Types of ocular movements

Ocular Movements are of 2 types

1. Unilateral
2. Binocular

Unilateral Ocular Movements

Unilateral movements are called ductions and include the following:

1. Adduction. It is inward eye movement (medial rotation) along the vertical axis.
2. Abduction. It is outward eye movement (lateral rotation) along the vertical axis.
3. Supraduction. It is upward eye movement (elevation) along the horizontal axis.
4. Infraduction. It is downward eye movement (depression) along the horizontal axis.
5. Incycloduction (intorsion). It is a rotatory movement along the anteroposterior axis in which superior pole of the cornea (12 O’clock point) moves medially (internal rotation).
6. Excycloduction (extorsion). It is a rotatory movement along the anteroposterior axis in which superior pole of the cornea (12 O’clock point) moves laterally (external rotation).

Binocular Ocular Movements

These are of two types:

• Versions
• Vergences.

Versions

Versions, also known as conjugate movements, are simultaneous symmetric movements of both eyes in the same direction. These include:

1. Dextroversion. It is the movement of both eyes to the right. It results due to simultaneous contraction of right lateral rectus and left medial rectus.
2. Levoversion. It refers to movement of both eyes to the left. It is produced by simultaneous contraction of left lateral rectus and right medial rectus.
3. Supraversion. It is upward movement of both eyes in primary position. It results due to simultaneous contraction of bilateral superior recti and inferior obliques.
4. Infraversion. It is downward movement of both eyes in primary position. It results due to simultaneous contraction of bilateral inferior recti and superior obliques.
5. Dextroelevation. It is movement to the right and up side. It is caused by simultaneous action of right superior rectus and left inferior oblique.
6. Dextrodepression. It is movement to the right and down side. It is caused by simultaneous action of right inferior rectus and left superior oblique.
7. Levoelevation. It is movement to the left and up side. It is caused by simultaneous action of left superior rectus and right inferior oblique.
8. Levodepression. It is movement to the left and down side. It is caused by simultaneous action of left inferior rectus and right superior oblique.
9. Dextrocycloversion. It is rotational movement around the anteroposterior axis, in which superior pole of cornea of both the eyes tilts towards the right.
10. Levocycloversion. It is just the reverse of dextrocycloversion. In this superior pole of comea of both the eyes tilts towards the left.

Vergences

Vergences, also called disconjugate movements, are synchronous and symmetric movements of both eyes in opposite directions e.g.

1. Convergence. It is simultaneous inward movement of both eyes which results from contraction of the medial recti.
2. Divergence. It is simultaneous outward movement of both eyes produced by contraction of the lateral recti.