IRIS Hook Assisted Phacoemulsification in Vitrectomized Eyes

Although phacoemulsification in previously vitrectomized eyes is a relatively safe procedure comparing with extracapsular cataract surgery, it is still more challenging than in eyes without previous vitrectomy because of the anatomical differences after PPV. Intraoperative difficulties such as abnormal anterior chamber deepening, unstable posterior capsules, and weakened zonules have been reported. The investigators aim to evaluate the efficacy and safety of a new simple iris hook assisted maneuver in phacoemulsification, then compare the incidence of intraoperative and postoperative complications of this technique with traditional phacoemulsification and phacoemulsification with 25-gauge vitreous irrigation. The latter two surgery methods are currently popular for cataract in vitrectomized eyes.

With the continuous evolution in vitrectomy techniques and instrumentation, an increasing number of vitreorential disorders are being successfully managed with pars plana vitrectomy (PPV). Cataract is one of the most common complications seen in phakic patients following PPV, and the incidence of it ranges from 4 to 80%, even up to 100% in various studies. Although phacoemulsification in previously vitrectomized eyes is a relatively safe procedure comparing with extracapsular cataract surgery, it is still more challenging than in eyes without previous vitrectomy because of the anatomical differences after PPV. Intraoperative difficulties such as abnormal anterior chamber deepening, unstable posterior capsules, and weakened zonules have been reported. The investigators aim to evaluate the efficacy and safety of a new simple iris hook assisted maneuver in phacoemulsification, then compare the incidence of intraoperative and postoperative complications of this technique with traditional phacoemulsification and phacoemulsification with 25-gauge vitreous irrigation. The latter two surgery methods are currently popular for cataract in vitrectomized eyes.

The traditional phacoemulsification in vitrectomized eyes usually with more Intraoperative difficulties such as abnormal anterior chamber deepening and unstable pupil. To evaluate whether the new method will increase the stability of anterior chamber and pupil.

To evaluate whether the new method will decrease CDE. CDE reflect the damage of phacoemulsification to the eye, It can be acquired automatically from the phacoemulsification machine. The unit of CDE is mJ.

The incidence of complications, including infusion deprivation syndrome, anterior capsulorhexis extension, iris trauma, descemets detachment, posterior capsular defect, nucleus drop, etc

The traditional phacoemulsification in vitrectomized eyes usually cause low IOP in the early stage, and sometimes induce detachment of choroid. To evaluate whether the new method will avoid the low IOP in the early stage.

Inclusion Criteria: patients with visually significant cataract following PPV After PPV vitreous substitutes were air / gas (Perfluoropropane:C3F8) or BSS, After PPV if vitreous substitute was silicone oil, that should be removed at least 3 months. The duration between PPV / silicone oil remove and phacoemulsification should more than 3 months Willing and able to comply with clinic visits and study-related procedures Provide signed informed consent Exclusion Criteria: Eyes with a history of acute angle-closure glaucoma, trauma, Eyes with a clinically dislocated or subluxated lens. Active ocular or periocular infection in the study eye Uncontrolled Blood Pressure Pregnant or breast-feeding women Participation in another simultaneous medical investigator or trial