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Manual Small Incision Cataract Surgery :
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MANUAL SICS IN DIFFICULT SITUATIONS |
1. Hypermature cataract
2. Posterior polar cataract
3. Pseudoexfoliation
4. Small pupil
5. Traumatic cataract
6. Complicated cataract
7. Coloboma iris
8. Ectopia lentis
Hypermature cataract
Difficulties:
Alterations:
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Err on a bigger section
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Linear capsulotomy (envelope technique)
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Double linear capsulotomy
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Extended on both sides with Vannas scissors
Linear capsulotomy in hypermature cataract
Click here to see Manual SICS in a hypermature cataract
Posterior polar cataract
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Axial, well circumscribed, densely white, onion whorl patterned opacity in the posterior capsule
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Congenital PC dehiscence in 10-25% of cases
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Rx
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Thorough preop slit lamp evaluation
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Must be prepared for congenital PC dehiscence
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Patient counseling
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After capsulorhexis, hydro free dissection
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Sweep cyclodialysis spatula under anterior capsule
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Hydro dissection avoided
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Hydrodelineation advised
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creates protective shell of epinucleus
Problem with hydro dissection in posterior polar cataract
Pseudoexfoliation
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weak zonules -- phacodonesis
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rigid,small pupil, compromised endothelium, Irido-capsular adhesions, risk of PC tear, postop iritis & fibrin formation
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Rx
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small pupil strategy
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meticulous, gentle capsulotomy
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nucleus prolapse with minimal stress on zonules
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liberal use of viscoelastics
AC lenses avoided
Small pupil
Differentiated from intraop miosis (iris manipulation)
Possible causes:
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postuveitic cataract
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diabetes
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glaucoma therapy
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trauma
Rx: pharmacological mydriasis
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viscoelastic - dilates pupil, releases posterior synechiae, opens space, increases visibility
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iris dilators, expanders, retractors, hooks
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stretch pupilloplasty (Kuglan's hooks)
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sector iredectomy, sphincterotomy
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posterior synechiae: synechiolysis & iridectomy
Stretch pupilloplasty with Kuglen's hooks
Click here to see a video of stretch pupilloplasty
Multiple sphincterotomies
Click here to see a video of multiple sphincterotomies
Keyhole iridectomy
Traumatic cataract
- Rule out I.O.F.B.
- Rule out subluxation of lens
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Assess corneoscleral tear (if any)
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Posterior segment evaluation (gentle B-scan)
Rx:
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first facial block (if perforating wound)
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no massage
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corneoscleral wound sutured first
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approach the area of posterior capsular tear last
If large pc tear, abandon IOL implantation
Secondary IOL after 3 months
Click here to see video of manual SICS in traumatic cataract
Complicated cataract
In high myopes:
Postuveitic cataract:
Rx:
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Synechiolysis (visco, cystitome, spatula, Vannas)
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Sphincterotomy, iridectomy if pupil small after synechiolysis
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Capsulotomy gently with sharp cystitome
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Heparin coated IOLs
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Postop steroids & short acting mydriatics
Coloboma iris
- small eye
- eccentric pupil
- poor mydriasis
- defective zonules
- posterior segment deformities
Preop:
S/L exam, 90 D exam, USG
Choice of IOL for eye of normal dimensions:
- PC IOL of 1 piece, 7mm optic, UV filter
- no laser ridge or positioning holes
For microphthalmos with coloboma:
6mm optic, 12-12.5mm
Surgical technique:
- temporal section
- superior iridectomy if poor mydriasis
- envelope capsulotomy
- haptic out of coloboma
Unilateral cataract in a child
Manual SICS in pediatric cases
Self sealing wound construction
- length of the tunnel according to optic size of IOL (0.5mm smaller than optic diameter)
- little more of clear corneal dissection (increases wound stability)
- more chances of button holing & premature entry
Role of suture
- wound leak in 100% of eyes < 11 years ECCE+PPC+AV+IOL
- wound leak in 33% of eye < 11 years ECCE+IOL(PCintact)
- no wound leak in > 11 years of age
Low scleral rigidity -- fishmouthing of internal aspect of wound
Suture pediatric incisions as a routine practice
Capsulorhexis
- lens capsule more elastic -- requires force before tearing
- decreased scleral rigidity -- +vitreous pressure pushes lens anteriorly; keeps anterior capsule taut-- difficulty in completing rhexis
For successful rhexis
- high mol.wt viscoelastic -- pushes anterior capsule posteriorly; creates laxity in anterior capsule & combat effect of vit pressure
- slightly smaller CCC
- tractional forces directed centripetally
- leaking lenticular content aspirated
Ant. capsulotomy -- with vitrectomy probe or with bipolar radiofrequency diathermy
Lens matter aspiration
- Hydro dissection -- easy lens matter aspiration; dislodges equatorial cells -- decreases chances of PCO
- In membranous & calcified cataract, anterior & posterior capsule fused
- Membranectomy & anterior vitrectomy before IOL insertion
- In some, central portion of thickened posterior capsule cut with Vannas scissors
- Anterior vitrectomy done with vitrectomy probe
- Posterior capsular opacification: significant concern in children < 2 years of age
- PPC + post. cpasulorhexis done
Management of posterior capsule
Intraop:
- ECCE+PPC+Ant. vitrectomy is more effective than ECCE+PPC
- prevents reopacification of PC
- Post. capture of IOL optic by PCCC
- Bag placement + PCCC capture of IOL + 360 apposition
- Formation of Sommering's ring
Postop:
- Yag capsulotomy
- Surgical membranectomy (thick PCO, uncooperative patient, recurrence of PCO after Yag, soft after cataract)
IOL implantation in children
- In the bag IOL is highly desirable
- Uveal tissue is highly reactive
- When in the bag is not possible, go for sulcus fixation
IOL power calculation! Controversial topic
Click here to see a video of manual SICS in pediatric cataract
Manual SICS in glaucoma
Special attention: long term pilo 2%, miotic pupil, prior trabeculectomy, rigid pupil, Pxf
In patients with pre-existing filtering bleb
Preop:
- miotics stopped
- use of other antiglaucoma medications
- no massage
Intraop:
- superior nasal or temporal, temporal approach
- avoid bleeding
- avoid conjunctival button holing, conj. tears
- adequate use of viscoelastic
- avoid peripheral extension of capsulotomy
Post filter eye with small pupil
Click here to see a video of manual SICS in post filter eye
Click here to see a video of manual SICS in subluxated cataract
SICS / Conventional ECCE in post filter eyes
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decreased conjunctival dissection
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less area used for surgery (decreases postop inflammation, maintains bleb function)
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minimal astigmatism, early rehabilitation
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greater comfort (no suture related problems)
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decreased incidence of expulsive hemorrhage -- closed pressure system
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intraop + vit pressure, shallow chamber managed
Click here to see a video of manual SICS and glaucoma surgery
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