I recently got a question about when a doctor might not prescribe glasses for a child, even if the child was nearsighted or farsighted. I did some research and found consensus guidelines for prescribing glasses published by the American Academy of Ophthalmology (Pediatric Eye Evaluations: Screening and Comprehensive Ophthalmic Evaluation, 2007, link to full text).
Before jumping to the guidelines, it’s worth emphasizing that these are general guidelines only, based on professional experience and not scientifically researched data. Let me repeat that: there are no good studies showing when a child should be prescribed glasses – this is in part due to the fact that prescribing glasses is complicated. Each doctor needs to take into account everything about the individual patient and there are many things that would lead a doctor to prescribe glasses at much lower refractive errors. These include strabismus or history of strabismus, developmental delays, other medical issues, visual acuity, acceptance of glasses, among other factors.
Prescribing Glasses to Children with Anisometropia
Children who have a significant difference in refractive error between their eyes (called “anisometropia”) are more likely to be prescribed glasses. This is because anisometropia is a significant factor is causing amblyopia. If one eye sees much better than the other, the brain is more likely to favor the vision from the “good” eye, leading to amblyopia.
Condition and refractive error for prescribing glasses to children with anisometropia (eyes have different refractive errors):
|
Age |
| Condition |
1 year and younger |
1 to 2 years |
2 to 3 years |
| nearsighted (myopia) |
-2.5 or worse |
-2.5 or worse |
-2 or worse |
| farsighted (hyperopia) |
+2.5 or worse |
+2 or worse |
+1.5 or worse |
| astigmatism |
2.5 or worse |
2 or worse |
2 or worse |
~~~
Prescribing Glasses to Children with Isometropia
For children whose eyes have similar refractive errors (so both eyes are seeing similarly), also called “isometropia”, doctors are less likely to prescribe glasses at lower refractive errors. In this case, there is a difference in prescribing guidelines for farsighted children depending on whether or not the child has strabismus or misaligned eyes. Again, this is due to the increased risk of developing amblyopia if strabismus is present.
| Condition and refractive error for prescribing glasses to children with isometropia (eyes have similar refractive errors): |
Age |
| Condition |
1 year and younger |
1 to 2 years |
2 to 3 years |
| nearsighted (myopia) |
-5 or worse |
-4 or worse |
-3 or worse |
| farsighted (hyperopia) with strabismus |
+3 or worse |
+2 or worse |
+1.5 or worse |
| farsighted (hyperopia) with no strabismus |
+6 or worse |
+5 or worse |
+4.5 or worse |
| astigmatism |
3 or worse |
2.5 or worse |
2 or worse |
It is again worth noting that these are only guidelines, and in fact, other studies have shown that many doctors prefer to prescribe glasses at lower refractive errors (Spectacle prescribing recommendations of AAPOS members).
The guidelines do fit closely with our own experience. When we first took Zoe in to the ophthalmologist, she was not crossing her eyes often, or severely. In fact, in some of the pictures we took with us, while it looked like her eyes were crossed, when you looked at the reflection of the flash in her pupils, they were actually aligned. Her refractive error at that time was probably around +4.5 or +5, high enough that the ophthalmologist told us to keep a close eye out for her eyes crossing and told us to come back in 6 months for a follow-up. Four months later, her eyes started crossing significantly, and her ophthalmologist had us back in and got her into glasses.
If you ever have a question as to why your doctor is or is not prescribing glasses for your child, please ask your doctor for an explanation. If you still are unsure, or if that explanation does not make sense, a second opinion may well be in order.
