We all know the basics of treating refractive errors: using spherical and cylindrical lenses! Easy. But, I remember as a student, It got more complicated when children and cycloplegia came into the equation.
Here’s your guide, you can thank me later.
Myopia:
As a general rule always fully correct the cycloplegic refraction of Myopia in young school aged children. Beware, Myopic patients tend to eat up the minuses, do not over correct.
Exceptions:
- Children under the age of 3 requiring more than -3 Dioptres: slightly undercorrect. Provide correction that is enough for functional vision. There is still a chance that the child might move towards emmetropia.
- Children under the age of 4 with astigmatism or anisometropia of more than -2.5D: fully correct.
- Child has a moderate to large esophoria or decompensating esophoria, is eso tropic, or has a high AC/A ratio. In this case, the minus lenses are inducing more convergence by triggering accommodation. Plus lenses (+1 to 3D)can be incorporated into bifocals or multifocals to reduce the accommodation/convergence effect at near.
- Child with intermittent exotropia: Full correction of Myopia. Even if the child is emmetropic, hypermetropic or slightly myopic, small amounts of minus lenses will help converge the eye inward.
- Emmetropic child with accommodation lag may benefit from small amounts of minus lenses.
Hypermetropia
Infants and toddlers often have moderate amounts of hyperopia (up to 6D), But they are very likely to progress towards emmetropia as they get older. Children also can efficiently accommodate at near (up to +5). So it is best to leave the hyperopia uncorrected for children under the age of 3 with prescriptions less than 4.5D.
- For children older than 3 with cycloplegic refractions of more than 4.5D, the general rule is to sligthly undercorrect them (by 0.75D).
- A child, older than the age of 3 with esotropia, fully correct their prescription if more than 1.5D
Beware and keep in mind that even the smallest amounts of uncorrected hyperopia can lead to amblyopia and esotropia, and the two are interdependent on each other.
Astigmatism
Fully correct astigmatism larger than 1.5D in children over the age of 2. As astigmatism can not be overcome by the accommodation of the lens, it can be ambylopic if not corrected.
Anisometropia
Hypermetropic anisometropia of more than 1.5D can lead to amblyopia and should be fully corrected
Myopic anisometropia of up to a difference of 3D is considered a low risk of myopia. Fully correct over -3D.
Accommodative dysfunction
Sometimes a child’s distance and near visual acuity is near perfect but parents often complain child is having trouble reading. While there is a chance the child is faking it to get glasses just like his friend; often, the child’s accommodation is locked up at near and is not able to fluctuate smoothly and clearly between near and far. Always check accommodative dysfunction and offer corresponding vision therapy training instead
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