Effects of Duane's retraction syndrome on sensory visual development

To study the effects of Duane's retraction syndrome on sensory visual development.

Monocular and binocular visual function and ocular motility have been studied and pattern reversal visual evoked potentials recorded from 22 patients with Duane's syndrome aged from 4 to 55 years.

Sixteen of the patients maintained binocular single vision using an abnormal head posture. All had normal visual acuities in both eyes. The 12 adults in this group had a mean stereoacuity of 78 seconds of arc with the Titmus stereotest and 101 seconds of arc with the TNO test. Both these values were significantly worse than for normal adults with a similar age range. The binocular VEPs from these patients showed enhancement of the binocular P100 VEP amplitude compared to the mean monocular P100 amplitude when they used their head posture but, unlike in normal subjects, this binocular enhancement was not reduced significantly after the age of 5. Six patients had lost binocular function and had a manifest convergent squint. Of these, 4 were anisometropic. VEPs in this group showed mildly delayed P100 latencies in the affected eye with asymmetric amplitudes even though their amblyopia had been successfully treated by patching and only one patient had a substantially reduced acuity. In neither group was there any relationship between the degree of restriction of ocular motility and the sensory changes.

Patients with Duane's syndrome who retain binocular single vision show abnormal binocular visual maturation after the age of 5 years. This results in reduced stereoacuity in the absence of amblyopia.