WOUND CLOSURE (VECTOR ANALYSIS) ECCE VERTICALLY APPLIED IOP AND TISSUE FORCES IN OPPOSITE DIRECTION...

WOUND CLOSURE(VECTOR ANALYSIS)

ECCE

• VERTICALLY APPLIED IOP AND TISSUE FORCES IN OPPOSITE DIRECTION

PHACO

• HORIZONTALLY APPLIED SUTURE FORCE

DYNAMICS OFSUTURELESS

CATARACT INCISIONS

THEORY

• Corneal flap mechanismTHEORY

• Square incisional geometry

SQUARE INCISIONAL GEOMETRY

EXTERNAL INCISIONINTERNAL INCISIONTUNNEL SIZE

astigmatically neutral funnel •

corneal astigmatism is directly proportional to the cube of the length of the incisioninversely related to the distance from the limbus

SELF-SEALING WOUND DEPENDS ONThe architecture of the woundDelicate handling of tissue

edgesAdequate intraocular pressure

PHACO INCISIONGOALS

INTRAOPERATIVELYPOSTOPERATIVELY

INTRAOPERATIVE

Allow Easy Entry Of The Phaco NeedleAllow Ease Of Mobility Of The Phaco NeedleMinimize Incision LeakPrevent Incision Burn.

POSTOPERATIVE

Self SealedAstigmatically NeutralBoth 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 insertion9. Paracentesis opening

INSTRUMENTS REQUIRED FOR THE PHACO INCISIONS(sclera tunnel)

A 15° freehand/preset depth (300 micronA 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 cauteryGroovingTunnel dissectionStab incisions and AC viscoinjectionAC entry

clear corneal incision (advantages)

• 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

• 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)

• limbal groove• Straight or • Parallel to limbus• Biplanar• Slightly wider than phaco tip

PARACENTESIS OPENING

required for bimanual techniquesUsually on the left side (30-90 degree) 0.6 to 1.0 mm in breadthsimple 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 cornealsurface is created with the pointed ends 0f the caliper.

A 150-300-um-depth groove is created

A paracentesis incision is created with thediamond blade fully extended

An oblique entry is created as the blade notonly driven through the corneal stroma to Descemet 'slevel. but also slices to the surgeon 's left. Notice thecompression of tissue being created because ofthe

relatively dull blade

Descemet's level is entered 1.75 mm fromthe epithelial level as the blade is swept to

the left.