Abstract
Abstract: :
Purpose: The low vision evaluator (LoVE) is an instrument capable of measuring and quantifying the visual capabilities of patients with very poor visual acuity. The purpose of this study was to determine whether reliable measurements of the visual acuity can be obtained with this instrument from young children with light perception (LP) acuity. In addition, we examined at what age reliable measurements of the visual acuity could be obtained from children with better visual function. Methods: The LoVE is equipped with a pair of goggles with white light-emitting diodes for a stimulus, a control box, a hand-held grip with a button to signal the detection of a stimulus, and a printer for permanent records. Stimuli of 9 different levels could be delivered in a random sequence with an audio signal presented 0.7 second prior to the light stimulus. Each eye was tested separately, and each stimulus magnitude (intensity × duration) was presented 3 times, and with 3 catch trials, a total of 30 stimuli were presented in one full examination for each eye. The subjects were 70 children with ocular diseases such as retinopathy of prematurity, leukoma, persistent hyperplastic primary vitreous, amblyopia, strabismus, ametropia, ciliary entropion and allergic conjunctivitis. Results: It was possible to grade the visual function of children with LP acuity into finer grades, and reliably measurements were obtained on different days and at different times. False positive responses (responses to the 6 catch trials) were less than 10% for children over 4-year-of age, and the responses of over 4-year-old children were significantly better than those of 3-year-olds. Conclusions: These results demonstrated that the LoVE instrument is capable of grading the visual function of children with conventional LP vision into finer steps. The testing procedures were simple, and reliable measurements could be obtained for even 4-year-old children.
Keywords: visual development: infancy and childhood • visual acuity • visual search