There are many, many different eye conditions, and they affect vision differently. Some result in loss of the central field, which affects reading and perception of fine detail. Others result in the loss of peripheral field, causing mobility problems, but leaving reading vision intact in the initial stages. Some eye conditions cause general loss across the whole visual field. Some children have vision that is variable from day to day, in different lighting conditions and weather.
Some eye conditions vary with general health.
Some eye conditions are associated with syndromes that have other effects on learning and behavior. That said, just as there is enormous variability among sighted children, there is also similar variability among the visually impaired. And just as has been said about other populations, blindness or visual impairment does not exclude the possibility of concomitant learning disabilities. The Wechsler Verbal Scale has traditionally been considered to give results that are comparable with those for sighted children. There are, nevertheless, certain items which may present problems for some types of visually impaired children, particularly the totally congenitally blind.