Correction of high myopia with different phakic anterior chamber intraocular lenses: ICARE angle-supported lens and Verisyse iris-claw lens

Phakic intraocular lenses: An overview

Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates of patients with high myopia which will result in increased rates of pIOL implantation. Three types of lenses can be distinguished: anterior chamber angle-supported, anterior chamber iris-fixated, and posterior chamber phakic IOLs. The efficacy of phakic intraocular lenses is generally very good, but pIOLs have undergone many changes over the years to improve the safety profile and decrease pIOL-related complications such as endothelial cell loss, corneal decompensation and cataract formation. This article describes the efficacy and safety profiles of the most recent pIOLs, as well as suggests gaps of knowledge that are deserve additional research to optimize the results of pIOLs.

One Year Follow-Up After Veriflex Phakic Intraocular Lenses Implantation for Correction of Myopia

Objectives:

The aim of this study was to evaluate visual and refractive outcomes after Veriflex phakic intraocular lenses (pIOL) implantation in moderately myopic eyes as well as postoperative complications.

Methods:

This prospective clinical study included 40 eyes of 26 patients which underwent implantation of Veriflex for correction of myopia from -6.00 to -14.50 diopters (D) in the Eye Clinic Svjetlost Sarajevo, from January 2011 to January 2014. Uncorrected distance visual acuity (UDVA), manifest residual spherical equivalent (MRSE), intraocular pressure (IOP), endothelial cell (EC) density were evaluated at one, three, six and 12 months. Other complications in postoperative period were evaluated. For statistical analysis SPSS for Windows and Microsoft Excel were used.

Results:

Out of 26 patients 14 had binocular and 12 monocular procedure, with mean age of 29.8±6.5 years. After 12 months mean UDVA was 0.73±0.20. Mean MRSE was -0.39±0.31D and 90% of eyes had MRSE within ±1D. EC loss was 7.18±4.33%. There was no significant change of IOP by the end of 12 months follow up period. The only intraoperative complication was hyphema and occurred in one eye. Few postoperative complications were: subclinical inflammation in three eyes (7,5%), pigment dispersion in four eyes (10%), ovalisation of papilla in 2 eyes (5%) and decentration of pIOL in 2 eyes (5%).

Conclusion:

Implantation of iris-claw phakic lenses Veriflex for treating moderately high myopia is a procedure with good visual and refractive results and few postoperative complications.

Two-Year Follow-Up of Artisan Iris-Supported Phakic Anterior Chamber Intraocular Lens for Correction of High Myopia

PURPOSE

To evaluate the results of Artisan iris-supported phakic anterior chamber intraocular lens (pIOL) implantation in patients with high myopia.

METHODS

Medical records of patients who underwent Artisan pIOL implantation for surgical correction of myopia were retrospectively reviewed. Only patients with at least a two- year follow-up were included. Spherical equivalent of manifest refractive error (SE), uncorrected visual acuity (UDVA), distance corrected visual acuity (CDVA), and endothelial cell density (ECD) were analyzed at six months, one year, and two years after surgery.

RESULTS

Sixty-two eyes of 42 patients were included in the study. All patients had a minimum anterior chamber depth of 3.0 mm from the endothelium. At two years, 68% of the patients were within ±0.50 D. Mean ECD was 2723 ± 311 cells/mm(2) preoperatively and 2630 ± 291 cells/mm(2) at six months postoperatively (3.4% loss, p = 0.001). ECD loss from six months postoperatively to two years postoperatively was not statistically significantly different. In three eyes (4.8%) of two patients, a temporary, steroid-induced increase in intraocular pressure (IOP) was detected.

CONCLUSION

Artisan pIOL implantation is a safe and highly effective procedure for surgical correction of high myopia. ECD loss stabilizes in the early postoperative period.

Pre-operative visual evaluation for implantable collamer lenses in highly myopic eyes

PURPOSE

The aim of this study was to evaluate a clinical procedure based on trial rigid gas-permeable (RGP) contact lenses fitting to assess the real pre-operative visual acuity (VA) of highly myopic eyes undergoing surgery with an implantable collamer lens.

METHODS

Highly myopic eyes with a spectacle visual acuity (SVA) of 0.2 logMAR (6/9.6 Snellen) or worse were enrolled. A trial RGP contact lens with high dioptric power was fitted before collamer lens implantation. The trial contact lens residual refractive error was corrected by spectacle over-refraction to estimate contact lens VA (CLVA). The three-month post-operative uncorrected vision and visual acuities were also measured. The safety and efficacy indices of collamer lens implantation were calculated based on pre-operative SVA and CLVA, respectively.

RESULTS

The study enrolled 42 patients with 68 highly myopic eyes with a mean pre-operative spherical equivalent of -16.40 ± 4.43 D. The mean pre-operative SVA was 0.38 ± 0.19 logMAR. Pre-operative trial RGP contact lens fitting resulted in a significant improvement of VA (2.02 ± 1.05 lines), which was statistically insignificantly different from the VA with the implantable collamer lens (2.07 ± 0.8 lines). The safety index of collamer lens implantation was 1.70 ± 0.38 in reference to the pre-operative SVA but significantly decreased to 1.02 ± 0.17 in reference to CLVA. Similarly, the efficacy index of 1.17 ± 0.48 on SVA decreased to 0.71 ± 0.28 on CLVA.

CONCLUSIONS

Trial RGP contact lens fitting was found to indicate the potential implantable collamer lens VA more accurately than spectacle refraction. Consideration should be given to the use a trial RGP contact lens as part of the pre-operative work-up prior to collamer lens implantation in order to provide an assessment of the patient's potential post-operative VA.

Long-term vision-threatening complications of phakic intraocular lens implantation for high myopia

AIM

To report the long-term vision-threatening complications in patients who underwent phakic intraocular lens (pIOLs) implantation for high myopia.

METHODS

This study was designed from a consecutive series of phakic intraocular lens complication and corrective surgeries. Sixteen eyes of 13 patients had implantation of phakic intraocular lens for correction high myopia and developed serious complications have been included in this study. The mean age of patients was 38.6±6.35y (range 32-50y) and the mean time of history of pIOL implantation for high myopia was 6±2y (range 2-10y). Before corrective surgery, best spectacle-corrective visual acuity (BSCVA) ranged from perception to 20/200 in the eyes in which severe complications occurred.

RESULTS

Corneal decompensation occurred in 12 eyes of 9 high myopic patients after anterior chamber pIOL implantation. Rhegmatogenous retinal detachment (RRD) occurred in 4 eyes of 4 high myopic patients following anterior chamber and posterior chamber pIOL implantation. Patients with corneal decompensation, had combined procedures consisting of pIOL removal and penetrating keratoplasty (PKP). Removals of pIOL, phacoemulsification and pars plana vitrectomy (PPV) with silicone oil tamponade were performed in patients with RRD. After corrective surgeries, all patients but one (P+, patient 2, right eye) achieved moderate BSCVA ranged from 20/200 to 20/50 at the last visit.

CONCLUSION

Phakic IOLs may be effective for the correction of high myopia. Although these IOLs may have severe complications and it affects safety and efficacy of this surgery. As seen here, corneal decompensation and rhegmatogenous retinal detachment are possible postoperative vision-threatening complications of phakic IOLs. Patients must be carefully examined before and after surgery for possible endothelial cell loss and vitreoretinal problems.

Phakic anterior chamber lenses in very high myopia: an 18-month follow up

BACKGROUND

To evaluate the efficacy and tolerance of two different foldable anterior chamber phakic intraocular lenses for high myopia.

DESIGN

A prospective interventional case series at the Eye Clinic, Kartal Training and Research Hospital, Istanbul, Turkey.

PARTICIPANTS

Sixty-two eyes of 31 patients received iris-claw lens (group 1) (Artiflex AC 401, Ophtec), and 43 eyes of 22 patients received angle-supported lens (group 2) (I-Care, Corneal).

METHODS

The mean preoperative spherical equivalents for group 1 and group 2 were -12.13 D and -18.95 D, respectively. Endothelial cell density was measured at day 1 and at 1, 3, 6, 12 and 18 months for follow ups.

MAIN OUTCOME MEASURES

  Percentage change in endothelial cell density and improvement in visual acuity.

RESULTS

At the 18-months follow up, uncorrected visual acuity improved to logMAR 0.37 ± 0.23 from 1.60 ± 0.10 in group 1, and logMAR 0.47 ± 0.14 from 0.70 ± 0.20 in group 2; best spectacle corrected visual acuity improved to logMAR 0.23 ± 0.22 from logMAR 0.36 ± 0.14) in group 1, and logMAR 0.29 ± 0.18 from logMAR 0.50 ± 0.20) in group 2 (P<0.001, in both groups). Mean decreased endothelial cell density was 241 cells/mm(2) (8.61%) and 223 cells/mm(2) (8.42%) at 18 months follow up in group 1 and 2, respectively (P=0.17) but significant in comparison to preoperative values for both groups (P<0.001).

CONCLUSIONS

Although both iris-claw and angle-supported lenses offer good refractive outcomes significant endothelial cell density was observed at 18 months follow up.

Refractive lens exchange versus phakic intraocular lenses

PURPOSE OF REVIEW

To review the evidential basis of current practice in refractive lens exchange (RLE) vs. phakic intraocular lens (pIOL).

RECENT FINDINGS

Visual outcomes after pIOLs are better than RLE. With RLE, there still remain risks of retinal detachment, cystoid macular oedema, glare, halos and posterior capsule opacification. With pIOLs, risks include pigment dispersion, cataract formation, glaucoma and inflammation. The decision to choose between either is broadly based on age and type of refractive error, and the choice follows thorough evaluation and counselling taking into consideration patient's needs and expectations.

SUMMARY

With advancing technology, newer IOL models for RLE and phakic correction are becoming available. pIOLs provide better visual outcomes for distance correction and currently do not provide near-vision correction possible with RLE.

Severe endothelial cell loss following uneventful angle-supported phakic intraocular lens implantation for high myopia

Endothelial decompensation is a serious complication of phakic intraocular lens (pIOL) implantation and is a major concern during the postoperative period. We report 3 eyes in which the same foldable angle-supported pIOL was implanted to correct high myopia. Rapid and severe postoperative endothelial cell loss occurred in all 3 eyes. An over-sized pIOL that induced excessive vaulting into the anterior chamber was the main risk factor. In 2 eyes, the pIOL was explanted uneventfully; 1 eye required Descemet's stripping automated endothelial keratoplasty because of total endothelial decompensation. These cases illustrate the importance of accurate sizing of foldable angle-supported anterior chamber pIOLs to avoid excessive vaulting. They also highlight the importance of regular follow-up and preventive pIOL explantation as soon as significant endothelial cell loss is detected.

Implants phakes de chambre antérieure versus chambre postérieure

At a time when some of the limitations of photoablation have been defined, such as worry concerning secondary ectasia, a renewed interest in phakic implantation has arisen. This is driven by the goal of avoiding correcting high ametropia with LASIK and is based on the development of soft foldable biomaterials. When all phakic IOLs are in front of the natural lens, two varieties of lenses can be distinguished, depending on whether it is located in the anterior or posterior chamber. The various models available in 2006 and those under current evaluation are reviewed. We do not report details of clinical studies that vary in cohort size and follow-up. The advantages and limitations are discussed for each type of phakic IOL. Adequate although not exclusive indications are deduced. There is no phakic lens that has proved to be superior to the others in terms of safety. All have the ability to provide a visual benefit with a gain in best corrected visual acuity. The difference is based on anatomical effects, requiring long-term follow-up in the evaluation of angles, lens, iris, and endothelium.

Efficacité réfractive et tolérance de l’implant phaque myopique souple à fixation irienne Artiflex® dans la correction chirurgicale de la myopie forte : résultats à deux ans

INTRODUCTION

A new foldable version of an anterior chamber phakic lens designed to surgically correct high myopia was evaluated.

PATIENTS AND METHODS

A prospective study on the efficacy and tolerance of a foldable phakic intraocular iris-supported lens, designed to correct moderately high myopia, is presented in this article. Twenty-five eyes of 25 patients were implanted uneventfully using this lens, newly designed and called the Artiflex lens. This phakic intraocular lens is an upgraded foldable version of the Artisan (or Verisyse) lens. The follow-up was complete (24 months) for all Artiflex-treated eyes and the targeted postoperative refraction was emmetropia. Inclusion criteria were moderately high myopia ranging from -8 to -14 D, unchanged refraction for 2 years, total contact lenses wearing intolerance, refractive cylinder power no greater than 1.5 D, anterior chamber depth greater than 3 mm, and endothelial cell count greater than 2,200 cells/mm2.

RESULTS

The preoperative spherical equivalent was -9.70+/-2.37 D. The spherical equivalent was -1.07+/-0.84 D at 2 years postoperatively. The surgically induced astigmatism was 0.42 D x 67.4-degree axis. The percentage of eyes with an uncorrected visual acuity greater than or equal to 0.5 and 0.8 was 66.6% and 33.3%, respectively. Neither intra- nor postoperative complications were noted during the entire follow-up period. The mean endothelial cell count value was 2267+/-352 at 2 years postoperatively. The objective and subjective quality of vision was acceptable, associated with a high level of patient satisfaction.

DISCUSSION

The refractive results and tolerance of the Artiflex lens are satisfactory and seem to be as good as other phakic intraocular lens outcomes.

CONCLUSION

To correct moderately high myopia, the Artiflex lens seems to provide a suitable refractive efficacy and a quick visual recovery, secondary to a lowering of induced astigmatism. Furthermore, this phakic intraocular lens is associated with satisfactory safety and quality of vision at each milestone of the entire follow-up period.