paresis of accommodation

Paresis of accommodation is a marked reduction in accommodative ability, usually of sudden onset and with an organic cause. When the accommodative system fails to respond to any stimulus, the condition is called paralysis of accommodation, which is very rare. The loss can affect one eye or both.¹

Paralysis of the ciliary muscle causes the loss despite a physically normal crystalline lens.¹ In a third nerve palsy, paresis of the ciliary muscle and the iris sphincter is called internal ophthalmoplegia, and a complete oculomotor palsy abolishes both pupil action and accommodation.² Damage to the ciliary ganglion or the short ciliary nerves, as in a tonic pupil, also causes accommodative paresis, because those nerves supply both the pupillary sphincter and the ciliary muscle.³ Other causes include infection, food poisoning, diabetes, cycloplegic drugs, and congenital, toxic, traumatic and neurologic disorders.¹

A nonpresbyopic patient who loses accommodation complains of blur, most noticeably when reading, and micropsia may accompany the blur.^3,4 Reported causes include trauma, toxicity, Adie's pupil, neuropathy and cycloplegic drugs, and the cause should be identified if possible.⁴