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Convergence Insufficiency
· What is Convergence Insufficiency? · Symptoms · Causes · Convergence Insufficiency and ADHD
What is Convergence Insufficiency? Simple Explanation of Convergence Insufficiency "This is a condition in which the muscles of the eye responsible for convergence (turning the eyes in) appear to be weak, at least relative to the muscles responsible for divergence (turning the eyes out). However, the patient's eyes remain straight in all fields of gaze. This results in "strained" eyes and the affected individual complains of headache, eyestrain, blurred vision, or fatigue with continued efforts at near work. This condition most commonly occurs in teenagers and young adults, though it can occur up through middle age." EyeMDLink.com: Convergence Insufficiency
Detailed Explanation of Convergence Insufficiency "Convergence insufficiency is a common condition that is characterized by a person's inability to maintain proper binocular eye alignment on objects as they approach from distance to near. There is typically an exophoria or intermittent exotropiaat near, a receded near point of_convergence, reduced positive fusional convergence amplitudes, and a low accommodation convergence/accommodation (AC/A) ratio. The symptoms associated with convergence insufficiency vary from mild to severe, but they are often extremely troublesome for those patients with this condition, especially when associated with a small angle exotropia at the near working distance." eMedicine - Convergence Insufficiency
Lack of Symptoms ”Many patients with objectively measured convergence insufficiency may not complain of symptoms. This usually occurs because of suppression of the nonfixating eye or avoidance of near vision tasks." eMedicine - Convergence Insufficiency
Most Common Symptoms "The most common symptoms associated with convergence insufficiency include asthenopia (eyestrain) and headache, diplopia [double vision], blurred vision, and moving of print." eMedicine - Convergence Insufficiency
"…Fatigue, frequent loss of place when reading, and frank binoculardiplopia associated with near point tasks are among the symptoms associated with this condition." eMedicine - Convergence Insufficiency
"Patients typically present as teenagers or in early adulthood, complaining of gradually worsening eyestrain, periocular headache, blurred vision after brief periods of reading, and, sometimes, crossed diplopia with near work. It is not unusual for the patient to squint one eye while reading to relieve blurring or diplopia. Few, if any, symptoms are present atdistancefixation. eMedicine - Convergence Insufficiency
"When the two eyes fail to work together as an effective team, performance in many areas can suffer (reading, sports, depth perception, eye contact, etc.)."
"Symptoms are aggravated by illness, lack of sleep, anxiety, and prolonged near work." eMedicine - Convergence Insufficiency
"The frequency of symptoms may increase with age as patients' ability to compensate for their relative divergent binocular alignment decreases with time. " eMedicine - Convergence Insufficiency
"The causes of convergence insufficiency are not completely clear. A connection has been made between accommodative insufficiency and convergence insufficiency. A significant exophoria at near with inadequate fusional convergence appears to be the primary underlying problem. von Graefe, who first described the condition in 1855, believed that this condition was myogenic in etiology, but subsequent electromyographic work has failed to demonstrate this theory." eMedicine - Convergence Insufficiency
Close-Up Work "…Many patients with this disorder have vocational and/or avocational visual demands that require prolonged close-up work. The most common presentation encountered by a clinician is that of a high school or college student who develops symptoms when excessive demands are placed on the visual system during extended periods of studying." eMedicine - Convergence Insufficiency
Accommodative Dysfunction and Convergence Insufficiency "Some cases of convergence insufficiency also appear to have an etiologic connection to accommodative dysfunction." eMedicine - Convergence Insufficiency
"Accommodative insufficiency often is associated with convergence insufficiency and symptoms of asthenopia [eyestrain] and headache. This occurs as the patient tries to eliminate near vision blur by increasing accommodative effort. The increased accommodative effort results in increased convergence, which may be more than what is required for the near vision task, thereby resulting in anesophoria (as mentioned above). This also explains why the frequent accompaniment of blurry vision and diplopia with asthenopia and headache symptoms occurs." eMedicine - Convergence Insufficiency
"This [eyestrain] most commonly occurs due to the sustained increased effort required to increase fusional convergence." eMedicine - Convergence Insufficiency
· Three-Dimensional Stereo Images
Convergence Exercises (Orthoptic Therapy) and/or Base-In Prisms "Convergence exercises (orthoptic therapy) and/or base-in prisms are the mainstays of treatment for convergence insufficiency. · Orthoptics · Near point of_convergence exercises: An accommodative target, such as the point of a pencil (ie, pencil push-ups), is placed remote to the patient’s near point of_convergence and gradually brought toward the tip of the nose with the patient converging to avoid diplopia. Just before there is a break in fusion, the patient holds fixation the target for 10 seconds. This so-called push-up is repeated 10 times, 2-4 times a day, until the patient is able to hold fixation to the tip of the nose. The exercises can be tapered and then used on an as-needed basis when the patient notices a recurrence of symptoms. · Other forms of convergence training: Base-out prism reading and stereogram cards may be used by an orthoptist to improve fusional convergence. New, affordable computerized fusional vergence training programs (e.g., Computer Orthoptics) are available. These self-paced programs can be used on a personal computer at the patient's home. · Base-in prisms for near only: These prisms can be ground into a separate pair of reading glasses, or Fresnel membrane prisms can be fitted over the reading segment of the patient’s bifocals." eMedicine - Convergence Insufficiency
More Information about Convergence Exercises "As previously mentioned, this condition is thought to be due to a relative imbalance in eye muscle strength. The patient may be instructed to perform a variety of eye exercises which result in convergence, that is, turning inwards of the eyes. This requires repeatedly bringing a small object, such as the head of a pencil, toward the face while maintaining fusion (keeping the image single). When fusion is lost (the image becomes double) the object is removed and the exercise repeated. These exercises are usually recommended several times a day. Adding a small base-out prism in front of one eye may increase the intensity of the exercise." EyeMDLink.com: Convergence Insufficiency
Other Problems to be Considered "Uncorrected high hypermetropia or myopia; …Convergence insufficiency associated with
accommodative insufficiency: Patients with combined convergence and
accommodative insufficiency are usually more symptomatic than those
with convergence insufficiency alone. However, symptoms alone are not
sufficient to distinguish between these 2 entities, and all patients who
present with convergence insufficiency should have accommodative amplitudes
checked since satisfactory treatment depends on a correct diagnosis. Anticholinergic
drugs, closed head trauma, and viral encephalopathies should be
considered in the pathogenesis of this disorder. In addition to treating the
convergence weakness, plus lenses should be prescribed to these
patients for reading. eMedicine - Convergence Insufficiency
Lack of Treatment Untreated, the exophoria at near may break down to a poorly controlled intermittent exotropia. Fortunately, in most cases, convergence insufficiency is very amenable to orthoptic treatment." eMedicine - Convergence Insufficiency
Psychological or Physiological? "In the past, many ophthalmologists considered convergence insufficiency and its associated symptoms to be a neurotic manifestation of nonrelated psychologic problems best dealt with by a psychiatrist. However, it is now clear that convergence insufficiency is a legitimate, problematic binocular dysfunction. The clinician must consider whether the behavioral manifestations displayed by patients really result from the frustration caused by their inability to perform desired near visual tasks." eMedicine - Convergence Insufficiency
While doing the pencil push-ups exercise it is important that you do not strain your eyes while looking at the pencil. Straining your eyes causes accommodative insufficiency. More information about accommodative insufficiency is included in the Causes section and on the Accommodative Insufficiency page.
More definitions for terms which may be found on the eMedicine - Convergence Insufficiency page
Convergence Insufficiency and ADHD "'Convergence insufficiency may not be well known outside the field of eye care specialists,' Granet told Reuters Health. 'We don't know if children are being misdiagnosed with ADHD [attention-deficit/hyperactivity disorder] when they truly have convergence insufficiency or vice versa,' he said. 'We also don't know if one causes the other or if medications used for ADHD cause convergence insufficiency,' he added." Eye disorder linked to ADHD in children
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