How to assess anterior hyaloid membrane (AHM) integrity in a posterior capsule tear (PCT) during cataract surgery?

Assessment of Anterior Hyaloid Membrane (AHM) Integrity During Posterior Capsule Tear

When a posterior capsule tear occurs during cataract surgery, assess AHM integrity using the Plunge Sign: inject dispersive OVD through the tear into Berger's space—if the OVD fills smoothly in a single plane with posterior displacement of the membrane, the AHM is intact; if a narrow snake-like stream plunges downward, the AHM is ruptured and immediate anterior vitrectomy is required.

Primary Assessment Methods

The Plunge Sign (Preferred Real-Time Method)

• Direct dispersive OVD through the posterior capsule tear into Berger's space (the potential compartment between the AHM and posterior capsule, bounded by Wieger's ligament) 1
• Intact AHM: OVD fills smoothly in a single plane, displacing the membrane posteriorly—this occurs even in elderly eyes with liquefied vitreous 1
• Ruptured AHM: A narrow, snake-like stream of OVD plunges downward through the defect into the vitreous cavity 1
• This technique is equipment-independent, requires no dye, and provides immediate intraoperative guidance without pausing surgery 1

Triamcinolone Staining (Alternative Method)

• Inject triamcinolone acetonide to visualize vitreous architecture and confirm vitreous prolapse 2
• Limitations: Requires immediate availability, necessitates pausing surgery, and provides only indirect assessment 1
• Most useful for confirming complete vitreous removal after anterior vitrectomy rather than initial AHM assessment 2

Flutter Sign (Observational Method)

• Assess the mobility and motion characteristics of the posterior capsular tear edges 1
• Limitations: Interpretation varies with tear morphology, lighting conditions, and intraoperative fluidics 1
• Less reliable than direct OVD assessment for definitive determination 1

Clinical Decision Algorithm

If AHM is Intact (Smooth OVD Filling Pattern)

• Convert the tear to a stable continuous curvilinear capsulorhexis 3, 4
• Avoid anterior capsule polishing, as this may destabilize remaining capsular support 5
• Proceed with careful IOL implantation, preferably with posterior optic capture 4
• Berger's space depth can vary from 33.5 μm to 383.1 μm, and excessive hydration during phacoemulsification may cause anterior displacement of the posterior capsule, increasing rupture risk 1

If AHM is Ruptured (Snake-Like OVD Plunge)

• Immediately plan one-port pars plana anterior vitrectomy 1
• Place irrigation anteriorly through a paracentesis 1
• Introduce vitrector through pars plana sclerotomy, advancing beneath the tear 1
• Position vitrector port facing upward to remove prolapsed vitreous without enlarging the capsular defect 1
• Choose between trocar system or direct sclerotomy under fornix-based flap based on intraoperative pressure considerations 1
• After vitrectomy, discontinue irrigation and instill diluted triamcinolone to confirm absence of residual vitreous 2, 1
• Seal sclerotomy without vitreous incarceration 1
• Convert posterior capsular tear to continuous rhexis, then proceed with IOL implantation with posterior optic capture 4, 1

Critical Pitfalls to Avoid

Berger's Space Considerations

• Anterior vitreolenticular interface dysgenesis is common in pediatric cataracts (55% of cases), particularly with posterior capsule plaques and unilateral cataracts 3
• In these cases, primary posterior capsulorhexis is more surgically demanding, with 58.6% developing detectable AHM breaks and 13.8% requiring unplanned anterior vitrectomy 3
• Wieger's ligament rupture can allow excessive Berger's space hydration, causing anterior displacement of the posterior capsule and increasing instrument touch risk 1

Anterior Capsule Tear Extension Risk

• Anterior capsule tears extend to the posterior capsule in approximately 48% of cases 4
• Extension can occur at any surgical stage: hydrodissection, phacoemulsification, irrigation/aspiration, or IOL implantation 4
• When anterior capsule tears are identified, consider redirecting a "safety" capsulorhexis to incorporate the tear 4

Vitreous Loss Complications

• Vitreous loss increases risk of retinal detachment—educate patients about symptoms (new floaters, flashes, visual field defects) and perform dilated fundus examination if these occur 5
• Risk factors for post-operative retinal detachment include axial myopia, male gender, younger age, and vitreous prolapse into the anterior chamber 2

Intraoperative OCT Confirmation

• Microscope-integrated intraoperative OCT can confirm Berger's space anatomy and detect hyperreflective particles (lens fragments, cellular material, or triamcinolone) that penetrate through discontinuous Wieger's ligament 1
• iOCT identifies Berger's space in 75% of cases intraoperatively and can demonstrate posterior bowing of the AHM during OVD injection 1