Refraction and Spectacles

The list contains a very important and difficult question, refraction and spectacles because early intervention teams and schools have difficulties in obtaining information on these two variables and especially on what was expected of children’s spectacles when they were prescribed: Are the spectacles for reading only or used all the time, at which distance the child’s vision is clearest, how the spectacles affect ocular motor functions, etc. When teachers or school nurses measure visual acuity values at school, sometimes there is no difference in the measured values with or without the spectacles if the child can compensate the refractive error for a short time or if the spectacles are for correction of an ocular motor problem. These details should be explained to parents and the child’s school. Especially, if there is under- or overcorrection, the reasons should be given. Undercorrection of high myopia of children with impaired vision is common and hyperopia of young children is usually overcorrected to give better function at the important intermediate distances. Both these peculiarities result in lower visual acuity at the standard distance of measurement of visual acuity at 3 meters than what the child has at close distance. This is often misunderstood at school as a sign that the spectacles are “wrong”. Vision rehabilitation clinics explain the use of spectacles well. This should become a standard in all offices.

Often the copy of the medical report does not mention what test was used in the measurement of visual acuity or contrast sensitivity, at what distance and at what luminance level. 

Despite the common triad of insufficient convergence and accommodation, and slow pupil reactions during convergence, children’s near corrections are so rarely prescribed that teachers have started to routinely observe and test near vision using +3 lenses in front of the child’s usual spectacles. Not knowing the type of the child’s spectacles, this test may not be correct in each case.

If a child has near correction because of poor accommodation, the lenses are usually bifocal lenses. It has not been understood that these children do not use their spectacles like children with accommodative esotropia but also need a progressive correction to compensate for poor accommodation at the intermediate distances. Another big problem has been that the frames are too small so that both the upper and the lowest part of the lens are cut away. The frames of children with poor head control should be nearly round because the lenses must be fitted much higher in the frame than usually in order to fit the position of the head and the line of sight during reading and when looking at the blackboard. The lenses must have large reading part and broad progression area so that children can use them, not the new compressed structure designed for small frames.