Surgical correction of high myopia in phakic eyes with Worst-Fechner myopia intraocular lenses

Implanting an anterior chamber intraocular lens in a phakic eye is an effective surgical procedure for the correction of high myopia. However, the potential risks on the anterior segment structures are not well-known. We conducted a prospective study to evaluate the effectiveness, predictability, and safety after Worst-Fechner lenses were implanted to correct high myopia.

We studied 32 eyes with preoperative myopia from -9.50 to -27.00 diopters (D) (-16.60 +/- 6.29 D). All 32 eyes were studied by clinical specular microscopy, and the endothelium was analyzed for cell density. Twenty eyes were additionally examined by fluorophotometry for lens transmittance changes. Thirty eyes were additionally examined using the flare mode of a laser flare cell photometer for anterior chamber inflammation; the patients were divided into three subgroups of ten eyes each according to when the postoperative flare measurements were done: 12 months, 18 months, and 24 months. Thirteen phakic eyes with myopia greater than -6.00 D were used as a control group for the flare study. The mean follow-up was 18.3 +/- 8 months (range 6 to 24 mo).

Fifty-seven per cent of eyes (16 of 28) had an uncorrected visual acuity of 20/40 or better 12 months after surgery, and 58% (10 of 17 eyes) at 24 months. Spectacle-corrected visual acuity improved: 0.15 at 12 months and 0.16 at 24 months (0.1 = one line) from preoperative values. Visual acuity was stable after 3 months. Eighty per cent of eyes (25 of 31) at 6 months, 75% (21 of 28) at 12 months, and 76.5% (13 of 17) at 24 months had been correctly planned to within +/-1.00 D of emmetropia. The refractive results were stable 3 months after surgery. The mean endothelial cell loss was 7.2% at 3 months, 10.6% at 6 months, 13% at 12 months, and 17.6% at 24 months after surgery. The mean lens transmittance loss was 0.62% at 3 months, 0.72% at 6 months, 0.82% at 12 months, and 1.03% at 18 months after surgery. Flare values were significantly higher for eyes implanted with Worst-Fechner lenses than were those of the control group in all periods under consideration (Mann-Whitney test, p < 0.05). A decentration greater than 0.5 mm was present in 43% of eyes (14 of 32), and halos in 56% (18 of 32). In three eyes (9.3%), fixation of the lens to the iris was not stable.

Our results for the Worst-Fechner myopia lens confirm earlier findings on the effectiveness of the refractive results. However, our study showed a continual decrease in endothelial cell density, a decrease in lens transmittance, and a chronic subclinical inflammation after the implantation of these lenses. Moreover, decentration was common, and the fixation of the IOL to the iris was not stable in some eyes.