The etiology of squint is unknown. This is the major cause of the uncertainty which still exists concerning the proper methods of treatment. Those who regard squint as a process in which binocular vision is prevented through obstacles of anatomical or dioptric nature will expect success through the reeducation of binocular vision after removal of the aforesaid obstacles ("orthoptic therapy"). Those who, on the contrary, are of the opinion that the capability for full binocular vision is fundamentally lacking in squint will, unless they share Worth's optimism, be satisfied with the treatment of the amblyopia, refractional anomaly, and anatomical deviation, expecting scant results from orthoptic procedures. The majority of ophthalmologists vacillate between these extreme positions but want to know how many cases come under consideration for orthoptic treatment, which cases, and with what chance for success.
Two lines of investigation are necessary to answer these questions: (1) an investigation dealing
CRONE RA, VELZEBOER MJ. Strabismus in Statistics on Strabismus the Amsterdam YouthResearches into the Origin of Strabismus. AMA Arch Ophthalmol. 1956;55(4):455-470. doi:10.1001/archopht.1956.00930030459002