When retinal detachment is suspected in children clinical assessment with or without an anaesthetic aims to determine if its is rhegmatogenous, exudative, tractional or due to combined mechanisms. The differential diagnosis of rhegmatogenous retinal detachment is trauma, previous intraocular surgery, and collagenopathies such as Sticklers syndrome. Once these are excluded there are rare syndromes that could be considered. We report two such cases and a third case who was a brother of one of the index cases where deep ocular phenotyping in the operating room led us to a clinical diagnosis of Knobloch's syndrome. We present novel aspects of the phenotype and genotype adding to the literature on this rare entity. Our cases highlight surgical dilemmas and suggest that conservative management is a reasonable option to pursue.