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The following available tests, which are norm-referenced for the patient’s age and grade in school, clearly indicate the developmental course of skill improvement:¾ Developmental Eye Movement Test (DEM)¾ King-Devick Saccade Test (K-D).Unfortunately, naming tasks confound the results because both eye movement skill and naming speed are required to complete the test successfully. However, because the DEM incorporates a subtest of naming speed that isolates eye movement skill for a more specific clinical diagnosis, it’s use is preferred.The Care Process 15Infrared eye-monitoring systems that directly compute reading eye movements (e.g., Visagraph III, ReadAlyzer) are also available. Although they do not measure saccade dynamics (accuracy, latency) or main sequence, these assessment tools provide a simulation of eye movements over the text. Information is available on the number of fixations required to read a sample of text, the duration of fixation, as well as the number of regressions and reading rate, and by inference, the putative span of recognition (span of attention or perceptual span) – the spatial region (number of character spaces) from which the reader extracts information during a fixation – which may be narrow in disabled readers.123 Particular interest should be paid to return sweep saccades, which are presumably dominated by visual and ocular motor control processes.Eye alignment is usually determined by a distance and near cover test. If a strabismus is found, the Optometric Clinical Practice Guideline for the Care of the Patient with Strabismus: Esotropia and Exotropia should be consulted for additional information.1244. Accommodative-Vergence FunctionEvaluation of accommodation and vergence amplitude, facility, accuracy, consistency, and sustainability is required and may include the following procedures or measurements:¾ Cover test¾ Near point of convergence¾ Heterophoria, distance and near¾ Fusional vergence amplitudes, distance and near¾ Vergence facility¾ Amplitude of accommodation¾ Accuracy of accommodation (lag)¾ Relative accommodation¾ Accommodative facility¾ Fixation disparity analysis¾ Stereopsis16 Learning Related Vision ProblemsThe evaluation of accommodation and vergence should include assessment of both the range and facility of response. The ability to make rapid changes in accommodative and vergence responses is important for school-related tasks (e.g., copying from the chalkboard or taking notes). Facility testing also probes sustainability of the response, which is important for extended near-point activities (e.g., reading). The clinical signs and symptoms of accommodative and vergence dysfunctions can be found in Table 2.
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