Posterior Implant of Iris-Claw Lens

My colleagues and I undertook a study in order to describe the safety and visual results of the primary or secondary implantation of an iris-claw PMMA lens (Verisyse; Advanced Medical Optics, Santa Ana, Calif) fixated at the posterior face of the iris. Cases included in the study had damage to the capsular bag or the zonules, to the extent that it prevents a secure in-the-bag implantation.

This retrospective study was conducted from Nov. 5, 2004 to Sept. 16, 2005. The included patients had an average follow-up of 7 ±3.6 months (range, 2 months to 13 months). We performed the procedure in 23 patients (25 eyes), of whom 10 were male and the average age was 63.5 ±26.¹ years (age range, 12 years to 88 years).

Six of the eyes were phakic, two were aphakic and 17 were pseudophakic. Of the phakic eyes, one had subluxation of the lens after contusion; one had lens instability or capsular pseudoexfoliation; and four had lentis ectopia, with or without Marfan's syndrome (Figure 1). The aphakic eyes were referred for secondary implantation.

Of the pseudophakic eyes, six had endothelial weakening with anterior chamber IOLs (AC-IOLs); five had posterior chamber IOLs (PC-IOLs) and bag instability/capsular pseudoexfoliation (Figure 2). Of these five eyes, two had minimal trauama. Six eyes had postoperative PC-IOL subluxation due to posterior capsule rupture and were referred for surgical management.

Surgical Technique
After introduction in the anterior chamber protected with ophthalmic viscosurgical device, the optic of the reversed iris-claw IOL (with its convex face placed posterior) is securely held together with forceps (Figures 3 and 4). Then the first haptic is gently introduced behind the iris (Figure 5). To attach each of the lens' haptics, the optic is slightly pulled forward so that the claw was located through the iris, and the other hand, using a micromanipulator, or a curved 25-gauge needle through a lateral side-port incision, inserts the iris into the claw (Figure 6). The second haptic is introduced and fixated in the same way (Figure 7), after control of centration of the IOL (Figure 8).

Complications
Nine eyes experienced complications. There were five cases of pupil ovalization, four of which were slight. One case had a vitreous hemorrhage that required pars plana vitrectomy. Two cases experienced corneal decompensation that required perforating keratoplasty; these eyes had preoperative endothelial cell counts of <800 cell/mm². One case ended up with induced astigmatism of >4.00 D.

There were no instances of cystoid macular edema, endophthalmitis or retinal detachment.

This retropupillary positioning of an iris-claw lens was first described by Rijneveld1 in association to a perforating keratoplasty. More recently, retinologists used this technique, especially for aphakic patients after lens extraction associated with pars plana vitrectomy;2 then it was used by anterior segment surgeons.³

I recommend using an A-constant of 116.5 to achieve emmetropia with this technique. The advantages of using an iris-claw lens with a posterior implantation technique in this patient population is that there is a short learning curve. The procedure is rapid and easy, there is less endothelial risk as compared with AC-IOLs, and there are fewer chorio-retinal risks compared with PC-IOLs that are fixated to the sclera.⁴

There are some disadvantages, however. The lens requires good iris support. This can be difficult in cases with important trauma or a lack of substance or fibrosis of the iris. The long-term stability has not yet been determined with this technique, and neither has the risk of cystoid macular edema. We also do not know if there may be problems with pigment dispersion and ocular hypertension.

Since we have been using this implantation technique, we have not used any AC-IOLs and we have not fixated any PC-IOLs to the sclera.

Pascal Rozot, MD, is in practice at the Clinique Monticelli, in Marseilles, France. He has no financial interest in the subject matter of this presentation. He may be reached at pcrozot2@wanadoo.fr or +33491162211.

1. Rijneveld WJ, et al. Iris claw lens: anterior and posterior iris surface fixation in the absence of capsular support during penetrating keratoplasty. J Refract Corneal Surg. 1994;10:14-19.
2. Mohr A, et al. Retropupillary fixation of the iris claw lens in aphakia. 1 year outcome of a new implantation technique. Ophthalmology. 2002; 99: 580-583.
3. Güell JL, Barrera A, Manero F. A review of suturing techniques for posterior chamber lenses. Curr Opin Ophthalmol. 2004; 15: 44-50.
4. Neuhann T. ESCRS 2004, free paper.