Day gets the child’s attention with a small blinking toy that can be held either by the photographer or an assistant. Making sure the child is looking in the right direction is not a problem, she says, because the toy is an effective attention grabber. An off-axis gaze is usually either readily apparent to the photographer or by looking at the picture.
If the child was gazing in the camera’s direction, the red glow appears when the pictures are developed. If the child is myopic, Day says, then the pupil is red except for a bright yellow crescent at the bottom. Hyperopic pupils have a crescent at the top. The bigger the crescent, as determined as a percentage of the total pupil size, the higher the refractive error.
Children with anisometropia have different sized crescents in each pupil. In children with strabismus, the red reflex may be asymmetrically located in one eye compared to the other. And, cataracts or other media opacities of the lens, cornea, or fluids show up as a darker spot in the red reflex. Though she says she has not tested enough infants or young children with no refractive error to know for sure, in adults and older children with reliable fixation they have never seen a crescent in an emmetropic eye.
Day says she has photographed more than 250 infants and children using this method. In a recently published study (Ophthalmol 1986;93:25-28), Day and her colleagues photographed 47 infants and young children, both with and without cycloplegic drops, and compared the results of photorefraction with the findings of conventional retinoscopy under cycloplegia. Take advantage of this opportunity – buy cheap cipro buy here to enjoy lowest prices online.