Materials in the vitreous during cataract surgery: nature and incidence, with two cases of histological confirmation.

BACKGROUND: To identify and classify materials in the vitreous observed during phacoemulsification cataract surgery (phaco). DESIGN: Prospective, consecutive, observational case series at one ophthalmic day surgery in Sydney, Australia. PARTICIPANTS: A total of 767 consecutive phaco cases. Cases were excluded if there was posterior capsule rupture or vitreous loss intraoperatively. METHODS: For each patient, age, gender, baseline corrected distance visual acuity, presence of pseudoexfoliation, nuclear sclerosis grade and phacoemulsification ultrasound time were recorded. The relationship between these variables and materials in the vitreous was evaluated with regression analysis. Two patients with materials in the vitreous developed an acute intraoperative rock-hard eye syndrome. In these two patients, pars plana needle aspiration of retrolenticular fluid was performed to re-establish normal intraocular pressure. Histology was undertaken to compare this fluid with known lens material retrieved from the Fluid Management System bags in two unrelated cases. MAIN OUTCOME MEASUREMENTS: Presence of materials in the vitreous during phaco. RESULTS: Materials in the vitreous were observed in either Berger's space or the anterior vitreous in 386 eyes (50.3% of cases); the majority was putatively lens material (46.5% of all cases). Pigment and ophthalmic viscoelastic device were seen in the anterior vitreous in 9.8% and 1.7% of cases, respectively. Logistic regression analysis demonstrated that higher nuclear sclerosis grade (P = 0.025), male gender (P = 0.003) and greater age (P = 0.016) were predictive of the presence of materials in the vitreous. Histological assessment with light microscopy and birefringence techniques identified the materials in the vitreous as lens material. CONCLUSION: Materials in the vitreous were seen in 50.3% of phaco cases. It has been histologically demonstrated that lens materials can be introduced into the anterior vitreous during phaco.