Injury or disorder affecting the function of the oculomotor nerve or ciliary muscle

In the Statement of Principles for Accommodation Disorder "an injury or disorder affecting the function of the oculomotor nerve or ciliary muscle" means "any pathological process affecting the brain stem or the oculomotor nerve anywhere along its course (including the oculomotor nucleus, fascicles, subarachnoid space, cavernous sinus or orbit) that leads to a disturbance in the oculomotor nerve function, or ciliary muscle function, causing impairment of accommodation".

• The oculomotor nerve is the third of twelve paired cranial nerves.  It controls most of the eye's movements, constriction of the pupil, and maintains open eyelids.
• The ciliary muscle is a muscle in the eye that controls the eye's accommodation for viewing objects at varying distances.  The ciliary muscle affects zonular fibers in the eye (fibers that suspend the lens in position during accommodation), enabling changes in lens shape for light focusing.  Tension of the ciliary muscle causes the release of tension of the zonular fibers which causes the lens to become more spherical, adapting to short range focus.  Alternatively, relaxation of the ciliary muscle causes the zonular fibers to become taut, flattening the lens, increasing long and short range focus.

Establishing the presence of the injury or disorder

The history of the condition causing impairment of accommodation should have been noted on the medical records.  If it is not clear if this condition was present at a particular time, seek medical advice.