IRIS Hook Assisted Phacoemulsification in Vitrectomized Eyes

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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IRIS Hook Assisted Phacoemulsification in Vitrectomized Eyes

Conditions
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Cataract, Vitrectomy

Intervention / Treatment
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* Device: IRIS HOOK
* Device: TRADITION


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: IRIS HOOK<br>iris hook assisted maneuver in phacoemulsification | Device: IRIS HOOK<br>* iris hook assisted maneuver in phacoemulsification<br>|
| Active Comparator: TRADITION<br>traditional phacoemulsification or phacoemulsification with 25-gauge vitreous irrigation | Device: TRADITION<br>* traditional phacoemulsification or phacoemulsification with 25-gauge vitreous irrigation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stability of anterior chamber and pupil | 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. | Intraoperative | 
| Time of operation | To evaluate whether the new method will shorten the operation time | Intraoperative | 
| Cumulative dissipated energy (CDE) | 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. | Intraoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The presence of intraoperative complications | The incidence of complications, including infusion deprivation syndrome, anterior capsulorhexis extension, iris trauma, descemets detachment, posterior capsular defect, nucleus drop, etc | Intraoperative | 
| Visual acuity (VA) | To evaluate whether the surgery can effectively increase VA. | 3 months after opreation | 
| Intraocular pressure(IOP) | 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. | 3 months after opreation | 
| The presence of postoperative complications | The incidence of complications, including corneal edema, cystoid macular edema, etc. | 3 months after opreation |