Introduction

Polypseudophakia can be defined as the implantation of two or more intraocular lenses (IOL) following phacoemulsification cataract extraction. This can be primary when the IOLs are placed together during surgery, or secondary when additional IOLs are placed at a later date. Polypseudophakia was first described by Gayton in 1993.1

Polypseudophakia can be complicated by interlenticular opacification (ILO), commonly developing within 6 months to 2 years.2 We previously published the results of our cohort of patients who underwent primary polypseudophakia, using dual in-the-bag poly-methyl-methacrylate (PMMA) IOLs, where we observed a new form of ILO (Case 1) after 3 years, and recommended longer-term follow-up of these patients.2 We now present the 10-year post-operative findings of our patients, and assess the stability of polypseudophakia cataract surgery. To our knowledge, there has been no previous published study of the long-term outcome of patients who underwent polypseudophakia for cataract surgery at 10 years.

Case reports

Of fifteen patients who underwent polypseudophakia surgery, three were available for review. There were no complications during surgery, and all patients received the same model of PMMA IOL (P359UV, Storz, Tuttlingen, Germany). One patient underwent primary polypseudophakia in both eyes, and two patients had secondary polypseudophakia in one eye. Clinical findings are summarized in Table 1.

Table 1 Demographic details of the cohort of patients, their biometry, and their long-term refractive and visual results

Case 1

A 57-year-old woman with a history of Laurence-Moon syndrome, nystagmus, retinitis pigmentosa, and hypermetropia in both eyes underwent cataract extraction for both eyes with primary polypseudophakia in 1999. Two IOLs were implanted in her right eye (both +16.00 D) and left eye (+16.00, +15.50 D). Her vision did not improve following surgery in either eye, despite technically successful procedures. At her 2-week and 15-month post-operative follow-up, a type of ILO was observed in both eyes in the form of centrally located pigment deposits surrounded by Newton's rings.2 At 10-year follow-up, posterior capsular opacification was observed in the right eye, and the previously observed central ILO was no longer observed in either eye although in the left eye inferior ILO was noted, but it remained off axis (Figure 1).

Figure 1
figure 1

Slit lamp photograph of the left eye of Case 1 showing inferior Elschnig pearls, ILO after pupil dilatation. These are unlikely to be visually significant.

Case 2

An 87-year-old woman with central corneal shagreen dystrophy had phacoemulsification cataract extraction with IOL implantation (+17.5 D) in her right eye in 1998, but developed a post-operative refractive surprise (Table 1). A piggyback IOL (+4.0 D) was inserted into the capsular bag in 1999, with a good post-operative outcome subjectively. At 10-year follow-up, the piggyback lens was nasally displaced by 1–2 mm (Figure 2).

Figure 2
figure 2

Slit lamp photograph of Case 2 demonstrating nasal displacement by 1–2 mm.

Case 3

A 48-year-old woman had phacoemulsification cataract extraction with IOL implantation (+20.0 D) in her right eye in 1995 (pre-operative refraction +6.75/−1.25 × 45 6/12), but remained hypermetropic (Table 1). A piggyback IOL (+5.00 D) was inserted into the capsular bag in 1999, with a good post-operative outcome subjectively. At 10-year follow-up, no decentration or tilt of the IOL, and no ILO was observed.

Discussion

Polypseudophakia can be used during phacoemulsification cataract surgery in patients with high levels of refraction, and can also be used for correction of refractive surprises, or to add multifocality,3 or a toric correction.4 In Case 1, primary polypseudophakia was chosen instead of a single high-powered IOL, as they were less readily available in 1999, and would often have to be custom made. We have also found from theoretical calculations that polypseudophakia offers better optical quality due to a reduction in spherical aberration5 than a single high-powered IOL.

We observed no tilt of the IOLs with the haptics remaining well aligned in all cases. Of our case series, only one patient showed decentration of the IOL, but her visual acuity was good, despite the presence of central corneal dystrophy. We also observed that the patients’ central corneal endothelial cell density (SP-2000P, Topcon, Tokyo, Japan) were reasonable, which provides much needed long-term evidence to support the use of polypseudophakia, following corneal graft surgery.6, 7

ILO is a well-recognized complication of polypseudophakia8, 9 associated with a reduction of visual acuity and hyperopic shift. We could not confirm this in our patient with ILO, but it was unlikely to be visually significant being off axis. In our previous study, we observed a new form of ILO, but this had since resolved and was not present in our other two patients. However, with a trend in using foldable IOLs to minimize wound size, placing one IOL in the sulcus has been found to minimize ILO.

In summary, we have demonstrated long-term stability of polypseudophakia following phacoemulsification cataract surgery using dual PMMA IOLs in the bag, with the haptics parallel one set to another. Corneal endothelial cell density was good, although our follow-up cohort was small. The IOLs remained well centered with minimal decentration, and complications of ILO were likely to be visually insignificant.