The success rate of wearing bifocals in children with Down's syndrome

Purpose:  Accommodation is reduced in approximately 75% of children with Down's syndrome (DS) compared to their peers (Woodhouse et al ., 1993). A study by Stewart et al . (2005) showed that bifocals improve focusing on near targets and they are currently prescribed regularly. The study also showed that wearing bifocals improved the children's own accommodative ability over time. The aim of this study is to evaluate the success of wearing bifocals in improving accommodation. Methods:  Clinical records of 37 children from the Cardiff University Down's Syndrome Vision Research Unit, who were prescribed bifocals, were reviewed. Their accommodation, using dynamic retinoscopy at 10, 16.7 and 25 cm, was noted before wearing the bifocals and during either their latest visit or when they stopped using bifocals. An accommodative lag of up to and including 0.75D at two or more testing distances is considered accurate (McClelland and Saunders, 2004). Results:  The accommodative ability of 23 out of 37 (62.16%) of the children had improved (through the distance part of the lens) after using the bifocals for an average of 29.38 months. Thirteen out of those 23 had accurate accommodation, one third of the overall number of children, without the use of bifocals. These 13 children have returned, or will shortly return, to single vision spectacles. Conclusions:  Using bifocals not only improves the children's accuracy of focusing on near objects through the bifocals, but also ‘trains’ their accommodative ability, with a success rate of 62.16% so far. For some children at least, bifocal wear can be a temporary management strategy.