Influence of pressure sensor equipped handpiece and vitreous removal on posterior capsule movement during occlusion break in porcine eyes

Abstract Posterior capsule stability is a key determinant of safety in phacoemulsification; however, the influence of the vitreous on its dynamics remains unclear. This non-clinical study evaluated the stabilizing effect of the Active Sentry (AS) handpiece and the impact of vitreous absence using an ex vivo vitrectomized porcine eye model. Posterior capsule elevation following an occlusion break was quantified across four vitrectomized groups (AS or Ozil [OZ] handpieces), with or without eyelid speculum [ES] and compared with previously reported vitreous-intact data from the same series using an identical protocol. At 20 mmHg intraocular pressure, the posterior capsule elevation ratio was significantly lower with the AS than with the OZ handpiece, both without ES (3.8 ± 1.3% vs. 8.4 ± 3.9%) and with ES (10.1 ± 12.3% vs. 20.0 ± 14.4%) (both P = 0.0010). Vitrectomized eyes showed reduced elevation compared with vitreous-intact eyes in the ES model: 10.1 ± 12.3% vs. 18.0 ± 19.1% with the AS ( P = 0.0215) and 20.0 ± 14.4% vs. 46.2 ± 20.2% with the OZ ( P = 0.0031). In conclusion, the AS handpiece stabilized the posterior capsule independently of vitreous support. Vitrectomized eyes did not show increased posterior capsule instability, and exploratory, independently sampled comparisons suggested that vitreous absence may be associated with attenuated elevation during surge events; this observation should be interpreted as hypothesis-generating.