Piggyback Intraocular Lens Research Articles

Interlenticular opacification of piggyback acrylic intraocular lenses

A dense interlenticular opacification developed 18 months after cataract surgery in a hyperopic patient with 2 acrylic piggyback intraocular lenses (IOLs) placed in the capsular bag. The patient developed a hyperopic shift with decreased vision, requiring explantation of the lenses. The dense interlenticular opacification did not allow separation of the lenses intraoperatively because of the tight adherence of the 2 IOLs.

Post cataract-intraocular lens (IOL) surgery opacification.

Intraocular lens (IOL) implantation has no doubt been one of the most satisfying advances of medicine. Millions of individuals with visual disability or frank blindness from cataracts had and continue to have benefit from this procedure. It has been reported by ophthalmologists that the modern cataract-intraocular lens (IOL) surgery is safe and complication-free most of the time. This makes the watchword for any cataract surgeon to be 'implantation,' 'implantation,' 'implantation.' In the mid-1980s, as IOLs were evolving rapidly, the watchword of the implant surgeon was 'fixation,' 'fixation,' 'fixation.' Most techniques, lenses and surgical adjuncts now allow us to achieve the basic requirement for successful IOL implantation, namely long-term stable IOL fixation in the capsular bag. However despite this advancement some items 'slipped through cracks.' In this article, we would like to alert the reader to a new watchword, namely 'opacification,' 'opacification,' 'opacification.' Here we will be talking about the good, the bad, and the ugly. Examples of the 'good' include the recent successes now being achieved in reducing the incidence of posterior capsule opacification. Examples of the 'bad' include various proliferations of anterior capsule cells, problems caused by silicone oil adherence to IOLs and problems with piggyback IOLs. The 'ugly' include the sometimes striking and often visually disabling opacifications occurring on and within IOL optics, both on some modern foldable IOLs as well as a poly(methyl methacrylate) (PMMA) optic degradation occurring with some models a decade or more after implantation.

Analysis of elements of interlenticular opacification

PURPOSE: To report the histopathologic and ultrastructural features of three cases of interlenticular opacification (ILO) between piggyback intraocular lenses. DESIGN: Interventional case series with clinicopathologic correlation. METHODS: Three pairs of acrylic piggyback lenses were explanted due to decrease in visual acuity associated with ILO. Lenses were evaluated with gross and light microscopic examinations in all cases. The anterior lens in one case was examined with scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: The material opacifying the interlenticular space was composed mostly of retained/regenerative cortical material in all cases. From the peripheral interface towards the central interface, the opacifying material changed as the interlenticular space was progressively narrower. The material attached to the peripheral interface, where the interlenticular space was wider, was very thick. At the midperipheral interface, the thick cortical material was broken into multiple globules due to liquefactive degeneration. At the paracentral zone, compression of the globules formed a flat, compact layer of an amorphous material. At the central interface (contact zone), almost no material could be found between the piggyback lenses. CONCLUSIONS: Analyses of ILO cases where all the components of the opacifying material were in situ allowed us to confirm that the pathogenesis of this complication is similar to that of posterior capsule opacification; thus, careful removal of lens epithelial cells and cortical material is mandatory in piggyback implantation.

Managing anterior capsule contraction by mechanical widening with vitrector-cut capsulotomy

We present a technique, vitrectorhexis, in which a vitrector-cut capsulotomy is used to treat anterior capsule contraction syndrome. A vitrector handpiece is used to remove all fibrous capsule tissue and residual lens epithelial cells from the anterior chamber. Vitrectorhexis may be an alternative to neodymium:YAG laser capsulotomy as it decreases the risk of radial tear extension to the zonules and of secondary IOL decentration. The technique was used in a 77-year-old man with capsulorhexis contraction syndrome and extensive fibrosis after phacoemulsification with silicone piggyback intraocular lens implantation. One day postoperatively, visual acuity improved from 20/60 to 20/30 and the anterior chamber reaction was minimal. At 1 month, best corrected visual acuity was 20/20. The IOL was well centered at 6 months.

Correction of pseudophakic anisometropia with the Staar Collamer implantable contact lens

Purpose: To assess the role of the Staar Surgical implantable contact lens (ICL) for the correction of pseudophakic anisometropia. Setting: Oxford Eye Hospital, Oxford, and Rosen Eye Center, Alexandra Hospital, Manchester, United Kingdom. Methods: Six patients with pseudophakic anisometropia ranging from 2.0 to 7.9 diopters (D) (mean 4.4 D) had ICL implantation as an alternative to intraocular lens (IOL) exchange or conventional piggyback IOLs. Results: All patients had a reduction in anisometropia to asymptomatic levels. The mean reduction was 3.15 D. No patient experienced adverse effects. Conclusions: The implantable contact lens offers an alternative approach to the management of pseudophakic anisometropia that avoids some of the risks associated with IOL exchange, corneal refractive surgery, and conventional piggyback IOLs.

Piggyback implantation using the AMO Array multifocal intraocular lens

Piggyback intraocular lens (IOL) implantation allows refractive correction in cases in which the IOL power requirement exceeds that of the available lenses. By combining a piggyback technique with the use of a multifocal IOL, one can obtain the optical advantages of both, achieving high-quality visual acuity for distance and near vision and reducing the optical aberrations of extremely high-powered single IOLs. We report 5 hyperopic patients (6 eyes) who had phacoemulsification and in-the-bag implantation of 2 foldable IOLs in the bag, a silicone multifocal IOL placed in front of a silicone monofocal IOL. Good results were obtained in near and distance uncorrected visual acuities, and patient satisfaction was excellent in all cases. However, in 2 cases, the anteriorly placed IOL was exchanged because of incorrect power calculation. Piggyback IOL implantation with a multifocal lens appears to be a safe, efficient procedure and a good refractive solution.

Pseudophakia and polypseudophakia in the first year of life

Purpose: To report a consecutive series of patients undergoing intraocular lens (IOL) implantation in the first year of life. A new procedure, referred to as temporary polypseudophakia, is reported. Methods: A retrospective chart analysis was conducted. Ocular growth and refractive change, complications and reoperation rates, and outcomes were analyzed. Results: Forty-seven eyes of 33 patients underwent IOL implantation in the first year of life. Average follow-up was 22 months (range, 7 weeks to 5 years). Thirty-two eyes of 22 patients had a single IOL implanted from 12 days to 11 months of age. Fifteen eyes of 11 infants received piggyback IOLs from 16 days to 6.8 months of age. Reoperation for complications within the anterior segment of the eye was needed in 23% of all patients (22% for single IOLs, 26% for piggyback IOLs). The average first postoperative refraction after single IOL was +7.98 D and after piggyback IOL was +1.67 D. The average last postoperative refraction was +1.76 D and −4.48 D, respectively. On average, eyes grew 2.68 mm over 17.5 months of follow-up. Eight patients were old enough for Snellen visual acuity, but each had deprivation amblyopia with visual acuities from 20/85 to 5/200. Of the remaining 25 patients, 17 had central, steady, and maintained fixation in the implanted eyes. Conclusion: IOL implantation in infancy is technically feasible and associated with a reoperation rate of approximately 25% in the first 2 years after implantation. Further follow-up is required before meaningful visual acuity data and long-term results can be reported. (J AAPOS 2001;5:238-45)

Intraocular lens power calculations using corneal topography after photorefractive keratectomy

PURPOSE: To report two patients (two eyes) with previous photorefractive keratectomy, who subsequently underwent cataract extraction years later. DESIGN: Case reports. METHODS: Corneal topography was used to determine corneal power used in intraocular lens power calculations. RESULTS: In two eyes of two patients, intraocular lens calculations after photorefractive keratectomy were inadequate, which resulted in a hyperopic postoperative refractive error requiring implantation of a piggyback intraocular lens. CONCLUSION: Corneal topography to determine corneal power in patients with previous photorefractive keratectomy may result in unpredictable intraocular lens power calculations. The clinical history method is the standard to determine corneal power and should be considered in intraocular lens calculations before cataract surgery. We recommend supplying refractive patients with preoperative data for use in future formulas for intraocular lens selection.

Interlenticular opacification in piggyback AcrySof intraocular lenses: explantation technique and laboratory investigations

BACKGROUND/AIMSInterlenticular opacification (ILO) is a recognised complication of piggyback intraocular lenses (IOLs). The aetiology, histopathology, and treatment are not clearly defined, however.METHODSTwo pairs of AcrySof IOLs were explanted from a...

Piggyback foldable intraocular lens implantation in patients with microphthalmos

Purpose To evaluate the clinical results of phacoemulsification and implantation of 2 foldable acrylic intraocular lenses (IOLs) in microphthalmic eyes. Setting University of Tokyo School of Medicine, Tokyo, Eguchi Eye Hospital, Hakodate, and Osaka Rosai Hospital, Osaka, Japan. Methods This study comprised 5 eyes of 3 patients whose manifest spherical equivalent was +10.5 to +18.0 diopters (D) and axial length was 15.79 to 16.82 mm. After phacoemulsification, 2 foldable acrylic IOLs with a mean power of +43.0 D ± 9.5 (SD) (range +32.0 to +55.0 D) were implanted in the capsular bag. Results There were no significant intraoperative complications, and there was significant improvement in uncorrected and best corrected visual acuities after surgery. The spherical equivalent decreased significantly; however, the postoperative refraction was considerably more hyperopic than predicted in all eyes. Except for posterior synechias in 2 eyes and slight interlenticular opacification in 2 eyes, no major postoperative complications occurred during the mean follow-up of 14.8 months. Conclusion Implanting 2 piggyback IOLs was beneficial in eyes with an extremely short axial length. However, the current system of lens power calculation markedly underestimates the required lens power, resulting in a hyperopic refractive error after surgery. The benefits of in-the-bag placement of 2 foldable lenses are questionable.

Morphological appearance and size of contact zones of piggyback intraocular lenses

Purpose To characterize the morphology, size, and change in size of the contact zone of piggyback intraocular lenses (IOLs) of different materials and optic designs. Setting Department of Ophthalmology, Vienna General Hospital, Vienna, Austria. Methods In a prospective study, 9 eyes of 7 patients received piggyback IOLs of the following materials: poly(methyl methacrylate) (PMMA), acrylic, hydrogel, and silicone. The contact zone between the anterior and posterior IOLs was photodocumented from 1 day to 1 year after surgery using specular microscopy. The contact zone area was measured. Results A contact zone was present with all IOL materials studied. The area of contact, however, differed significantly. With PMMA IOLs, the contact zone was small and surrounded by Newton rings, indicating the tiny gap between the IOLs. With IOLs of soft material, such as silicone and hydrogel, it was larger than with PMMA IOLs and had a slightly irregular shape. With foldable acrylic IOLs, it was regular, round, and slightly larger than with the soft materials. The contact area enlarged primarily during the first 3 months after surgery. After 1 year, 2 eyes with acrylic piggyback IOLs had a membrane formation around the contact zone and 2 eyes developed Elschnig pearls between the IOLs. Conclusion In piggyback IOL eyes, the shape and size of the contact zone were strongly dependent on the IOL material and optic design. Contact area enlargement seemed to be induced by capsule shrinkage. Fibrous membrane formation around the contact zone and Elschnig pearl formation between the piggyback IOLs were long-term complications of this technique.

Opacification of piggyback IOLs associated with an amorphous material attached to interlenticular surfaces

Purpose To report the pathological and ultrastructural features and interval surgical management of an atypical case of opacification between piggyback intraocular lenses (IOLs). Setting Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and Nature Coast EyeCare Institute and Surgery Center, Perry, Florida, USA. Methods Opacification between 2 acrylic piggyback lenses was observed 16 months after implantation, with decreased best corrected visual acuity and a hyperopic shift. Elschnig pearls were observed in the peripheral interface between the lenses, and the central interface was occupied by an amorphous material. The pearls were surgically aspirated, but attempts to remove the central material were unsuccessful. The lenses were explanted and sent to the laboratory. Staining with hematoxylin and eosin (H&E), examination under a light microscope, and scanning electron microscopic analysis were performed. Results The surfaces of the anterior IOL were relatively clear. The amorphous material, mostly attached to the center of the anterior surface of the posterior IOL, was homogeneously stained with H&E. No cell nucleus was observed in this region. Scanning electron microscopy showed that the IOL edge presented a smooth, regular surface relatively free of deposits. The most central region was covered by an irregular layer of an amorphous compact material with some cracks, fissures, or both on its surface. Conclusions Although the exact composition of the material between the lenses could not be established, hypotheses were advanced to understand the pathological mechanism associated with this condition. This case is different from those in previous reports of opacification composed of cortex and cells between piggyback IOLs.

Interpseudophakos intraocular lens surface opacification as a late complication of piggyback acrylic posterior chamber lens implantation

We present a case involving opacification of the apposing surfaces of 2 acrylic intraocular lenses (IOLs) that had been implanted in a piggyback fashion 16 months previously. Clinical observations derived from our experience with piggyback acrylic lens implantation are presented, along with a discussion of late complications of piggyback IOL implantation and recommendations.

Transscleral suture fixation of posterior chamber intraocular lenses in children under 3 years

Children who have undergone lentectomy for congenital or traumatic cataract do not have adequate capsular support for secondary posterior chamber intraocular lens (PC-IOL) implantation and thus will become severely amblyopic if contact lens intolerance occurs. In order to prevent amblyopia we fixed PC-IOLs by transscleral sutures in three children younger than 3 years. Clinical outcome, visual acuity and course of refraction were studied. Four eyes of three children with contact lens intolerance were operated. Posterior chamber lenses (PC-IOL) were sutured in the ciliary sulcus by transscleral sutures. Two children had monocular traumatic cataract and one child underwent surgery on both eyes for congenital cataract. To allow adjustment of refraction in situ without removing the primarily implanted and transsclerally fixed PC-IOL we used the piggyback intraocular lens system for implantation. Visual acuity improved in all four eyes. The two children with traumatic cataract achieved visual acuity of 0.7 and 1.0, respectively, and stereopsis. No complications related to the technique of transscleral suture fixation of the PC-IOL were observed. Postoperative changes in refractive power were caused by a myopic shift between -1.0 D and -9.0 D. Follow-up was 25-70 months. Transscleral suture fixation of PC-IOLs did not cause specific complications during follow-up of up to 70 months. This technique offers an important option for the correction of an aphakic refractive error which cannot be corrected otherwise. In future the piggyback intraocular lens system may help to rather atraumatically correct postoperative changes in refractive power.

Piggyback posterior chamber multifocal intraocular lenses in anisometropia

A 63-year-old white man with anisometropic hyperopia presented with cataract in both eyes. He had uneventful temporal limbal phacoemulsification with intracapsular placement of a multifocal 3-piece silicone intraocular lens (IOL) in his right eye (model SA-40N, Allergan, Inc.). One week later, 2 intracapsular 3-piece silicone IOLs (1 monofocal backward, Allergan model SI-40NB; 1 multifocal in front, Allergan model SA-40N) were implanted in his left eye. At 8 days postoperatively, uncorrected visual acuity was 20/20 for distance and J1 for near vision in the right eye and 20/30 and J2, respectively, in the left. These values remained constant until the patient was seen 7 months postoperatively. Power calculation and insertion order of the piggyback IOLs were considered.

Refractive lensectomy to correct ametropia

Purpose To assess the postoperative outcome of refractive lensectomy for ametropia. Setting Pacific Eye Center, Brisbane, Australia. Methods One hundred thirty-eight cases of refractive lensectomy performed from September 1994 to September 1997 by 1 surgeon were analyzed retrospectively. Preoperative refractive spherical equivalent (SE) ranged from –0.25 to –23.75 diopters (D) in the myopic group and from +0.25 to +11.62 D in the hyperopic group. In all cases with a low SE, the astigmatism was greater than −2.00 D. Eyes were divided into 6 groups by the preoperative SE. Results Overall, 90.0% of eyes achieved an uncorrected visual acuity of 20/40 or better; 81.2% achieved 20/30 or better. Postoperative SE was within ±2.0 D of emmetropia in 93.5% of eyes and within ±1.0 D in 78.3%. The postoperative incidence of retinal detachment was 0.7%; intraocular lens (IOL) exchange, 2.8%; late uveitis, 0.7%; piggyback IOL, 2.1%; and neodymium:YAG capsulotomy, 8.0%. No cystoid macular edema, capsule tear, or endophthalmitis was seen. Conclusion Refractive lensectomy can achieve excellent visual acuity and refractive outcomes with few complications. The surgery can be considered in selected patients with myopia, hyperopia, and astigmatism and to correct residual ametropia after refractive surgery.

Refractive aspects of cataract surgery.

The refractive aspects of cataract or lens surgery has formed a new field of operations. To reduce astigmatism and high myopia, surgeons are looking into alternatives and using various incision techniques as well as phakic intraocular lenses or clear lens extraction to achieve emmetropia. High hyperopia with short axial length and high required intraocular lens power are corrected by piggyback intraocular lens implantation. The use of multifocal intraocular lenses compensates for the loss of accommodation after lens extraction.

Standardizing constants for ultrasonic biometry, keratometry, and intraocular lens power calculations

Purpose: To provide a method and values that facilitate standardization of constants for ultrasonic biometry, keratometry, and intraocular lens (IOL) power calculations.Setting: University of Texas Medical School, Houston, Texas, USA.Methods: Keratometry and ultrasonic biometry provide the two measured input variables for the six variable vergence equations used to calculate the appropriate IOL power for a specific patient with a cataract. A review of the literature reflecting the past 156 years of research and development reveals the appropriate index of refraction to be used with the keratometer for net optical corneal power, the location of the principal planes of the cornea, the nominal value for retinal thickness, and the appropriate velocities for ultrasonic measurement of the axial length. The relationship of the thick IOL to the thin IOL is derived along with the physical location of the thick lens. Two methods are described that provide the best IOL constant to be used by a manufacturer to minimize the prediction error for a surgeon using the lens for the first time. The formulas for phakic IOLs and secondary piggyback IOLs are also derived and applied to methods described above for standard IOLs.Results: Using a standardized net index of refraction of 4/3 for the cornea eliminates a variability of 0.56 diopter (D) in the predicted refraction. Using a standardized 1532 m/s velocity for axial length measurements and adding a value of 0.28 mm reduces the tolerance of axial length measurements to ±0.03 mm for any length eye. The physical location of the thick IOL's secondary principal plane must be anterior to the thin lens equivalent by approximately the separation of the principal planes of the thick lens. For biconvex poly(methyl methacrylate) IOLs, the separation in the principal planes is approximately 0.10 mm. Using these relationships, the physical position of the thick lens within the eye can be used to confirm the lens constant for any IOL style.Conclusions: Standardizing the constants for keratometry, ultrasonic biometry, and IOL power calculations can significantly improve the predictability of refractive outcomes. Back-calculating and physically measuring the position of the lens within the eye can provide surgeons with an initial lens constant known to have a standard error of the mean of ±0.05 mm (±0.10 D). Other parameters such as the cardinal points of a lens, the shape factor, the lens-haptic plane, and the center lens thickness would allow further refinement of IOL power calculations.

Piggyback intraocular lens with exchangeable optic

The exchange of a posterior chamber intraocular lens (IOL) is difficult if the lens is transsclerally or iris fixated or if a large posterior capsulotomy exists. A piggyback IOL system was developed that allows adjustment of refraction in situ without removing the primarily implanted IOL. The system comprises a posterior chamber IOL and a separate, exchangeable optic. Three succeeding designs were implanted in human donor eyes. The piggyback system's optical performance exceeded the requirements for conventional posterior chamber IOLs. Thus, the lens could be used in eyes in which postoperative refraction is likely to change or is incorrect (e.g., in children or cases of combined cataract extraction and corneal implantation).