Phakic anterior chamber lenses for the correction of myopia: a 7-year cumulative analysis of complications in 263 cases

Pupillary block after phakic anterior chamber intraocular lens implantation

A 49-year-old patient developed pupillary block glaucoma with an intraocular pressure (IOP) of 29 mm hg after implantation of a phakic intraocular lens (IOL) (NuVita, Bausch & Lomb) in the left eye. the anterior chamber deepened again, and the iop decreased to 16 mm hg after a neodymium: YAG iridotomy. Pupillary block glaucoma may occur after phakic IOL implantation without iridotomy, and we advocate that routine iridotomy be performed during phakic IOL surgeries.

Retinal pathology occurring after excimer laser surgery or phakic intraocular lens implantation: evaluation of possible relationship

The increasing number of patients undergoing refractive surgery has led to an awareness of the potential retinal complications of these procedures. The purpose of this review is to summarize the reports of retinal pathology and myopic maculopathy that have occurred after excimer refractive surgery or implantation of phakic intraocular lenses, and to evaluate theoretical pathogenetic mechanisms. We found it reasonable to conclude that retinal detachments and macular hemorrhages are not caused by laser surgery, but are rather characteristic of the natural history in the myopic eye. However, although there is no clear-cut evidence for a cause-and-effect relationship between excimer laser surgery and retinal pathology, it is very important to inform patients that refractive surgery only corrects the refractive aspect of myopia, and that the myopia itself still has the potential for serious complications.

Phakic intraocular lenses

Since Zaldivar's review of phakic intraocular lenses in these pages in 2000 [1**], further reports of experience with this technology have emerged. Their relative advantages and disadvantages over competing technologies are becoming clearer. Clinical trials, including Food & Drug Administration (FDA) trials, have shown predictability, stability, and efficacy. Safety of these implants over the long term remains a concern, but in some situations, at least, phakic intraocular lenses are becoming the refractive correction of choice. This brief review looks at the most recent data to emerge regarding phakic intraocular lenses.

Vitreous hemorrhage following phakic anterior chamber intraocular lens implantation in severe myopia

PURPOSE

To describe two cases of vitreous hemorrhage following phakic anterior chamber lens (AC-IOL) implantation in high myopia.

CASE REPORT

In case 1, hemorrhage developed one month after surgery, without retinal involvement, and visual acuity (VA) resulted 20/200 after pars-plana vitrectomy (PPV). In Case 2, vitreous hemorrhage was complicated by retinal detachment (RD). PPV and silicone oil injection were performed, with AC-IOL removal and cristalline lens extraction. After 2 years the retina was attached and VA was 20/80.

DISCUSSION

Only few cases of RD, posterior uveitis and endophthalmitis are reported following phakic AC-IOL implant. Vitreous hemorrhage could represent an additional posterior segment complication. Intraoperative manoeuvres, hypotony-induced posterior vitreous detachment and/or peripheral retina traction could play a role in engendering this complication in highly myopic eyes.

Iris-claw Phakic Intraocular Lens for High Myopia

PURPOSE

To evaluate the efficacy, safety, predictability, and stability of implanting a polymethylmethacrylate (PMMA) phakic intraocular lens (PIOL) (the Artisan myopia lens) to correct high myopia.

METHODS

An Artisan myopia lens was implanted in 78 consecutive eyes of 49 patients with preoperative myopia that ranged from -6.25 to -28.00 D. Mean patient age was 42.4 years. Mean follow-up was 10.7 months and all patients were followed for at least 6 months; 45 eyes had follow-up of 12 months, and 10 eyes had 24 months. The desired outcome was emmetropia in all eyes except for those eyes with preoperative myopia greater then -23.00 D.

RESULTS

Fifty-three eyes (67.9%) had a postoperative refraction at the last follow-up examination within +/-1.00 D of emmetropia, and 39 eyes (50.0%) had a postoperative refraction +/- within 0.50 D of emmetropia. The postoperative refraction remained stable during the entire follow-up period. Mean spectacle-corrected visual acuity improved from 20/32 preoperatively to 20/25 postoperatively. Mean postoperative uncorrected visual acuity was 20/32. There was no significant change in endothelial cell density from baseline. We did not encounter major complications.

CONCLUSION

Implantation of the Artisan myopia lens to correct high myopia resulted in a stable and fairly predictable refractive outcome. A significant endothelial cell change was not detected.

Ultrasound biomicroscopy of ZSAL-4 anterior chamber phakic intraocular lens for high myopia

PURPOSE

To evaluate the intraocular location and anatomic relationship to other structures of the ZSAL-4 angle-supported anterior chamber phakic intraocular lens (IOL) for high myopia using ultrasound biomicroscopy (UBM).

SETTING

Clínica de Nuestra Señora de la Concepción, Fundación Jiménez Díaz, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Madrid, Spain.

METHODS

Eight phakic myopic eyes corrected by ZSAL-4 angle-supported anterior chamber phakic IOLs were examined by UBM. The distance between the corneal endothelium and the IOL at the central and peripheral cornea and between the phakic IOL and the iris was measured.

RESULTS

The mean distance between the central cornea and the IOL was 2361.37 microm +/- 109.62 (SD); between the edge of the IOL optic and the endothelium, 1646.24 +/- 27.06 microm; and between the IOL and the iris, 354.46 +/- 41.61 microm. The IOL footplates appeared to be correctly positioned in the anterior chamber angle in all eyes.

CONCLUSION

The space between the IOL and the endothelium was greater in eyes with the ZSAL-4 angle-supported phakic IOL than in eyes with other angle-supported phakic IOLs. The possibility of intermittent contact between the IOL edge and the midperipheral cornea plays a minor role in the mechanism of endothelial damage with this lens model.

Relationships between vitreoretinal and refractive surgery

OBJECTIVE

To describe retinal complications after posterior chamber phakic intraocular lens (PCPIOL) implantation and refractive surgery complications after scleral buckling surgery.

DESIGN

Retrospective, noncomparative, small case series.

PARTICIPANTS

Four patients in whom retinal detachment developed after PCPIOL implantation and two patients with previously placed encircling scleral buckles in whom corneal steepening developed after laser in situ keratomileusis (LASIK).

INTERVENTION

The four patients with retinal detachment after PCPIOL implantation underwent vitreoretinal surgery. One of the two patients in whom corneal steepening developed after LASIK underwent buckle removal.

MAIN OUTCOME MEASURES

The main parameters evaluated were vitreoretinal findings, corneal topography, and pachymetry.

RESULTS

Retinal attachment was achieved for all patients. Mean postoperative best-corrected visual acuity (BCVA) was 20/30. One patient lost one line of BCVA. One patient with corneal steepening achieved partial corneal flattening after buckle removal.

CONCLUSIONS

Vitreous base stimulation related to PCPIOL implantation and manipulation during LASIK may trigger retinal complications. Laser in situ keratomileusis in patients with previously placed scleral buckles may result in unexpected corneal steepening.

The cornea in young myopic adults

AIMS

To further understand the effect of refractive error on the corneal dimensions and function.

METHODS

Corneal curvature, corneal thickness, and axial length measurements were performed, as well as specular microscopy and fluorophotometry, on patients with various refractive statuses. 216 subjects, mean age 22.2 (SD 4.2) years, were examined. Patients with previous contact lens wear history, external eye diseases, as well as previous ocular surgeries, were excluded.

RESULTS

The corneas were flatter in eyes with longer axial length (r = -0.22, p = 0.003). Eyes with more myopic spherical equivalent had longer axial length (r = -0.90, p <0.001) as well as less corneal endothelial density (r = 0.20, p = 0.037). Corneal endothelial density decreased in eyes with longer axial length (r = 0.24, p = 0.019); however, it correlated neither with corneal thickness (r = -0.06, p = 0.59) nor with corneal curvature (r = -0.07, p = 0.52). The corneas had a mean corneal thickness of 533 (SD 29) microm and were thinner in more myopic eyes (r = 0.16, p = 0.021). The corneas tended to be thinner in eyes with longer axial length. However, the correlation did not reach statistical significance (r = -0.11, p = 0.14). Besides, there was no significant correlation between the corneal thickness and the corneal curvature (r = -0.13, p = 0.093) and the endothelial permeability (r = 0.042, p = 0.69). The corneas with higher endothelial density had larger corneal transfer coefficient (r = 0.26, p = 0.024) and higher permeability to fluorescein molecules (r = 0.28, p = 0.014). Nevertheless, the corneal endothelial permeability did not correlate significantly with either the axial length (r = -0.18, p = 0.11) or the degree of myopia (r = 0.12, p = 0.26).

CONCLUSION

Changes in the anterior segments as the eyeball elongates in myopia progression included flatter corneal curvature, decreased corneal thickness, as well as decreased endothelial density. These factors should be considered in refractive surgery.

Reversal of Myopic Anisometropic Amblyopia With Phakic Intraocular Lens Implantation

PURPOSE

To report a case of reversal of myopic anisometropic amblyopia with phakic intraocular lens implantation.

METHODS

A 6-year-old boy with anisometropic amblyopia with spherical equivalent refraction of right eye: -14.00 -3.00 x 100 degrees, left eye: -0.50 -3.25 x 90 degrees, was treated for 2 years with occlusion to the left eye, with poor results. Refractive surgery was planned because of contact lens intolerance at age 8 years. A -15.00-D iris claw Artisan intraocular lens (IOL) was implanted.

RESULTS

Following surgery, treatment of the amblyopia and spectacle correction of -4.00 D cylinder at 85 degrees in the right eye and -3.50 D cylinder at 90 degrees in the left eye was necessary. Visual acuity 6 months after surgery was 20/25 in the right eye and 20/20 in the left eye, and has remained stable 18 months after surgery.

CONCLUSION

Myopic anisometropic amblyopia in an 8-year-old boy was treated successfully with implantation of an Artisan iris claw phakic anterior chamber IOL, combined with occlusion therapy, and resulted in reversal of amblyopia.

Clear lens phacoemulsification for correction of high myopia

PURPOSE

To assess phacoemulsification and posterior chamber intraocular lens (IOL) implantation as an effective, safe, and predictable technique for the correction of high myopia.

SETTING

University Eye Clinic of Verona, Verona, Italy.

METHODS

A series of 25 eyes with myopia higher than -12.0 diopters (D) had clear lens extraction by phacoemulsification and IOL implantation in the capsular bag. The mean postoperative follow-up was 42.92 months +/- 3.76 (SD).

RESULTS

No serious intraoperative complications occurred. Uncorrected visual acuity improved in all cases. The mean postoperative best corrected visual acuity improved by an average of 1 line. One case (4.0%) of postoperative retinal detachment (RD) occurred at 12 months. One case (4.0%) of biometric error (3.0 D) occurred.

CONCLUSION

Clear lens extraction by phacoemulsification and IOL implantation in a series of highly myopic eyes was effective and had an acceptable predictability and a low rate of complications. Careful evaluation of the retinal periphery by indirect ophthalmoscopy is recommended to avoid postoperative RD.

Pigmentary dispersion syndrome induced by a posterior chamber phakic refractive lens

PURPOSE

To report a case of bilateral pigmentary dispersion syndrome (PDS) induced by the implantation of posterior chamber phakic refractive lenses (PRLs).

METHOD

Case report.

RESULTS

Following bilateral implantation of posterior chamber phakic refractive lenses in 38-year-old woman, unilateral elevated intraocular pressure (IOP) developed within months that was attributable to pigment dispersion within the anterior chamber. Findings consistent with PDS included bilateral transillumination defects of the iris in areas contacting the anterior surface of the PRLs, pigment deposits on the anterior surface of the PRLs, Krukenberg spindles, and bilateral dense pigmentation of the trabecular meshwork. The patient's IOP is presently under control and she has not developed glaucomatous damage.

CONCLUSIONS

The development of PDS in this case demonstrates that posterior chamber phakic refractive lenses can make contact with the posterior iris and induce pigment dispersion syndrome in susceptible patients.

Safety of posterior chamber phakic intraocular lenses for the correction of high myopia: anterior segment changes after posterior chamber phakic intraocular lens implantation

OBJECTIVE

To assess the safety of posterior chamber phakic intraocular lens (PCPIOL) implantation in patients with high myopia.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty eyes of 10 patients were included.

INTERVENTION

Staar Collamer Implantable Contact Lens PCPIOLs were implanted for the correction of high myopia.

MAIN OUTCOME MEASURES

Intra- and postoperative complications were recorded. Specular microscopy, lens fluorophotometry, laser flare-meter, and ultrasound biomicroscopy were performed before surgery and at different stages of the follow-up period to evaluate endothelial cell density, crystalline lens transmittance, aqueous flare, and anatomic relations of the implanted lenses with the other structures of the anterior segment.

RESULTS

There were no intraoperative complications. One patient experienced pupillary entrapment by the lens in the immediate postoperative period, which was resolved without incident. Pigmentary dispersion or cataracts did not appear during the postoperative period. All the lenses remained correctly centered, and no patient reported night halos or glare. Anterior chamber depth showed a statistically significant reduction, between 9% and 12%. Central endothelial density was significantly decreased after surgery. The percentages of cell loss after 3, 6, 12, 18, and 24 months were 4.41%, 4.83%, 5.17%, 5.46%, and 6.57%, respectively. Aqueous flare increased by 49.19% in the first postoperative month in relation to preoperative values. Afterward, it decreased and then remained above preoperative values for the entire follow-up period (33.76% at month 3, 27.81% at month 6, 27.65% at month 12, 23.39% at month 18, and 27.27% at month 24). Crystalline lens transmittance decreased by 0.72% at month 3, by 1.44% at month 6, by 1.95% at month 12, by 2.25% at month 18, and by 2.24% at month 24. Finally, by ultrasound biomicroscopy it was observed that the PCPIOL and the crystalline lens were in contact on the peripheral level in 12 patients (60%) and in the center in another three patients (15%) during at least one checkup. In all the patients, contact between the PCPIOL and the posterior iris surface could be observed.

CONCLUSIONS

Posterior chamber phakic IOL implantation for the surgical correction of high myopia is a safe procedure with regard to immediate visual and refractive results. The short-term clinical benefit and lack of immediate surgical complications are impressive. However, the increase in flare, the endothelial cell loss, the decrease in crystalline lens transmittance, and the iris-PCPIOL and crystalline lens-PCPIOL contact are findings that suggest caution regarding the long-term safety of this lens implant.

Anterior chamber depth measured by two methods in myopic and hyperopic phakic IOL implant

AIM

To evaluate the accuracy and reliability of the optical versus ultrasonic measurement of anterior chamber depth (ACD) in a group of patients affected by high myopia or hyperopia, before phakic IOL implant.

METHODS

18 consecutive patients (34 eyes) were enrolled in this study, and asked to undergo phakic IOL implant to correct high myopia or hyperopia. The mean age was 29.5 (SD 3.4) years, the male/female ratio was 10/8. 13 patients (24 eyes) were myopic (mean myopia -16.17 (4.39) D, range -9 to -24 D), whereas five patients (10 eyes) were hyperopic (mean hyperopia 7.4 (2.01) D, range 5.5-11 D). For each patient, ACD was evaluated comparing an optical system (Orbscan topograph system) with a standard A-scan ultrasound system. To evaluate the reliability of the two methods, the average of three optical and 10 ultrasonic consecutive measurements were considered. Statistical analysis was performed by means linear regression.

RESULTS

The average difference between optical and ultrasound values was 0.17 (0.1) mm (4.68% (2.52%)). There was a constant underestimation of the ACD with the optical system compared with the ultrasound measurement, more evident in the hyperopic eyes (5.20% (1. 95%)) than in myopic ones (4.46% (2.72%)). The reliability of measurements, as showed by the standard deviation values, was higher in the optical system (0.03 (0.02)) than in the ultrasound (0.1 (0. 05)), with a statistical difference (p<0.001). The linear regression analysis between optical and ultrasound measurements was 0.8992 (p<0. 0001).

CONCLUSIONS

The optical measurement of ACD is an accurate and reliable technique in high myopic and hyperopic eyes. It gives a small underestimation of the ACD values, but it could be preferable to the ultrasound technique, because it demonstrates more repeatability and has the advantages of a non-contact technique.

Cataract surgery in highly myopic eyes corrected by phakic anterior chamber angle-supported lenses(1)

PURPOSE

To assess the incidence of cataract, potential causes of its development, and the outcome of cataract surgery after previous implantation of phakic angle-supported anterior chamber intraocular lenses (AC IOLs) in highly myopic patients.

SETTING

Instituto Oftalmológico de Alicante, Department of Refractive Surgery, Spain.

METHODS

Two hundred sixty-three highly myopic phakic eyes of 160 patients had implantation of a phakic AC IOL. Follow-up was up to 8 years (range 38.4 to 103.2 months). Eyes that subsequently developed cataract had cataract extraction and were studied during follow-up for clinical association to other preoperative or postoperative data. Cataract surgery was performed after phakic IOL explantation by phacoemulsification and posterior chamber IOL (PC IOL) implantation (Domilens-Chiron AL3).

RESULTS

Nuclear cataract developed in 9 cases (3.42%) a mean of 42.91 months +/- 17.7 (SD) after phakic AC IOL implantation. Final best spectacle-corrected visual acuity (BSCVA) was not significantly different from that after phakic AC IOL implantation (P =.25, paired Student t test). Mean endothelial cell loss after cataract surgery was 6.87% +/- 0.42% cells/mm(2). Age at implantation of older than 40 years and axial length greater than 30. 0 mm were the 2 factors significantly related to nuclear cataract development (r = 1.69 and 1.98, respectively; P <.05).

CONCLUSIONS

There is a potential risk of nuclear cataract development after phakic AC IOL implantation to correct high myopia in patients older than 40 years and with very high (greater than 30.0 mm) axial myopia. Phakic IOL explantation, phacoemulsification, and PC IOL implantation successfully resolved this complication. The benefits in terms of BSCVA and spherical equivalent obtained after phakic AC IOL implantation were preserved after cataract surgery.

Surgical correction of severe myopia with an angle-supported phakic intraocular lens

PURPOSE

To evaluate the effectiveness, predictability, and safety of a fourth-generation angle-supported anterior chamber phakic intraocular lens (IOL) in patients with severe myopia.

SETTING

Refractive Surgery and Cornea Unit, Alicante Institute of Ophthalmology, Miguel Hernández University School of Medicine, Alicante, Spain.

METHODS

In this prospective study, 23 eyes (16 patients) with a mean preoperative myopia of -19.56 diopters (D) +/- 1.76 (SD) (range -16.75 to -23.25 D) were implanted with the ZSAL-4 phakic IOL. Basic examinations were performed before and after surgery in all patients. Eighteen eyes were also studied by clinical specular microscopy, and the endothelium was analyzed for cell density, coefficient of variation in cell size, and hexagonality. The location of the IOL in the anterior chamber was evaluated in 10 eyes by A-scan biometry. To evaluate haptic geometry, a theoretical mechanical model was used. The follow-up was 24 months in all patients.

RESULTS

Uncorrected visual acuity was 20/40 or better in 13 eyes (56.0%) 12 months after surgery and in 14 eyes (60.8%) at 24 months. Best spectacle-corrected visual acuity improved 0.19 at 12 and 24 months (0.1 = 1 line) from preoperative values. The efficacy index was 1.12 at 24 months and the safety index, 1.45. The mean postoperative spherical equivalent was -0.65 +/- 0.65 D at 24 months. The postoperative spherical equivalent was within +/-1.00 D of emmetropia in 19 eyes (82.6%) at 12 and 24 months. The mean endothelial cell loss was 3.50% at 12 months and 4.18% at 24 months. The coefficient of variation in cell size decreased from 0.34 before surgery to 0.28 at 24 months after surgery. The IOL was located 0.79 +/- 0.24 mm in front of the crystalline lens. Postoperative complications included night halos in 6 eyes (26.1%) at 12 and 24 months and pupil ovalization in 4 eyes (17.4%). Intraocular lens rotation was observed in 10 eyes (43.5%) at 24 months. Two eyes (8. 7%) developed a slight inflammatory response during the first 6 months. Our mechanical model predicted that the compression forces against the angle structures were greater at the first footplate than at the second.

CONCLUSIONS

Implantation of the ZSAL-4 IOL in the anterior chamber of phakic eyes was effective and predictable in correcting severe myopia. However, the ZSAL-4 did not prevent pupil ovalization, IOL rotation, or low-grade postoperative uveitis. Improvements in haptic design following our mechanical model could decrease these haptic-related complications.

Phakic posterior chamber intraocular lens for the correction of anisometropia and treatment of amblyopia

PURPOSE

To assess the potential visual benefits of posterior chamber phakic intraocular lens implants in eyes of children with anisometropic amblyopia.

METHODS

In a prospective study, three girls 9, 14, and 18 years old with high anisometropia and deep amblyopia were included in this study. The phakic posterior chamber intraocular lens (ICL; STAAR Surgical AG, Nidau, Switzerland) was used to correct the anisometropia. This intraocular lens was inserted in the anterior chamber through a 3.0-mm temporal clear cornea incision and manipulated into the posterior chamber using an iris manipulator. A peripheral iridectomy was performed using the Ocutome Probe (Storz; Premiere, St. Louis, Missouri). Local therapy with corticosteroids and antibiotics were prescribed for 2 weeks, and patients were followed regularly for a period of 6 to 9 months.

RESULTS

In the three amblyopic eyes of the three patients, the preoperative best-corrected visual acuity of 6/30, 6/60, and 6/30 improved, to 6/7.5 (20/25), 6/30 (20/100), and 6/15 (20/50), respectively, 6 months after the surgery. Binocular functions with development of fusional abilities and stereopsis were observed in two of these patients after the intraocular lens implantation. In the third patient, the fusional abilities developed only after surgical correction of the exotropia. The intraocular pressure remained within normal limits, and there was no significant change in the corneal endothelial cell count during the period of follow-up. No major intraoperative or postoperative complications were observed, except for a temporary pigment dispersion.

CONCLUSIONS

Implantation of phakic posterior chamber intraocular lenses may be beneficial for the treatment of amblyopia in children with anisometropia. Although additional cases and long-term follow-up observations are necessary, it appears that amblyopia may be overcome by the use of posterior chamber phakic intraocular lens implants, even in eyes of children beyond the age generally considered to be responsive to anti-amblyopic treatment.

Advances in refractive surgery: 1975 to the present

PURPOSE

To review the major advances in the field of refractive surgery occurring over the past 25 years.

METHODS

Literature review.

RESULTS

The major developments in refractive surgery over the past 25 years are reviewed.

CONCLUSIONS

The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.

Phakic intraocular lenses: which to choose

Phakic intraocular lenses have been increasingly popular with refractive surgeons because of the good refractive results achieved and because there are few serious complications. The purpose of this review is to compare the different types of phakic intraocular lenses, regarding implant selection, surgical technique, refractive outcome, and anatomical evaluation. New uses of phakic intraocular lenses are also presented. Although phakic intraocular lenses have gone a long way, the quest for the ideal lens remains a challenge.

Scotopic measurement of normal pupils: Colvard versus Video Vision Analyzer infrared pupillometer

PURPOSE

To prospectively measure the scotopic pupil diameter in a normal population and to compare 2 infrared pupillometers for these measurements.

SETTING

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

METHODS

The Colvard infrared pupillometer was compared to the Video Vision Analyzer (VIVA) infrared pupillometer under scotopic light conditions in 33 participants (aged 19 to 55 years). Reliability was assessed by 2 independent examiners (E1, E2). Statistical analysis was performed using a comparison method by Bland and Altman.

RESULTS

Mean pupil diameter was 6.16 mm +/- 1.20 (SD) (range 3.20 to 9.00 mm) with all measurements taken under scotopic illumination. The mean scotopic pupil diameter was 6.08 +/- 1.16 mm (range 3.2 to 8.4 mm) with the Colvard pupillometer and 6.24 +/- 1.28 mm (3.5 to 9.0 mm) with the VIVA pupillometer. The mean differences between the Colvard and VIVA were -0.27 mm (E1) and -0.05 mm (E2). Limits of agreement ranged from 1.4 (Colvard) to 2.4 (VIVA). The coefficients of repeatability ranged from 0.7 (Colvard) to 1.1 (VIVA).

CONCLUSIONS

A mean scotopic pupil diameter of 6.15 mm with a maximal pupil size of 9.00 mm can be expected in a normal population; this should be considered in refractive corneal and refractive lens surgery. Measurements with the Colvard pupillometer were more reliable and precise than those with the VIVA pupillometer.

Scanning electron microscopic characteristics of phakic intraocular lenses

OBJECTIVE

To analyze the surface quality of new generation phakic intraocular lenses (IOLs).

DESIGN

Experimental materials study.

MATERIALS

Three different new generation phakic IOLs: angle-fixated anterior chamber lens Chiron Vision NuVita MA20 (polymethylmethacrylate [PMMAD, iris-fixated anterior chamber lens Ophtec Artisan Iris-Claw (PMMA), posterior chamber lens Staar ICM (polymer from porcine collagen and 2-hydroxyethyl methacrylate [HEMA]).

METHODS

Representative samples of three different phakic IOLs underwent surface and edge-finish examination with light microscopy (LM). The phakic IOLs were then examined by use of scanning electron microscopy (SEM), and particular attention was given to optic surface quality, edge finish, haptic, and optic/haptic junction.

RESULTS

In all IOLs the LM examination showed a smooth and homogeneous surface. No irregularities, particularly at the optic front and back surface, optic edge, haptic, and the optic/haptic junctions, were detected by SEM. One exception was a minor surface roughness at the claws of an Artisan iris-fixated anterior chamber IOL.

CONCLUSIONS

Phakic IOLs are implanted either in the anterior or posterior chamber of healthy eyes, and high standards for their surface quality are required. The evaluation of surface properties with LM and SEM did not reveal any defects that contraindicate the implantation of phakic IOLs.

Long-term Results of Correction of High Myopia With an Iris Claw Phakic Intraocular Lens

PURPOSE

Anterior chamber phakic intraocular lenses (PIOLs) are one of the modalities used to correct high myopia. We report the long-term results of our prospective study on the Artisan 5-mm optic myopia lens.

METHODS

We studied 67 eyes of 38 consecutive patients with preoperative myopia ranging from -5.38 to -28.00 D. All patients were operated by one surgeon. Mean follow-up was 35 months (24 months in 67 eyes and 36 months in 61 eyes).

RESULTS

In 45 eyes (67.2%), postoperative residual refraction was within +/- 1.00 D of emmetropia. The mean refraction was stable statistically during the entire follow-up period. Mean best spectacle-corrected visual acuity improved from 20/40 to 20/32. Mean endothelial cell loss at 6 months was 5.5% (range, -52.4% to +9.3%), at 12 months, 7.21% (range, -53.2% to +20.1%), at 24 months, 9.1% (range -43.6% to +13.6%), and at 36 months, 10.9% (range, -43.0O% to +11.4%). The majority of eyes had an increase in best spectacle-corrected visual acuity; 5 eyes lost best spectacle-corrected visual acuity. We encountered no major complications.

CONCLUSION

Implanting the Artisan 5-mm optic myopia lens in high myopic eyes resulted in a stable and accurate refractive outcome. The apparent progressive corneal endothelial cell loss remains a matter of concern.

The phakic intraocular lens implant: in-depth focus on posterior chamber phakic IOLs

Phakic Intraocular surgery has come a long way in the past 20 years, especially in the evolution of posterior chamber phakic intraocular lenses (PC PIOLs). Clinical trials worldwide are showing acceptable results concerning efficacy, predictability, stability, and safety. PC PIOLS are proving to be a promising option for patients with high and extreme ametropia who cannot benefit from conventional corneal refractive procedures. This article provides an in-depth examination of PC PIOLs, their origin and evolution, and the results of past and current clinical studies. Reports of historical importance and studies published since the 1990s in peer-reviewed journals, textbooks, and monthly eye magazines, as well as Food and Drug Administration preliminary clinical findings, are reviewed. Anterior chamber phakic intraocular lenses are mentioned briefly.

Endophthalmitis after phakic intraocular lens implantation to correct high myopia

A 36-year-old woman had uneventful implantation of an angle-supported anterior chamber phakic intraocular lens (IOL) to correct high myopia. On the first postoperative day, she developed infectious endophthalmitis likely associated with intraoperative contamination. Group B beta-hemolytic Streptococcus endophthalmitis was confirmed by microbiologic studies. To our knowledge, this is the first documented case of infectious endophthalmitis after anterior chamber phakic IOL implantation to correct high myopia.