Patients with congenital nystagmus sometimes have other eye problems as well, such as cataracts, glaucoma, astigmatism or strabismus (cross-eyes). When these patients have eye muscle surgery to correct a problem, such as strabismus, their nystagmus also improves. Researchers think that simply cutting the muscles might produce this beneficial effect. This study will test this hypothesis-the horizontal muscles of the eye will be cut and then reattached in the same position. This procedure has been tried in one sheepdog with good results.