Strabismus Surgery for Esotropia, Down Syndrome and Developmental Delay; Is an Altered Surgical Dose Required? A Literature Review

BACKGROUND AND PURPOSE: There is a high rate of strabismus, in particular esotropia, in children with Down syndrome or developmental delay, which frequently requires surgical correction. A paper in 1994 advocated that the surgical dose be adjusted due to an altered response in these children. The aim of this literature review is to evaluate the available evidence to establish whether an altered surgical approach is required in either population. METHODS: A literature review was conducted using PubMed and Web of Knowledge. Only English language papers were eligible for inclusion. The papers were collated in chronological order for analysis, and their references searched for further relevant papers. Forward citation searches were also undertaken. RESULTS: A 2 × 2 comparison is made between publications on Down syndrome (in isolation) and developmental delay populations (including Down syndrome) with adjusted versus non-adjusted surgery. Published surgical success rates on esotropia from unaltered surgical doses range from 62.0%–85.7% (four papers) in the Down syndrome cohort, with none of the adjusted surgeries having a successful outcome. Surgical success rates from adjusted surgical doses in developmental delay cohort range from 37.5%–86.0% (seven papers), with one unadjusted surgical success rate of 76.0%. The results across the studies are summarised in a table and discussed. CONCLUSIONS: An exaggerated surgical effect in individuals with developmental delay has been reported, and this population may benefit from a reduced surgical dose. Published research does not support giving a reduced surgical dose in individuals with Down syndrome, but more research needs to be done to make a definitive conclusion.