(From BMJ learning unit, based on BMJ article BMJ 2015:350:h1716)
- Have child sitting on parent’s lap, facing you, parent leaning slightly backwards
- Sing a nursery rhyme for distraction
- Visual inspection of the eyes
- Dim lights & use ophthalmoscope from a distance to check for red reflex
- Get baby’s interest by smiling, then move back slowly to look for maximum distance at which they fix on your eyes – this helps estimate visual acuity. Lack of smiling/eye contact by 4 – 5 weeks may indicate a visual problem.
- Check pupillary constriction with dimmed light and pen torch. Slow or limited constriction may indicate problem with optic nerve or retina. If baby isn’t trying to squinch eye shut in the light, that might also indicate visual problem.
- If nystagmus is present, get child to follow toy and check nystagmus is same pattern in each direction of looking. If not, or if unilateral, or irregular, or late onset, consider CNS tumour.
- Cover each eye to check vision in each eye. A child with poor vision in one eye may actively try to avoid having the good eye covered.
- Bring a toy into view in each quadrant in turn and see whether child looks towards it. Rapidly bring a second toy into view in another quadrant & look for fast eye movement (saccade), then remove 1st toy from vision as child fixes on 2nd.
- Get parent to rotate child in each direction while holding vertical, and look for reflex horizontal flicking eye movements. Absence of these (saccade initiation failure), replaced instead by tonic movement of the eyes to one side, may indicate that the child isn’t seeing.
Tests for this include:
- Extruding mucus from the duct by gently pressing on it.
- Putting fluorescein in the eye and waiting five minutes. It should drain out in that time; if it doesn’t, that suggests duct blockage.
Shine a light in the child’s eyes and look at light reflecting back from pupils – the corneal reflex. Should be central in both pupils; if not, this confirms squint.
Cover test: get child to look at a toy, then cover the eye that seems to be fixing on it.
- If child actively tries to avoid cover, that may indicate poor vision in the squinting eye. So may lack of movement of the uncovered eye toward the toy (which sounds potentially confusing, since surely that would also indicate lack of squint?)
- Movement of the uncovered eye towards the toy confirms squint.
- Look at what happens when the cover is removed. If the child shifts back to looking through the original eye, that may indicate a visual problem in the squinting eye. If the child shifts attention to squinting eye, that probably indicates equal vision.
Always check for red reflexes in cases of squint.
White pupil. May indicate cataract or retinoblastoma. Can also be a false positive in photos, but refer if any doubt.
Examine for red reflex first from 10 – 20 cm with ophthalmoscope set at zero, then, if asymmetrical or no red reflex, set to +10 and view at 10 cm, or +20 and view at 5 cm. (This helps to distinguish cataract from pathology behind the lens.)