Background

The Tohono O’odham Vision Screening Program is a collaborative program conducted by The University of Arizona Department of Ophthalmology and Vision Science, sponsored by The Tohono O’odham Nation, and funded by the National Institutes of Health/National Eye Institute (NIH/NEI).

Many Tohono O’odham children have an eye problem called astigmatism, which causes blurred vision for objects up close and far away. Often, people with astigmatism can see well if they wear eyeglasses.

Eyeglasses do not always help, though. Doctors have found that the blurred vision caused by astigmatism in children can lead to the development of a condition called amblyopia, which is poor vision that cannot be corrected simply by putting on eyeglasses. Amblyopia is caused by poor development of the visual part of the brain. The treatment for amblyopia is to wear eyeglasses consistently for weeks or months. The eyeglasses allow the visual part of the child’s brain to receive clear images, and help the brain learn to see normally.

Over the years, the National Eye Institute of the National Institutes of Health has provided funding for doctors at the University of Arizona to work in collaboration with the Tohono O’odham Nation, the Tohono O’odham Early Childhood Head Start Program, and the schools on the Tohono O’odham Reservation to conduct studies to better understand how astigmatism and amblyopia develop in Tohono O’odham children, and to better understand how and when amblyopia is best treated in Tohono O’odham children. Many Tohono O’odham children have received eye examinations and eyeglasses through these programs.

History of the Tohono O’odham Vision Screening Program (TOVSP): 1997-2010

Phase I (1997-2001). The first phase of TOVSP was a five-year study of astigmatism and amblyopia in Tohono O’odham preschool children. As a result of this study, an effective vision screening method for identifying preschool children who have high astigmatism was developed. This screening method is currently being used by the Head Start Program, and follow-up eye examinations are being conducted by the doctors at the I.H.S. Optometry Clinic. In addition, we learned that many young children who have high astigmatism have amblyopia - they do not see normally, even when they wear their eyeglasses. Therefore, it is very important for young children with astigmatism to wear their eyeglasses, as it is likely that they will see better over time if they wear them.

Phase II (2000-2005). The second phase of TOVSP was a five-year study of astigmatism and amblyopia in Tohono O’odham grade-school children. There is strong evidence that amblyopia is more treatable when children are young than when they are older. Some evidence shows that if children do not receive glasses by age 7, eyeglasses may not be effective in treating amblyopia. However, the results of Phase II showed that even children older than age 7 benefit from eyeglass treatment.

Phase III (2005-2010). The third phase of TOVSP is a five-year study of astigmatism and amblyopia in Tohono O’odham children from age 6 months through 1st grade. The results of this part of the study will help us learn when astigmatism and amblyopia develop. These findings will help doctors develop treatment guidelines for prescribing eyeglasses in very young children with astigmatism, and will help determine how effective eyeglass treatment of amblyopia is in preschool children.