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1. Heterophoria
investigation and
management
Ananta poudel
B.optom 1st batch
NAMS

2. introduction
 Heterophoria is a condition where in the tendency of
the eyes to deviate is kept latent by the fusional reflex
 Orthophoria occurs where both visual axes are
directed towards the fixation point and no deviate on
dissociation.

3. intro.cont.
 large as 25˚
 small as 5˚ (microtropia).
 Nature of deviation depends upon the degree of fusion
amplitude.

4. EVALUATION.
1) Examination of patient comprises of detailed history.
2) Determination of visual acuity,refractive error
(retinoscopy) under cycloplegia.(Dry and wet after
orthoptic evaluation)
3) Ocular movements should also be tested in all
positions of gaze.[uniocular & binocular]

5. 4) Cover-uncover test:
 It should be performed for both distance and near.
 One eye of the patient is covered while fixating with
other eye at a distant target. The eye is then
uncovered and any movement of the eye to take up
fixation is noted.

6.  After the cover is removed, the speed and smoothness
of recovery indicates the strength of motor fusion.
 The direction of deviation, the degree of deviation and
speed of recovery is noted.

7. COVER UNCOVER TEST

8. 4) Measurement of heterophoria:
 Measured for both distance and near.
 Full optical distance correction.
 Near phoria measured at 33 cm.[using a
accommodation target.

9.  Measurement includes following two criteria
A. objective tests: prism and cover test.
 Measuring the angle of deviation objectively.
 Prism with apex toward the deviation placed in front
of one eye fixate with other

10.  Prism and alternet cover test :
 Test should be performed for distance and near.
 Prism with apex towards the deviation paced in front
of one eye and the px is asked to fixate a target with the
other eye.
 Alternate cover test is performed till there is no
recovery movement of the eye under cover .
 This will tell the amount of deviation in prism
dioptres

12. B. Subjective test :
1. Maddox rod test :
 Based on the principle of physiological diplopia.
 Consist of a series of parallel glass cylinders of high
power
 Produces a linear image of a point light.
 Through the rod line image is formed perpendicular
to the axis of the cylinders.

13.  Due to dissimilar image of the two eyes fusion is
broken and heterophoria becomes manifest.

14.  Measured by the superimposition of the two images by
mean of prism placed in front of one eye.

15. 2.Maddox wing test :
 instrument by which amount of phoria for near is
measured [33 cm]
 Based on the principle of dissociation of fusion by
dissimilar objects.
 Through its two slit right eye sees vertical white
arrow & horizontal red arrow & left eye sees
vertical and horizontal line of numbers

17. Ask patient :
 White arrow is pointing at which number of
horizontal line. [amount of horizontal phoria]
 Red arrow is pointing at which number of vertical
line.[amount of vertical phoria]
 For cyclophoria ask patient to align the red arrow with
the horizontal line of number

18. 5.Measurement of NPC,NPA,Ac/A
 Near point of convergence [NPC] can be measured
with RAF rule .normal NPC is considered to be around
7cm.
 Near point of accommodation NPA can be
measured with RAF rule. normal NPA varies with the
age of patients.

19.  AC/A ratio :
 Normal AC/A ratio 3-4 PD for 1 dioptre of
accommodation.
 it can be measured by eg, heterophoric method.

20. 6.Measurement of fusional reserve
 Can be measured with the help of synoptophore or
prism bar.
 Normal values:
 Vertical fusional reserve :1.5⁰-2.5⁰
 Horizontal –ve fusional reserve [abduction]:3⁰-5⁰
 Horizontal +ve fusional reserve [adduction range]
:20⁰-40⁰

21. Treatment of heterophoria
INDICATION:
In Adults: indicated only if the px suffering from
symptoms.
In Childrens: if the phoria is showing a tendency to
decompensate into a manifest deviation,wether
symptoms are present or not.

22. Treatment In heterophoria
includes,
1. Optical correction.
2. Orthoptic exercise.
3. Prismotherapy.
4. Surgery.

23. 1.Optical correction
 Optical correction may eliminate the phoria in some
patients.
 Guidelines for prescription glasses.
1. Difference in Refractive error between two eyes
should be eliminated.
2. In exophoria, both eyes may be undercorrect by an
equal amount of spherical plus power.
3. In esophoria, optimum spherical plus correction
which gives best visual acuity.

24. 4. Bifocal glass, for near vision with px having
esophoria of convergence excess type.
5. In hyperphoria, optical correction by decentred to
achieve prismatic effect , relieving the stress on
vertical vergence.
6. In cyclophoria, correction of astigmatic refractive
error.

25. Orthoptic treatment.[vision
therapy]
 Aim is to improve fusinal reserve so that the bifoveal
single vision can be maintained without effort.

26. Orhtoptic exercise for esophoria
Divergence exercise with prism:
1. BI before one eye while s/he fixating an object
where the esophoria is maximum.
 trained to maintain single vision by relaxing the
convergence. [for few minutes at each week visit]

27.  Divergence exercise on synoptophore:
 Using stereopsis slides which provides strong stimulus
to fusion.
 Trained to maintain a single vision by relaxing
convergence.[5 min at each week visit]

28.  Physiologic diplopia exercise:
 Using stereogram or pencil in the crossed position
 Px fixing at distance object ,stereogram card held at 25
cm in front of eyes.
 Px perceives four pictures.
 Trained to fuse two central pictures,in which patient
perceives three pictures.

29.  Here patient is converging for the distance target while
accommodating for near.

30.  Other method for orthoptic exercise for esophoria :
1. Exercise using diploscope
2. Exercise using remy separator
3. Reading bar exercise

31. Orhtoptic exercise for exophoria
 Aim is to improve the fusional convergence :
Convergence exercise with prisms
1. BO before one eye while s/he fixating an object
where the exophoria is maximum.
2. Trained to maintain single vision by relaxing the
divergence

32.  convergence exercise using synoptophore:
 Using stereopsis slides which provides strong stimulus
to fusion.
 Trained to maintain a single vision by relaxing
divergence.[5 min at each week visit]

33.  Physiologic diplopia exercise using stereogram in
the uncrossed position:
 Using stereogram or pencil in the uncrossed position.
 Px stereogram card is held at arm length in front of
patient and pencil (fixating point) placed between
eyes and the card
 While looking at the pencil ,patient will notice
diplopia(uncrossed)of the card i.e four pictures

34.  Trained to fuse two central pictures clearly,in which
patient pereives three pictures.
 In doing so patient is converging for the fixation object
and accommodation for the distance.

35. 3) Role of miotic drugs
 Treatment of choice in near esophoria due to high
AC/A ratio.
 Miotics facilitate accommodation, so that less than
normal innervations is necessary to obtain a given
accommodative response and there occur less
accommodative convergence

36. Surgical treatment of heterophoria
 Indication :
 Surgery becomes necessary only when symptoms
cannot be relieved by other method like, optical
correction, orthoptic exercise, using miotic

37. Thank you

38. ref
aimu.us/2017/12/10/heterophoria-symptoms-causes-
diagnosis-and-management
 Khurana ak/theory and practice of squint and orthoptis
 Internet (images ,video)
 Noorden gk von fixation disparity and heterophoria