2. It is based on the principle of dissociation
Maddox Rod consists of a series of plano cylinder
lenses about 3mm in diameter, mounted in a trial
frame lens or in a refractor head
A spot of light viewed through the Maddox rod
appears as an elongated streak
The Maddox rod is often colored usually red.
3.
4.
5. USES
Used to find out presence of heterophoria .
Easy for patient to understand
Easy to administer
Very useful for vertical deviation
May be done in free space
6. MADDOX ROD TEST
Equipment required are
(1) Maddox rod
(2) Small fixation light
(3) Prism(to asses the degree of deviation)
7. PROCEDURE
Reduce room illumination
Maddox rod is placed in front of one eye
Measuring horizontal deviations Maddox rod axes
are placed horizontal which produces vertical
streak
Measuring vertical deviations Maddox rod axes are
placed vertical which produces horizontal streak
Patient initially views with both eyes open
8. PROCEDURE FOR HORIZONTAL DIVIATION
Maddox rod is placed horizontally(vertical streak) in
front of right eye
With strabismics,the Maddox Rod is best placed
over the fixating eye.
Ensure that patient can see white light and streak
simultaneously
Ask if the streak is to the right or to the left of the
light.
9.
10. With Maddox Rod in front of the right eye
If the vertical streak of line passes directly through
the centre of the spot light it indicates orthophoria
If the vertical streak of light appears to the left of the
spot light it indicates exophoria.
If the vertical streak of light appears to the right of
the streak light it indicates esophoria.
11. The amount of deviation can be assessed by
placing prism bar in front of the eye.
Place base out for eso and base in for eso
deviation.
Keep on increasing the strength of the prism until
the streak of the light passes through the centre of
the prism.
The strength of the prism indicates the amount of
deviation present.
12. FOR VERTICAL DIVIATION
Same procedure is followed expect Maddox rod is
placed with its axes vertically producing horizontal
streak of light
If the horizontal streak of light is above the fixation
light it indicates presence of hypo deviation
If the horizontal streak of light is below the fixation
light it indicates presence of hyper deviation.