Study on pattern visual evoked potential of children with unilateral congenital ptosis

【Objective】 To assess objectively the effect of unilateral congenital ptosis on visual function by pattern visual evoked potential.【Methods】 Fifty-one children with unilateral congenital ptosis were selected,at the age of 2.5 to 3 years old,excluding strabismus、 anisometropia or severe refractive errors.Pattern visual evoked potential examination at 30',15',7'spatial frequency stimulation performed in both the ptotic and normal eyes.【Results】 P100 amplitudes at each frequency of ptotic eyes were significantly lower than those of normal eyes(respectively,t =3.15,2.81,4.02,P =0.02,0.03,0.01).Only at 7' spatial frequency stimulation,P100 latencies were significantly longer in ptotic eyes(t =-2.96,P =0.03).At 15'and 7' frequency,severe drooping eyes had significantly longer P100 latencies(respectively,t =-3.46,-5.02,P =0.02,0.01),and lower amplitudes(respectively,t =3.04,4.12,P =0.03,0.01),compared with moderate drooping eyes.【Conclusion】 Unilateral congenital ptosis can cause visual impairment without associated to strabismus or refractive status,particularly eyes with severe ptosis.To patients under 3 years old,PVEP can be chosen as objective indicators of surgery timing.