Strabismus (squint)

Question 1

Features

Answer 1

Tends to manifest from ~2 wks to 3–4 mths when eye used

Most are sensory with normal muscles

75% are convergent

Affect normal development of binocular vision

Question 2

Types

Answer 2

Transient: common in neonates, not a problem

Manifest or constant: always present—a serious problem

Alternating: less serious but requires referral

Latent: evidence under stress (e.g. fatigue, provocative testing)

Pseudo: apparent due to wide epicanthal folds and nasal bridge

Question 3

Refractive errors

Answer 3

Anisometropia:

• significant difference in refractive error of two eyes

Astigmatism:

• variations in corneal curvature (e.g. conical cornea)
• affects normal focusing of light
• needs a corrective lens

Myopia (short sightedness):

• uncommon in infants and children
• but progressive in teens
• needs glasses with a concave lens or contact lenses

Hypermetropia (long sightedness):

• mild cases usual in infancy and early childhood
• —may be associated with convergent squint
• correction with convex lens

Question 4

Referral guidelines (preferably preschool)

Answer 4

Amblyopia

Any parental concern, inc. observation of any type of squint

Risk factors (e.g. physical abuse, in utero infections)

Head tilting on testing acuity

Visual acuity 6/12 or worse in one or both eyes

Constant squint

Alternating squint esp. after 6 mths

Latent squints