Small Incision Cataract Surgery (SICS) / Manual SICS (MSICS)

Definition

Historical Context

Steps of MSICS (Surgical Technique)

1. Incision - Scleral Tunnel

• A self-sealing sclero-corneal tunnel is created, approximately 5-7 mm wide
• The tunnel is constructed so the internal opening is wider than the external (valve mechanism) - this prevents leakage without sutures
• The incision is placed about 2 mm posterior to the limbus

2. Anterior Capsulotomy (Capsulorhexis)

• Trypan blue dye (0.1%) is injected to stain the anterior capsule, making it visible (especially useful in mature/hypermature cataracts)
• A continuous curvilinear capsulorhexis (CCC) of ~5-6 mm is created
• Alternatively, a can-opener capsulotomy may be used

3. Hydrodissection

• Balanced salt solution (BSS) is injected under the anterior capsule to separate the cortex from the capsule and free the nucleus
• This allows smooth nucleus prolapse and rotation

4. Nucleus Expression

• The nucleus is manually prolapsed into the anterior chamber using a lens dialer or Sinskey hook
• It is then delivered out through the scleral tunnel in one piece using a wire vectis or irrigating vectis
• This is the defining step - the nucleus comes out intact without ultrasound energy

5. Cortical Aspiration

• Residual cortical material is aspirated using a Simcoe double-lumen cannula (irrigation + aspiration simultaneously)
• The posterior capsule is carefully preserved

6. IOL Implantation

• A posterior chamber IOL (PCIOL) is implanted into the capsular bag
• A rigid PMMA IOL can be used (unlike phaco, where a foldable IOL is needed)
• OVD (viscoelastic) is used to maintain the anterior chamber depth and protect the endothelium

7. Wound Closure

• The self-sealing scleral tunnel usually requires no sutures
• The wound is checked for watertight closure (Seidel test)

Advantages of MSICS

Disadvantages / Limitations

• Larger incision than phacoemulsification (5-7 mm vs 2-3 mm) - slightly more trauma
• Higher risk of induced astigmatism compared to phaco (though less than conventional ECCE)
• Requires more surgical skill than ECCE for nucleus delivery
• Not ideal for very soft or very hard nuclei equally well (best for grade 2-4 nuclear sclerosis)

Comparison: MSICS vs Phacoemulsification

Key Points to Remember for Exam

1. MSICS = variant of ECCE, not phaco
2. The scleral tunnel is self-sealing - key architectural feature
3. Trypan blue stains the capsule for safe capsulorhexis
4. Nucleus is removed in one piece - no fragmentation
5. Simcoe cannula for cortex removal
6. Visual rehabilitation is comparable to phacoemulsification
7. Preferred technique for high-volume, low-resource settings (e.g., eye camps in India/Africa)

SICS - 12 Steps as per A.K. Khurana

Definition

The 12 Steps

Step 1 - Bridle Suture

• A superior rectus bridle suture (4-0 black silk) is placed to fix and depress the globe
• This brings the superior limbal area into the operative field
• Provides counter-traction during tunnel construction

Step 2 - Conjunctival Peritomy (Flap)

• A fornix-based conjunctival flap is raised from 10 o'clock to 2 o'clock position
• Bare sclera is exposed superiorly
• Bleeding is controlled with bipolar diathermy cautery

Step 3 - Scleral Groove (Partial Thickness Incision)

• A linear groove is made in the sclera, 2 mm posterior to the limbus, ~6-7 mm wide
• Depth: approximately 1/2 to 2/3 scleral thickness
• This marks the external opening of the tunnel
• A crescent knife is used for this step

Step 4 - Sclerocorneal Tunnel Dissection

• Using the crescent knife, a lamellar tunnel is dissected forward into clear cornea (1-1.5 mm beyond the limbus)
• The tunnel is triplanar - scleral plane → limbal plane → corneal plane
• Internal opening is wider than external opening (valvular/trapezoid shape) = self-sealing
• The inner corneal lip (shelf) creates the valve mechanism

Step 5 - Internal Corneal Entry (Keratome Entry)

• A keratome (3.2 mm) or bent needle enters the anterior chamber through the inner tunnel lip
• The anterior chamber (AC) is entered at the level of the posterior limbus
• A side-port paracentesis (1 mm) is also made at 2-3 o'clock for a second instrument

Step 6 - Anterior Capsulotomy

• Trypan blue 0.1% is injected to stain the anterior capsule (especially in mature cataracts)
• OVD (viscoelastic) is injected to maintain AC depth
• A Continuous Curvilinear Capsulorhexis (CCC) of 5-6 mm is made using a cystotome or Utrata forceps
• Alternatively, a can-opener capsulotomy using a 26G needle is performed

Step 7 - Hydrodissection and Hydrodelineation

• Hydrodissection: BSS injected under the anterior capsular rim to separate cortex from capsule - creates a fluid wave behind the nucleus
• Hydrodelineation: BSS injected into the nucleus to separate the epinucleus from the endonucleus (creates a "golden ring")
• This loosens and mobilizes the nucleus, allowing free rotation

Step 8 - Nuclear Prolapse into Anterior Chamber

• The nucleus is rotated and prolapsed into the anterior chamber using a Sinskey hook or nucleus rotator
• Gentle pressure at the inferior limbus with a second instrument helps prolapse the nucleus through the capsulorhexis opening
• OVD is placed above and below the nucleus to protect the corneal endothelium

Step 9 - Nuclear Delivery (Expression)

• The nucleus is delivered out through the sclerocorneal tunnel in one piece
• Two main methods:
  • Vectis method: Irrigating vectis is passed under the nucleus and lifts it out
  • Viscoexpression: OVD injected behind the nucleus to push it out (Blumenthal technique)
  • Phaco-sandwich / wire loop: for harder nuclei
• No ultrasound energy is used

Step 10 - Cortical Aspiration

• Residual cortical matter is aspirated using a Simcoe double-lumen cannula (irrigation + aspiration in one instrument)
• 360° cortex is removed systematically
• The posterior capsule is polished to remove any residual lens epithelial cells (reduces PCO)
• AC is maintained throughout with irrigation

Step 11 - IOL Implantation

• AC is refilled with OVD to maintain depth and protect the endothelium
• A rigid PMMA posterior chamber IOL (PCIOL) (5.5-6 mm optic) is implanted into the capsular bag
• The leading haptic is placed first, then the optic is dialed in, followed by the trailing haptic
• If capsulorhexis is intact - bag fixation; if not - sulcus fixation
• OVD is thoroughly removed after IOL placement to prevent IOP spike

Step 12 - Wound Closure

• The sclerocorneal tunnel is self-sealing - no sutures required (the valvular architecture closes on hydration)
• Stromal hydration of side port with BSS to ensure watertight closure
• Conjunctival flap is reposited and secured with bipolar cautery or absorbable suture (8-0 Vicryl)
• AC is checked for formed depth and no wound leak (Seidel test)
• Subconjunctival antibiotic + steroid injection given at the end

Summary Table

Key Points for Exam

• The triplanar tunnel is the basis of self-sealing (no sutures needed)
• Trypan blue - stains capsule in mature cataract
• Simcoe cannula - used for cortex aspiration (irrigation + aspiration combined)
• Vectis - instrument for nucleus delivery
• Incision size: 5-7 mm external, wider internally
• Visual outcomes comparable to phacoemulsification - but no expensive machine needed
• Best suited for dense/mature cataracts and high-volume settings

• Steps 1-5 = Getting IN (access to the eye)
• Steps 6-8 = Preparing the lens (capsule + nucleus)
• Steps 9-10 = Removing the lens (nucleus + cortex)
• Steps 11-12 = Finishing (IOL + closure)