In schools, vision screening services shall be provided annually for all children in grades kindergarten, second, and _________.

The correct answer is eighth. In the context of Illinois state requirements for vision screening in schools, the law mandates that screening be conducted annually for specific grade levels to ensure that children's vision issues are detected early. The required grades include kindergarten, second grade, and eighth grade. This particular focus on eighth grade is significant, as it often coincides with critical stages of visual development and preparation for high school, where vision-related learning challenges can become more pronounced.

While the other options include grades that are important in their own right, they do not align with the specific regulations set forth for annual vision screenings as required by Illinois law. Thus, eighth grade is the only correct answer in this context, reflecting the statutory needs for monitoring children's vision health during these formative years.