Accommodative excess
Inability to relax accommodation for near work.
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Accommodative excess, also termed excessive accommodation or accommodation excess, is a condition in which an individual uses more than the normal amount of accommodation for near work. Traditionally defined as accommodation persistently higher than expected for the patient's age, it is now regarded as an inability to relax accommodation readily. It is notable for its association with excessive convergence.
Causes
Accommodative excess may occur in young hypermetropes as a physiological adaptation for clear vision. Young myopes performing excessive near work may also use excessive accommodation along with excessive convergence. An astigmatic eye or an early presbyopic eye can induce accommodative excess, as can improper or ill-fitting spectacles.
Systemic drugs such as Morphine, Digitalis, Sulfonamides, and Carbonic anhydrase inhibitors may cause it. Unilateral cases may arise from trigeminal neuralgia or head trauma causing ciliary spasm, while bilateral cases may follow encephalitis, syphilis, head trauma, influenza, or meningitis. It can also be secondary to convergence insufficiency, where reduced positive fusional vergence prompts excessive accommodation to stimulate accommodative convergence.
Did You Know?
- Pseudomyopia, also known as artificial myopia, refers to an intermittent and temporary shift in refractive status towards myopia and may occur due to excessive accommodation or spasm of accommodation.
- Parinaud's syndrome can mimic some aspects of spasm of the near reflex, such as excessive accommodation and convergence, but features pupillary near-light dissociation rather than miosis.
More in Disorders of Ocular Muscles, Binocular Movement, Accommodation and Refraction
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Accommodative excess (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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