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Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

Part 2 book “Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders” has contents: Accommodative dysfunction, eye movement disorders , cyclovertical heterophoria, fixation disparity, refractive amblyopia, interactions between accommodation and vergence, and other contents. | 13 Eye Movement Disorders his chapter discusses the characteristics, diagnosis, and management of fixational, saccadic, and pursuit eye movement disorders. We use the term ocular motor dysfunction to refer to the condition in which there are problems in all three areas of eye movement function. In our experience, this is the most common clinical presentation. It is unusual to find saccadic dysfunction in isolation of fixational or pursuit anomalies, or pursuit dysfunction in isolation of fixational or saccadic anomalies. Eye movement disorders are a diagnostic and management concern of optometrists because of the effect such problems may have on the functional capability of an individual. Unlike accommodative (1) and binocular vision skills (2), which reach adult levels of development very early in infancy, clinical assessment indicates that eye movement development is considerably slower, continuing through the early elementary school years (3,4). The clinical picture of slow development is not consistent with the basic research data that suggest the presence of normal eye movements by approximately age 1 or 2 years. This apparent difference is likely to be related to cognitive and attentional factors affecting eye movements through about age 12. Because of the long developmental process for eye movement control, slow development can leave a child with inadequate skills to meet the demands of the classroom (5). Saccadic and pursuit dysfunction, therefore, primarily interfere with performance in schoolchildren, although some authors have reported the presence of these problems in adults as well (6,7). Much of the emphasis of both researchers and clinicians has been on the relationship between eye movements and reading. During reading, the three important components of eye movements are saccades, fixations, and regressions. Saccades take up approximately 10% of the reading time. The average saccade is about 8 to 9 character spaces, which is about a 2-degree visual .