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Scleral‐fixated posterior chamber intraocular lenses (SFIOL) are an attractive option for optical correction of aphakia in people with ectopia lentis. Postoperative intraocular lens (IOL) tilt/decentration have been reported in 5–10% of eyes that undergo SFIOL implantation.1,2 We report the case of a boy with aniridia who underwent SFIOL implantation and had intraoperative IOL tilting, and the management of intraoperative tilting.
A 16‐year‐old boy had been diagnosed at 4 weeks of age to have bilateral aniridia with almost completely absent irides, ectopia lentis, anterior polar cataracts, macular hypoplasia and nystagmus. Sequence analysis of the coding exons of the PAX6 gene revealed a C→T variant at nucleotide 1017 of the cDNA M93650 (http://pax6.hgu.mrc.ac.uk/About/pax6cdna.htm). This novel mutation (Q219X) introduces a stop codon in the homoeodomain of the PAX6 protein, and truncating mutations in this domain are associated with classic aniridia.3 For 16 years, he maintained visual acuity of 6/60 from his right eye with aphakic correction. In September 2005, a break was seen in the anterior lens capsule of the right eye. Pars plana vitrectomy (PPV) and lensectomy with implantation of SFIOL were planned.
Standard three‐port PPV and lensectomy were performed. Two‐point fixation technique4 was adopted for SFIOL (Alcon CZ70BD IOL (Alcon laboratories, Fort Worth, Texas, USA), 12.5 mm length, 7 mm optic). Partial‐thickness scleral flaps were created at 3:00 and 9:00 positions and a straight 10‐0 polypropylene suture needle was passed into a 27‐gauge needle to exit at the opposite ciliary sulcus, 1 mm posterior to the limbus. A superior, clear corneal incision was created, the anterior chamber was filled with viscoelastic material, the suture was externalised, divided and the ends secured to the IOL eyelets. The IOL was inserted and the sutures secured in the beds of the flaps.
The classic aniridia with almost total absence of iris allowed, at this point, the IOL to rotate 90° about a line joining 3:00 limbus position to 9:00 limbus position, and came to rest with its surface oriented anteroposteriorly. To manage this, support was provided using 10‐0 polypropylene suture in the coronal plane perpendicular to its axis of rotation (fig 11).). The straight needle was inserted into the eye behind the limbus at 12:30 position, passed behind the IOL, to the 5:30 position where it exited the eye posterior to the limbus. The needle was passed again in a similar fashion, from 6:30 position to 11:30 position, and the suture was tied (fig 11).). The IOL was now stable.
This case demonstrates an intraoperative problem in aniridia that probably occurred due to absence of the iris that would normally restrict rotation of the IOL. We are unaware of any previous reports of this problem. This tilt was managed by providing support in the coronal plane perpendicular to its axis of rotation, posterior to the IOL. Support anterior to the IOL could have served the purpose just as well. Alternatively, four‐point fixation of the IOL may also help; however, it is uncertain to what extent it might prevent such rotation.
Postoperative course was uneventful. When examined in December 2005, his visual acuity was 3/60, and the IOL was well supported in the optimal position.
This case suggests that IOL tilt is a potential problem when implanting SFIOLs in patients with classic aniridia. We propose provision of additional support in such cases.
We thank Chris Willcock for research assistance. We acknowledge the support from the Ophthalmic Research Institute of Australia.
Competing interests: None declared.