1. Mahbuba Khondaker PGDO Intern, School of Optometry Aravind Eye Hospital Basics & Classification

2. Introduction Misalignment of eye visual axis Its may congenital or acquired It may also related with any other syndrome In some cases it is hereditary Is a condition which can be unilateral or bi lateral. It is a common condition among children. It may also occur in adults.

3. Squint: Definition Squint is a misalignment of the two eyes so that both the eyes are not looking in the same direction in same object. The misalignment can be- Constant Intermittent

4. Causes for squint: Birth injuries. Hereditary. Loss of coordination between the muscles of the two eyes Need for glasses Certain eye diseases interfering vision of one eye (e.g: unilateral cataract Illness - can make it obvious Fatigue, stress or extended work load

5. Extra Ocular Muscles of Eye Total 6 (4-rectus, 2- Oblique ) Muscles functions in particular gazes are- Medial rectus (MR):moves the eye toward the nose (Adduction) Lateral rectus (LR):moves the eye away from the nose (Abduction) Superior rectus (SR):primarily moves the eye upward and secondarily rotates the top of the eye toward the nose (Elevation, Abduction, Intortion) Inferior rectus (IR):moves the eye downward & secondarily rotates the top of the eye away from the nose (Depression, abduction, Extortion) Superior oblique (SO):primarily rotates the top of the eye toward the nose & secondarily moves the eye downward (Adduction and depression) Inferior oblique (IO):primarily rotates the top of the eye away from the nose secondarily moves the eye upward (Abduction and elevation)

6. Extra Ocular Muscles of Eye

7. Squint Classification According to direction of deviation According to amount of deviation in different gazes

8. Squint Classification

10. Types of Squint and Definiton A pseudosquint mimics a squint. It is caused by prominent epicanthic folds causing one eye to appear to be looking in. Esotropia (not to be confused with entropion) is a convergent squint, in which one eye is turned inward. Exotropia (not to be confused with ectropion) is a divergent squint, in which one eye is turned outward.

11. Treatment Goals of treatment: Development of normal vision in both eyes. Straighten the eyes. To make both eyes work together Treatment : Glasses/ Spectacles: Some type of squint are corrected by glass (e.g accommodative esotropia) Patching of the lazy eye: Stimulate bad eye to see more and improve vision. Surgery : Squint correction

12. Types: Squint Correction Surgery Resection Recession