Assessing visual development and following up children born preterm
All children who were born preterm should be assessed by an ophthalmologist, whether or not they have had retinopathy of prematurity (ROP). However, there are no agreed guidelines on when this should be done.
At both initial and follow-up visits, the ophthalmologist should consider the following:
Is the child developing normally?
Does the child seem to have normal vision?
Is strabismus or nystagmus present?
Does the retina look normal/healthy?
Is there a significant refractive error?
Are there any other eye problems, such as cataract?
Table: Ocular complications of preterm birth and suggested timing of first examination
|Preterm baby with ….||What to look for||Level of risk||Timing of first and subsequent examinations|
|No ROP||Myopia||Low||At two years of age and annually thereafter|
|ROP, but no laser treatment needed||Myopia, astigmatism, strabismus||Moderate||At one year of age and annually thereafter|
|ROP, treated with laser||High myopia, astigmatism, strabismus, cerebral visual impairment, anisometropia||High||At three months of age and then every three to four months until two years of age, then every six months to six years of age and annually thereafter|
Measuring visual acuity in young children is extremely difficult, but their visual functioning can be assessed using visual development milestones (see the illustration below). Children who are irreversibly visually impaired or blind should be referred for vision rehabilitation.
The ophthalmologist should assess the ocular alignment and eye movements and perform a dilated examination of the retina and optic disc. When needed, they should also measure intraocular pressure (IOP) and axial length.
NOTE: Refraction should be performed with cycloplegia (paralysis of the ciliary muscles in the eye). If refraction is unreliable, refraction with atropine cycloplegia under general anaesthesia should be considered
Visual milestones for children aged 3 - 36 months
- 3 months: Looks at mother’s face
- 6 months: Tries to touch object
- 9 months: Smiles at mirror image and picks objects directly
- 12 months: Stares at objects and imitates other’s actions
- 24 months: Enjoys looking at pictures
- 36 months: Draws pictures.
Prescribing and dispensing spectacles for young children
As a young child’s visual world is near, it is not necessary to prescribe, or fully correct, all low levels of myopia. Suggestions for prescribing at different ages are shown in the table below, which should be tailored to the individual child. Correcting significant refractive errors early is very important, as good vision is needed for a child to develop normally.
Table: Prescribing guidelines for young children born preterm
|Age||Prescribe if…||Prescribe on individual basis if…|
|3 - 18 months||Sphere more than ±5D and/or Cylinder ≥2.5D and/or Anisometropia >1.5D||Sphere less than ±5D and Cylinder less than 2.5D and Anisometropia less than 1.5D|
|18 months onwards||Sphere less than ±5D and Cylinder less than 2.5D and Anisometropia less than 1.5D||The refractive error is the same on two consecutive visits two months apart|
Young children do not have a well-formed bridge to their nose, and they require small frames and accurate centration of the lenses. The arms of the frame should fit around the ears, or the arms can be tied behind the child’s head. Light, plastic lenses should be used.
Parents may be shocked and upset when they hear that their small child needs to wear spectacles or needs occlusion. This is particularly true for parents of babies who have been treated for ROP as they will already have had many anxieties and hurdles to overcome. Careful and repeated counselling is required to ensure that parents fully understand the need for their child to wear spectacles, that frequent follow-up will be required and the spectacles may need to be replaced.
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