1. STRABISMUS (SQUINT) AmakaAzie GPST2

2. It is a condition in which the eyes are misaligned • Can lead to amblyopia in childhood or diplopia in adult hood • Amblyopia (lazy eye),happens when because of lack of use of the eye in childhood, vision becomes poor • Latent squint– Also known as heteroPHORIA is a very slight squint not present all the time and can be seen in only certain circumstances • Manifest squint- HeteroTROPIA is present all the time

3. ANATOMY: MUSCLES OF EYE MOVEMENT • All movement of the eyes are enabled by the third nerve • Except superior oblique=> fourth nerve and lateral rectus =>sixth nerve • The third, fourth and sixth nuclei and the higher brain centres are involved • When the eyes are looking straight ahead =primary position

4. TYPES OF SQUINT Non-paralytic squint (concomitant squint): • Normal eye movements but only one eye is directed to the target. • Unrelated to the direction of gaze • More common in children Paralytic squint (Incomitant squint): • Weakness or paralysis of one or more muscles of eye movement • Dependent on direction of gaze and usually worse where eye is moved towards the field of action of affected muscle or nerve

5. IMORTANT TERMS • ESOtropia=> Inwards • EXOtropia=>Outwards • Hypotropia=>Downwards • Hypertropia=>Upwards

6. IMORTANT POINTS TO NOTE • Squint could be classified as congenital (Onset before 6 months) or acquired • Squint or some form of ocular misalignment are common in newborns. • Should be intermittent, reducing by 2 months of age and disappear by 4 months of age • Esotropias are more common than exotropias. Hypo and hypertropias are not common

7. Non-Paralytic squint SUSPECT IF: • May be noticed by parents • May be detected in pre-school screening • Children may tilt their head or chin to compensate for amblyopia SCREENING : Hirschberg’s test: Pen torch some distance in front of eyes. Reflection should lie centrally bilaterally on the cornea normally. It can also be used to estimate degree of deviation

8. CAUSES: • Family history • Neonatal jaundice • Prematurity • Fetal alcohol syndrome • Encephalitis, mengitis • Down syndrome/Turners syndrome • Refractive error • Cataracts • Retinoblastoma

9. Diagnosis=Cover/uncover testAlternate cover test=> Latent squint Cover /uncover test COVER TEST vs ALTERNATE COVER TEST Cover one eye for a few second while uncovered eye focuses on object. Remove and place on other eye. If initially covered eye moves outwards=> Esophoria. Alternate cover test detects latent squint by breaking bifoveal stimulation. Done by switiching occlude rapidly between both eyes

10. MANAGEMENT Referral to eye clinic • Neonate with constant squint, worsening squint from 2 months or squint still present after 4 months • Any older child with a suspected squint • Management include spectacles, patches, cycloplegic drops and surgery • Prognosis is good if detected early

11. Thanks for listening.