WOUND CLOSURE VECTOR ANALYSIS PHACO VERTICALLY APPLIED IOP

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 • Corneal flap mechanism • Square incisional geometry

SQUARE INCISIONAL GEOMETRY üEXTERNAL INCISION üINTERNAL INCISION üTUNNEL SIZE

astigmatically neutral funnel ücorneal astigmatism is directly proportional to the cube of the length of the incision üinversely related to the distance from the limbus •

SELF-SEALING WOUND DEPENDS ON üThe architecture of the wound üDelicate handling of tissue edges üAdequate intraocular pressure

PHACO INCISION GOALS üINTRAOPERATIVELY üPOSTOPERATIVELY

INTRAOPERATIVE ü Allow Easy Entry Of The Phaco Needle ü Allow Ease Of Mobility Of The Phaco Needle ü Minimize Incision Leak ü Prevent Incision Burn.

POSTOPERATIVE ü Self Sealed ü Astigmatically Neutral ü Both In Short Term And Longterm

vital statistics of a phaco incision ü 1. Site (limbal or …) ü 2. Placement (time of incision!) ü 3. Style(mood of the incision!) ü 4. The length of the external incision ü 5. Length of the sclerocorneal tunnel ü 6. Depth of tunnel dissection ü 7. Size of initial opening for phacoemulsification 8. Size of incision for IOL insertion ü 9. Paracentesis opening

INSTRUMENTS REQUIRED FOR THE PHACO INCISIONS(sclera tunnel) ü A 15° freehand/preset depth (300 micron ü A 2. 0 mm broad crescent blade ü A suitable breadth keratomewith a 90 degrees angle at the tip (bevel up) ü A 0. 6 to 1. 0 mm broad blade for the paracentesis ü A blunt tipped extender blade (bevel down) ü A caliper

TECHNIQUE OF MAKING A PHACO (Scleral Tunnel) INCISION ü Peritomy and cautery ü Grooving ü Tunnel dissection ü Stab incisions and AC viscoinjection ü AC 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 ü required for bimanual techniques ü Usually on the left side (30 -90 degree) ü 0. 6 to 1. 0 mm in breadth ü simple stab or shelved

Clear Cornea Incision üWith initial partial thickness vertical incision üWithout an initial incision

ASTIGMATIC INDUCERS ü 1. Longer incision. ü 2. Corneal incision. ü 3. Limbus parallel incision. ü 4. Uniplanar incision. ü 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 0 f 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.