Chen’s Dual-Blade Viscoseal Technique: Fluidic Mechanics, Zero-Trauma Fixation, and Anterior Chamber Stability in Cataract Surgery
In phacoemulsification, main incision architecture serves as the foundation of intraocular surgery. Poor incision dynamics or early anterior chamber (AC) instability can trigger a cascade of complications, including iris prolapse, endothelial cell loss, and anterior capsule rupture.
Developed by ophthalmologist Dr. Alexander Chen (陳冠博醫師), the Chen’s Dual-Blade Viscoseal Technique was awarded the Best Popularity Award at the 2024 TSCRS (Taiwan Society of Cataract & Refractive Surgeons) Video Competition. The protocol addresses the fluidic limitations of small-gauge (27G) ophthalmic viscosurgical device (OVD) delivery by combining dual-blade fixation with a dispersive OVD fluidic barrier.
💡1. The Fluidic Dilemma of Traditional Incision Protocols
In surgical settings where routine dispersive OVD (such as Viscoat) is supplied with a high-resistance 27G cannula, traditional incision workflows present specific hydrodynamic challenges:
【Hydrodynamic Pitfalls of Conventional Incision Sequences】
- Paracentesis First ➔ Main Incision:
- Standard approach, but junior surgeons often struggle with visualization and awkward left-hand entry angles.
- Main Incision First ➔ Paracentesis:
- Large open wound. Slow entry or downward pressure easily trigger immediate AC collapse.
- Main Incision Only ➔ Delayed Paracentesis:
- High initial psychological stress; requires an unnecessary return step to create sideport later.
Aqueous Egress Through Wide Incisions: Inserting a narrow 27G cannula through a 2.2-2.4mm main incision leaves substantial gaps around the shaft. As OVD enters slowly through the 27G resistance, intraocular aqueous escapes rapidly around the cannula, inducing sudden AC shallowing.
Iatrogenic Conjunctival Trauma: Conventional stabilization using toothed forceps, cotton swabs, or fixation rings induces localized conjunctival tears, subconjunctival hemorrhage, and mechanical disruption of goblet cells, worsening postoperative iatrogenic dry eye disease (DED) and conjunctivochalasis.
💡2. Core Mechanism: Dual-Blade Fixation and Viscoseal Barrier
The Chen’s Dual-Blade Viscoseal Technique combines two techniques:
- Dual-Blade Fixation: The left-hand sideport blade (such as an MVR knife) enters the paracentesis and remains stationary to serve as an internal mechanical anchor, eliminating the need for conjunctival grasp instruments.
- Viscoseal Technique: Prior to inserting the 27G cannula into the main incision, dispersive OVD is applied over the external wound. The high surface tension and dispersive properties of the OVD create an external “water-gate,” preventing spontaneous aqueous outflow during instrument entry.
Chen’s Dual-Blade Viscoseal Technique was awarded the Best Popularity Award at the 2024 TSCRS Video Competition.
💡3. Step-by-Step Surgical Protocol (5-Step Workflow)
Step 1: Dual-Blade Setup ➔ Step 2: Sideport Anchor ➔ Step 3: Main Keratome Incision
➔ Step 4: External Viscoseal Application ➔ Step 5: Immediate OVD Injection
- Dual-Blade Engagement: Hold the sideport blade (MVR) in the non-dominant hand and the keratome (2.2-2.4 mm) in the dominant hand simultaneously.
- Paracentesis and Internal Stabilization: Advance the sideport blade horizontally into the paracentesis. Once inside the anterior chamber, keep the blade completely stationary to act as the primary globe stabilizer without touching or clamping conjunctival tissue.
- Single-Plane Main Incision: With the eye stabilized internally by the sideport blade, perform a clear corneal single-plane main incision with the keratome at an angle of 60-120 degrees (ideally 90) from the paracentesis.
- Mandatory Instrument Withdrawal Order: Retract the main keratome first, and then withdraw the sideport blade. Reversing this order risks downward torque on the lower lip of the main incision, inducing sudden AC decompression.
- External Viscoseal Application: Place the 27G Viscoat cannula at the external entry of the main keratome wound and extrude a thin layer of dispersive OVD directly over the incision surface. This layer seals the physical opening.
- Immediate Deep OVD Injection: Slide the 27G cannula through the OVD barrier into the main incision, initiating continuous OVD injection immediately upon entry to maintain uniform anterior chamber depth throughout.
💡四、 臨床效益與適應症評估
| Clinical Parameter | Chen’s Dual-Blade Viscoseal Technique | Conventional Forceps-Assisted Incision |
| Workflow Efficiency | Bimanual simultaneous execution; saves 30–60 seconds. | Repetitive instrument exchanges (forceps, blade, keratome, OVD). |
| Ocular Surface Integrity | Zero conjunctival manipulation; preserves goblet cells and limbal vasculature. | Toothed forceps create focal tears, hemorrhage, and ocular surface inflammation. |
| AC Hydrodynamic Stability | Viscoseal surface layer reduces spontaneous aqueous leakage during 27G entry. | Wide gap around 27G cannula allows rapid aqueous escape and chamber collapse. |
💡5. Indications, Contraindications, and Safety Guardrails
- Primary Indications: Routine and complex phacoemulsification cases aiming to minimize ocular surface trauma, streamline surgical flow, and optimize anterior chamber chamber stability with 27G OVD cannulas.
- Conversion Criteria & Contraindications:
- Uncooperative Patients: Severe involuntary eye movements or inability to fixate warrant immediate conversion to conventional toothed forceps or fixation rings.
- Extremely Shallow Anterior Chamber (AC): In cases of acute angle closure or plateau iris with an exceptionally shallow chamber, inject OVD via the paracentesis first before executing the main incision.
This unedited cataract surgery video demonstrates the Chen Dual-Blade Viscoseal Technique. I have performed this technique for more than three years and found it both safe and effective in over 99% of cases.
💡FAQs on Chen’s Dual-Blade Viscoseal Technique
Q1: What is the main innovation of the Chen’s Dual-Blade Viscoseal Technique?
Dr. Chen：The technique combines internal globe stabilization using a sideport blade (eliminating conjunctival trauma from forceps) with an external dispersive OVD seal over the main incision. This seal prevents sudden anterior chamber shallowing when injecting Viscoat with a 27G cannula.
Q2: Why must the keratome be withdrawn before the sideport blade?
Dr. Chen： Withdrawing the sideport blade first removes globe support while the keratome is still in the incision, which can compress the lower stromal lip of the main wound and trigger immediate aqueous loss. Retracting the keratome first ensures ideal wound architecture and maintains anterior chamber stability.
Q3: How does the Viscoseal technique prevent anterior chamber collapse with a 27G cannula?
Dr. Chen： Because a 27G cannula is significantly smaller than a 2.2-2.4 mm clear corneal incision, aqueous fluid readily leaks around the needle. Applying a layer of high-viscosity dispersive OVD outside the wound prior to cannula entry creates a physical surface tension barrier that prevents intraocular fluid egress.
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