macular lesions were always associated with central vision loss; however, over a period of years visual acuity gradually improved in several patients. Individuals with more severe ocular involvement were also afflicted with the most extensive central nervous system deficits, which occurred following exposure during the earliest weeks of gestation.

CONCLUSIONS: Although congenital infection due to rubella virus has been almost completely eradicated in the United States, the long-term survivors from the prevaccination period continue to experience major complications from their early ocular and cerebral defects. They may be afflicted by the persistence of virus in their affected organs and the development of late manifestations of their congenital infection. Congenital toxoplasmosis continues to be the source of major defects for 3,000 to 4,100 infants in the United States each year; the spectrum of defects is wide and may vary from blindness and severe mental retardation to minor retinochoroidal lesions of little consequence. Effective solutions for either the prevention or treatment of congenital toxoplasmosis have not been developed in this country but are under intensive and continuing investigation.