Abstract
Purpose: :
Periocular infant vascular lesions may cause amblyopia by any of 3 mechanisms: occlusion; strabismus; and anisometropia. In some children vascular birthmarks are present and intermittently occlude one eye, but clinical findings of amblyopia are lacking. We undertook a study of 4 such infants to learn whether electrophysiological changes occur even in the absence of clinically recognizable amblyopia.
Methods: :
4 consecutive infants with unilateral periocular vascular lesions and no clinical evidence for amblyopia were evaluated, ranging in age from 7 to 19 months. No child had anisometropia greater than 0.75 D in the greatest meridian. In one, occlusion at birth for 2 weeks required early eyelid surgery, with no resulting clinical signs of amblyopia. In the others no surgery was required. Sweep VEP vernier acuity was measured under monocular viewing conditions with the fellow eye tested as the control. Infants were situated so that the lesion did not block the view of the stimulus. Sweep range was 8 to 0.5 arc min. Multiple trials were averaged, and response amplitude and phase were compared in the affected and fellow eyes.
Results: :
Response amplitudes were significantly diminished in the affected eyes. A phase analysis showed a significant slowing of the response in the affected eyes compared with the control eyes.
Conclusions: :
An amblyopia-like effect on vernier acuity occurred in infants with unilateral periocular vascular birthmarks when the lesion caused intermittent occlusion of the eye. Whether long term effects will occur is unknown, but children with apparently no amblyopia in the setting of a vascular mark probably should be followed, since sVEP findings suggest amblyopia is present.
Keywords: amblyopia • visual acuity • electrophysiology: clinical