Multifocal IOLs represent an enormous advance in cataract surgery; they can offer patients independence from glasses and/or contact lenses. But what about those patients who have already received monofocal IOLs following cataract surgery? These patients often require glasses for near vision and, when combined with residual astigmatism or a refractive defect, they may also be dependent on glasses for distance vision.

We propose a new method for the correction of refractive residual defects for eyes with monofocal pseudophakia, with the creation of a multifocal cornea and correction of the refractive residual defect, in order to achieve spectacle independence for this group of patients.

Procedure & technique

Figure 1: Creating a multifocal cornea in pseudophakia. Ablation involved the creation of a peripheral high dioptric power zone.

A total of 15 pseudophakic eyes that had previously undergone uncomplicated phacoemulsification were selected for this treatment. All eyes had previously been corrected to 20/50 or better for distance vision and to J1 for near vision. No macular disease was present. Pupils were completely round in all cases with a minimum diameter of 3.7 mm and a maximum of 4.6 mm. The treatment consisted of the correction of the refractive residual defect with the Visx Star S4 CustomVue with iris registration (AMO), plus the addition of multifocal ablation (Figure 1). This consisted of peripheral ablation with the creation of a high peripheral power cornea, leaving the distant vision in the centre of the cornea and the periphery for near.

The mean age of patients was 66 years (range: 59 to 74 years). Cataract surgery was performed, on average, 9.2 months preoperatively (range: 3.2 months and three years). Mean follow up was 7.8 months (range: 4.5 months to 15.5 months).

In 13 eyes the surgical technique was LASEK, while LASIK was performed in the remaining two eyes. The mean preoperative refractive defect measured as spherical equivalent was +1.64 (-0.94 to +2.77). All eyes underwent a complete ophthalmological evaluation preoperatively, including a wavescan examination and the same postoperative evaluation at one, three and six months and every three months thereafter.

It's all in the results

Figure 2: Example of a preoperative pseudophakic cornea (left) and the cornea post multifocal ablation (right).

All eyes demonstrated an improvement in uncorrected distance visual acuity (UCDVA): four eyes achieved 20/50, six eyes achieved 20/30 and five eyes achieved 20/20. In terms of best corrected distance visual acuity (BCDVA): three eyes gained two lines and all eyes achieved 20/30 or better. No eyes lost lines of BCVA (Figures 2 & 3).

Figure 3: Example of a preoperative pseudophakic cornea (left) and the cornea post multifocal ablation (right).

Preoperatively, eight eyes were dependent on glasses for distance vision, however, postoperatively no eyes required glasses. The mean postoperative spherical equivalent was -0.22 with a range of -0.02 to +0.28.