2. It is based on the principle of dissociation
Maddox Rod consists of a series of plano
cylinder lenses about 3 mm 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
Fakhruddin Aliasger
5. Uses
Used to find out presence of heterophoria or
heterotropia
Easy for patient to understand
Easy to administer
Very useful for vertical deviations.
May be done in free space
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6. Maddox rod test
Equipment required are
1. Maddox rod
2. Small fixation light
3. Prisms ( to asses the degree of deviation )
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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
Fakhruddin Aliasger
8. Procedure for horizontal
deviation
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
Fakhruddin Aliasger
10. With maddox rod infront of 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
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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 exo
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
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12. For vertical deviations
Same procedure is followed except 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
Fakhruddin Aliasger