Heterophoria Or Latent Squint

Easily learn the Topic Latent Squint

1. UTTAR PRADESH UNIVERSITY OF MEDICAL SCIENCES

2. Guided by – PRITI MAM P resented by – KRISHNA KUMAR Topic - HETEROPHORIA B.Optom. 3 rd year

3. SQUINT or STRABISMUS Refers to misalignment of visual axes of the two eyes. Squint also known as CROSSED EYE or deviation of the eye. Fixation target

4. Perfect alignment of the two eyes is denoted by the terms ORTHOPOSITION and ORTHOPHORIA . Fixation target Orthoposition Orthophoria

5. Squint may be further divided in to two categories Heterophoria Heterotropia Hetrotropia is the manifest deviation of the eyes from the orthoposition that can not be overcome by the fusion reflex . RE LE

6. HETEROPHORIA The term Heterophoria introduced by STEVENS It is also known as ‘ Latent squint ’. A condition of latent squint in which the deviation of visual axes is present on dissociation of the two eyes, but is absent on removal of dissociating factor. The error of alignment that takes place when fusion is suspended is called heterophoria. The fusion reflex maintains correct alignment of the two eyes.

7. TYPES OF HETEROPHORIA Depending upon the direction of deviation,heterophoria may be: Esophoria Exophoria Hyperphoria Cyclophoria

8. (1) ESOPHORIA In this condition , when fusion is interrupted, the non-fixating eye becomes convergent , i.e. deviate nasally. Eye moves nasally under cover OR

9. Clinical types Esophoria may be- Convergence excess type Divergence weakness type Etiological types Accommodative esophoria - It may be associated with: (a)Uncorrected high hypermetropia (b)High AC/A ratio 2. Tonic esophoria

10. CAUSE Anatomical (narrow PD) Refractive (high hypermetropia) High AC/A ratio Weak divergent(negative) fusional reserves

11. ( 2) EXOPHORIA In this condition, when fusion is interrupted, the non-fixating eye become divergent, i.e deviates temporally. Eye moves temporally under cover OR

12. TYPES Exophoria may be following types: Convergence weakness type Divergence excess type CAUSE Anatomical (wide PD) Refractive(myopia, presbyopia ) Weak convergent(positive) fusional reserves Age

13. ( 3) HYPERPHORIA ( VERTICAL PHORIA) It is a vertical deviation occurring on dissociation in which on eye rotate upwards or the other downwards depending upon the fixation OR Eye moves up or down under cover

14. Right hyperphoria The right eye rotates upward, when it is not fixating and when the right eye is fixating, the left eye rotates downwards and reverse to it occurs in Left hyperphoria

15. (4) CYCLOPHORIA- It is the tendency of the either eye to wheel rotate around the antero-posterior axis on dissociation. When the 12 o’ clock meridian of cornea rotate nasally, it is called incyclophoria . And when it rotates temporally it is called e xcyclophoria .

16. SYMPTOMS OF HETEROPHORIA D epending upon the symptoms, Heterophoria is of two types- Compensated heterophoria - It is associated with no subjective symptoms . Decompensated heterophoria - It is associated with multiple symptoms. Symptoms of muscular fatigue Symptoms due to failure to maintain binocular vision. Symptoms of defective postural sensations