CYCLIC STRABISMUS - A CRITICAL-REVIEW OF THE LITERATURE AND REPORT ON2 NEW CASES

Cyclic strabismus. A critical review of the literature and report on t wo new cases. Description of cyclic strabismus has been restricted for a Long lime to circadian esotropia. In this mysterious phenomenon, th e eyes are crossed every other day with no binocular vision, but remai n perfectly normal during the straight days. The usual characteristics are those of a non-accommodative and non-paretic strabismus, with ons et in early childhood. There is no response to conservative treatment, and the cycles become irregular with time until the deviation becomes constant, with an excellent functional result after surgery in every case. Recently, other papers comprising data irrelevant to the classic picture suggest that cyclic strabismus includes, in fact, several dif ferent entities. The only common point is the existence of ocular moti lity disorders that recur more or less regularly, and whose pathologic substrate is primarily heterogeneous, whether it is thought as a mere hypothesis or a likely mechanism. Two new cases of circadian esotropi a are presented together with a review of the literature relating to t he criteria of the syndrome.