Project Title: Secondary Analyses of data from the Infant Aphakia Treatment Study: Patching in Children with Unilateral Congenital Cataracts and Poor Visual Acuity Project Summary: Unilateral congenital cataracts (UCC) are one of the most difficult problems in pediatric ophthalmology. Early surgical intervention, and consistent optical correction and patching therapy are necessary to allow for the possibility of achieving good vision in this eye. Currently, children treated for UCC are advised to patch the unaffected eye for 50% of waking hours throughout the first five years of life, and often into the elementary school years. Even with early surgery and consistent patching relatively few of these eyes develop good visual acuity (VA) by the time the children enter school. A high proportion of children who do not develop useable vision in the treated eye and many caregivers have difficulty patching their children for the prescribed amount of time. Therefore, the utility of extended patching in eyes destined to have poor vision is unclear, and the costs of therapy need to be weighed against possible benefits. However, few data are available regarding how to help caregivers adhere to prescribed patching protocols or to help providers and caregivers determine when the costs of such patching outweigh the potential benefits. These gaps have limited the development of treatment protocols to address the needs of this population. Therefore, there is little evidence which can be used to guide clinicians and caregivers in deciding how much patching to provide and when to discontinue patching. The proposed project will leverage unique secondary data collected in the Infant Aphakia Treatment Study (IATS) in order to provide guidance on establishing patching habits that may improve outcomes. We will also conduct analyses that will improve understanding of the costs and benefits of patching in the latter part of the preschool period in children treated for UCC. Specifically, we will determine whether it is possible to accurately identify children who will ultimately have little usable vision in their affected eye using information collected in the first four years of life, and if quality of life is impacted by prolonged patching in children who ultimately will not see well. The IATS is a randomized controlled trial designed to compare two treatments for UCC: leaving children aphakic versus implanting an intraocular lens (IOL) at the time of cataract surgery. The primary study is one of the largest currently-available cohorts of children treated for UCC, and has provided important evidence about outcomes in these children prior to school-entry. The proposed R21 will leverage data from this unique, well- characterized cohort of children treated for UCC who have been followed for more than 10 years to generate new knowledge about important questions related to treatment of UCC.