Clear Lensectomy and Intraocular Lens Implantation in Normally Sighted Highly Hyperopic Eyes. Three-year Follow-up

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.

Retinal detachment after clear lens extraction for high myopia: seven-year follow-up

OBJECTIVE

To prospectively evaluate the incidence of complications, particularly retinal detachment, 7 years after clear lens extraction (CLE) for myopia greater than -12 diopters (D).

DESIGN

Extended follow-up of noncomparative case series.

PARTICIPANTS

Fifty-two eyes of 30 patients with preoperative myopia greater than -12 D, best-corrected visual acuity (BCVA) of 20/100 or better, and intolerance of contact lenses.

INTERVENTION

Patients with lattice degeneration, retinal tear, or hole underwent photocoagulation before CLE. The authors performed phacoemulsification through a 3.2-mm-wide incision using primary irrigation and aspiration, widened the incision to 6.5 mm, and implanted a one-piece polymethyl methacrylate intraocular lens (IOL).

MAIN OUTCOME MEASURES

The BCVA, uncorrected visual acuity (UCVA), stability of spherical equivalent (SE), neodymium:YAG (Nd:YAG) capsulotomy rate, and complications (especially retinal detachment).

RESULTS

At 7 years, the SEs of 29 eyes (59.1%) were within +/-1.0 D of emmetropia and 42 eyes (85.7%) were within +/-2.0 D. Mean SE was -1.01 D (+/-0.94). At 7 years, mean UCVA was 20/80 compared with 20/66 at 1 year. BCVA and UCVA were better in eyes with open capsules versus intact capsules. During the 7 years, 30 eyes (61.2%) required capsulotomy for opacification. Mean time for capsulotomy was 48.4 months after CLE. The authors performed ten argon laser retinal treatments after surgery, with all but one in the first postoperative year. The overall incidence of posterior vitreous detachment was 16.3%. The incidence of retinal detachment during the 7 years was 4 of 49 eyes, or 8.1% (vs. 2.0% at 4 years). One patient had bilateral retinal detachments.

CONCLUSION

Despite advances in surgical technique, retinal detachment remains a major concern after CLE for high myopia. In the authors' series, the incidence of retinal detachment after CLE was nearly double that estimated for persons with myopia greater than -10 D who do not undergo surgery. Although CLE has advantages, including rapid and predictable visual rehabilitation, stable refraction, the ability to replace the IOL, and often superb optical quality with no irregular astigmatism, it is invasive and can result in severe vision loss. Long and continuous follow-up of the outcomes of CLE for high myopia is absolutely necessary before the authors can consider CLE as a routine option for patients with high myopia.

Clear Lensectomy and Intraocular Lens Implantation for Hyperopia from +7 to +14 Diopters

BACKGROUND

Our results of clear lens extraction and intraocular lens implantation to correct hyperopia from +6.75 to +13.75 D are presented, as well as evaluation of two intraocular lens calculation formulae.

METHODS

Clear lens extraction and posterior chamber intraocular lens implantation was performed in 35 normally sighted eyes of 21 patients with a mean baseline hyperopic spherical equivalent refraction of +9.19 +/- 0.34 D (range +6.75 to +13.75 D). The refractive goal was -1.50 D, using the SRK II formula in 17 eyes and the SRK-T formula in 18 eyes. Follow-up was up to 5 years.

RESULTS

Mean uncorrected visual acuity after surgery was 0.8 (range 0.5 to 1.0). Stability of refraction was noted from the second month after surgery. No eyes lost any lines of spectacle-corrected visual acuity. Using the SRK II formula, 100% of eyes were within +/-1.00 D of emmetropia and with the SRK-T formula, 83.3% for a combined 91.4% of eyes within +/-1.00 D of emmetropia. One eye required intraocular lens exchange and another eye required photorefractive keratectomy for myopia. Both procedures were necessitated by an intraocular lens miscalculation of more than +/-2.00 D. Nineteen eyes (54.2%) developed posterior capsular opacification and were treated with Nd:YAG laser capsulotomy.

CONCLUSION

Clear lens extraction is a safe, effective, and predictable procedure for the treatment of hyperopia from +6.75 to +13.75 D. The SRK II formula proved slightly superior to the SRK-T in intraocular lens calculation when using the "-1.50 D rule."

Clear lensectomy and implantation of a low-power posterior chamber intraocular lens for correction of high myopia: a four-year follow-up

PURPOSE

To evaluate the 4-year postoperative outcomes of patients who are highly myopic who underwent clear lensectomy via phacoemulsification and low power posterior chamber intraocular lens implantation.

METHODS

The authors performed surgery in 52 eyes of 30 patients in which prophylactic retinal treatment, clear lensectomy, and posterior chamber intraocular lens implantation were used to treat high myopia of 12 diopters (D) or greater. A total of 49 eyes of 28 patients were evaluated at the 4-year postoperative timeframe. Visual acuity, complications, and refractive stability were assessed.

RESULTS

The incidence of retinal detachment through 4 years was 1.9%. No new macular complications were observed. Two patients had posterior vitreous detachment without clinical impact between 1 and 4 years after surgery. The incidence of neodymium:YAG (Nd:YAG) capsulotomy was 36.7%. The mean postoperative spherical equivalent was -0.92 D. Four patients had a myopic shift of 0.50 D to 1.00 D from the 1- to 4-year timeframe. Corrected visual acuity of 20/40 or better was achieved in 82% of eyes that had undergone Nd:YAG capsulotomy versus 56% of untreated eyes. Uncorrected visual acuity of 20/100 or better was achieved in 82% of eyes treated with the Nd:YAG laser versus 62% of untreated eyes.

CONCLUSION

Visual acuity and refractive outcomes with clear lensectomy are favorable. Retinal detachment remains the major concern of this procedure. Continuous follow-up of these patients is necessary.