Data in the literature differ widely regarding the incidence and age at which posterior vitreous detachment occurs. We investigated the incidence of posterior vitreous detachment in elderly patients and whether this varied between eyes with and without age-related macular degeneration (AMD). Patients ranged in age from 51 to 89 years (median: with AMD 74 years, without AMD 70 years). A total of 251 eyes were examined by B-mode ultrasonography for the presence of posterior vitreous detachment. In 119 eyes no pathological changes were found in the macular region. The other 132 eyes exhibited either exudative or non-exudative age-related macular degeneration. Ultrasonography revealed complete posterior vitreous detachment in only 19% of eyes without and 15% of eyes with macular degeneration. Eyes with macular degeneration, though, had a significantly higher (p = 0.0059) incidence of incomplete vitreous detachment than eyes without macular degeneration. Whether this represents a cause or a consequence of the macular degeneration remains unclear. Our results show that complete posterior vitreous detachment is rarer in the elderly than hitherto assumed.