Abstract
Purpose: :
Amblyopia is a developmental disorder of the central visual pathways (L.Kiorpes, J.A. Movshon 2003). Abnormal visual development in strabismic amblyopia drastically affects visual perception and properties of neurons in primary visual cortex (V1). But results of visual evoked potentials (VEP) in patients with amblyopia are usually normal. The pronounced light sensitivity reduction, its nasal-temporal asymmetry in the visual field periphery in strabismus of early onset was found (V. Herzau, 1998). There are no changes in ERG and almost no changes in Mf ERG in amblyopic patients. Purpose was to find any correlation between light sensitivity of temporal and nasal retinal segments, Mf ERG and VEP in children with disbinocular amblyopia (DA) and to elucidate privilege level of visual impairment in this kind of amblyopia the study was conducted.
Methods: :
35 children with DA 5-8 years old with visual acuity of 0,04 - 0,1 with eccentric fixation, without ocular fundus disturbances and 15 normal children were examined. Light sensitivity thresholds were measured with the help of Automatic Perimeter. Mf ERG and VEP were performed using RetiScan Roland System Germany. Using ISCEV guides for VEP, Mf ERG - N1, P1, N2, P2 were evaluated.
Results: :
The significant P1 amplitude decrease and latency increase was found in VEP of DA children in comparison with normal group. Changes in Mf ERG correlated significantly (especially in 2 (2,3-8 centigrade) and 5 th (24-32 circles, centigrade) in those children who had lower nasal periphery light sensitivity at 25-30 degrees eccentricity and lower temporal periphery light sensitivity at above 30 degrees eccentricity. In normal children peripheral light sensitivity did not correlate with Mf ERG amplitudes or latencies.
Conclusions: :
It is suggested that developmental impairments in children with high amblyopia are not only in primary cortex but in retina as well.
Keywords: amblyopia • electrophysiology: clinical • electroretinography: clinical