Visual electrophysiological screening in diagnosing infants with congenital nystagmus.
OBJECTIVE
To determine the value of visual electrophysiological screening in evaluating retinal and postretinal visual pathway function in infants with congenital nystagmus.


METHODS
In 28 infants with congenital nystagmus electroretinogram (ERG) was recorded with skin electrodes and, since the infants were alert, visual evoked potentials (VEP) were simultaneously recorded. The first recording was performed before the age of 1 year (age 2-11 months, mean age 6.8 months). Follow-up was performed between the ages of 7 months and 6 years (mean age 2.7 years). ERG was detected to flash stimulus and VEP to flash and/or pattern-reversal stimulus.


RESULTS
In infants less than 1 year of age, retinal dysfunction was recognised in 36% of infants who had been diagnosed as Leber's congenital amaurosis, achromatopsia and retinal dystrophy; postretinal dysfunction was recognised in 32% of infants who had been diagnosed with ocular albinism, optic nerve hypoplasia and neurological nystagmus; retinal or postretinal function was normal in 7% of infants that had been diagnosed as congenital idiopathic nystagmus, while retinal function was normal and postretinal function was undefined in 25% of infants that had been diagnosed as optic nerve hypoplasia, neurological nystagmus and congenital idiopathic nystagmus. At follow-up the findings were: retinal dysfunction in 36%, postretinal dysfunction in 50% and normal retinal and postretinal function in 14% of children. All those children with normal retinal and postretinal function had been diagnosed as congenital idiopathic nystagmus.


CONCLUSIONS
Visual electrophysiological screening of infants with congenital nystagmus can establish or exclude retinal and postretinal pathway dysfunction. Therefore simultaneous skin ERG and VEP which is a non-invasive approach for infants enables an objective means for identifying the basis of congenital nystagmus, thereby assisting in its classification.
Brecelj
Jelka
J
Eye Clinic, University Medical Centre, Zaloska c. 29a, 1525 Ljubljana, Slovenia. jelka.brecelj@kclj.si
Stirn-Kranjc
Branka
B
D002648:Child; D002675:Child, Preschool; D003117:Color Vision Defects / Q000175:diagnosis / Q000503:physiopathology; D004596:Electroretinography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D020417:Nystagmus, Congenital / Q000175:diagnosis* / Q000503:physiopathology; D009759:Nystagmus, Pathologic / Q000175:diagnosis / Q000503:physiopathology; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology; D010775:Photic Stimulation; D015203:Reproducibility of Results; D014786:Vision Disorders / Q000175:diagnosis / Q000503:physiopathology; D014793:Visual Cortex / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology