Despite recent advances in surgical technique and refractive correction, amblyopia remains a significant problem in the treatment of monocular infantile cataracts. Amblyopia therapy recommended by different authors during the preverbal period has varied from no patching to nearly full-time occlusion of the phakic eye. We measured preferential looking (PL) acuities sequentially in four infants following monocular cataract surgery and contact lens correction. This information was used to adjust occlusion of the phakic eye, which was prescribed 25%-100% of waking hours. Patching schedules were altered, on average, every three to four months in response to changes in PL acuities. Four increases in patching intensity retarded acuity development in the phakic and benefited development in the aphakic eyes. Nine decreases enhanced progress or yielded no change in the phakic and, with two exceptions, impeded progress in the aphakic eyes. Recognition acuities now available for two of the children show continuity with previous PL acuities and confirm useful vision in the aphakic eyes. We describe guidelines for adjusting occlusion based on our experience. We believe that PL modulation of patching therapy may result in more favorable visual outcomes for both eyes of infants with monocular cataracts.