Aims: To study the epidemiology and risk factors contributing to displacement of nuclear fragments into the vitreous (DNFV) complicating phacoemulsification in the United Kingdom.
Methods: Cases were collected prospectively between March 2003- March 2004 by active surveillance through the British Ophthalmological Surveillance Unit (BOSU). Case control analysis of risk factors was performed by visiting 10 randomly selected centres using a total of 521 cases of uncomplicated phacoemulsification. Validation analysis to assess under-reporting was performed in a total of 13 randomly selected units.
Results: 610 cases of DNFV were confirmed during the reporting period. The estimated incidence of DNFV was 0.19-0.28%. The complications group was significantly older than the control group (mean 76.8 versus 74.3 years: p<0.001). Significant pre-operative risk factors were posterior synechiae (5.1% versus 2.2%), incomplete pupil dilation (59.5% versus 8.8%), pseudoexfoliation (5.6% versus 1.4%) and previous vitrectomy (7.8% versus 2.2%). Significant operative variables related to surgical experience, topical (14.3% versus 3.1%) and subtenon’s anaesthesia (51.4% versus 37.2%) and requirement for vision blue (trypan blue ophthalmic solution) (13.7% versus 2.4%).
Conclusions: The estimated incidence of DNFV during phacoemulsification surgery in the UK is 2 to 3 per 1000 operations. Risk factors have been identified which should help guide case selection for phacoemulsification surgery and modify techniques.