Heterophoria is a latent eye misalignment where the eyes are directed at the fixation point but tend to deviate when fusion is interrupted. It is classified based on direction of deviation (esophoria, exophoria, hyperphoria, cyclophoria) and symptoms (compensated vs decompensated). Esophoria involves a nasal deviation, exophoria a divergent deviation, and hyperphoria/hypophoria an upward/downward deviation of one eye. Compensated heterophoria causes no symptoms while decompensated heterophoria occurs when the deviation cannot be controlled due to weak fusion, leading to issues like blurred vision, diplopia,

1. HETEROPHORIA
PRESENTED BY
RANJANA ARYAL
BOVS-2ND YEAR

2. DEFINITION
• Condition wherein tendency of the
eyes to deviate is kept latent by
fusional reflex
• Both visual axes are directed
towards the fixation point but
deviate in dissociation
• Also called latent strabismus

3. CLASSIFICATION
A)ON THE BASIS OF DIRECTION OF
DEVIATION
1)Esophoria
 Convergence excess
 Divergence excess
 Non specific(basic)

4. 2)Exophoria
 Convergence weakness
 Divergence excess
 Non specific(basic)
3)Hyperphoria /hyophoria
4)Cyclophoria

5. B)ON THE BASIS OF SYMPTOMS
1)Compensated
2)Decompensated

6. 1)ESOPHORIA
 Non deviating eye becomes
convergent i.e deviates nasally
when fusion is interrupted
 Less frequent than exophoria
CLINICAL TYPES
a)Convergrnce excess :esophoria
greater on near fixation than on
distance fixation

7. b)Divergence weakness:eso greater
on distance than near
 c)Non specific:doesnot vary in
degree for any distance

8. ETIOLOGY
 Endopthalmos
 Narrow IPD
 Eom anomalies
 Refractive
causes:hypermetropia,anisometropi
a,
high AC/A ratio,weak divergent
fusional reserve

9. 2)EXOPHORIA
 Non fixitating eye becomes
divergent on dissociation
 Commonest type of heterophoria
CLINICAL TYPES
a)Convergence weakness;exophoria
greater on near than distant fixation
b)Divergence excess:exo greater on
distance than near fixation
c)Non specific:no variation of degree
for any distance

10. ETIOLOGY
 Anatomical
anomalies:exopthalmos,wide
IPD,EOM anomalies
 Refractive
anomalies:myopia,presbyopia &
anisometropia
 Weak convergent fusional reserve
 Passage of time

11. 3)HYPERPHORIA/HYPOPHORIA
 Vertical deviation occurring on
dissociation in which one eye
rotates upwards and the other
downwards depending on the
fixation
ETIOLOGY
 Refractive: High myopia (heavy eye
syndrome)
 Weak vertical fusional reserves
 Anatomical: Displaced globes,
abnormal extraocular muscles,
ptosi

12. 4)CYCLOPHORIA
 Either eye wheel rotates on
dissociation, so that the upper end of
the vertical axis is nasal
(incyclophoria) or temporal
(excyclophoria)
ETIOLOGY
 Oblique astigmatism

13. B1)COMPENSATED
HETEROPHORIA
 Controlled heterophia with no
symptoms
 Accounts for majority of population
2)DECOMPENSATED
HETEROPHORIA
 Occurs with the inability to control
the angle of deviation through
inadequate fusional amplitudes

14. CAUSES OF DECOMPENSATION
 Optical: Under-, over- or
uncorrected refractive errors.
Wrongly prescribed spectacles. Ill-
fitting spectacles. Aniseikonia.
 Medical: Poor general health.
Fatigue. Head injury affecting
fusional abilities. Drugs affecting
accommodation. Alcohol.
Dissociative/monocular viewing

15. symptoms Generic description
Blurred vision
Diplopia
Distorted image
Visual perceptual
distortions
Difficulty with
stereopsis
Monocular comfort
Dificulty in changing
focus
Binocular factors
Headache
Sore eye
Aching eye
General irritation
Asthenopic factors

16. Refrences
 Pickwell’s binocular vision anomalies
 Binocular vision and orthoptics
 A.K Khurana