Duction Explained

A duction is an eye movement involving only one eye.^[1] There are generally six possible movements depending upon the eye's axis of rotation:

1. Abduction refers to the outward movement of an eye.
2. Adduction refers to the inward movement of an eye
3. Supraduction / sursumduction / elevation
4. Infraduction / deorsumduction / depression
5. Incycloduction / intorsion
6. Excycloduction / extorsion

Forced duction test

The forced duction test is performed in order to determine whether the absence of movement of the eye is due to a neurological disorder or a mechanical restriction.^[2]

The anesthetized conjunctiva is grasped with forceps and an attempt is made to move the eyeball in the direction where the movement is restricted. If a mechanical restriction is present, it will not be possible to induce a passive movement of the eyeball.^[3]

See also

• Extraocular muscles
• Eye examination
• Vergence
• Version (eye)

Notes and References

1. Kanski, JJ. Clinical Ophthalmology: A Systematic Approach. Boston:Butterworth-Heinemann;1989.
2. http://www.biology-online.org/dictionary/Forced_duction Forced duction - definition from Biology-Online.org
3. Kunimoto D, Kanitkar K & Makar M. The Wills Eye Manual. Office and Emergency Room Diagnosis and Treatment of Eye Disease. Fourth Edition. Lippincott Williams & Wilkins; 2004