#250250 and #250220 The non-translucent LEA SYMBOLS® chart #250250 is the original folding distance chart for preschool and kindergarten children and for assessment of vision of persons with difficulties in testing based on letters or numbers. It was designed in 1976 as one of the LEA Vision Test System tests to assess visual acuity. This… Read more »
#260200 – #260260 Large & Standard Stimulus, 16 HueDesigned by Lea Hyvärinen, MD Table of Contents To the Tester Neural Functions in Colour Vision Clinical Evaluation of Colour Vision Congenital Colour Vision Defects Acquired Colour Vision Defects Testing Procedures Older Children and Adults Young Children Acquired colour vision defect tested with different sorting tests Interpretation… Read more »
#252900 Developed by Lea Hyvärinen, M.D. We can see in bright daylight and in twilight. In daylight vision (photopic vision) we use cone cells. Activity in the cone cell pathway inhibits the rod cell pathway. When the luminance level becomes lower, input from cone cells decreases and input from rod cells increases (mesopic vision). When… Read more »
#254700 The LEA Mailbox Game (#254700) was designed for assessment of visual recognition of line directions. Some children and adults with brain lesions may be able to turn a ‘letter’ (the plastic card simulating a letter) in correct orientation when the task is to drop it through the slot, yet are unable to tell the… Read more »
#254600 The LEA Rectangles Game contains two groups of rectangles with different shades of grey. The total surface area of each rectangle is the same. This set of rectangles is a modification of Efron’s rectangles and was designed to allow observations on a child’s ability to see differences in size. To make the test situation… Read more »
#254500 The Heidi Expressions Test Game (#254500) has been developed to improve early evaluation of vision for communication. Among the vision impaired children there are some who cannot see expressions and/or do not recognize people by their faces. These children may have nearly normal results in routine vision tests (i.e. large visual field and normal… Read more »
#253000 & #253100 The smallest fixation stick (#253000) in the test materials has a picture of a smiling face 5 cm (2 in) in diameter. This kind of happily smiling face was chosen based on the studies by Robert Fantz. Normally developing infants respond to it, follow it with combined eye and head movements at the… Read more »
Causes of Changes in Processing of Visual InformationDisorders of the Eyes and Anterior Visual PathwaysLateral Geniculate NucleusProcessing of Visual Information in the BrainEarly Processing of Visual InformationProcessing of Visual Information in Ventral and Dorsal StreamThe Profile of Visual FunctioningRefraction and SpectaclesFactors Affecting the Test SituationsVisual SphereVisual FieldVisual AttentionFollowing Movements and SaccadesIllumination and PositionVideo RecordingsSummary Disorders… Read more »
If you do not have a test to assess central visual field, you can make it yourself. If you use the same place of a room with the same illumination each time, the visual field measurements are comparable over time. For the measurement on white paper you can arrange a low luminance level or a… Read more »
#280000 The LEA Flicker Wand is part of a functional vision assessment to estimate quickly the size of the visual field. For a quick estimate to determine whether major field losses exist, the findings are approximate. For exact measurements, use the flicker and the non-flicker stimulus on an arch perimeter. The luminance of the light… Read more »