Transcript WOUND CLOSURE VECTOR ANALYSIS

WOUND CLOSURE
(VECTOR ANALYSIS)
PHACO
• VERTICALLY APPLIED
IOP AND TISSUE
FORCES IN OPPOSITE
DIRECTION
ECCE
• HORIZONTALLY
APPLIED SUTURE
FORCE
DYNAMICS OF
SUTURELESS
CATARACT INCISIONS
THEORY
THEORY
• Corneal flap mechanism
• Square incisional
geometry
SQUARE INCISIONAL
GEOMETRY
EXTERNAL INCISION
INTERNAL INCISION
TUNNEL SIZE
astigmatically neutral funnel
corneal astigmatism is directly
proportional to the cube of the length of
the incision
inversely related to the distance from
the limbus
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SELF-SEALING WOUND
DEPENDS ON
The architecture of the wound
Delicate handling of tissue
edges
Adequate intraocular pressure
PHACO INCISION
GOALS
INTRAOPERATIVELY
POSTOPERATIVELY
INTRAOPERATIVE
Allow Easy Entry Of The Phaco Needle
Allow Ease Of Mobility Of The Phaco Needle
Minimize Incision Leak
Prevent Incision Burn.
POSTOPERATIVE
Self Sealed
Astigmatically Neutral
Both In Short Term And Longterm
vital statistics of a phaco incision
 1. Site (limbal or …)
 2. Placement (time of incision!)
 3. Style(mood of the incision!)
 4. The length of the external incision
 5. Length of the sclerocorneal tunnel
 6. Depth of tunnel dissection
 7. Size of initial opening for phacoemulsification
8 . Size of incision for IOL insertion
 9. Paracentesis opening
INSTRUMENTS REQUIRED FOR THE
PHACO INCISIONS(sclera tunnel)
A 15° freehand/preset depth (300 micron
A 2.0 mm broad crescent blade
A suitable breadth keratomewith a 90 degrees
angle at the tip (bevel up)
A 0.6 to 1.0 mm broad blade for the
paracentesis
A blunt tipped extender blade (bevel down)
A caliper
TECHNIQUE OF MAKING A PHACO
(Scleral Tunnel)
INCISION
Peritomy and cautery
Grooving
Tunnel dissection
Stab incisions and AC viscoinjection
AC entry
clear corneal incision (advantages)
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Well suited for topical anesthesia
lesser risk of bleeding
better accessibility
better red reflex
eliminates the conjunctival incision
minimal or no effect on astigmatism
disadvantages of clear corneal incision
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technical difficulty
lack of forehead support
need to enlarge for use of nonfoldable IOLs
difficulty in converting to a ECCE
potential for greater endothelial cell loss
.possible corneal thermal burns
.higher incidence of endophthalmitis in some
studies
Proposed incision for begginers
(changing ECCE to phaco)
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limbal groove
Straight or
Parallel to limbus
Biplanar
Slightly wider than phaco tip
PARACENTESIS OPENING
required for bimanual techniques
Usually on the left side (30-90 degree)
0.6 to 1.0 mm in breadth
simple stab or shelved
Clear Cornea Incision
With initial partial thickness vertical
incision
Without an initial incision
ASTIGMATIC INDUCERS
1. Longer incision.
2. Corneal incision.
3. Limbus parallel incision.
4. Uniplanar incision.
5. Sutured incision
The caliper is set at 2.8 mm.
A light indentation on the peripheral corneal
surface is created with the pointed ends 0f the caliper.
A 150-300-um-depth groove is created
A paracentesis incision is created with the
diamond blade fully extended
An oblique entry is created as the blade not
only driven through the corneal stroma to Descemet 's
level. but also slices to the surgeon 's left. Notice the
compression of tissue being created because ofthe
relatively dull blade
Descemet's level is entered 1.75 mm from
the epithelial level as the blade is swept to
the left.