with midazolam (Roche, Madrid, Spain). One drop of 1% pilocarpine (Isoptocarpine, Alcon Cusi, Barcelona, Spain) is instilled into the eye 30 min before surgery.

The size of the haptic required depends on the sul- cus-to-sulcus measurement. One millimetre is added to the sulcus-to-sulcus measurement and the nearest largest haptic size is chosen (12.0, 12.5, 13.0 and 13.5 mm). For example, an eye with a sulcus-to-sulcus measurement of 11.3 mm will require a 12.5 mm haptic.

Operative Procedure

A 1 mm paracentesis is performed inferiorly corresponding to the steepest meridian. Then, a 2.5-mm or 2.0-mm corneal incision is made with a carbon knife (Accutome, Malvern, PA, USA). Preservative-free lidocaine (0.2 ml of 1%) is then used to irrigate the anterior chamber. Healon (Pharmacia, Upsala, Sweden) is injected until the anterior chamber is completely filled.

A peripheral iridotomy is performed in the superior quadrant using a surgical vitrectomy cutter. Subsequently, the haptic of the lens is then introduced, placing it in an oblique meridian. The optic part of the lens is prepared in the cartridge of a Medport injector (Bausch & Lomb, Irvine, CA, USA), with its surface curved down and eyelets perpendicular to the main axis of the cartridge. The cartridge was previously lined with 2% hydroxypropyl methylcellulose (Celoftal, Alcon Cusi, Barcelona, Spain). A small piece of silicone sponge is used to prevent damage to the optic when the metal piston of the injector is pushing the lens into the eye. After the optic is injected into the anterior chamber, the eyelets of the optic is fixed to the hooks of the haptic using either two Lester or Sinskey hooks.

Healon is then removed from the anterior chamber by irrigation with balanced salt solution (BSS, Alcon Cusi, Barcelona, Spain). The corneal incision is hydrated and 0.1 ml of 1% Cefuroxime injected in the anterior chamber before the end of surgery (Fig. 5.13).

Post-Operative Care

Post-operative treatment consists of Maxidex (Alcon Cusi, Barcelona, Spain) one drop three times daily for 2 weeks and Oftacilox (Alcon Cusi, Barcelona, Spain) one drop every 12 h for 3 days.

Fig. 5.13 Kelman-Duet PIOL in the eye

Results

We examined 169 eyes of 110 patients with moderate or high myopia 1 year after implantation with the Kelman-Duet PIOL at our centre (VISSUM/Instituto Oftalmologico de Alicante, Alicante, Spain).

Refractive Outcomes

Mean pre-operative spherical equivalent refraction was −15.01 ± 4.53 D (range: −8.75 to −26.00 D). At 12 months, spherical equivalent refraction was within ±0.50 D in 57.72% of eyes (71) and within ±1.00 D in 81.30% of eyes (100). (Spherical equivalent refraction was recorded in only 123 eyes at 12 months.) At 12 months, the refraction of plano was reached in 20.54% of cases. The predictability is summarised in Fig. 5.14.

At the last post-operative visit, UCVA was 20/40 or better in 108 (83.72%) eyes and 20/20 or better in 37 (28.68%) eyes (Fig. 5.15). Best spectacle-corrected visual acuity improved by two or more Snellen lines in 68 (56.20%) eyes (Fig. 5.16). No eye lost two or more Snellen lines of BSCVA. The efficacy index was 1.18

± 0.43 at 6 months and 1.19 ± 0.40 at 12 months.

Corneal Endothelium

Endothelial morphometric data are shown in Table 5.1. There was a decrease in pre-operative endothelial cell density and 3-month post-operative measurements, and between 3-month and 6-month post-operative measurements. However, the difference was not statistically significant for either time period. But, when preoperative and 12-month post-operative measurements

Percentage of eyes (%)

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

Postoperative spherical equivalent (D)

Fig. 5.14 Predictability results at 12 months after implantation with the Kelman-Duet phakic intraocular lens. All parameters were recorded for all eyes only at the pre-operative visit. Data for some of the post-operative visits are missing because the

patient did not follow up. Total number of eyes: pre-operative = 146, 1 month = 146, 3 months = 128, 6 months = 131, and 12 months = 123

Fig. 5.15 Cumulative post-operative uncorrected visual acuity (UCVA) at 12 months after implantation with the Kelman-Duet phakic intraocular lens vs. cumulative pre-operative best spectacle-corrected visual acuity (BCVA)

Cumulative Snellen Visual acuity (20/__)

Fig. 5.16 Change in best spectacle-corrected visual acuity (BCVA) at 12 months after implantation with the Kelman-Duet phakic intraocular lens

Percentage of eyes(%)

were compared, the total decrease in cell density is statistically significant. As in any study concerning the endothelial cell loss in PIOLs, longer follow-up is necessary to confirm this observation.

Loss of endothelial cell density was more than 15% in 19 (17.27%) eyes. Of these cases, pupil ovalisation occurred in 8 (42.11%) eyes and the lens appeared decentred at the anterior segment in 6 (31.58%) eyes. In 4 (50.0%) of the eyes with pupil ovalisation, the haptic was exchanged to improve the situation.

Complications

Surgery was completed successfully in all eyes with no intraoperative complications. Post-operatively, no lens

opacification, chronic increased IOP, or pupillary block occurred, and none of the lenses had to be explanted during the follow-up period.

In the early post-operative period, one (0.59%) eye experienced synechiae between the iris and the optic of the lens. This was resolved by widening the iridotomy. Endothelial cell density loss was >20% in this eye. Additionally, significant flare reaction occurred in 1 (0.59%) eye at 1 month post-operatively but was resolved with injection of intracameral triamcinolone acetonide. Mild and severe levels of pupil ovalisation were present in 17 (10.06%) eyes. Normally, this phenomenon is produced by inadequate adjustment of the total length of the haptic to the internal intertrabecular distance of the eye. For this reason, haptic exchange