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CATARACT & REFRACTIVE
ERRANT Rhexis There are ways to master the complication of a disobeying rhexis in phacoemulsification. Soosan Jacob MD reports
A
continuous, perfectly circular, sized and centred rhexis is the all-desirable step in phacoemulsification – stretching comfortably for phaco manoeuvres without wrap-arounds and overlapping the IOL optic 360 degrees around, thus preventing posterior capsular opacification, delayed asymmetric capsular shrinkage, pea-podding of haptic, IOL vaulting or decentration, optic edge capture or IOL position/ refraction changes. Increasing surgeon experience, aids such as corneal rhexis markers, millimetre-marked rhexis forceps, imageguided overlay technologies as well as the femtosecond laser or the Zepto capsulotomy systems have further helped increase precision. Many of us, however, still mostly rely on a manual rhexis with either forceps or cystitome, and are sometimes faced with a disobeying rhexis. This article helps deals with this.
The little rhexis trick in four steps. A: Peripheral extension
B: Capsular flap unfolded to lie flat. Holding the flap as close to the root as possible, it is first pulled backwards in a horizontal plane along the circumference of the completed segment of rhexis
C: With flap held stretched, force is directed more centrally to bring the rhexis back in
D: The rhexis is then continued again
or posterior pressure. Alternately, a microrhexis forceps may be used, which, as compared to Utrata forceps, requires only a tiny incision and therefore avoids escape of viscoelastic. Whenever required, viscoelastic should be replenished to maintain a flat anterior capsule. The flap edge is released and regrasped close to the tearing edge for better control.
The initial nick should be just short of the desired radius as it enlarges slightly on turning circularly. The rhexis edge mirrors the curve of the capsular flap edge and maintaining the flap flat and circular against the lens gives a perfect circle. Turning the flap inwards or outwards can make the rhexis smaller or larger respectively. Near the main port, avoid a floating flap from sliding out through the incision,
PEARLS FOR A GOOD RHEXIS A flat anterior lens capsule and low intralenticular pressure help keep the rhexis on track. It is therefore important to have a soft eye, a patient who is not straining and lids that are not squeezing. Beginners may be benefitted by a peribulbar block and a Pinkie ball or Honan balloon application. A selfretaining speculum helps decrease the effect of lid squeezing. Good topical anaesthesia and a dilated pupil make both surgeon and patient more comfortable. Capsular dye (Trypan blue 0.06%) improves visualisation. A partial entry allows better retention of viscoelastic in the anterior chamber (AC) and can be widened later. An oblique bend to the cystitome tip allows it to be visualised as opposed to a right-angled bend. Shaft angulation should avoid incisional distortion secondary to excessive anterior EUROTIMES | MARCH 2019