Also found in: Dictionary, Thesaurus, Encyclopedia.
The inability of the eye to sustain accommodation over time. It is usually due to repeated or sustained visual effort.
See also: fatigue
Medical Dictionary, © 2009 Farlex and Partners
Insufficient amplitude of accommodation that is unequivocally below the appropriate level for the age. It may be due to extreme fatigue, influenza, high stress, systemic medication, ocular inflammation, head trauma, thyroid disease or the juvenile form of diabetes mellitus. The condition is often associated with convergence insufficiency, general fatigue, measles, multiple sclerosis, or myotonic dystrophy, etc. It is the most common accommodative dysfunction. Patients complain of blurred vision, or difficulty in sustaining clear vision at near; this is often accompanied by a frontal headache and even sometimes by pain in the eye. A mild form of accommodative insufficiency is often referred to as ill-sustained accommodation (accommodative fatigue) in which the response may be initially normal but cannot be maintained. It is easily discovered with accommodative facility exercises. Ill-sustained accommodation may be a precursor of accommodative insufficiency. Treatment is aimed at the primary cause, but plus lens correction, and in some cases exercises such as accommodative facility training are prescribed. Syn. premature presbyopia. See convergence insufficiency; ocular headache; thyroid ophthalmopathy.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann