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FLACS ophthalmic viscosurgical device press to prevent radial anterior capsular tears

  • Steve A. Arshinoff
    Correspondence
    Correspondence to Steve A. Arshinoff, MD, York Finch Eye Associates, 2115 Finch Ave. W. #316, Toronto, Ont. M3N 2V6.
    Affiliations
    York Finch Eye Associates, Toronto, Ont.

    Humber River Hospital and University of Toronto, Toronto, Ont.

    McMaster University, Hamilton, Ont.
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Published:August 27, 2020DOI:https://doi.org/10.1016/j.jcjo.2020.05.016
      The quality of the capsulotomy created by femtosecond lasers has been an issue.
      • Chan T.
      • Pattamatta U.
      • Butlin M.
      • Meades K.
      • Bala C.
      Inter-eye comparison of femtosecond laser-assisted cataract surgery capsulotomy and manual capsulorhexis edge strength.
      An American Society of Cataract and Refractive Surgery (ASCRS) committee 2013 review quoted the incidence of incomplete femtosecond laser assisted cataract surgery (FLACS) capsulotomies as having been reduced from over 10% initially, to about 1%.
      • Donaldson K.E.
      • Braga-Mele R.
      • Cabot F.
      • et al.
      for the ASCRS Refractive Cataract Surgery Subcommittee. Femtosecond laser-assisted cataract surgery.
      However, in 2015, a large series (>4000 eyes) revealed 1.84% anterior capsular tears with FLACS compared with 0.22% with phaco (p < 0.0001).
      • Abell R.G.
      • Darian-Smith E.
      • Kan J.B.
      • Allen P.L.
      • Ewe S.Y.P.
      • Vote B.J.
      Femtosecond laser-assisted cataract surgery versus standard phacoemulsification cataract surgery: outcomes and safety in more than 4000 cases at a single center.
      The microscopic serrations induced by femtosecond lasers have been blamed for the reduced strength of a FLACS capsulotomy, and manufacturers have adjusted the power and distribution of laser pulses to make the serrations finer and overlapping. Other contributing causes are optical shielding of the capsule by corneal scars; the anterior capsule being irregular, crenated, or fibrotic; adhesions to underlying cortical fibers; and increased intracapsular pressure (hypermature cataract).
      A free cap may be attached at a single small point, have multiple discreet residual attachments, or have floated free over 80%–90% of its surface, folded back over the peripheral lens and remain anchored to a broad attachment area in a radially awkward-to-access position. To reduce tear-outs, it is desirable to have a surgical strategy to reliably complete capsulotomies as the very beginning of surgery.
      An incompletely free cap tear-out is most similar to Argentinean flag sign, where there is increased posterior pressure pushing forward against the anterior capsule, because femto-created gas from nuclear softening may be trapped intralenticularly.
      • Arshinoff Steve A.
      OVDs for intumescent cataracts: pressure equalized cataract surgery. Letter.
      When the surgeon grasps the capsular flap and pulls radially, and inevitably anteriorly as well, the tear wants to spiral outward. The common method of grasping the cap centrally with microforceps and pulling the edges of the flap centrally, thus attempting to mimic the Little tear-out rescue radially, usually works, but may be insufficient in some cases to avoid outward extension.
      • Little B.C.
      • Smith J.H.
      • Packer M.
      Little capsulorhexis tear-out rescue.
      Instead, a pressure-equalized cataract surgery method, “the FLACS OVD press,” similar to what I have described for hypermature cataracts will just about always work, because the induction of pressure anterior to the anterior capsule with an ophthalmic viscosurgical device (OVD) pushing posteriorly counterbalances the forward-pushing intracapsular pressure and encourages the capsule to tear inward.

      Technique

      Trypan blue is not used because, unlike with Argentinean flag sign, the capsulotomy is mostly completed and clearly visible in FLACS cases. The addition of trypan blue would allow the anterior chamber (AC) to shallow, lowering the AC pressure and thereby encouraging extension of the tear.
      After prepping and draping the eye, a mixture of 1% isotonic nonpreserved xylocaine and 0.1% phenylephrine is injected intracamerally through the side port to pressurize the eye and enhance anaesthesia and pupil dilation.
      After waiting about 20 seconds for pupil dilation, Healon or Healon GV (preferred for their 27-gauge thin-walled cannulas that are easier to insert under the corneal dome) is injected over the centre of the laser-created cap until the cap becomes concave. If the cap has folded over the peripheral capsule, it is simply directed back with Healon or Healon GV, which is easier than if the more viscous Healon5 is used.
      Observation of the cap at this point will clearly show where the cap is free (separated from the peripheral capsule in an arc), and where it remains attached. The small sharp tips of a fine capsulorhexis instrument are used to grasp the capsule near the residual adhesions to depress the cap posteriorly and pull it centrally. With a circular motion (learned in another context, from James Gills, many years ago), of combined depression into the lens and central dragging, the tear is completed (Fig. 1, Fig. 2; Videos 1 and 2). The combination of pressure-equalized cataract surgery to depress the central capsular surface, and the inverted Gillsean capsulorhexis prevents the capsulotomy from tearing outward, and can be initiated anywhere over the 360 degrees of the cap. In 352 consecutive cases, 2 of 102 cases had suffered anterior capsulotomy extensions before I developed this technique, whereas 0 of the 250 subsequent cases using this technique developed anterior capsular tears (p < 0.05, calculated at www.openepi.com/TwobyTwo/TwobyTwo.htm; mid P exact).
      Fig 1
      Fig. 1(A) Case 1, where a crescent of freed cap is visible from 10 o'clock going clockwise to 5 o'clock. The cap does not appear to be free from 7 to 9 o'clock. (B) As the ophthalmic viscosurgical device (OVD), here Healon GV, is injected and the central aspect of the cap begins to become concave, the crescent outlining the freed part of the cap is increasing, but the small area at 9 o'clock is not free. (C) As OVD injection progresses and the central area of the cap has become concave, only a small area at 9 o'clock appears to still not free. (D) When the sharp points of the forceps are used to depress the cap posteriorly and pull it centrally, the 9 o'clock area of the cap becomes completely free and the capsulotomy is intact.
      Fig 2
      Fig. 2(A) More difficult case 2, in which the cap has remained attached to the peripheral capsulotomy clockwise from 3 to 9 o'clock. (B) As injection of ophthalmic viscosurgical device (OVD), here Healon GV, progresses and the centre of the cap becomes concave, the cap remains attached to the capsulotomy clockwise from 3 to 9 o'clock. (C) The capsulotomy forceps tips are used to depress the peripheral cap while pulling centrally and toward 6 o'clock to encourage the cap to tear free. (D) As the forceps tips depress and pull the cap centrally, creating a small fold in the cap, the 6 o'clock gas bubble can be seen to begin to emerge from the space between the cap and peripheral capsular margin, indicating that the capsulotomy is now complete in this area.

      Footnotes and Disclosure

      The author has no proprietary or commercial interest in any materials discussed in this article.

      Appendix. Supplementary materials

      References

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        Inter-eye comparison of femtosecond laser-assisted cataract surgery capsulotomy and manual capsulorhexis edge strength.
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