Small amounts of uncorrected astigmatism especially when oblique can have marked effects on clarity at distance and near. Anything that causes blur at distance and near during the educational formative years can prevent the achievement of full educational potential.
Your patient seems to be having some problems with her reading and writing, according to the parents. They are often good at picking up on educational underachievement especially if there are older siblings for comparison.
The R visual acuity does improve with the refractive correction and it is likely that the L visual acuity will be a sharper 6/6 as will the BE 6/6 with refractive correction than without.
I suggest you ask each parent to sit in turn in the examination chair and look at the letter chart with a +0.50 cylindrical lens in front of the R eye, placed at 45 degrees and the L eye closed. This will mimic the blur caused by -0.50 oblique astigmatism. Do the same for the left eye with a +0.25 cylindrical lens placed at 135 degrees and with the R eye closed. Finally, ask each parent to look at the letter chart and close print with these lenses with BE together. This will demonstrate the reduction in clarity with these low levels of astigmatism can cause.
Advise the use of glasses to your prescription for all classroom activities, homework, and any leisure reading. Review in three months’ time and ask how things are going with her reading and writing. Then review again in three months. It is very very likely that her reading and writing abilities will have increased. Review every six months or sooner if there are new symptoms and check for any change in refractive error.