Long-term results of implantation of phakic posterior chamber intraocular lenses

Comparison of Collamer toric implantable [corrected] contact lens implantation and wavefront-guided laser in situ keratomileusis for high myopic astigmatism

PURPOSE

To compare the postoperative visual outcomes after implantation of a Collamer toric implantable contact lens (ICL) and after wavefront-guided laser in situ keratomileusis in high myopic astigmatism.

SETTING

Department of Ophthalmology, Kitasato University, Kanagawa, Japan.

METHODS

This study comprised 30 eyes (18 patients) having toric ICL implantation and 24 eyes (17 patients) having wavefront-guided LASIK (Technolas 217z) to correct high myopic astigmatism (manifest spherical equivalent [SE] <or=-6.0 diopters [D]; manifest refractive cylinder >or=1.0 D). The safety, efficacy, predictability, stability, and adverse events were assessed preoperatively and 1 week and 1, 3, and 6 months postoperatively.

RESULTS

At 6 months, the mean safety index was 1.28+/-0.25 (SD) in the ICL group and 1.01+/-0.16 in the LASIK group and the mean efficacy index, 0.87+/-0.15 and 0.83+/-0.23, respectively. All eyes in the ICL group and 71% of eyes in the LASIK group were within +/-1.00 D of the targeted SE correction at 6 months. The mean change in manifest refraction from 1 week to 6 months was -0.04+/-0.24 D in the ICL group and -0.60+/-0.49 D in the LASIK group. There were no significant complications in the ICL group; 2 eyes (8.3%) in the LASIK group required enhancement ablations.

CONCLUSION

Toric ICL implantation was better than wavefront-guided LASIK in eyes with high myopic astigmatism in almost all measures of safety, efficacy, predictability, and stability, suggesting that toric ICL implantation may become a viable surgical option to treat high myopic astigmatism.

Time course of accommodation after implantable collamer lens implantation

PURPOSE

To assess the time course of accommodative function after Implantable Collamer Lens (ICL) implantation and to investigate the relationship between patient age and accommodation in ICL-implanted eyes.

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

We prospectively examined 69 eyes of 40 consecutive patients with myopic refractive errors of -3.25 to -22.75 diopters (D) who were undergoing ICL implantation. We assessed the amplitude of accommodation using an accommodometer before and one, three, six, and 12 months after surgery. We also investigated its relationship with patient age.

RESULTS

The accommodation was 6.36 +/- 3.94 D (mean +/- standard deviation) before surgery and 4.89 +/- 2.72 D, 4.98 +/- 2.67 D, 5.16 +/- 2.72 D, and 5.72 +/- 2.85 D at one, three, six, and 12 months after surgery, respectively. The variance of data was statistically significant (P = .02, repeated-measures analysis of variance). Multiple comparisons demonstrated significant differences between measurements made before surgery and at one month after (P = .004, Fisher least significant difference test), before surgery and at three months after (P = .007), and before surgery and at six months after (P = .01). There was a significant correlation between patient age and accommodation before (Pearson correlation coefficient, r = -0.665; P < .001) and one year after (r = -0.803; P < .001) ICL implantation.

CONCLUSIONS

Accommodation was impaired transiently in the early postoperative periods, and then recovered gradually over time, indicating that transient dysfunction of the ciliary muscles by ICL fixation may occur after ICL implantation even if the crystalline lens remained intact. As patients aged, the amplitude of accommodation became significantly smaller not only in normal eyes but also in ICL-implanted eyes.

Phakic intraocular lens correction of high ametropia in children with neurobehavioral disorders

PURPOSE

A subset of children with high ametropia and neurobehavioral disorders have chronic difficulties with spectacle or contact lens wear. We report the results of refractive surgery in a series of these children treated using bilateral or unilateral phakic intraocular lenses (IOLs) for ametropia >10 D.

METHODS

Clinical course and outcome data were collated prospectively in a group of 12 children (mean age, 10.1 years; range, 4-17 years) with neurobehavioral disorders exacerbated by poor compliance with spectacles. Myopia in 18 eyes ranged from -10.0 to -22.75 D (mean, -15.2 D) and in 2 hyperopic eyes from +10.25 to +10.75 (mean, +10.5 D). Goal refraction was approximately 0 to +1 D. Correction was achieved by implantation of an iris-enclaved phakic IOL under general anesthesia. Mean follow-up was 9.1 months (range, 3-15 months).

RESULTS

Myopia correction averaged 14.5 D and hyperopia correction 9.4 D. Eighty-six percent of eyes (17/20 eyes) were corrected to within +/- 1 D of emmetropia and the remaining 14% (3 eyes) to within +/- 2 D. Uncorrected visual acuity improved substantially in all 20 eyes (60-fold; from a mean of 20/3400 to a mean of 20/57). Ocular comorbidities in each child accounted for residual postoperative, subnormal visual acuity (eg, amblyopia, nystagmus, albinism, regressed retinopathy of prematurity). Visual functions (measured using a 23-item validated survey) improved. One eye required IOL exchange; no other clinically significant complications have been encountered.

CONCLUSIONS

Phakic IOL implantation improves visual function substantially in neurobehaviorally impaired children who have high ametropia and difficulties wearing glasses.

Crystalline lens changes in porcine eyes with implanted phakic IOL (ICL) with a central hole

Background

We calculated the smallest diameter of a hole in the center of the optic at which the optical character of a phakic IOL (ICL) may be maintained. The changes induced in the aqueous humor dynamics and the pathology of cataract development with such a hole were investigated.

Methods

A simulation was performed using ZEMAX software to calculate the hole diameter that makes possible the maintenance of a stable optical character of a phakic IOL. After a hole of calculated diameter was trepanned in the center of the optic of the ICL, the latter was implanted into one eye of a 5-month-old minipig, and an unperforated ICL into the other. The postoperative course was observed for 3 months. Then, Evans blue was injected into the vitreous body under general anesthesia to stain the anterior capsule of the crystalline lens. Within 30 min, the eye was enucleated and the tissues removed were fixed.

Results

The MTF of the perforated ICL (hole diameter, 1.0 mm) in the center of the optic resembled that of the unperforated ICL. In all cases with non-perforated ICLs, subcapsular turbidity developed, but no staining caused by EB was observed in the anterior capsule. On the other hand, the anterior capsules of the eyes fitted with ICLs with a 1.0-mm hole were stained, but exhibited no turbidity.

Conclusion

An ICL with a central hole of diameter 1.0 mm in the optic is similar to an unperforated ICL. The size of the hole influenced the aqueous humor dynamics and increased the aqueous humor perfusion volume over the entire anterior surface of the crystalline lens. The possibility of preventing cataracts was therefore suggested.

Optical Coherence Tomography of the Anterior Segment in Eyes with Phakic Refractive Lenses

PURPOSE

To evaluate the dynamics of the phakic refractive lens (PRL) in myopic and hyperopic eyes in the nonaccommodated state and during subjective accommodation with Visante optical coherence tomography (OCT).

DESIGN

Cross-sectional study.

PARTICIPANTS

Forty-one myopic eyes and 11 hyperopic eyes of 52 patients (mean age, 34 years; range, 24-49) were examined at least 1 year after PRL implantation using Visante OCT. Thirty-one myopic eyes had the PRL model 101 and 10 eyes had the smaller PRL model 100 implanted. The hyperopic model, PRL 200, is available in only one size.

METHODS

Noninvasive high-resolution anterior OCT was used to measure distance changes between the PRL and adjacent intraocular structures in the nonaccommodative state (baseline) and during accommodation.

MAIN OUTCOME MEASURES

Mean distance changes from the anterior lens surface (ALS) to the PRL and from the corneal posterior surface to the ALS and the PRL, and changes in the pupil diameter.

RESULTS

At baseline, the mean distances between the PRL and crystalline lens were 0.38, 0.30, and 0.32 mm for the PRL 101, PRL 100, and PRL 200, respectively. The PRLs were significantly closer to the crystalline lens with increasing patient age. Three PRLs were in contact with the crystalline lens (6%), and there were lens opacities in 2 of these eyes. During accommodation, the ALS of all PRL models showed significant forward movement (P<0.05), whereas the distance between the PRL and crystalline lens decreased significantly with the PRL 101 and PRL 200 (P<0.05). The distance between the PRL 100 and crystalline lens remained unchanged during accommodation.

CONCLUSION

The PRL moved forward during accommodation in all eyes, with the distance preserved between the PRL and the ALS with the PRL 100. The distance decreased with the other 2 models. In 85% of cases, there was no mechanical contact with the ALS during accommodation.

Diagnosis and treatment of refractive errors in the pediatric population

PURPOSE OF REVIEW

The diagnosis and successful treatment of visually significant refractive errors in children are a subject of continued study and debate.

RECENT FINDINGS

Treatment of significant refractive errors is widely accepted to reduce lifelong vision loss from amblyopia. Children aged 3-5 years may be screened for unexplained vision loss, refractive errors and amblyogenic factors using traditional eye charts as well as newer modalities such as autorefractors and photoscreeners. The accuracy of various screening methods is variable throughout the literature. Debate remains as to who is best suited to administer vision screening tests. Compliance with follow-up with an eye-care professional once a child is identified with an amblyogenic factor remains suboptimal. Treatment of significant refractive errors in certain populations of pediatric patients with refractive surgery shows promise but requires further study.

SUMMARY

The timely diagnosis of significant refractive errors in children remains a significant challenge, especially for ages 3-5 years, but treatment may provide significant improvement of visual acuity and quality of life.

Comparison of Anterior Chamber Depth Measurement Between Orbscan IIz and Ultrasound Biomicroscopy

PURPOSE

To compare the measurement of anterior chamber depth exclusive of corneal thickness using Orbscan IIz and ultrasound biomicroscopy (UBM) and evaluate the repeatability of each method.

METHODS

Three consecutive measurements of anterior chamber depth were prospectively performed using Orbscan IIz and Paradigm 50-MHz UBM in 40 eyes in 20 individuals. Mean values were compared using the paired t test. For 12 eyes in 6 individuals, anterior chamber depth measurements were performed 5 times to estimate the repeatability of each method by a coefficient of variation. Refractive errors were measured to correlate with anterior chamber depth.

RESULTS

The mean anterior chamber depth was 2.82 +/- 0.46 mm with the Orbscan IIz and 2.91 +/- 0.43 mm in UBM. This difference was statistically significant (P < .001), but not clinically meaningful. The coefficient of variation was 1.15% and 1.10% in Orbscan IIz and UBM, respectively. A negative correlation between anterior chamber depth and spherical equivalent refraction was noted within the range of -5.50 to +3.00 diopters.

CONCLUSIONS

The mean anterior chamber depth of Orbscan IIz was 0.087 mm less than that of UBM. Both methods were precise. Orbscan IIz seems to be a useful and more convenient method to measure anterior chamber depth for phakic intraocular lens implantation.

Visian Collamer Phakic Intraocular Lens in High Myopic Asian Eyes

PURPOSE

To evaluate the safety and efficacy of the Implantable Collamer Lens (Visian), a phakic intraocular lens (PIOL), in the correction of high myopia in Asian eyes.

METHODS

This prospective study comprised 61 eyes in 40 Chinese patients with mean preoperative manifest spherical equivalent refraction of -14.54 +/- 3.61 diopters (D) (range: -7.00 to -24.75 D) who underwent Visian PIOL implantation from May 2002 to December 2004. The anatomical differences between Asian and Caucasian eyes were compared.

RESULTS

Mean follow-up was 13.67 +/- 8.51 months (range: 1 to 32 months). Predictability of the manifest spherical equivalent refraction to within +/- 1.00 D was achieved in 88% of eyes and +/- 0.50 D in 72.5% of eyes. The mean postoperative manifest spherical equivalent refraction was -0.10 +/- 0.74 D, with 97% of eyes maintaining or gaining > or = 1 lines of best spectacle-corrected visual acuity (BSCVA). Two eyes lost 1 line of BSCVA. Retinal detachment developed in 1 eye 15 months after initial surgery. Because of the statistical differences in anterior chamber depth and white-to-white distance between Caucasian and Chinese eyes, the Visian PIOL size was more accurate if the calculation was modified so that 0.5 mm was added to the white-to-white measurement if the anterior chamber depth was < or = 3.0 mm and 1.0 mm to the white-to-white measurement if the anterior chamber depth was >3.0 mm. Initial incorrect sizing using the original nomogram led to the only cataract in our series.

CONCLUSIONS

The implantation of the Visian PIOL for correcting moderate to high myopia in Asian eyes shows similar safety and efficacy to the FDA clinical trial of Caucasian eyes. Proper sizing of the Visian PIOL is important and differs slightly in Asian eyes.

Refractive surgery for high bilateral myopia in children with neurobehavioral disorders: 2. Laser-assisted subepithelial keratectomy (LASEK)

INTRODUCTION

A subpopulation of children with high myopia and neurobehavioral disorders is noncompliant with spectacle wear and ill-suited to correction using contact lenses. We report the results of refractive surgery in a series of these children treated bilaterally using excimer laser technology.

METHODS

Clinical course and outcome data were collated prospectively in a group of 9 children (mean age, 10.2 years; range, 3-16 years) with neurobehavioral disorders exacerbated by chronic noncompliance with spectacle wear, causing profoundly low functional vision. Myopia in the 18 eyes ranged from -3.75 to -11.5 D (mean -16.6 D) and the desired refraction was approximately +1D. Correction was achieved by bilateral laser-assisted subepithelial keratectomy (ie, LASEK) performed under brief general anesthesia. Mean follow-up was 17 months (range, 6-36 months).

RESULTS

Myopia correction averaged 7.9 D. Eighty-nine percent (16/18 eyes) were corrected to within +/-1 D of goal refraction. Uncorrected acuity improved postoperatively in all 18 eyes, with commensurate gains in behavior and environmental visual interaction in 88% (15/17 children). Myopic regression averaged approximately 0.8 d/year. the only complication encountered was mild (1+) corneal haze in 35% of treated eyes.

DISCUSSION/CONCLUSIONS

Bilateral excimer laser surgery is effective for improving functional vision substantially in highly myopic, neurobehaviorally impaired children who have difficulties wearing glasses. Myopic regression is common. Further study is indicated to determine the long-term safety of these and alternative refractive procedures in similar pediatric populations.

Refractive surgery for high bilateral myopia in children with neurobehavioral disorders: 1. Clear lens extraction and refractive lens exchange

INTRODUCTION

A subpopulation of children with high myopia and neurobehavioral disorders is noncompliant with spectacle wear and ill-suited to correction using contact lenses. We report the results of refractive surgery in a series of these children treated using lensectomy alone (clear lens extraction), or lensectomy with simultaneous implantation of an intraocular lens (refractive lens exchange).

METHODS

Clinical course and outcome data were collated prospectively in a group of 13 children (mean age 10.4 years, range 1 to 18 years) with neurobehavioral disorders exacerbated by chronic noncompliance with spectacle wear, causing profoundly low functional vision. Myopia in the 26 eyes ranged from -14.25 to -26.00 D (mean -19.1 D). Goal refraction was approximately +1 D. Correction was achieved by lensectomy alone in 10 eyes, and lensectomy with intraocular lens implantation in 16 eyes. Primary posterior capsulectomy/subtotal vitrectomy was performed during the primary procedure in 11 eyes (42%). Mean follow-up was 4.5 years (range 1.3 to 7.5 years).

RESULTS

Myopia correction averaged 19.9 D. Eighty-one percent (21 eyes) were corrected to within +/-2 D of goal refraction and the remaining 19% (5 eyes) to within +/-4 D. Uncorrected acuity improved substantially (ie, an average 2 log units) in all 26 eyes, with commensurate gains in behavior and environmental visual interaction in 85% [corrected] of children (11/13) [corrected] Myopic regression averaged -0.16 D/year. Capsular regrowth and/or opacification necessitated vitrector or YAG-laser membranectomy in 13 [corrected] eyes (50%) [corrected] Focal retinal detachment (successfully repaired) occurred after eye contusion in one eye (4%) with cicatricial retinopathy of prematurity.

CONCLUSIONS

Bilateral refractive lensectomy is effective for improving functional vision in neurobehaviorally impaired children who have high myopia (beyond the range of excimer laser correction: see companion publication) and difficulties wearing glasses. Posterior capsule regrowth/opacification is common, necessitating secondary membranectomy. Further study is indicated to determine the long-term safety of this procedure in similar pediatric populations.

Cataractous Changes due to Posterior Chamber Flattening with a Posterior Chamber Phakic Intraocular Lens Secondary to the Administration of Pilocarpine

OBJECTIVE

To present the first reported case of cataract formation as a consequence of instillation of pilocarpine in an eye with a posterior chamber phakic intraocular lens (IOL).

DESIGN

Interventional case report.

INTERVENTION

A 46-year-old man received a hyperopic implantable collamer lens (ICL) bilaterally.

MAIN OUTCOME MEASURES

Determination of best-corrected visual acuity (BCVA); contrast sensitivity testing with and without glare; and intraocular pressure (IOP), specular endothelial cell, and slit-lamp examinations were performed serially. In addition, the distance between the ICL and crystalline lens was measured with optical coherence tomography.

RESULTS

Both eyes underwent uneventful ICL implantation for the correction of a manifest spherical equivalent of +7 diopters (D) in the right eye and +7.1 D in the left eye. The left eye was followed for 2 years without developing complications. The right eye, however, showed on the first postoperative day a fleckenlike opacification on the anterior pole of the crystalline lens after instillation on the operative day of 2% pilocarpine in an attempt to accelerate recovery from unwanted pupil dilation causing patient complaints of glare disability after surgery. Optical coherence tomography demonstrated complete contact of the ICL with the natural lens 24 hours postoperatively. Serial IOP measurements were always within the normal limits. The instillation of 1% cyclopentolate resulted in an increase in the ICL vault that measured 132 mum 24 hours later. Three days after the completion of a 3-day course of topical 1% cyclopentolate, the opacification was less dense and demarcated, and a 124-mum vault was measured. Three months postoperatively, the cataract was associated with a 3-line loss of BCVA and considerable degradation of the contrast sensitivity, especially at higher spatial frequencies and with a glare source, and corneal endothelial cell changes were within normal limits. One year after ICL implantation, the right eye had to undergo phacoemulsification and IOL implantation, which were uneventful.

CONCLUSIONS

Posterior chamber flattening with resulting crystalline lens opacification can occur immediately after the instillation of pilocarpine in an eye with a hyperopic ICL. Therefore, caution should be taken with the administration of cholinergic agonists such as pilocarpine in patients with phakic IOLs, at least if they are hyperopic ICLs.

Visual improvement in high myopic amblyopic adult eyes following phakic anterior chamber intraocular lens implantation

PURPOSE

To evaluate the efficacy and safety of angle-supported phakic anterior chamber intraocular lenses in amblyopic adult eyes with very high myopia.

METHODS

We evaluated 12 eyes in nine patients with very high myopic amblyopia who received angle-supported phakic intraocular lenses (Phakic 6H) and followed them for more than six months. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and complications were evaluated. A satisfaction score was rated by patients using a 5-point (1-5) numeric scale.

RESULTS

The mean age of patients was 37.3 +/- 9.4 years, ranging from 29 to 59 years old. The preoperative mean refraction (spherical equivalent, SE) was -20.10 +/- 5.41 diopters (D). The postoperative mean refraction (SE) was -1.75 +/- 0.76 D at six months. The postoperative BCVA improved an average 3.92 +/- 1.24 lines over preoperative values, and mean endothelial cell loss was 8.9% at six months. Development of cataracts, glaucoma, and pupil abnormalities were not demonstrated in any case during the study. The patients were all very satisfied, as the average satisfaction score was 4.3.

CONCLUSIONS

This study indicates that angle-supported phakic anterior chamber intraocular lens implantation may be an effective surgical alternative for the correction of amblyopic adult eyes with very high myopia. However, long-term evaluation is necessary to assess possible complications and long-term safety.

Age-related behavior of posterior chamber lenses in myopic phakic eyes during accommodation measured by anterior segment partial coherence interferometry

PURPOSE

To evaluate age-related position shifts of the crystalline lens and the implantable contact lens (ICL, Staar Surgical) by a new, commercially available, anterior segment partial coherence interferometer, the ACMaster (Carl Zeiss Meditec), during accommodation in myopic eyes.

SETTING

ALZ Augenklinik, Munich, Germany.

METHODS

Fifty-three eyes of 29 consecutive patients were measured after myopic ICL implantation before and during subjective accommodation to a stimulus of 3 diopters (D) by anterior segment partial coherence interferometry (PCI). Nine eyes were also measured with a 5.00 diopters (D) stimulus; 14 eyes were measured repeatedly at different visits. The mean patient age was 33 years +/- 9 (SD) (range 21 to 59 years). The preoperative mean sphere was -7.6 +/- 1.9 D (range -5.0 to -11.5 D) and the cylinder, -1.4 +/- 1.1 D (range 0 to -4.25 D).

RESULTS

Older patients had a tendency toward smaller vaults on desaccommodation between the ICL and the crystalline lens compared to younger individuals. In younger patients, there was a decrease of the vault on accommodation, whereas it increased in older persons (P = .005). During accommodation, the more the anterior lens surface shifted forward, the more the ICL bulged (P = .005). The change in vaulting was significantly larger at 5.00 D than at 3.00 D accommodation stimulus (P = .012).

CONCLUSIONS

The behavior of ICLs in relation to the crystalline lens during accommodation varied with age and could be shown by PCI. The position shift of the ICL depended on the initial vault at desaccommodation and the ability of the anterior lens surface to bulge forward. Even though the crystalline lens stiffened, and therefore accommodation deteriorated with age, there was still a movement of the ICL, pointing to the role of the ciliary muscle movement in accommodation.

Decentration and Cataract Formation 10 Years Following Posterior Chamber Silicone Phakic Intraocular Lens Implantation

PURPOSE

To report a 10-year follow-up for bilateral implantation of a Chiron Adatomed silicone posterior chamber phakic intraocular lens (PIOL).

METHODS

A 32-year-old man presented with bilateral blurred vision and monocular diplopia in the left eye of 2 years' duration.

RESULTS

Slit-lamp microscopy showed bilateral anterior subcapsular cataract and temporal PIOL decentration, and no visible space between the PIOL and crystalline lens in the right eye. After explantation of the posterior chamber PIOL, lens aspiration, and IOL implantation, uncorrected visual acuity improved to 20/15 in the right eye. Scanning electron microscopy examination showed denser deposits on the central portion of the back surface when compared with the edges.

CONCLUSIONS

Long-term follow up of certain designs of posterior chamber PIOLs may reveal late occurrence of complications. Cataract formation may be related to direct contact between the implanted and crystalline lenses.

Phakic intraocular lenses

PURPOSE OF REVIEW

Laser in-situ keratomileusis has been tremendously successful in treating patients with mild and moderate ametropias. For patients with high degrees of refractive error, however, phakic intraocular lenses provide superior quality of vision without the risk of corneal ectasia. Early international results, as well as United States Food and Drug Administration clinical trials, have demonstrated the early safety and efficacy of phakic intraocular lenses. Nevertheless, long-term corneal endothelium cell density and crystalline lens clarity remain a concern.

RECENT FINDINGS

Several new studies demonstrate the superior visual outcomes of phakic intraocular lenses over laser in-situ keratomileusis in patients with moderate and high myopia, particularly in the areas of visual quality and contrast sensitivity. New anterior segment imaging and measurement technologies have provided valuable information about in-vivo structure and function, with and without phakic lens implants. More is being learned about long-term endothelial cell stability and cataract formation, particularly in relation to implant positioning. New applications of phakic intraocular lenses in presbyopia and in other conditions are being explored.

SUMMARY

Once plagued by complications and marginal outcomes, improved designs of phakic intraocular lenses are providing increasing safety and efficacy for the correction of severe ametropias. Long-term concerns with endothelial cell loss remain, but recent data suggest stabilization with time. Proper sizing and positioning are important and increasingly achievable with new imaging modalities. With continued research and experience, phakic intraocular lenses are becoming an invaluable addition to the mainstream refractive surgery armamentarium.