The authors undertook partial tenotomies combined with graded marginal recession of single vertical rectus muscles to treat small angle hypertropia in four adults with fusion potential. They report dose response, surgical technique and outcomes. Dose response closely matched the theoretical predicted effect for 66, 75, 80 and 90% tenotomise. Three of four patients had resolution of diplopia with one procedure. One patient regressed and needed a second procedure. The author concluded the graded marginal procedure is safe and effective for these small deviations with binocular potential.