A clinical study on the detection of strabismus, anisometropia or ametropia of children by simultaneous photography of the corneal and the fundus reflexes.

Twenty two strabismus and 106 straight eyed patients with anatomically normal eyes were first photographed with a conventional camera equipped with a weak 100 mm teleobjective and coaxial flashlight and then examined clinically. The possibility of detecting strabismus, anisometropias and ametropias in the photographs by noting the localisation of the corneal reflexes and examining the appearance and lightness of the fundus reflexes and their possible asymmetry were tested in a double blind study. Even small angled strabismus cases could be found because of the asymmetrical localisation of the corneal reflexes. In 18 of the 22 strabismus cases (82%) there was asymmetrical lightness of the fundus reflexes and the fundus reflex of the deviating eye was lighter than that of the fixating eye. All the straight eyed anisometropias of 3.0 diopters or more (five cases) were observed in the photographs because of the asymmetrical appearance of the fundus reflexes. In straight eyed anisometropias of under 3.0 diopters, the fundus reflexes were symmetrical in 90 cases and asymmetrical in 11 cases (11%). Only three out of eight hyperopias of fomr +4.5 to +6.0 diopters were found because of the light crescent in the low part of the pupil. All myopias of over -4.0 diopters (14 cases) were observed because of the light crescent appearance in the upper part of the pupil. No pupillary crescents appeared with refractions of less than -1.75 diopters myopia or less than +4.5 diopters hyperopia; 172 eyes came within this range. Even a technician can perform, without premedication, the method tested here for rapid and simple screening to detect strabismus and straight eyed anisometropias of 3.0 diopters or more in small children or other patients who do not co-operate well in normal clinical examination. Over -4.0 diopters myopias can also be found. The method was rather unreliable for finding hyperopias, presumably because no cycloplegic drops were used.