manishchaudhary

1. Presented By: Manish Chaudhary
B.Sc.Optometry ,3rd year

2.  To understand the occular movements and their
mechanisms, a frame reference against which the
movement may be quantified is necessary.
 There are mainly 3 position of eye i.e.
Primary position
secondary position
Tertiary Position

3.  Primary position of the eye is that position from which
all other ocular movements are initiated changing the
position of eyeball from primary to secondary or
tertiary.
 The primary position has been described by the scobee
as that of that position of the eyes in binocular vision
when, with the head erect,the object of regard is at
infinity.

4.  These are the position assumed by the eyes , while
looking straight up ( supraversion ),straight
down(infraversion),to the right(dextroversion), and
to the left(levoversion).

5.  These described the position assumed by the
eyes,when combination of vertical and
horizontal movements occur.
 These include position of the eyes in
dextroelevation,dextrodepression,levoelevati
on,and levodepression.

6.  All the extraoccular muscles have a given tone
for every position of gaze.
 There are total 9 position of gaze,these include,
1 primary gaze,4 secondary gaze ,4 tertiary
gaze.

8.  These are the position which allow
examination of each of the 12 extraoccular
muscles of the two eyes,in their main field of
action .

9.  It refers to a hypothetical point around which
the eyeball performs rotatory movements.
 Earlier this has been assumed that the center
of rotation is a fixed point.
 It has been reported that the center of rotation
moves in a semicircle in the plane of
rotation,this is called the space centroid.

10.  Ficks described three axes to analyse all
movement of the globe around the
hypothetical centre of rotation.
 The proposed three axes are perpendicular to
each other and intersect the center of rotation
of the eye.

11.  It lies horizontally ,when the head is in an
upright position.
 Rotation around the horizontal axis result in
elevation (sursumduction)or depresssion
(deosursumduction).

12.  The anteroposterior axes of the two eyes
are parallel to each other and
perpendicular to the horizontal axis
results in elevation or depression.

13.  It extends vertically when the head is in upright
position and is perpendicular to the x and y axes.
 Rotation of globe around the vertical axes are
known as adduction and abduction.

14.  The listing plane also contains two oblique axes o-o
which allow the eyeball to rotate obliquely up and in
and out ,down and down and out.

15.  THANK
YOU