Visual Evoked Potentials in Management of Amblyopia in Children

Overview

Goal:
The authors want to point out the possibility of using the visual evoked potentials (VEP) in the diagnostic process of amblyopia, especially in preverbal children. We also researched the possibility of screening for amblyopia with VEP in young patients with anisometropia without strabismus being present, especially those who come from affected families. The authors followed changes in the course of an occlusion therapy and suggest that VEP could be used to predict a success of the amblyopia therapy.

Material and methods:
We analyzed group of 45 pediatric patients ages 2–10 years who were investigated in years 2006–2009 at Pediatric Ophthalmology Department of Children University Hospital in Bratislava with amblyopia. This group was compared with a control group of 25 healthy children. The cause of amblyopia in a majority of children (29 patients) was hyperopic anisometropia, 13 children had hyperopic isometropia, 3 patients had myopia over -3D. These causes in 22 children were combined with strabismus. The monocular pattern of VEP was evaluated in all patients. In cooperative children (25) we also evaluated binocular pattern of VEP. 18 patients with amblyopia had a second VEP evaluation done during the occlusion therapy, among those were 23 amblyopic eyes. The time frame from the first VEP evaluation to the second VEP evaluation was 1–11 months, average 5,1 months. The material was statistically evaluated.

Results:
Our study showed statistically significant prolongation of the latency of both P and N2 waves (p = 0.01) in children with amblyopia. This can be used in diagnostic process of amblyopia in preverbal children as well as in the screening for amblyopia. We also followed changes during the occlusion therapy and we discovered persistent prolongation of the latency of the P wave and also changes in the amplitudes (p = 0.05) During repeated measurements and with applied therapy one can follow the dynamics of amblyopia, course of therapy by VEP changes.

Conclusions:
Results of our research suggest a great contribution of VEP especially in the diagnosis of anisometropic amblyopia, especially in preverbal children. The advantage of VEP is in the screening, prediction and dynamics of therapy too. The amblyopia management is a long lasting process requiring a thorough communication and cooperation among the patient, parent and a doctor.

Key words:
visual evoked potentials, VEP, amblyopia, occlusion therapy