Lecture on Squint For 4th Year MBBS Undergraduate Students By Prof. Dr. Hussain Ahmad Khaqan

1. Squint
Prof. Dr. Hussain Ahmad Khaqan
 MD
 FRCS(Glasgow)
 FCPS(Ophth.)
 FCPS(Vitreo Retina)
 MHPE (KMU)
 CICO(UK)
 CMT(UOL)
 Fellowship in Medical Retina (LMU, Munich)
 Fellowship in Vitreo Retinal Surgery (LMU, Munich)
 Consultant Ophthalmologist & Retinal Surgeon
Professor of Ophthalmology
Lahore General Hospital, Lahore
Ameer Ud Din Medical College, Lahore
Post Graduate Medical Institute, Lahore
Shaukat Khanum Memorial Cancer Hospital & Research Centre ,Lahore

2. DEFINITION
• Strabismus is a condition in which the eyes do not
properly align with each other when looking at an
object.

3. TYPES CONTINUE..
1. Heterophoria
• Esophoria
• Exophoria
• Hyperphoria
• Hypophoria

4. 2. Heterotropia
• Esotropia
• Exotropia
• Hypertropia
• Hypotropia
TYPES

5. HETEROPHORIA

6. DEFINITION
Heterophoria or latent squint is defined as a
condition in which eyes in the primary position
or in their movement are maintained on the
fixation point under stress only, with the aid of
corrective fusion reflexes. When the influence of
fusion is removed, the visual axis of one eye
deviates.

7. TYPES
1. Esophoria - Inward imbalance
2. Exophoria - Outward imbalance
3. Hyperphoria - Latent upward imbalance
4. Hypophoria - Latent downward imbalance

8. HETEROTROPIA

9. HETEROTROPIA
Definition:
• Implies a manifest deviation in which the visual axes
do not intersect at the point of fixation

10. TYPES Continue..
1. Esotropia - is a form of strabismus in which one or
both eyes turns inward. The condition can be
constantly present, or occur intermittently, and can
give the affected individual a "cross-eyed"
appearance (Manifest deviation).

11. 2. Exotropia - is a form of strabismus where the eyes
are deviated outward (Manifest deviation).
3. Hypertropia - Upward displacement of one eye
relative to the other
4. Hypotropia - Downward displacement of one eye
relative to the other
TYPES

12. ESOTROPIA
Esotropia
Primary
Accommodative Varies with
accommodation
Normal AC:A ratio
Resolves with
hypermetropic correction
Fully accommodative
esotropia
Normal AC:A ratio
improves with
hypermetropic correction
partially accommodative
esotropia
High AC:A ratio Convergence excess
esotropia
Non- accommodative Constant Starting <6mo Infantile esotropia
Starting >6 mo Basic esotropia
Varies with fixation
distance despite relief of
accommodation
Near fixation only Near esotropia
Distance fixation Distance esotropia
Varies with time Cyclical Cyclic esotropia
Secondary Organic visual acuity Secondary esotropia
Post-exo Previous surgery for
exotropia
Consecutive esotropia

13. LEFT EYE ESOTROPIA

14. EXOTROPIA
Exotropia
Primary Constant Starting <6mo Infantile exotropia
Starting >6mo Basic exotropia
Variable Worse for near Near exotropia
Worse for distance
High AC:A ratio
Simulated distance
exotropia
Worse for distance
normal AC:A ratio
True distance
exotropia
Secondary Organic visual acuity Secondary exotropia
Post - eso Develops with time in
absence of fusion
Consecutive exotropia

15. RIGHT EYE EXOTROPIA

16. TREATMENT

17. TREATMENT Continue
Heterophoria:
1. Orthoptic treatment is of most value in convergence
weakness exophoria.
2. Any significant refractive error should be
appropriately corrected.

18. 3. Symptom relief may otherwise be obtained
using temporary stick-on Fresnel prisms and
may be subsequently incorporated into
spectacles (maximum usually 10–12 Δ, split
between the two eyes).
TREATMENT Continue

19. 4. Surgery may occasionally be required for
larger deviations.
TREATMENT Continue

20. Esotropia
A- Accommodative esotropia
1. Fully accommodative esotropia:
• Correction of refractive error
TREATMENT Continue

21. 2. Partially accommodative esotropia:
• In partially accommodative esotropia, surgery
to improve appearance is best delayed until
requested by the child. This avoids early
consecutive exotropia. It should aim to correct
only the residual squint present with glasses.
TREATMENT Continue

22. 3. Convergence excess esotropia:
• Bifocals may be prescribed to relieve
accommodation
• Recession of both medial rectus muscles
TREATMENT Continue

23. B- Non-accommodative esotropia:
• Surgery by the age of 12 months only after
amblyopia and refractive error has been
corrected
TREATMENT Continue

24. Exotropia:
A- Constant exotropia:
• Surgery (lateral rectus recession and medial
rectus resection)
TREATMENT Continue

25. B- Variable exotropia:
1. Spectacle correction
2. Part-time occlusion of the non-deviating eye
TREATMENT Continue

26. 3. Surgery:
Unilateral lateral rectus recession and medial
rectus resection are generally preferred
except in true distance exotropia when
bilateral lateral rectus recessions are more
usual.
TREATMENT

27. THANK YOU