At times the best option is to just prescribe glasses for full time wear . Fully correcting a child's refractive error can often stop a child developing amblyopia (a lazy eye) and can correct some types of squint. If the optometrist is monitoring the child then the child may well be recalled frequently to check their vision and how they are getting on with their glasses.
In other cases the optometrist may have to put drops into the eyes to dilate pupils and allow the eye muscles to relax. These drops do sting (quite a bit) so we suddenly become very unpopular after we have put the first drop in. However it does allow us to get the full prescription and can make all the difference between monitoring in practice with glasses or referring to be treated under the hospital eye service where drops are put in on almost every visit. Children are usually referred to the hospital if the vision stays uneven between the eyes or if there is a turn that they may be able to treat.
However it is not all doom, gloom, horrible patches and stinging eye drops. Correct a child's sight and they will be grateful and at times you can really make a difference to both their future and their now.
I tested a 4 year old whose mother had a lazy eye and was worried about her son developing a similar problem because of how it had affected her. Initial investigation showed a moderately high hypermetropic prescription which put the child at risk of developing a lazy eye or a turn, this meant we had to put drops in. I went from being quite nice to being horrible in one fell swoop as far as the child was concerned. After the drops had taken effect a bit more plus came out for overall refractive error of about +9.00 with -2.00 cyls. However after he had had time to adapt to wearing the trial frame he grew to appreciate the clarity he was seeing with compared to the without, so by the time he had chosen his glasses he was happy and I got a high five on the way out! I didn't get a chance to do the collection sadly but I can only hope it was similar to the viral video of Piper, the 10 month old.