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Modified neodymium-doped yttrium aluminium garnet laser capsulotomy for complete anterior capsular contraction syndrome

      Anterior capsular contraction syndrome (ACCS) is defined as an exaggerated reduction of the capsular bag diameter, as a result of the contact between residual lens epithelial cells and intraocular lens (IOL), on the edge of continuous curvilinear capsulorhexis. It is a well-known but rare complication after uneventful cataract surgery.
      • Davison JA
      Capsule contraction syndrome.
      The aetiology remains unclear. However, a number of factors have been associated, including small rhexis (<4 mm diameter), pseudoexfoliation, uveitis, high myopia, retinitis pigmentosa, myotonic dystrophy, and diabetes.
      • Davison JA
      Capsule contraction syndrome.
      Additionally, IOL biomaterial and design are well-established related factors.
      • Hayashi K
      • Hayashi H
      Intraocular lens factors that may affect anterior capsule contraction.
      Silicone IOLs are known to lead to a greater degree of capsular contraction than acrylic IOLs.
      ACCS typically occurs within the first 3 postoperative months. The degree of phimosis can be significant enough to displace IOL causing secondary refractive shift or occlude the visual axis and reduce vision. Both require anterior capsulotomy either with a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser or surgically.
      • Hayashi K
      • Hayashi H
      Intraocular lens factors that may affect anterior capsule contraction.
      We report a case of anterior capsular contraction with complete occlusion of the visual axis. Treatment with Nd:YAG laser was performed after a C-shaped superior arcuate pattern.
      A 65-year-old woman presented to our institution, complaining of gradual deterioration of vision in her right eye. Written consent was obtained from the patient. Four months before her visual symptoms, she had undergone uneventful cataract surgery. A monofocal, single-piece, hydrophilic IOL (RayOne, Rayner, Ltd) was implanted at the time of surgery. She was otherwise fit and well with no ocular history.
      On examination, her best-corrected visual acuity was RE 6/60 and LE 6/6. Slit-lamp biomicroscopy revealed marked thickening of the anterior capsule with capsular contraction and complete occlusion of the capsulorhexis opening (Fig. 1).
      Fig 1
      Fig. 1Anterior segment photographs. Anterior capsular contraction syndrome with complete occlusion of anterior capsulorhexis. Red hemicircle represents the C-shaped neodymium-doped yttrium aluminium garnet laser pattern (left). One month postlaser (middle). Six months postlaser (right).
      Anterior chamber (AC) was deep and quiet without any signs of uveitis or zonular weakness. Anterior segment optical coherence tomography showed a central thick hyper-reflective band placed between the iris plane and IOL, occluding the visual axis (Fig. 2).
      Fig 2
      Fig. 2Anterior segment optical coherence tomography on presentation with central thick hyper-reflective band placed between the iris plane and intra-ocular lens, occluding the visual axis (left). Inferior displacement of the thick opacity 1 month postlaser (middle). Six months postlaser (right).
      Our primary approach was an Nd:YAG laser anterior capsulotomy. Initial attempts to laser the central thick membrane in a cross-shaped pattern failed. Despite higher energy settings, the laser did not penetrate the thickened anterior fibrosis. Subsequently an arcuate Nd:YAG laser capsulotomy was successfully performed. This involved directing laser shots to the peripheral anterior capsule in a C-shaped 200-degree pattern starting superiorly (Fig. 1, red hemicircle). This anterior capsulotomy configuration resolved contraction and displaced the thick opacity inferiorly.
      One month after laser treatment, visual acuity improved to 6/6 unaided, the IOL remained stable, and no recurrence of phimosis noted.
      Subsequent review at 6 and 12 months showed a similar clinical picture with unaided vision of 6/6 maintained, and the capsulotomy site remained clear (Fig. 1).
      The majority of recent ACCS incidents have been reported after the implantation of hydrophilic acrylic IOLs.
      • Zaugg B
      • Werner L
      • Neuhann T
      • et al.
      Clinicopathologic correlation of capuslorhexis phimosis with anterior flexing of single-piece hydrophilic acrylic intraocular lens haptics.
      These case reports include the following IOLs: one Akreos MI60, one Raysoft 574, five Quatrix IOL, and six Akreos IOL lens.
      Our case of ACCS is likely related to the IOL biomaterial because the patient had no other risk factors. A single-piece, hydrophilic acrylic IOL (26% water content) with a 360-degree square-edged optic and 2 closed-loop haptics (RayOne, Rayner, Ltd) was used. Hydrophilic acrylic IOLs have been described to have high biocompatibility but weak adhesion to the capsule, which may significantly induce fibrosis. An IOL with a square-edged optic design can reduce the incidence of posterior capsular opacification but may cause a higher rate of ACCS.
      • Hayashi K
      • Hayashi H
      Intraocular lens factors that may affect anterior capsule contraction.
      Primary management is usually Nd:YAG laser anterior capsulotomy. This is performed by creating several cuts around the capsulorhexis margin either radial (linear or parabolic fashion) or circumferential. Surgical approaches are numerous and include the use of a vitrector to create a circular capsular opening and removal of capsular and fibrotic remnants, along with intra-ocular diathermy and incisions with microscissors.
      • Yeh PC
      • Goins KM
      • Lai WW
      Managing anterior capsule contraction by mechanical widening with vitrector-cut capsulotomy.
      Wild et al. reported 2 cases in which anterior Nd:YAG laser capsulotomy was performed in a continuous circular fashion. In both cases free-floating remnants dropped into the AC. This was reported to interfere with vision and induced endothelial cell loss with associated corneal oedema. The authors recommended Nd:YAG anterior capsulotomy in a spoke-like pattern of at least 4 cuts radiating from the rhexis but not extending beyond the IOL optic edge.
      • Wilde C
      • Ross A
      • Awad M
      • Chen HC
      • Dua HS
      Management of anterior capsular contraction syndrome: pitfall of circular capsulotomy technique with the neodymium YAG laser.
      C-shaped Nd:YAG capsulotomy is a known technique used for the treatment of posterior capsular opacification but never reported as a treatment of ACCS. We suggest this modified C-shaped Nd:YAG superior hemicircular anterior capsulotomy to be performed outside the central, thick, and fibrosed membrane but within the edge of the optic. This releases tension created superiorly by the phimosis. Additionally, it promotes downward displacement of the central opacity, avoiding floating remnants in the AC and clearing the visual axis. On the contrary, the capsular remnant could potentially increase the risk of uveitis-glaucoma-hyphema–type syndrome owing to iris chafing if the capsular flap is rubbing on posterior iris. However, this was not observed in our case, and 12 months’ follow-up showed no intra-ocular complications and no need for further laser or surgery.
      In our case, C-shaped anterior laser capsulotomy was effective, required less energy, and subsequently had lower risk of postoperative complications. However, a prospective study with higher number of cases is required before guidelines can be recommended.

      Disclosure

      The authors have no proprietary or commercial interest in any materials discussed in this article.

      Appendix. Supplementary materials

      References

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        Clinicopathologic correlation of capuslorhexis phimosis with anterior flexing of single-piece hydrophilic acrylic intraocular lens haptics.
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