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

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

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

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2ers. We use the term oculur motor dysfunction to refer to the condition in which there are. problems in all three areas of eye movement function. In o

ur exjKtrience, this is the most common clinical presentation. Il is unusual lo find saccadic dysfunction in isolation of fixational or pursuit anomal Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

ies, or pursuit dysfunction in isolation of taxational or saccadic anomalies.Eye movement disorders are a diagnostic and management concern of optomet

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

rists because of the effect such problems may have on the functional capability of an individual. Unlike accommodative (1) and bin ocular vision skill

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2er, continuing through the. early elementary school years (3,4). Ihe clinical picture of slow development is not consistent with the basic research da

ta that suggest the presence, of normal eye movements by approximately age I or 2 years. Ibis apparent difference is likely to be related to cognitive Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

and attentional factors affecting eye movements through about age 12. Because of the long developmental process for eye movement control, slow develo

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

pment can leave a child with inadequate skills to meet the demands of the classroom (Ó). Saccadic and pursuit dysfunction, therefore, primarily interf

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2sis of both researchers and clinicians has Ix'.e.n on the relationship Ixtlween eye movements and reading. During reading, the three important compone

nts of eye movements are saccades, fixations, and regressions. Saccades take up approximately 10% of the reading time. The average saccade is about 8 Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

to 9 character spaces, which is about a 2 degree visual angle (8). The duration of the saccade is a function of the. distance covered. I or instance,

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

a 2-degrce saccade, lakes about 25 lo 30 milliseconds (ms), and a 5-dcgree saccade lakes about 35 lo 40 ms (8). Between saccades, the eye is relativel

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2ng eye movements is the great variability both within anil between subjects. Saccade lengths can vary from 2 to 18 character spaces, and fixation dura

tion values can range from 100 to over 600 ms, (or a single reader within a single passage (8). The third important characteristic of reading eye move Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

ments is the regression. A regression is a right-to-left movement, and it occurs 10% to 20% of the time in skilled readers. Regressions occur when the

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

reader overshoots the target, misinterprets the text, or has difficulty understanding the lexl.Because eye movement deficiencies intuitively seem Io

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2s are equivocal and, at times, confusing. Limitations and differences in experimental design, methodology, statistical procedures, and assumptions amo

ng these studies have created difficulty in their interpretation (6). Two basic viewpoints have evolved about the relationship between eye movements a Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

nd reading. The first suggests that eye movement disorders can cause below-avcrage reading ability (9-27). Investigators, using a variety of methods t

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

o assess eye movements, have found that poor readers tend to make more fixations and regressions than normal readers (10-20,27). rhe second view is th

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2, the reading difficulty itself leads to erratic and inconsistent eye movements (26.28-32).A third perspective is probably most likely to be correct a

nd is essentially a combination of the first two viewpoints. This alternative (4) suggests that, in some cases, problems with fixation and saccadic ab Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

ilities may be a primary factor interfering with a child's ability to read quickly, comfortably, and with adequate comprehension. In other cases, the

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

eye movement deficiencies observed during reading may simply be a reflection of poor reading ability.368(c) 2015 Wolters Kluwer. All Rights Reserved.c

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2cesses such as attention, memory, and the utilization of the perceived visual information (3,33-40). Some optometrists believe that there is a relatio

nship between poor ocular motor skills and atten-lional problems (41). When such a relationship exists, treatment of eye movement disorders may lead t Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

o improvement in attention and concentration (38-41).There have been few studies of the prevalence of eye movement disorders, particularly in the popu

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

lation of normally achieving children and adults. In children with reading and other learning difficulties, several studies have found a very high pre

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2und that 96% had problems with ocular motor inefficiency (saccadic and pursuit problems). He did not state how eye movements were evaluated or his cri

teria for establishing a diagnosis ol ocular motor inefficiency. Hoffman (43) reported on a sample ol 107 children between the ages ol 5 and 14 years Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

with learning problems. He evaluated pursuits and saccades using the qualitative scales described in chapter 1 along with an objective assessment usin

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

g the Eye 'I rac. The criteria for a diagnosis of ocular motor dysfunction were performance below a 3 I on the subjective clinical observation or 2 ye

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2 on the results of 25 children without learning problems and found that 24% had ocular motor problems. It is interesting to note that both Hoffman and

Sherman found that ocular motor dysfunction was the most prevalent vision disorder in their samples of learning disabled children. I ieberman (44) st Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

udied the prevalence of vision disorders in 55 children Ixtlween the ages of 8 and 10 years al a scluxd for children with emotional disorders. I le us

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

ed oliscrvational scales and the New York Stale Oplomelric Association King-1 x-.vick lest (NYSOA K-D) lest to evaluate saccades, llic NYSOA K-l) lest

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2 of the children had saccadic dysfunction and 43% had pursuit anomalies. In this same study. Lieberman reported that in a sample of 1.681 children in

a normal population, the prevalence of saccadic dysfunction (using the NYSOA K D test) was 22.6%.Jainla and Kajxtula (45) examined the relationship Ix Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

Hwecri saccades and vergence control during real text nailing. Ihirlcen dyslexic and seven non-dyslexic children read the I Tench lexl I .’Allouelle"

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

in two viewing distances (40 cm vs. I (X) cm), w hile bin

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2ity. The fixation disparity was larger for dyslexic children, making a larger demand on their sensory fusion processes. The authors concluded that vis

ual/ocular motor imperfections may exist in dyslexic* that lead Io fixation instability ami thus. Io instability of the letters or words during readin Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

g.In our experience, anti in the three studies described alxwe (42—44), eye movement disorders are rarely pre_se.nl in isolation. Rather, they arc gen

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

erally fount! associated will) accommodative, bimxrular, and visual perceptual dysfunctions. As a result, treatment of eye movement deficiencies gener

13Eye Movement Disordershis chapter discusses the characteristics, diagnosis, and management oi fixational. saccadic, and pursuit eye movement disorde

Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2eeded into the prevalence of eye movement disorders to clarify their role in reading and other areas of function. Regardless of these shortcomings in

the literature, clinicians are regularly faced with children and adults presenting with signs and symptoms suggestive of fixation, saccadic, and pursu Ebook Clinical management of binocular vision heterophoric, accommodative, and eye movement disorders (4/E): Part 2

it disorders. Psychologists ami educators often refer children with concerns about poor tracking, skipping words and lines, and losing place when read

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

ing. In addition, Solan (6) has demonstrated that there are adults with eye movement problems that interfere with their performance in school and at w

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