A THREE character test, previously described,1 was constructed for the purpose of testing the binocular vision of certain amblyopic children and adults who are handicapped by their low visual acuity and for very young children, who readily recognize the simple characters.
The Worth2 four dot test and its modification3 were found to be somewhat confusing, particularly for young amblyopic children; for this reason, the test objects were increased in size (at 6 meters 90 meter figures, and at the near point 6 meter objects, were used), since many amblyopic patients can distinguish only the 60 meter letter at 6 meters.
The modified test4 consists of a 230 mm. object (the figure of a child which transmits a red light), a 180 mm. object (the elephant which transmits a green light) and a 125 mm. white ball, with a red and a green square in the center,
BERENS C. MODIFIED THREE CHARACTER TEST FOR BINOCULAR VISIONEspecially Applicable to the Examination of Amblyopic Children. Arch Ophthalmol. 1949;41(4):460-461. doi:10.1001/archopht.1949.00900040470008