My 7 year old son was recently diagnosed with severe astigmatism and mild far sightedness. When the optometrist prescribed glasses for him, she also described astigmatism and expressed concern that if this condition were not corrected through use of glasses, he would have permanent vision loss by the time he was 9 or 10 years old (she was confident we had caught it in time to see complete or close to complete correction with lenses). I am unclear as to what this permanent vision loss would be. I am also confused because my son does not complain of eye fatigue, headaches, bluriness, or any complaint that I would associate with astigmatism. However, when reading, he often complains that it is "too hard" and he is "too tired" to read any more after a certain amount. I have been unsure if this was merely due to the fact that he is still an early reader and it is hard work or whether this is a symptom of eye strain.
When the optometrist discussed this condition with us, she said (something like)astigmatism causes blurriness which the brain then ignores because it cannot focus on that information, so effectively there would be blind spots. I am not sure if I understood this correctly and have not seen anything in my web search about this or the concern for treating severe astigmatism before the child is 9 or 10 to prevent permanent damage. Is it possible that my son does not see some things at all? Could this help explain his clumsiness?
Also, the optometrist said that the reason he sees well without glasses is because the farsightedness and the astigmatism compensate for each other causing him to "focus on zero" or focus on the retina so that there is little bluriness, and this would be why he has not complained about not being able to see.
Can you help clarify this for me? Specifically, what would my son be seeing or not seeing now? Why is the age 9 or 10 of concern? And at what age should a child with severe astigmatism be wearing corrective lenses when there is little complaint from the child and no obvious physical discomfort expressed? What about his younger siblings? (aged 4 and 6 months) At what age should they be checked?