Artisan toric phakic intraocular lens for the correction of high astigmatism

The efficacy of 2 different phakic intraocular lens implant in keratoconus as an isolated procedure or combined with collagen crosslinking and intra-stromal corneal ring segments: a systematic review and meta-analysis

PURPOSE

To compare the efficacy of phakic intra-ocular lenses in isolation or in combination with corneal crosslinking (CXL) and/or intra-stromal corneal ring segments (ICRS) in keratoconus.

METHODS

Data extracted from the publications meeting the selection. The outcome parameters included mean pre- and post-operative uncorrected distance visual acuity, corrected distance visual acuity (CDVA), sphere and cylinder of refraction and complications. Available data analyzed with Cochrane Review Manager.

RESULTS

A total of 23 studies including 464 eyes were included. All the parameters showed significant improvement in all subgroups other than CDVA in ACPIOL + CXL subgroup and cylinder in PIOL + CXL subgroups. There was not a significant difference between PCPIOL and ACPIOL in the outcomes, exception was more improvement of CDVA in "ACPIOL only" than" PCPIOL only" subgroup.

CONCLUSION

Both PCPIOLs and ACPIOLs are comparably safe and efficient options in management of KCN and their efficacy significantly improves when combined with CXL/ICRS.

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.

Long-term changes in visual outcomes and ocular morphometrics after myopic and toric phakic intraocular lens implantation: Five- and 10-year results

PURPOSE

To evaluate the long-term refractive and visual, anterior chamber depth, and axial length (AL) changes and complications after rigid iris-fixated phakic intraocular lens (pIOL) implantation to treat myopia or astigmatism.

SETTING

University Eye Clinic Maastricht, Maastricht UMC+, the Netherlands.

DESIGN

Prospective case series.

METHODS

The study evaluated patients who had implantation of an Artisan myopic or toric iris-fixated pIOL as of January 1998. Changes were measured annually and reported after 1, 5, and 10 years postoperatively.

RESULTS

The study comprised 460 eyes (250 patients; mean age 41.1 years ± 10.7 [SD]). Over 10 years, the mean myopization was -0.79 diopters (D) (P < .001), with 52% of eyes within ±1.0 D of target. The mean increase in the logarithm of the minimum angle of resolution (logMAR) corrected distance visual acuity (CDVA) over 10 years was 0.05 (P < .001); 95% of eyes had a CDVA of 20/40 or more and 7% lost 2 or more lines of CDVA. The mean logMAR uncorrected visual acuity (UDVA) increased by 0.14 over 10 years (P < .001); 96% had a UDVA 20/40 or better. The AL increased by 1.14 mm over 10 years (P = .009). Ten percent of pIOLs were explanted because of cataract formation after a mean of 97.9 ± 34.9 months. A higher preoperative age (hazard ratio [HR], 1.08; P < .001) and longer AL (HR, 1.34; P < .001) were risk factors for shorter survival because of cataract formation.

CONCLUSION

Ten years after rigid iris-fixated pIOL implantation, the CDVA and UDVA decreased significantly as a result of significant myopization caused by an increased AL unrelated to the pIOL.

Comparison between using INTEGRA and manual method in determining axis for intraocular lens implantation: Preliminary retrospective study

The aim of this study was to explore the efficacy, repeatability, and efficiency of a new intraoperative contactless device (INTEGRA Optomed, Chorzów, Poland) for determining the axis for toric intraocular lens implantation and then to compare this with that determined using a manual method.This study was conducted at the Ophthalmological Center for Children and Adults Optomed, Chorzów, Poland.This nonrandomized, retrospective, observational study included 20 eyes of 12 patients (5 males and 7 females) who had toric intraocular lens implanted. A video recording of each surgery using the INTEGRA system was made showing the analysis. The surgeon and one of the researchers then independently assessed the location of the implant axes determined with both digital and manual slit-lamp methods, and compared them.The implantation axes suggested for both the manual and INTEGRA methods were similar. The median axis disparities were 0.0 degree and 0.5 degree, and standard deviations were 0.61 and 0.81 for researcher 1 and 2, respectively. The dominant value was 0.0 in both groups. The INTEGRA axis designation was not statistically different from the manual method (level of significance: α < 0.01).The INTEGRA system is a digital ink-free device for image tracking scleral vessels. It was helpful for determining the implantation axis in a precise and repeatable manner, and measurements were comparable with a manual technique.

Long-Term Endothelial Cell Loss in Patients with Artisan Myopia and Artisan Toric Phakic Intraocular Lenses: 5- and 10-Year Results

PURPOSE

To evaluate the long-term change in endothelial cell density (ECD) after the implantation of 2 types of rigid iris-fixated phakic intraocular lenses (pIOLs) for the treatment of myopia and astigmatism.

DESIGN

Prospective, clinical cohort study.

PARTICIPANTS

A total of 507 eyes of 289 patients receiving the Artisan Myopia or Artisan Toric (Ophtec B.V., Groningen, The Netherlands) iris-fixated pIOL for the treatment of myopia or astigmatism at the University Eye Clinic Maastricht as of January 1998.

METHODS

A total of 381 myopic and 126 toric pIOLs were implanted. Five- and 10-year follow-ups were completed by 193 and 127 eyes implanted with the myopic pIOL and by 40 and 20 eyes implanted with the toric pIOL, respectively.

MAIN OUTCOME MEASURES

Chronic endothelial cell (EC) loss, percentage of eyes with a decrease of ≥25% in ECD, and percentage of eyes with an ECD <1500 cells/mm².

RESULTS

Chronic EC loss was calculated from 6 months postoperatively to the end of follow-up and showed an annual ECD decline of 48 cells/mm² (standard error, 3.14) and 61 cells/mm² (standard error, 6.30) in the myopic (P < 0.001) and toric (P < 0.001) groups, respectively, resulting in a total EC loss of 16.6% and 21.5% from 6 months to 10 years postoperatively, respectively. Ten years after implantation, ECD had decreased by ≥25% in 7.9% and 6.3%, whereas ECD was <1500 cells/mm² in 3.9% and 4.0% in the myopic and toric groups, respectively. Explantation of the pIOL occurred in 6.0% in the myopic group and 4.8% in the toric group. Risk factors for increased EC loss were a shallow anterior chamber depth (ACD) (P ≤ 0.005) and a smaller distance between the central and peripheral pIOL edge to the endothelium (P ≤ 0.005).

CONCLUSIONS

A significant linear chronic EC loss was reported after implantation with myopic or toric iris-fixated pIOLs. A smaller ACD and smaller distance between pIOL edge and endothelium were risk factors for EC loss. Modification of preoperative age-related ECD thresholds is indicated to maintain an ECD that warrants safe future combined pIOL explantation and cataract surgery.

Comparison of Toric Foldable Iris-Fixated Phakic Intraocular Lens Implantation and Limbal Relaxing Incisions for Moderate-to-High Myopic Astigmatism

PURPOSE

To compare the effectiveness of toric foldable iris-fixated phakic intraocular lens (pIOL) implantation and non-toric foldable iris-fixated pIOL implantation with limbal relaxing incisions (LRIs) for correcting moderate-to-high astigmatism in myopic eyes.

MATERIALS AND METHODS

The medical records of 146 patients (195 eyes) with myopic astigmatism who underwent toric foldable iris-fixated pIOL implantation (toric group; 94 eyes) or non-toric foldable iris-fixated pIOL implantation with concurrent LRIs (LRI group; 101 eyes) were retrospectively reviewed. For subgroup analysis, the two groups were subdivided according to preoperative astigmatic severity [moderate, 2.00 to <3.00 diopters (D); high, 3.00-4.00 D]. Visual and astigmatic outcomes were compared 6 months postoperatively.

RESULTS

The uncorrected distance visual acuity was at least 20/25 in 100% and 98% of the toric and LRI group eyes, respectively. The toric group had lower mean residual cylindrical error (-0.67±0.39 D vs. -1.14±0.56 D; p<0.001) and greater mean cylindrical error change (2.17±0.56 D vs. 1.63±0.72 D; p<0.001) than the LRI group, regardless of the preoperative astigmatic severity. The mean correction index (1.10±0.16 vs. 0.72±0.24; p<0.001) and success index (0.24±0.14 vs. 0.42±0.21; p<0.001) also differed significantly between the groups.

CONCLUSION

Both surgical techniques considerably reduced astigmatism and had comparable visual outcomes. However, toric foldable iris-fixated pIOL implantation was more reliable for correcting moderate-to-high astigmatism in myopic eyes.

Artisan iris-fixated toric phakic intraocular lens for the correction of high astigmatism after deep anterior lamellar keratoplasty

We report the refractive correction of high astigmatism in one eye of a 23-year-old woman following deep anterior lamellar keratoplasty (DALK) using an Artisan iris-fixated, toric, phakic intraocular lens (IOL). One year after implantation, uncorrected and corrected distance visual acuities were both 20/25, refraction was -1.00 D cylinder, and the endothelial cell count was 1827 cells/mm(2). Iris-fixated phakic IOLs are not recommended for every postkeratoplasty patient with high refractive error; however, this procedure can offer good outcomes in carefully selected cases of previous DALK.

Five-year follow-up after anterior iris-fixated intraocular lens implantation in phakic eyes to correct high myopia

PURPOSE

To evaluate the 5-year follow-up of safety, efficacy, predictability, stability, and complications of anterior iris-fixated phakic intraocular lens (pIOL) implantation to correct high myopia, and patients' satisfaction after implantation.

DESIGN

Prospective, nonrandomized, and comparative (self-controlled) trial.

METHODS

A prospective clinical trial of 84 eyes of 43 patients with high myopia was conducted. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, endothelial cell count, intraocular pressure (IOP), anterior chamber depth, slit lamp biomicroscopy, and indirect ophthalmoscope were measured preoperatively and postoperatively.

RESULTS

At the 5-year follow-up, UCVA was significantly improved, with 85.7% of eyes reaching 20/25 or better. No eyes experienced a loss in BSCVA, and 71.4% gained one or more lines of their preoperative BSCVA. There was a significant reduction in spherical errors in all patients after operation. Loss of endothelial cells was observed 3 years after operation and no more loss was observed 4 years after operation in statistical analysis. No increase in IOP was observed 5 years after operation in statistical analysis. No intraoperative complications were observed in this study. However, pigment precipitates of varying intensities on the lens optic were noted in all patients 1 day after operation, and only five eyes were observed to have the pigment residual five years after operation.

CONCLUSION

At the 5-year follow-up, the implantation of the anterior iris-fixated pIOL was proved to be effective, predictable and capable of reversibility to correct high myopia in phakic eyes. It was a safety addition to the laser refractive surgery. However, longer follow-up with larger numbers of patients is still necessary to evaluate long-term complications.

Comparison of patient outcomes after implantation of Visian toric implantable collamer lens and iris-fixated toric phakic intraocular lens

PURPOSE

We compared visual and refractive outcomes after implantation of Visian toric implantable collamer lenses (toric ICLs) and iris-fixated toric pIOLs (toric Artisans).

PATIENTS AND METHODS

A comparative retrospective analysis was performed. Toric ICLs were implanted into 30 eyes of 18 patients, and toric Artisans into 31 eyes of 22 recipients. We measured the logarithms of the minimum angle of resolution of uncorrected visual acuity (logMAR UCVA), logMAR of best spectacle-corrected corrected VA (logMAR BSCVA), MR, SE, and astigmatism (by the power vector method) before surgery and 1, 3, and 6 months thereafter. Differences between patients receiving each type of lens were compared by using a mixed model of repeated measures.

RESULTS

Visual improvements were evident after operation in both groups. By comparing the attempted to the achieved SE values, we were able to confirm that correction of refractive error was similar in both groups. However, the logMAR UCVA was significantly higher in the toric ICL group at all postoperative time points. Although manifest cylinder power and astigmatism (calculated by using the power vector method) gradually decreased in the toric ICL group, cylinder power 1 month postoperatively increased from -2.62 to -2.75 D; astigmatism was also increased at this time in the toric Artisan group.

CONCLUSION

The two tested toric pIOLs were similar in terms of the ability to correct refractive error, as assessed 3 months postoperatively. However toric ICLs corrected astigmatism more rapidly and safely. Notably, the large difference in astigmatism level between the two groups 1 month postoperatively indicates that toric ICLs are more effective when used to correct astigmatism.

Artiflex phakic intraocular lens implantation after corneal collagen cross-linking in keratoconic eyes

PURPOSE

To evaluate the safety, efficacy, and stability of the Artiflex (Ophtec BV) foldable anterior iris-claw phakic intraocular lens (PIOL) following corneal collagen cross-linking (CXL) in select cases of progressive keratoconus.

METHODS

This prospective, comparative study, conducted between March 2007 and June 2008, involved 11 eyes with progressive keratoconus. Inclusion criteria were progressive keratoconus (Amsler-Krumeich classification grades I and II) with no corneal opacities, corneal thickness >450 μm, endothelial cell count >2500 cells/mm(2), anterior chamber depth >3.2 mm, spherical equivalent refraction >4.50 diopters (D) (with a cylinder component <2.00 D), and no other treatment for keratoconus other than contact lens. Each patient underwent CXL in the keratoconic eye with implantation of the Artiflex IOL 6 months thereafter. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and refraction and topographic profiles were examined at 1, 6, and 12 months after the CXL procedure.

RESULTS

All eyes achieved UDVA of 0.3 logMAR or better. Final spherical and cylindrical error ranged from 0 to -1.50 D and 0 to -1.75 D, respectively. No eyes lost lines of preoperative CDVA. Statistically significant reductions in mean maximum (2.14 D, P<.001) and minimum (1.17 D, P=.02) keratometry values were present 12 months after the CXL procedure. No complications were observed.

CONCLUSIONS

Combined CXL and Artiflex implantation was a safe and effective treatment in this subset of eyes with progressive keratoconus. Good results in terms of visual acuity, postoperative residual refractive error, and keratometry values were identified.

Axis alignment and rotational stability after implantation of the toric implantable collamer lens for myopic astigmatism

PURPOSE

To assess axis alignment and stability of the Toric Implantable Collamer Lens (TICL; STAAR Surgical Co) over time.

METHODS

Thirty-five consecutive eyes of 19 patients received the TICL for treatment of myopic astigmatism. Manifest refraction spherical equivalent (MRSE) and manifest refractive cylinder were measured preoperatively and at 3 months postoperatively. The axis alignment of the TICL was measured using the internal OPD map obtained with the OPD-Scan II (NIDEK Co Ltd).

RESULTS

Mean refractive cylinder was reduced from 2.80+/-1.45 diopters (D) preoperatively to 0.63+/-0.75 D at 3 months postoperatively; MRSE was -7.61+/-4.02 D preoperatively and -0.14+/-0.38 D at 3 months. Mean absolute value of the measured axis misalignment from baseline (day 1) to 1 month was 2.90+/-2.11 degrees and from 1 month to 3 months was 4.6+/-11.2 degrees. Mean absolute value of the measured changes in axis misalignment from baseline to 3 months was 2.68+/-2.11 degrees (after excluding one eye that required repositioning due to TICL rotation). At 3 months postoperatively, 96.8% (30/31) eyes had <or=8 degrees and 90.3% (28/31) had <or=5 degrees of axis misalignment.

CONCLUSIONS

The TICL showed minimal axis misalignment after implantation and remained stable 3 months postoperatively.

Postoperative astigmatism and axis stability after implantation of the STAAR Toric Implantable Collamer Lens

PURPOSE

To evaluate the efficacy, safety, and rotational and footplate stability of the STAAR Toric Implantable Collamer Lens (TICL; STAAR Surgical Co) for correction of myopic astigmatism.

METHODS

In this prospective, consecutive, interventional case series, a TICL was implanted uneventfully in 30 consecutive eyes of 20 patients with myopia and astigmatism. The uncorrected visual acuity, best spectacle-corrected visual acuity, refraction, and astigmatism were measured preoperatively and at last follow-up. To evaluate postoperative axis deviation from the intended axis and footplate displacement, a digital anterior segment photograph was taken after full mydriasis and ultrasound biomicroscopy for the four footplates of the TICL in each eye at last follow-up. Possible risk factors for TICL rotation were analyzed through correlation analysis.

RESULTS

After mean follow-up of 7.6 months, the mean refractive astigmatism decreased from 2.43 +/- 1.24 diopters (D) preoperatively to 0.73 +/- 0.47 D postoperatively, and the mean difference between intended and achieved TICL axes was 4.03 +/- 3.39 degrees. The absolute value of TICL rotation had significant correlation with the spherical power of the TICL (P = .037). The footplates of all TICLs were in situ in the ciliary sulcus except for one case in which one of the four footplates was located below the ciliary sulcus.

CONCLUSIONS

Implantation of the STAAR TICL appears to be an effective and safe method for correction of myopic astigmatism. No clinically significant rotation or footplate displacement of the TICLs was detected postoperatively during mean follow-up of 7.6 months.

[Iris-fixated intraocular lenses: reinforced monitoring]

In 1986, the concept of the claw lens was applied to correct myopia in phakic patients. Since then, progress has made iris-fixated phakic intraocular lenses (IOL) relatively safe, predictable, and effective for the correction of myopia, hyperopia, and astigmatism. All these models have undergone a series of design improvements to prevent complications. Despite having excellent refractive results, the principal risk is a potential progressive endothelial cell loss. Many authors have presented encouraging results. Phakic iris-fixated IOL surgery is a potentially reversible procedure, but the surgeon cannot rule out the possibility of complications. Therefore, long-term follow-up is mandatory.

Case of late-onset corneal decompensation after iris-fixated phakic intraocular lens implantation

A 48-year-old myopic patient with bilateral anterior chamber depth of 3.1 mm and endothelial cell density (ECD) of 2525 cells/mm(2) and 2638 cells/mm(2) preoperatively had bilateral implantation of an Artisan iris-fixated phakic intraocular lens (pIOL). Five years postoperatively, unilateral corneal stromal edema was seen in a circumscribed area overlying the temporal ridge of the pIOL in the right eye; the ECD was 1631 cells/mm(2) and the pachymetry, 586 microm. Explantation of the pIOL was refused by the patient. Seven years postoperatively, the ECD was 413 cells/mm(2) in the right eye and corneal decompensation occurred. The progressive unilateral endothelial loss was explained by excessive rubbing of the eyes because of chronic itching and an anterior shift of the pIOL over the 7 years as demonstrated by anterior optical coherence tomography.

Custom-designed toric phakic intraocular lenses to correct high corneal astigmatism

PURPOSE

To analyze the results of a custom-designed posterior chamber toric phakic intraocular lens (PIOL).

METHODS

A 40-year-old woman with high astigmatism and thin corneas underwent bilateral PIOL implantation with the toric Implantable Collamer Lens (ICL) custom-designed and manufactured by STAAR Surgical. The appropriate toric ICL power was calculated to be -8.00 +8.00 x 96 degrees for the right eye and -8.50 +7.50 x 86 degrees for the left eye. Optical zone was 5.5 mm and 6.875 mm at the corneal plane.

RESULTS

At 3 and 6 months postoperatively, uncorrected visual acuity (UCVA) and best-spectacle corrected visual acuity (BSCVA) of both eyes had improved to 20/20 and 20/16, respectively. At 19 months, UCVA was 20/20 and 20/16 in the right and left eyes, respectively, and BSCVA had improved to 20/16 and 20/10, respectively. The subjective refraction was stable, with a change of -0.37 +/- 0.17 D from preoperative to 19 months postoperatively. Throughout the postoperative period, iridotomies remained patent and the corneas were clear.

CONCLUSIONS

Bilateral implantation of the custom-designed toric ICL successfully corrected the patient's high astigmatism. Preoperative subjective refractive cylinder of -5.25 x 6 degrees in the right eye and -5 x 176 degrees in the left eye changed to -0.5 x 77 degrees and -0.5 x 115 degrees, respectively, after toric IOL implantation. There was almost no change in corneal astigmatism. This customized approach led to UCVA of 20/20 in the right eye and 20/16 in the left eye, and BSCVA of 20/16 in the right eye and 20/10 in the left eye. This is the first report of a toric PIOL being specifically manufactured to meet the refractive cylinder requirements of a specific patient.

Long-term Follow-up of Endothelial Cell Change after Artisan Phakic Intraocular Lens Implantation

OBJECTIVE

To report endothelial cell densities (ECDs) and their correlation to anterior chamber depth (ACD) after implantation of the Artisan intraocular phakic lens.

DESIGN

Prospective observational case series.

PARTICIPANTS

Three hundred eighteen eyes of 173 myopic patients treated with the Artisan iris-fixated phakic intraocular lens (IOL).

METHODS

Eyes with an ACD ranging between 2.89 and 4.5 mm were implanted with the Artisan phakic IOL. Endothelial cell density measurements were performed preoperatively and at each follow-up examination using a noncontact specular microscope.

MAIN OUTCOME MEASURES

Endothelial cell density (cells per square millimeter).

RESULTS

Follow-up ranged between 1 (82 eyes) and 7 years (13 eyes) (mean, 35.3+/-20.7 [standard deviation] months per eye). After 3 years, there was a significant loss in ECD (P< or =0.03). At 5 years, mean observed endothelial cell loss was 8.3% (5.3% corrected for a natural endothelial cell loss of 0.6% a year). Endothelial cell density loss remained progressive throughout our follow-up period. After 3 years, a significant negative correlation between ACD and endothelial cell loss was revealed (P< or =0.03). Patient age, gender, refractive error, incision size, and side of the eye were not correlated to ECD loss. All corneas remained clear throughout the study.

CONCLUSION

After 3 years, a significant ECD loss was revealed. This ECD loss was significantly negatively correlated to the ACD. We therefore suggest that eyes just meeting the minimum ECD requirement have greater ACDs to compensate for possible greater endothelial cell loss and that patients with shallow anterior chambers have higher ECDs. Artisan phakic lens implantation in young eyes narrowly meeting the minimum criteria of endothelial cell density (2,000 cells/mm(2)) and ACD (2.6 mm) should perhaps be reevaluated, due to longer exposure to higher rates of endothelial cell loss.

Position of rigid and foldable iris-fixated myopic phakic intraocular lenses evaluated by Scheimpflug photography

PURPOSE

To evaluate the postoperative intraocular positional stability of 1 rigid poly(methyl methacrylate) (PMMA) phakic intraocular lens (pIOL) model and 2 foldable polysilicone-PMMA iris-fixated pIOL models.

SETTING

Department of Ophthalmology, Johann Wolfgang Goethe-University Frankfurt am Main, Germany.

METHODS

One of 3 iris-fixated pIOL models (Artisan, Artiflex I, and Artiflex II, Ophtec BV) was implanted in 45 eyes of 26 patients with myopia or myopic astigmatism. The central distance between the pIOL and corneal endothelium and between the pIOL and anterior surface of the crystalline lens was evaluated using Scheimpflug photography 6 and 12 months after surgery.

RESULTS

The mean preoperative spherical equivalent was -9.32 diopters +/- 1.78 (SD) (range -6.5 to -13.5 D). Each IOL model was implanted in 15 eyes. The median distance from the central corneal endothelium to the anterior surface of the pIOL at 6 months and 12 months was 2.65 mm and 2.64 mm, respectively, in the Artisan group, 2.47 mm and 2.50 mm, respectively, in the Artiflex I group, and 2.48 mm and 2.52 mm, respectively, in the Artiflex II group. The median distance between the posterior surface of the pIOL and the anterior surface of the crystalline lens at 6 months and 12 months was 0.40 mm and 0.48 mm, respectively, in the Artisan group, 0.53 mm and 0.55 mm, respectively, in the Artiflex I group, and 0.68 mm and 0.66 mm, respectively, in the Artiflex II group. At 12 months, the distance between the pIOL and crystalline lens was statistically significantly greater in the Artiflex II group than in the Artisan group (P<.01).

CONCLUSION

The intraocular position of rigid pIOLs and foldable silicone iris-supported pIOLs showed a difference between the 3 pIOL models in space to the crystalline lens and the corneal endothelium, which may affect long-term results in terms of IOL interaction with surrounding tissue.

[Toric phakic intraocular lenses]

After more than 3 years of follow-up, the satisfactory results achieved with the toric iris-fixated phakic intraocular lens (IOL) mean we can regard implantation of this lens as a procedure with the potential to provide safe, predictable, effective and stable correction of astigmatic errors, providing patients are carefully selected and receive adequate preparation for surgery. The iris-fixated toric phakic IOL (Verisyse, Advanced Medical Optics; Artisan, Ophtec) is a PMMA lens with a total diameter of 8.5 mm and an optic diameter of 5 mm. It has a spherical anterior and a toric posterior surface. Its refractive power ranges from -2 dpt to -21 dpt for myopia and from +2 dpt to +12.5 dpt for the correction of hyperopia. Cylindrical correction is available from 2 dpt to 7.5 dpt. The Visian toric implantable Collamer lens (Staar) differs in that it is foldable and can be inserted through a very small incision of about 2.8 mm. It is placed in front of the natural lens in the ciliary sulcus. The aim of implanting these phakic IOLs is to correct the entire refractive error, meaning both the spherical and the astigmatic error, in a single step. Different lens models are available, and the selection depends on the direction of the cylinder axis and the anatomical situation, among other things.

Evaluation of Verisyse and Artiflex phakic intraocular lenses during accommodation using Visante optical coherence tomography

PURPOSE

To perform a dynamic study of the relationship between Verisyse (AMO) and Artiflex (Ophtec B.V.) phakic intraocular lenses (pIOLs) and anterior chamber structures during accommodation using optical coherence tomography (OCT) (Visante, Carl Zeiss Meditec, Inc.)

SETTING

Institutional practice.

METHODS

Eleven myopic patients were randomly selected to have implantation of a Verisyse pIOL in 1 eye and an Artiflex pIOL in the other. Using a 2-dimensional image, dynamic measurements of the relationship between the anterior surface of the pIOL and the corneal endothelium, the posterior surface of the pIOL and the anterior surface of the crystalline lens, and the pupil diameter were performed using Visante OCT. Physiological accommodation was stimulated by adding lenses in 1.00 diopter (D) steps from +1.00 to -7.00 D.

RESULTS

Both groups had a significant decrease in pupil diameter (P<.0001, generalized linear model [GLM]) and in the distance between the anterior surface of the pIOL and the corneal endothelium (P<.0001, GLM) with accommodation. There were no statistically significant changes in the distance between the posterior surface of either pIOL and the anterior surface of the crystalline lens (P = .2845, GLM). There were no statistically significant differences between the 2 pIOLs in any measurement (P>.05, GLM).

CONCLUSIONS

The results fit with Helmholtz' theory of accommodation as forward movement of the diaphragm iris-crystalline lens was seen. There was a decrease in the distance between the pIOL and corneal endothelium and in the pupil diameter, whereas the distance between both pIOLs and the crystalline lens remained constant throughout the accommodation examination. This suggests that the risk for cataract from intermittent contact between the crystalline lens and IOL from accommodative effort is unlikely.

Calculating the power of toric phakic intraocular lenses

BACKGROUND AND PURPOSE

A toric phakic intraocular lens (IOL) implanted in the anterior or posterior chamber of the eye has the potential to correct high or excessive ametropia and astigmatism with high predictability of the postoperative refraction and preservation of phakic accommodation. The calculation of spherical phakic lenses has been described previously, but a formalism for estimating the power of toric phakic lenses has not yet been published. The purpose of this study is to describe a mathematical strategy for calculating toric phakic IOLs.

METHODS

The method presented in this paper is based on vergence transformation in the paraxial Gaussian space. Parameters used for the calculations are the spherocylindrical spectacle refraction before implantation, corneal power (sphere and astigmatism) and (spherocylindrical) target refraction, together with the vertex distance and the predicted position of the phakic IOL. The lens power is determined as the difference in vergences between the spectacle-corrected eye and the uncorrected eye at the reference plane of the predicted lens position. The axes of the preoperative refraction, the target refraction and the corneal astigmatism are at random (not necessarily aligned).

RESULTS

The method was applied to two clinical examples. In example 1 we calculate the power of a phakic lens for the simple case, when the target refraction is plano and the axis of the preoperative refraction is aligned to the axis of the corneal astigmatism. In example 2, the cylindrical axis of the preoperative refraction is not aligned to the corneal astigmatism and the target refraction is spherocylindrical (and the axis of the target refraction is not aligned to the preoperative refractive cylinder or the corneal astigmatism). The calculations for both examples are described step-by-step and illustrated in a table.

CONCLUSIONS

The calculation scheme can be generalized to an unlimited number of crossed cylinders in the optical pathway. Based on paraxial raytracing, the spherical and cylindrical power as well as the orientation of the cylinder are determined from the preoperative refraction (including vertex distance), the corneal power, the intended target refraction (including vertex distance) and the predicted position of the phakic lens implant provided by the lens manufacturer. This calculation scheme can be easily implemented in a simple computer program (i.e. in Microsoft excel or matlab).

[LASIK treatment for graft astigmatism]

OBJECTIVE

To analyze the advantages of LASIK as a treatment for postkeratoplasty residual astigmatism.

PATIENTS

and

METHOD

Retrospective, noncomparative, monocentric study on 14 patients with penetrative keratoplasty. Visual acuity, objective refraction, intraocular pressure, slit lamp biomicroscopy, videotopography, pachymetry, and patient satisfaction were studied before and after surgery.

RESULTS

Refraction was stable 6 months after treatment in 93% (13/14) of the patients. The mean uncorrected visual acuity increased from 0.16 to 0.4. Two out of four patients (14.3%) were retreated because visual acuity did not improve after the first treatment; 35% did not need any optical correction after the intervention. The measured astigmatism showed a significant decrease, from 65% greater than 5 D before treatment to 82% under 2 D after treatment. Only two out of 14 patients (14.3%) were not satisfied. No intraocular or postoperative complications were reported in this study.

CONCLUSION

LASIK seems to be an interesting option in the treatment of postkeratoplasty residual astigmatism. This study has shown its efficacy and safety in this indication. Its originality lies in the one-step procedure, with the flap and photoablation done in a single step. However, it is still dependent on the operator and most particularly the equipment (laser, microkeratome, aberrometry).

Long-term Study of Artisan Phakic Intraocular Lens Implantation for the Correction of Moderate to High Myopia

PURPOSE

To determine the long-term performance of the Artisan phakic intraocular lens (PIOL) for the correction of myopia.

DESIGN

Long-term (10 years) retrospective follow-up study.

PARTICIPANTS

Eighty-nine eyes of 49 patients who underwent Artisan PIOL implantation for the correction of myopia.

METHODS

Comparisons were made between preoperative clinical data and the clinical data at 1, 6, and 10 years after surgery.

MAIN OUTCOME MEASURES

Refractive stability, refractive predictability, safety, efficacy, best-corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), intraocular pressure, intraoperative problems, corneal endothelial cell density, corneal endothelial cell loss, and glare levels were evaluated.

RESULTS

The mean spherical equivalent (SE) after 10 years was -0.70+/-1.00 diopters (D; range, -4.00 to 2.00 D), with no significant change in mean SE between 1, 6, and 10 years. At 10 years, 68.8% of all eyes were within 1.0 D of the intended correction. At 10 years, 31.2% (n = 24) gained 1 or more Snellen lines of BCVA and 2.6% (n = 2) lost more than 2 Snellen lines of BCVA; 93.3% reached a BCVA of 20/40 or better, and 82.0% reached a UCVA of 20/40 or better. The mean intraocular pressure remained stable and was 15.5+/-3.5 mmHg (range, 7-25 mmHg) at 10 years. The mean endothelial cell loss was -8.86+/-16.01% (range, -51.69% to 34.43%) at 10 years.

CONCLUSIONS

Long-term results demonstrate that the implantation of an Artisan PIOL for the correction of moderate to high myopia is a stable, predictable, and safe method when strict inclusion criteria for surgery are applied. There was no significant loss of corneal endothelial cells and no reports of long-term glare.

Magnification and accommodation with phakic intraocular lenses

BACKGROUND AND PURPOSE

The calculation of phakic lenses (PL) was described by van der Heijde et al. [Klin. Monatsbl. Augenheilkd (1988) Vol. 193, pp. 99-102], but a formalism for estimating relative magnification compared with spectacle correction and accommodation effects are not yet published. The purpose of this study was to describe a mathematical strategy for calculating PL and relative magnification as a function of object vergence (phakic accommodation).

METHODS

Parameters used for the calculations are the spectacle refraction before and after (target refraction) surgery, the vertex distance, corneal refraction, and the predicted position of the phakic intraocular lens. The lens power is determined as the difference in vergences between the spectacle-corrected eye and the uncorrected eye at the reference plane of the predicted lens position. If we simplify the crystalline lens to a single refracting surface located at the principal plane of the crystalline lens, the vergence of the eye with spectacle correction and with PL is determined as a function of object distance [object vergence 0 D (infinity) to 10 D (object at a distance of 10 cm)] to evaluate accommodation effects of the crystalline lens.

RESULTS

The method was applied to two clinical examples. In example 1 we calculated the power of a PL for correction of a 10-D myopia and determined the relative magnification and the vergence at the principal plane of the crystalline lens as a function of object vergence. Magnification gain increases with objects at near from 17% to 26%, whereas the vergence at the principal plane of the crystalline lens changes by 3.04 D less than in the spectacle-corrected eye. In example 2, a 20-D myopia was corrected with a PL. The gain in magnification changed from 33% to 58% with nearer objects. The change in vergence at the principal plane of the crystalline lens with objects at near was much higher with the PL compared with the spectacle correction, which implies that the refractive change necessary for focusing objects at near distance is much higher in the PL correction.

CONCLUSIONS

Even if the predictability of postoperative refraction with PL is comparable or better than in other methods of correcting high or excessive ametropia, the effects of lateral magnification change and accommodation have to be considered to avoid image-size disparities (aniseikonia) and to maintain binocular vision, especially with monocular PL implantation and anisometropia.

Artisan iris-fixated toric phakic and aphakic intraocular lens implantation for the correction of astigmatic refractive error after radial keratotomy

We report 2 patients who had radial keratotomy (RK) to correct myopia. The first patient developed a postoperative hyperopic shift and cataract. Nine years post RK, she had intracapsular cataract extraction and implantation of an Artisan aphakic intraocular lens (IOL). Twenty years post RK, hyperopia and astigmatism progressed to +7.0 -5.75 x 100 with a best corrected visual acuity (BCVA) of 20/20. Due to contact lens intolerance, the Artisan aphakic IOL was exchanged for an Artisan toric aphakic IOL. Three months later, the BCVA was 20/20 with +1.0 -0.50 x 130. The second patient demonstrated residual myopic astigmatism 6 years after bilateral RK and had become contact-lens intolerant. An Artisan toric phakic IOL was implanted in both eyes. Four months later, the BCVA was 20/25 with a refraction of +0.25 -1.0 x 135 and 20/20 with a refraction of -1.0 x 40. Both patients were satisfied with the visual outcomes.

Endothelial Cell Loss After Toric Iris-fixated Phakic Intraocular Lens Implantation: Three-year Follow-up

PURPOSE

To study quantitative changes in endothelial cell count after implantation of the toric iris-fixated phakic intraocular lens.

METHODS

A prospective, non-randomized, self-controlled clinical trial was conducted of 40 eyes (28 myopic, 12 hyperopic) of 23 patients with high ametropia and astigmatism. Non-contact computer-assisted endothelial microscopy was performed before and 1, 2, and 3 years after surgery.

RESULTS

In the myopic group, mean preoperative endothelial cell count was 3179 +/- 531 cells/mm2 (range: 1800 to 3900 cells/mm2). The mean intra-individual endothelial cell loss was -1.83 +/- 2.25% (range: -9.09% to 0%) in the first year; -1.83 +/- 2.95% (range: -7.74% to 3.80%) in the second year; and -3.20 +/- 4.43% (range: -14.25% to 1.91%) three years after surgery, compared to preoperative values. In the hyperopic group, mean preoperative endothelial cell count was 3107 +/- 125 cells/mm2 (range: 2932 to 3300 cells/mm2). The mean endothelial cell loss was -1.63 +/- 1.76% (range: -3.23% to 1.67%) in the first year; -0.05 +/- 1.25% (range: -1.65% to 1.75%) in the second year; and -2.88 +/- 2.03% (range: -5.33% to -0.13%) three years after surgery, compared to preoperative values.

CONCLUSIONS

Annual cumulative cell loss was -1.9% for the myopic group and -1.6% for the hyperopic group, which is two to three times greater than physiological annual cell loss in normal eyes without surgery. An annual endothelial cell count analysis is highly recommended in every patient after iris-claw lens implantation to detect potential progressive cell loss at an early stage.

Toric Implantable Collamer Lens for moderate to high myopic astigmatism

PURPOSE

To assess the efficacy of the Toric Implantable Collamer Lens (ICL) to treat moderate to high myopic astigmatism.

DESIGN

Prospective nonrandomized clinical trial.

PARTICIPANTS

Two hundred ten eyes of 124 patients with between 2.38 and 19.5 diopters (D) of myopia (spherical equivalent [SE]) and 1 to 4 D of astigmatism participating in the United States Food and Drug Administration clinical trial of the Toric ICL.

INTERVENTION

Implantation of the Toric ICL.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), refraction, best spectacle-corrected visual acuity (BSCVA), adverse events, and postoperative complications.

RESULTS

At 12 months postoperatively, the proportion of eyes with 20/20 or better UCVA (83.1%) was identical to the proportion of eyes with preoperative 20/20 or better BSCVA (83.1%); 76.5% had postoperative UCVA better than or equal to preoperative BSCVA. The mean manifest refractive cylinder dropped from 1.93 D (+/-0.84) at baseline to 0.51 D (+/-0.48) postoperatively, a 73.6% decrease in astigmatism. Although only 21.0% of eyes had 1-D refractive cylinder preoperatively (none less), 91.4% of cases had < or =1 D of cylinder postoperatively. Furthermore, 65.6% had < or =0.5 D and 40.9% had < or =0.25 D of refractive cylinder postoperatively. Mean manifest refraction SE (MRSE) improved from -9.36 D (+/-2.66) preoperatively to 0.05 D (+/-0.46) postoperatively. A total of 76.9% of eyes were predicted accurately to within +/-0.5 D, 97.3% to within +/-1.0 D, and 100% to within +/-2.0 D of predicted MRSE. Postoperatively, 37.6% of eyes had a BSCVA of 20/12.5 or better, compared with a preoperative level of 4.8%. Furthermore, BSCVA of 20/20 or better occurred in 96.8% postoperatively, compared with 83.1% preoperatively. Mean improvement in BSCVA was 0.88 lines; there were 3 cases (1.6%) that lost > or =2 lines of BSCVA after 12 months postoperatively, whereas 18.9% of cases improved by > or =2 lines. A total of 76.4% of cases gained > or =1 lines of BSCVA, whereas only 7.5% of cases lost the equivalent amount. Three ICL removals were performed without significant loss of BSCVA, and 1 clinically significant lens opacity was observed.

CONCLUSION

The results support the efficacy and predictability of Toric ICL implantation to treat moderate to high myopic astigmatism. Important safety concerns were not identified.

Iris-fixated toric phakic intraocular lens: Three-year follow-up

PURPOSE

To evaluate the 3-year safety, efficacy, predictability, and stability of iris-fixated toric phakic intraocular lens (pIOL) implantation for the correction of myopia or hyperopia with astigmatism.

SETTING

Department of Ophthalmology, Johannes Gutenberg University, Mainz, and Department of Ophthalmology, University Clinic, Bochum, Germany.

METHODS

A prospective clinical trial of 40 eyes of 23 patients with high ametropia and astigmatism was conducted. Best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity, refraction, astigmatism, intraocular pressure, slitlamp biomicroscopy, and indirect ophthalmoscopy were measured preoperatively and postoperatively.

RESULTS

Of the 40 eyes, 28 were myopic and 12 were hyperopic. Three years postoperatively, 70% of eyes were within +/-1.00 diopter (D) of the targeted refraction. In the myopic group, mean preoperative BSCVA was 20/40 and improved postoperatively to 20/25. Sixty-six percent of eyes gained 1 or more lines from the preoperative BSCVA. The mean cylinder decreased from -3.58 D +/- 1.26 (SD) preoperatively to -1.15 +/- 1.01 D postoperatively. In the hyperopic group, preoperative BSCVA was 20/25 and improved to 20/20 postoperatively. Thirty-six percent of eyes gained 1 or more lines from the preoperative BSCVA. The mean cylinder decreased from -3.37 +/- 0.88 D to -1.53 +/- 0.69 D postoperatively. The correction was stable in all eyes 3 years after surgery. No potentially sight-threatening complications occurred.

CONCLUSION

The 3-year follow-up showed the iris-fixated toric pIOL was effective in correcting high ametropia and astigmatism.

The Influence of Incision-Induced Astigmatism and Axial Lens Position on the Correction of Myopic Astigmatism with the Artisan Toric Phakic Intraocular Lens

PURPOSE

To evaluate postoperative astigmatism with regard to incision-induced astigmatism and deviation in axial alignment with the use of preoperative limbal marking with the Javal keratometer (Haag Streit, Bern, Switzerland) in eyes implanted with the Artisan toric phakic intraocular lens (IOL) (Ophtec, Groningen, The Netherlands).

DESIGN

Prospective nonrandomized trial.

PARTICIPANTS

Fifty-four eyes of 33 patients with myopia (mean, -9.67 diopters [D]) and astigmatism (mean, -3.44 D).

INTERVENTION

The enclavation site was marked on the limbus using the Javal keratometer. The Artisan toric phakic IOL was implanted according to the axis marked on the limbus. Follow-up was a minimum of 6 months.

MAIN OUTCOME MEASURES

Safety index, efficacy index, predictability, safety, and vector analysis of total refractive correction were determined. The effects of axis misalignment and incision-induced astigmatism on the final refractive error were evaluated.

RESULTS

At 6 months after surgery, the safety index was 1.29+/-0.29 and the efficacy index was 1.04+/-0.35. Mean spherical equivalent subjective refraction reduced from -11.39+/-4.86 D before surgery to -0.38+/-0.57 D at 6 months. Sixty-seven percent of eyes were within 0.50 D of attempted refraction and 89% were within 1.00 D. Mean preoperative cylinder was 2.92+/-1.60 D at 91.4 degrees . At 6 months, the mean cylinder was 0.28+/-0.54 D at 174.3 degrees . No eyes lost 2 or more lines of best-corrected visual acuity at 6 months. Eighty-three percent of eyes achieved uncorrected visual acuity of 20/40 and 28% achieved 20/20. Vector analysis of total surgically induced astigmatism revealed a mean cylindrical change of 3.21+/-1.71 D. Average axis misalignment was 0.37+/-5.34 degrees . The mean incision-induced astigmatism was 0.74+/-0.61 D at 0.2 degrees .

CONCLUSIONS

Implantation of the myopic toric IOL leads to safe, efficacious, and predictable results. The level of unpredictability caused by minor axis IOL misalignment has minimal effects on the residual refractive error. The procedure of axis alignment with the Javal keratometer seems to be an accurate method of marking the eye for toric IOL implantation. Incision-induced astigmatism can result in an overcorrection of the cylinder. A systematic undercorrection of -0.50 D for attempted cylindrical outcome could result in an achieved correction closer to emmetropia.

Toric phakic intraocular lens for the correction of hyperopia and astigmatism

PURPOSE

To evaluate the Artisan toric phakic intraocular lens (pIOL) for the correction of hyperopia and astigmatism.

SETTING

Department of Ophthalmology, Erasmus MC, Rotterdam, The Netherlands, and Department of Ophthalmology, Sint Truiden, Belgium.

METHODS

In this prospective study of 47 eyes of 28 patients with hyperopia and astigmatism, Artisan toric pIOLs were implanted between April 1999 and June 2004. Uncorrected visual acuity (UCVA), best corrected visual acuity, refraction, astigmatism, safety, and predictability were analyzed. Change in astigmatism was analyzed with vector analysis. Refractive cylinders are expressed in minus form.

RESULTS

Mean preoperative spherical equivalent was +4.33 diopters (D) +/- 2.26 (SD). Mean follow-up was 11.1 months (range 6 to 36 months). A gain of 1 or more lines in best spectacle-corrected visual acuity (BSCVA) was seen in 36.2%. Safety index and efficacy index after 6 months were 1.06 and 0.87, respectively. The mean postoperative astigmatism at 6 months was 0.19 D at an axis of 144 degrees. At 6 months, about three quarters (76.6%) of the eyes had a UCVA of 20/40 or better. One eye lost 2 lines of BSCVA. In 1 eye, the lens position had to be changed because of a large axis misalignment. No serious complications developed in any of the treated eyes during follow-up.

CONCLUSIONS

Artisan toric pIOLs can correct moderate to high hyperopia combined with astigmatism with good refractive results. In this study, there were no serious complications. However, the predictability of the refractive results appeared to be lower than those in the correction of myopia and astigmatism with toric Artisan lenses.

Traumatic Dislocation and Successful Re-enclavation of an Artisan Phakic IOL With Analysis of the Endothelium

PURPOSE

To present a case of traumatic dislocation of an Ophtec Artisan phakic intraocular lens (PIOL) and an analysis of the endothelial cell count.

METHODS

The patient presented with blurred vision in his left eye after sustaining a brow laceration. History included uncomplicated bilateral implantation of an Artisan PIOL to correct myopia.

RESULTS

The brow laceration was sutured and topical dexamethasone 0.1% qid was prescribed. One week after presentation, the PIOL was relocated. Postoperatively, endothelial cell count analysis was performed in both eyes.

CONCLUSIONS

A decrease in the hexagonality of the endothelial cells was noted in both eyes, which was substantially lower in the injured eye.

Phakic Intraocular Lenses

An analytical review of the data available in the field of phakic intraocular lens implantation was conducted. Particular attention was paid to the more critical issues of intraocular lens sizing and safety guidelines. A comprehensive, competitive analysis of different implantation sites, intraocular lens model designs, and safety guidelines has been included. Specialized biometry techniques, such as very high frequency ultrasound and Scheimpflug imaging, have been reviewed, and a critical review of commercial claims regarding intraocular lens technologies has been included. Clinical studies of phakic intraocular lenses demonstrate increasing promise for the correction of refractive errors not amenable to mainstream excimer laser refractive surgery. The main issues currently revolve around adequate lens design (VHF ultrasound study suggests that custom-design and sizing may be the most effective and safest approach for every phakic IOL model), because these devices will be required to remain physiologically inert and anatomically compatible with internal ocular structures and relations for several decades. The possibility of safe removing or exchanging the IOL should remain a feasible option over time. It is of utmost importance that we continue to critically evaluate current encouraging short-term outcomes, which are being extrapolated to the longer term by ongoing high resolution imaging and monitoring of the anatomical and functional relations of implanted phakic IOLs.

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.