Visually significant calcification of hydrogel intraocular lenses necessitating explantation

Clinical Characteristics of Patients with Intraocular Lens Calcification after Pars Plana Vitrectomy

AIM

To determine the clinical risk factors that may increase the occurrence of intraocular lens (IOL) calcification in patients who had undergone pars plana vitrectomy (PPV).

METHODS

The medical records of 14 patients who underwent IOL explantation due to clinically significant IOL opacification after PPV were reviewed. The date of primary cataract surgery, technique and implanted IOL characteristics; the time, cause and technique of PPV; tamponade used; additional surgeries; the time of IOL calcification and explantation; and IOL explantation technique were investigated.

RESULTS

PPV had been performed as a combined procedure with cataract surgery in eight eyes and solely in six pseudophakic eyes. The IOL material was hydrophilic in six eyes, hydrophilic with a hydrophobic surface in seven eyes and undetermined in one eye. The endotamponades used during primary PPV were C2F6 in eight eyes, C3F8 in one eye, air in two eyes and silicone oil in three eyes. Two of three eyes underwent subsequent silicone oil removal and gas tamponade exchange. Gas in the anterior chamber was detected in six eyes after PPV or silicone oil removal. The mean interval between PPV and IOL opacification was 20.5 ± 18.6 months. The mean BCVA in logMAR was 0.43 ± 0.42 after PPV, which significantly decreased to 0.67 ± 0.68 before IOL explantation for IOL opacification (p = 0.007) and increased to 0.48 ± 0.59 after the IOL exchange (p = 0.015).

CONCLUSIONS

PPV with endotamponades in pseudophakic eyes, particularly gas, seems to increase the risk for secondary IOL calcification, especially in hydrophilic IOLs. IOL exchange seems to solve this problem when clinically significant vision loss occurs.

Delayed surface opacification of a hydroview intraocular lens

The insertion of an intraocular lens during cataract surgery is routine but delayed opacification of hydrophilic foldable intraocular lenses (IOLs) has been increasingly noticed as a late post-operative complication. Such opacification may present with reduced visual acuity and can be diagnosed with slitlamp biomicroscopy. Lens explantation may be required. We report an 89-year-old female presenting with opacification of a Hydroview IOL and correlate the clinical findings of the lens in situ with the light microscopy of the explanted lens, as well as transmission electron microscopy (TEM), scanning electron microscopy (SEM) and elemental analysis. Pathological analysis of an explanted IOL may assist in a better understanding of the condition and may become relevant in medico-legal proceedings.

Changes in Opacification of Hydrophobic Acrylic Intraocular Lenses According to Temperature and Hydration

Purpose

To investigate optic opacification of hydrophobic acrylic intraocular lens (IOL) depending on hydration and temperature conditions.

Methods

IOL (Acrysof^® MA60BM Alcon, Fort Worth, Texas, USA) extracted from a 55-year-old male who underwent binocular cataract 11 years ago were used for the analysis. On slit lamp examination, the binocular IOL optics showed homogenous opacification. After extraction of the IOLs, the IOL opacification disappeared during dry storage at 4°C. To investigate the changes in IOL opacification according to temperature and hydration, an extracted IOL was stored in either dry conditions or normal saline at 4°C, room temperature, or 37°C for 24 hours, and then the degree of haziness was examined. To investigate the impact of an opaque optic on visual function, light transmission was performed using an ultraviolet-visible spectrophotometer (U-3000, Hitachi High-Technologies Corp., Tokyo, Japan).

Results

The extracted IOL optics at 4°C, room temperature, and 37°C were transparent at dry conditions. When the dried IOL was immersed in normal saline at room temperature and 37°C, opacification appeared. However, when the dried IOL was immersed in normal saline at 4°C, opacification of the IOL did not appear. When compared with the control, light transmission of the extracted IOLs from the right and left eyes stored in 37°C normal saline decreased by 4.7% at 453 nm and by 5.1% at 482 nm, respectively.

Conclusion

In acrylic hydrophobic IOLs, optic opacification can occur depending on temperature and hydration conditions.

Piggybacking technique for vitreous protection during opacified intraocular lens exchange in eyes with an open posterior capsule

We describe a surgical technique for the safe exchange of opacified 1-piece IOLs in eyes that have had a neodymium:YAG laser posterior capsulotomy. Initially, the opacified IOL is freed from the capsule adhesions using a dispersive ophthalmic viscosurgical device, which is also injected beneath the opacified IOL to protect the vitreous interface. The IOL is then brought into the anterior chamber. A new 3-piece clear IOL is injected before the opacified IOL is removed and is placed behind the opacified IOL, preventing the vitreous from prolapsing. The pupil is constricted pharmacologically, and the opacified IOL is removed through a standard 2.75 mm corneal incision using the hinge technique.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Experimental investigation on mechanism of hydrophilic acrylic intraocular lens calcification

PURPOSE

To construct a model simulating intraocular lens (IOL) opacification attributable to the formation of calcium phosphate deposits and to investigate the kinetics of deposit formation.

DESIGN

Prospective laboratory investigation.

METHODS

SETTING

Department of Ophthalmology, Medical School and Department of Chemical Engineering, Laboratory of Inorganic and Analytical Chemistry, University of Patras, Greece.

STUDY POPULATION

Three hydrophilic acrylic IOLs (26% water content) were placed inside a 10-mL double-walled thermostated reactor simulating the anterior chamber. Simulated aqueous humor was injected continuously into the reactor using a pump with variable speed.

OBSERVATION PROCEDURES

The observation of IOLs was carried out in situ daily by optical microscopy. Scanning electron microscopy and energy-dispersive radiographic spectroscopy were used for the identification of the morphologic features and the composition of the deposits.

RESULTS

The lenses were removed and inspected 5, 9, and 12 months after the initiation of the experiment. Investigation showed deposits of calcium phosphate crystallites in the interior of opacified IOLs. However, these deposits were not observed on the surface of the IOLs.

CONCLUSIONS

In agreement with earlier reports by our group and in the literature, IOL opacification is the result of calcification. It is suggested that the surface hydroxyl groups of the polyacrylic polymeric components of the IOLs are capable of inducing surface nucleation and crystal growth of calcium phosphates. However, most important is the finding that the calcification of IOLs is initiated from their interior through the development of sufficiently high local supersaturation, realized through the diffusion of calcium and phosphate ions.

Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD^™ lens is an aspheric, hydrophilic acrylic intraocular lens (IOL). The hydrophilic design of the lens is optimized to address dysphotopsia while maintaining biocompatibility, optical clarity, resistance to damage, and resistance to biocontamination. Aspheric lenses decrease postoperative spherical aberration. The addition of the Softec lens provides clinicians with another option for IOL placement; however, randomized comparative studies of this lens to others already on the market remain to be completed.

Clinical efficacy and complications of intraocular lens exchange for opacified intraocular lenses

PURPOSE

To evaluate the clinical efficacy and complications of intraocular lens (IOL) exchange.

METHODS

A review of medical records was performed for 52 eyes that had undergone an IOL exchange due to IOL opacification. Surgical complications and their incidences were analyzed. The mean best corrected visual acuity (BCVA) after the IOL exchange was compared with the mean pre-exchange BCVA and with the mean BCVA after the initial IOL implantation. Prediction error of refraction and biometric data obtained for the IOL exchange were, if available, compared with those obtained for the initial IOL implantation. The prediction error for the IOL exchange, calculated from the biometric data obtained before the IOL exchange, was compared with that calculated from the measurements obtained before the initial IOL implantation.

RESULTS

The overall complication rates were low and no serious complications were found. The mean BCVA improved significantly after the IOL exchange and was not significantly different from that obtained after the initial IOL implantation. However, the refractive prediction for the IOL exchange was not as good as it was for the initial IOL implantation, which was thought to be related with difficulties in axial length (AL) measurements. Biometric data taken before the initial IOL implantation was associated with a significantly better refractive prediction than those taken before the IOL exchange.

CONCLUSIONS

IOL exchange was both efficacious and safe for visual recovery. However, IOL exchange was related with increased difficulty of predicting postoperative refraction; difficulties in AL measurements are the suggested cause.

Opacification of hydrophilic acrylic intraocular lens attributable to calcification: investigation on mechanism

PURPOSE

To identify the nature and to investigate the biochemical mechanisms leading to late opacification of implanted hydrophilic acrylic intraocular lenses (IOLs).

DESIGN

Retrospective laboratory investigation.

METHODS

setting: Department of Ophthalmology, Medical School, Department of Chemical Engineering, Laboratory of Inorganic and Analytical Chemistry, University of Patras and FORTH-ICEHT, Greece. study population: Thirty IOLs were explanted one to 12 years postimplantation attributable to gradual opacification of the lens material. observation procedures: Materials analysis was done using scanning electron microscopy (SEM) equipped with a microanalysis probe (EDS), confocal microscopy, x-ray diffraction (XRD), and Fourier transform infrared (FTIR) for the identification of the substances involved in the opacified lenses.

RESULTS

SEM investigation showed plate-like as well as prismatic nanoparticle deposits of calcium phosphate crystallites on the surface and in the interior of opacified IOLs. The plate-like deposits exhibited morphology and particle size typical for octacalcium phosphate (OCP), while the respective characteristics of the prismatic nanocrystals were typical of hydroxyapatite (HAP). EDS analysis confirmed the chemical composition of the deposits. Aqueous humor analysis showed that the humor is supersaturated with respect to both OCP and HAP, favoring the formation of the thermodynamically more stable HAP, while the formation and kinetic stabilization of other transient phases is also very likely. In vitro experiments using polyacrylic materials confirmed the clinical findings.

CONCLUSIONS

Hydrophilic acrylic IOLs' opacification may be attributed to the deposition of calcium phosphate crystallites. HAP is the predominant crystalline phase of these crystallites. Surface hydroxyl groups of the polyacrylic materials facilitate surface nucleation and growth.

Mineralization of radiation-crosslinked polyvinyl alcohol/polyvinyl pyrrolidone hydrogels

A study of the calcification of the polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) hydrogels during their exposure to a calcium chloride solution or a simulated body fluid has been carried out. On the basis of the experiments, using a two-compartment permeation cell, the diffusion of calcium ions and their subsequent deposition in the hydrogels were elucidated. Steady-batch experiments were also performed to further elaborate the deposition pattern and the types of calcium deposits. It was demonstrated that Fick's second law of diffusion can describe the diffusion of calcium ions through PVA/PVP hydrogels at 310 K. The diffusion coefficient was determined to be (4.4+/-0.1)x10(-10) m2/s and the partition coefficient for the hydrogels was 0.06. Formation of calcium deposits was noticed taking place both on the surface and inside the hydrogels. The deposits formed on the surface have flake morphology, while the deposits inside the hydrogels are more like globular aggregates. Both types of deposits have been characterized as being comprised calcium and hydroxyl ion deficient apatites with chloride ions the most likely substituting species at the hydroxyl sites.

Surgical and visual outcomes following exchange of opacified Hydroview intraocular lenses

AIM

To report the clinical and surgical outcomes following exchange of opacified Hydroview intraocular lenses (IOLs), and to relate the final visual and anatomic results to clinical and surgical variables.

METHODS

This is a prospective study of seventy-three eyes that underwent exchange of opacified Hydroview IOLs in Waterford Regional Hospital, Ireland. Preoperative, intraoperative and postoperative details were recorded.

RESULTS

This study comprised 73 eyes of 71 consecutive patients undergoing IOL exchange, performed at mean (+/-SD) intervals of 36.64 (+/-9.9) months following the primary cataract surgery. The mean (+/-SE) follow-up following the exchange procedure was 13 (+/-1) months (range: 1-45 months). The secondary IOL was placed in the capsular bag, in the sulcus, and in the anterior chamber in 22 (30.1%), 24 (32.9%) and 27 (37%) cases, respectively. The IOL exchange procedure was uneventful in 36 eyes (49.3%), whereas intraoperative events such as posterior capsule rupture, vitreous loss and zonular dehiscence were seen in the remainder (50.7%). Following the IOL exchange procedure, a significant improvement in best corrected visual acuity (BCVA) was noted at one and at three months, and at the final visit (Wilcoxon signed ranks test: p<0.001, p = 0.006, and p<0.001, respectively). Following exclusion of eyes with visually consequential ocular comorbidity, a better final BCVA was noted among those eyes where the secondary IOL was placed in the capsular bag or in the sulcus when compared with placement of the secondary IOL in the anterior chamber (IOL in the bag or sulcus: 26 eyes (35.6%), median (IQR) final BCVA: 0.2 (0.10-0.40); IOL in the anterior chamber: 19 eyes (26.02%), median (IQR) final BCVA: 0.5 (0.20-0.60); Mann Whitney U Test: p = 0.004).

CONCLUSION

IOL exchange is a technically challenging, but visually rewarding procedure. However, placement of the secondary IOL in the anterior chamber is associated with a poorer visual outcome when compared with placement of the secondary IOL in the sulcus or in the capsular bag.

Hydroview lens implant calcification: 186 exchanges at a district general hospital

AIM

This paper describes the experience at a district general hospital of coping with an abrupt onset of calcification of Hydroview intraocular lens (IOL) implants requiring exchange surgery mostly for symptoms of glare, even though the visual acuities were relatively good.

METHODS

In this retrospective study, the operative details of 174 consecutive lens exchanges by one surgeon were retrieved from the surgeon's notes. Of these, pre and post-operative details of 106 consecutive patients were obtained from the hospital notes.

RESULTS

Of the 174 lens exchanges, all were sutureless except one and 31 eyes (18%) had had previous capsulotomies. Of 143 eyes with intact posterior capsules, eight (5.6%) needed anterior vitrectomy. Lens replacements were in the bag in 136 (95%), in the sulcus in five (3.5%), and in the anterior chamber in two (1.5%). Of the 31 eyes with previous capsulotomies, 10 (32%) needed anterior vitrectomy. Lens replacements were in the bag in 22 (71%) and in the sulcus in the remaining nine cases (29%). Postoperatively the best-corrected visual acuity was improved in 53%, remained the same in 35%, and deteriorated in 12%.

CONCLUSION

The lens exchange procedure was mostly predictable with satisfactory visual results allowing preoperative counselling of risks to be similar to that for cataract surgery. The onset and resolution of the period of implantation of lenses requiring exchange has not been explained.

Opacification of the Hydroview H60M intraocular lens: total patient recall

PURPOSE

To report the prevalence of intraocular lens (IOL) opacification and related clinical features in patients implanted with Hydroview IOL.

SETTING

Gloucestershire Eye Unit, Gloucestershire, United Kingdom.

METHODS

A total of 1330 eyes of 1265 patients who had cataract surgery with Hydroview IOL implantation between September 2000 and April 2001 were reviewed between April and October 2004. The visual acuity, visual symptoms, IOL status, and associated ocular comorbidity were recorded.

RESULTS

One hundred ninety-three (14.5%) of 1330 eyes had evidence of IOL opacification. A total of 56 (4.2%) had visually significant opacification and had IOL exchange. The prevalence of IOL opacification ranged from 1.1% in patients who had surgery in September 2000 to 36.3% in the December 2000 group. In eyes with IOL opacification, the visual symptoms were decreased vision (57%), glare (32%), and mistiness of vision (27%). One hundred forty-four eyes (75%) with IOL opacification had visual acuity of 6/12 or better; 21.5% of diabetic eyes had IOL opacification compared with 14.3% of nondiabetic eyes (P =.06); 20.5% of glaucomatous eyes had IOL opacification compared with 14.0% of nonglaucomatous eyes (P = .033).

CONCLUSIONS

This is the first large sample recall of patients implanted with the Hydroview H60M IOL. The overall prevalence of IOL opacification was 14.5%, with peak prevalence in patients who had surgery in December 2000.

Screening for drug-induced spoliation of the hydrogel optic of the AlphaCor™ artificial cornea

Clinical experience and in vitro investigations demonstrated that AlphaCor, a hydrogel keratoprosthesis, can undergo both surface spoliation and internal depositions/colourations after exposure to certain medications, alone or in combination. While the most commonly used medications have not been associated with spoliation in vivo, many medications are reportedly used due to the complex co-pathologies in many recipients, and regional variations in available medications. We screened a number of drugs used or proposed by surgeons for use in AlphaCor patients to evaluate their potential to cause visually significant optic spoliation (surface or intragel, or colour changes). Poly(2-hydroxyethyl methacrylate) discs with an identical composition to AlphaCor's optic were incubated with each medication and then with simulated aqueous humour (SAH) at 37 degrees C for 7 days. They were then examined under magnification and by histology (selected samples). Clinical feedback for the test medications was reviewed and compared with the in vitro results. A minority of the drugs caused surface spoliation (TobraDex, Prednefrin Forte, Azopt) or colour staining (including Zymar, Vigamox, Quixin) when tested alone, but SAH appeared to promote hydrogel cloudiness and surface deposits. The in vitro spoliation occurred more frequently than in vivo reports of spoliation in recipients of the same medications. This study is consistent with earlier findings in demonstrating involvement of topical medications in hydrogel spoliation, although a much lower incidence of spoliation is reported for AlphaCor in human recipients than indicated by the laboratory findings. The interactions of biological fluids and drugs require further study.

[Opacification of a hydrophilic acrylic intraocular lens]

PURPOSE

To report pathological and histochemical analysis of an explanted opacified hydrophilic acrylic intraocular lens.

PATIENTS

and method: A hydrophilic acrylic intraocular lens--Orion IFP3D6--was explanted 2 years after routine phacoemulsification because of its opacification associated with significant visual impairment (20/40). The intraocular lens was examined by gross and light microscopy. Full-thickness cut sections of the lens were stained with 1% alizarin red (a special stain for calcium).

RESULTS

Microscopic analyses revealed the presence of granules of various sizes distributed in a line parallel to the anterior and posterior curvatures of the lens. The granules stained positively for alizarin red.

CONCLUSION

Such opacification has been described with the SC60B-OUV, MDR Inc., which is also a one-piece foldable-design intraocular lens (28% hydrophilic material). The opacification of the intraocular lens occurred over various periods after surgery. Forty percent of these lenses have been explanted. Microscopic and histochemical evaluation of these intraocular lenses revealed the same type of granulation deposits within the lenses. The origin and mechanism of the opacification are still not fully understood.

Effect of multipurpose solutions for contact lens care on the in vitro drug-induced spoliation of poly(2-hydroxyethyl methacrylate) in simulated aqueous humour

Drug-induced spoliation of hydrogels as contact lenses or as implants in the anterior eye is a frequent occurrence in clinical practice. This study explores the capacity of three commercial multipurpose solutions for contact lens care to reduce the spoliation of poly(2-hydroxyethyl methacrylate) (PHEMA) specimens exposed to a simulated aqueous humour formulation and to three topical drugs commonly administered after insertion of artificial corneas (Predsol, Optimol and Depo-Ralovera). ReNu MultiPlus (Bausch & Lomb), Complete Blink-N-Cleantrade mark Lens Drops (Allergan) and Complete Protein Remover Tablets dissolved in Complete ComfortPLUS (both from Allergan) were evaluated. All multipurpose solutions were able to dislodge passively the deposits formed on hydrogels in the simulated aqueous and in the presence of Predsol and Optimol, but none were effective against the deposits induced by Depo-Ralovera. A reduction of the calcium content in deposits caused by Predsol and Optimol was confirmed after treatment with the protein remover preparation, while the other multipurpose solutions caused the complete removal of the deposits. In experiments designed to evaluate the preventive action of the multipurpose solutions, no such effects were observed regardless of the drug involved. The prospect of using multipurpose solutions as eye drops following implantation of a hydrogel artificial cornea is a valid alternative for reducing device spoliation, however it appears to depend on the nature of the postoperative medication.

Free volume study on calcification process in an intraocular lens after cataract surgery

An opacified intraocular lens explanted from a patient in the postoperative period after phacoemulsification was investigated to find the cause of opacification. From the UV-visible and energy dispersive X-ray spectroscopy (EDS) measurements, the opacification in the present case seems to be due to calcification of the intraocular lens and not due to modification in the UV absorber material of the lens. The average free volume size of the intraocular lens both in unimplanted and explanted state were obtained from positron lifetime spectroscopy (PLS). Further, the combined FTIR and PLS results indicate that calcium gets into the free volume cavities of the intraocular lens matrix as a cationic moiety, may be in the form of Ca(++). The small decrease in glass transition temperature of the calcified lens seems to indicate the plasticizing action of calcium ions. The present results could be of some use in the design of the intraocular lens material in which calcification would be minimum.

Calcification of intraocular hydrogel lens: evidence of dystrophic calcification

PURPOSE

To report and describe the surface calcification of three cases of implanted intraocular hydrogel lens.

METHODS

Three surgically extracted hydrogel intraocular lenses were studied by light and transmission electron microscopy as well as by energy dispersion X-ray microanalysis.

RESULTS

The lens surfaces were covered by granular deposits of calcium phosphate, clearly delineated by von Kossa and alizarin stains for calcium. Transmission electron microscopy showed the deposits to be located within the superficial lens material to a depth of 7 microm and to be associated with what appear to be traces of cellular material including basement membrane and plasmalemma. To the authors' knowledge there has been only one other transmission electron microscopic study. Energy dispersion X-ray microanalysis showed the deposits to contain calcium and phosphorous in all cases.

CONCLUSIONS

This study confirms and extends the previous reports of five cases of calcification of hydrogel intraocular lenses. The exact mechanism of calcification remains obscure but evidence suggesting cell-mediated dystrophic calcification of the lens surface is presented. Further study is required to monitor the incidence and development of this phenomenon.

Calcification postopératoire des lentilles intraoculaires acryliques hydrophiles : aspects cliniques et pathologiques

PURPOSE

The aim of this study was to evaluate the clinical aspects of ten eyes with calcified hydrophilic acrylic intraocular lenses and pathological data obtained from seven explanted lenses.

MATERIAL AND METHODS

Forty-seven eyes of 40 patients received the same implant in the first 6-month period of 2001. Ten eyes showed intraocular lens opacification detected 6-18 months after the operation: seven lenses were explanted and three were left in place because they were not causing a decrease in visual acuity or glare at light. Five of ten eyes were diabetic. The explanted lenses were examined under the light microscope and the electron microscope. The elemental analysis of the lens surfaces was made by energy dispersive spectrometry.

RESULTS

The light microscopy showed an irregular surface covered by a gray-white opacity. The electron microscopy detected multiple granulations on the front and back surfaces of the lenses including some portions of the haptics. The size and density of these granulations were smaller on the back surface. The energy dispersive spectrometry showed the presence of calcium and phosphate on both surfaces. The spikes of calcium and phosphate were smaller for the back surface of the lenses.

DISCUSSION

Calcification was predominantly seen on the surfaces that were in contact with aqueous not covered with anterior capsule. Half (5/10) of the cases were diabetic even though 18% of all patients receiving this lens were diabetic. The presence of diabetes is very common in other series. These data suggest the role of a metabolic factor influencing the milieu of the lens in this calcification process.

CONCLUSION

Calcification of the hydrophilic acrylic lenses is a relatively serious complication, but the conditions leading to its appearance and the physiopathology have not yet been fully elucidated. The surgeon should be very careful in the choice of the intraocular lens to implant, and even more so if the patient is diabetic.

In vitro drug-induced spoliation of a keratoprosthetic hydrogel

PURPOSE

To investigate in vitro the effects of selected drugs on the spoliation of poly(2-hydroxyethyl methacrylate) (PHEMA), a synthetic acrylic hydrogel currently used for the manufacture of a keratoprosthesis, AlphaCor. The experiments were carried out both in the presence of simulated aqueous humor (SAH) and in its absence.

METHODS

Disks of PHEMA were incubated and shaken with 9 commonly prescribed drugs at 37 degrees C in sterile conditions for 1 week. Samples were incubated either in SAH only (controls), in each drug preparation, or in each drug for 1 week followed by 1 week in SAH. The drugs selected for this study were steroids (prednisolone, dexamethasone, fluorometholone, medroxyprogesterone), antiglaucoma drugs (timolol maleate and pilocarpine), and antibiotics (chloramphenicol, cephazolin, and ciprofloxacin), as commercially available formulations. Following incubation, the PHEMA specimens were examined visually and then histologically, after staining with alizarin red for the presence of calcium in the spoliating sediments/deposits.

RESULTS

Although only 5 of the drug formulations (dexamethasone as Maxidex, fluorometholone as FML, pilocarpine as Isopto Carpine, chloramphenicol as Chlorsig, and medroxyprogesterone as Depo-Ralovera) induced spoliation of the hydrogel in the absence of SAH, all drugs induced spoliation after postincubation in SAH, and calcium was detected in the majority of samples. The deposits on the hydrogel specimens incubated first in cephazolin (as Cefazolin-BC), pilocarpine (as Isopto Carpine), and chloramphenicol (as Chlorsig) and then in SAH did not contain calcium, despite its presence in SAH.

CONCLUSIONS

The study appears to confirm our earlier clinical observations that topical medication may play a role in the spoliation of the hydrogel ophthalmic devices. Presence of calcium in the deposits seems to be correlated to the nature of drug. Although the incidence of spoliation in real clinical situations is much lower than suggested by this extreme-case in vitro simulation, topical therapy after implantation of AlphaCor should be carefully considered, kept to the minimum required, and additive-free where possible.

Evaluation of calcification of a hydrogel intraocular lens by optical coherence tomography

We describe 2 cases of calcification of hydrogel intraocular lenses (IOLs) evaluated by optical coherence tomography. Dense or slight surface opacities of hydrogel IOLs were detected initially by slitlamp biomicroscopy in a 55-year-old woman and a 77-year-old woman. The opacities resulted in complaints of hazy vision after uneventful phacoemulsification and IOL implantation. Optical coherence tomography was used to further assess the opacities and showed calcification by high reflectivity on the anterior and posterior IOL surfaces in the first patient and on the anterior surface in the second patient. No abnormal reflectivity was seen on the surface of a hydrophobic acrylic IOL in the second patient's fellow eye. Optical coherence tomography may be useful to detect calcification of a hydrogel IOL.

Opacification of a silicone intraocular lens caused by calcium deposits on the optic

We describe opacification of a plate-haptic silicone intraocular lens (IOL) caused by calcification in a diabetic patient with asteroid hyalosis. The IOL was explanted 48 months after uneventful phacoemulsification because opacification of the posterior surface was causing significant visual disturbance. Light and scanning electron microscopy and x-ray spectrometry of the explanted IOL showed the opacification consisted mainly of calcium and phosphate, presumably hydroxyapatite, in the form of precipitations on the posterior surface of the optic.

Limitation of Scheimpflug videophotography system in quantifying posterior capsule opacification after intraocular lens implantation

PURPOSE

To assess the applicability of Scheimpflug videophotography system for the quantitative comparison of posterior capsule opacification after intraocular lens (IOL) implantation of different materials.

DESIGN

Retrospective, nonrandomized, interventional case series.

METHODS

Three groups (n = 15 eyes, each) underwent cataract surgery with implantation of acrylic, silicone, or hydrogel IOL. One year after surgery, the scatter light density at the anterior IOL surface level was measured using EAS-1000. Another three groups (n = 32 eyes, each) received acrylic, silicone, or hydrogel lens. One week after surgery, the scatter light density at the posterior capsule was measured.

RESULTS

Scatter light density at the anterior IOL surface 1 year after implantation was 7.5 +/- 3.0 computer-compatible tape (CCT) steps in the acrylic group, 6.0 +/- 2.3 CCT steps in the silicone group, and 5.0 +/- 3.2 CCT steps in the hydrogel group; the density in the acrylic group was significantly greater than that in the hydrogel group (P =.026). Scatter light density at the posterior capsule level 1 week after surgery was 28.3 +/- 8.9 CCT steps in the acrylic group, 22.2 +/- 2.0 CCT steps in the silicone group, and 26.7 +/- 6.7 CCT steps in the hydrogel group; there was a significant difference between the acrylic and silicone groups (P =.0005) and between the silicone and hydrogel groups (P =.008).

CONCLUSIONS

The IOL material significantly influences the scatter light density measurements of Scheimpflug videophotography system, and thus the intensity of posterior capsule opacification quantified by this system cannot be directly compared with different optic materials.

Evidence of octacalcium phosphate and Type-B carbonated apatites deposited on the surface of explanted acrylic hydrogel intraocular lens

Fourier-transform infrared (FTIR) microspectroscopy combining with attenuated total reflection (ATR) microsampling technique and micro-Raman spectrophotometer were used to detect the deposited materials on the surface of acrylic hydrogel intraocular lens (IOL) with or without ocular implantation. Surface morphology and the interface of this IOL were further examined by a confocal laser scanning microscope. The brand-new IOL exhibited a very smooth, transparent and featureless surface, but the explanted IOL had an irregular cerebriform-like opaque appearance. Both FTIR/ATR and Raman microspectroscopic analyses showed the deposits on the surface of acrylic hydrogel IOL after ocular implantation to consist of octacalcium phosphate (OCP) and Type B carbonated apatites, leading to the opalescence of acrylic hydrogel IOL. Both vibrational microspectroscopic examinations also confirmed the mineralization still in progress on the surface of acrylic hydrogel IOL after ocular implantation for 2 years.

Proposed pathogenesis for the delayed postoperative opacification of the hydroview hydrogel intraocular lens

PURPOSE

To report the clinical, histopathologic, ultrastructural, and elemental features of 17 opacified Hydroview (Bausch and Lomb Surgical, Rochester, New York, USA) hydrogel intraocular lenses (IOL) necessitating explantation and discuss from a clinicopathologic perspective why these lenses became opacified. Interventional case series with clinicopathologic correlation.

METHODS

Seventeen hydrogel lenses were explanted from 17 different patients owing to decreased visual acuity or quality of vision an average of 29 months after uneventful phacoemulsification and IOL implantation and associated with a granular-appearing opacification superficially within the optic. Lenses were examined by light microscopy, transmission electron microscopy (TEM), and energy dispersion x-ray (EDX) spectroscopy. A control IOL was included in our study.

RESULTS

All explanted lenses showed positive staining for calcium by light microscopy. Transmission electron microscopy disclosed electron-dense crystalline deposits in the superficial substance of the IOL optic. Energy dispersion x-ray spectra analyses showed the presence of calcium and phosphorus mainly in the electron-dense periphery of the deposits in all of the specimens and the presence of silicon mainly in the electron-lucent center of the deposits in the majority of the specimens. No positive staining or deposits were observed on the IOL control or in the haptics.

CONCLUSIONS

Our study is the first to demonstrate that the calcium deposits are associated with silicon, which was presumably derived from the silicone gasket in the Surefold (Bausch and Lomb Surgical, Rochester, New York, USA) packaging system, manufactured specifically for this IOL. Silicon may act as a nidus for calcium deposition within the lens, which is consistent with our findings. There may be other factors involved, and this important clinical problem requires further study.

Calcification of modern foldable hydrogel intraocular lens designs

PURPOSE

To report and compare clinical and pathological features of hydrophilic acrylic intraocular lenses (IOLs) of three major designs, explanted from patients who had visual disturbances caused by opacification of the lens optic.

METHODS

Eighty-seven hydrophilic acrylic IOLs (25 Hydroview, 54 SC60B-OUV, and 8 Aqua-Sense lenses) were explanted and sent to our center. Most patients became symptomatic during the second year after cataract surgery. A fine granularity was observed on the surface of the lens optic in the case of Hydroview. With the SC60B-OUV and Aqua-Sense lenses, the opacity resembled a nuclear cataract. Gross examination, light microscopy and staining with alizarin red and the von Kossa method (for calcium) were performed. Some lenses were submitted for scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

RESULTS

Light microscopic and SEM analyses revealed the presence of irregular granular deposits on the external optical surfaces of Hydroview lenses. With the SC60B-OUV lenses, the opacity was caused by the presence of multiple fine, granular deposits within the lens optic, distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath its external surfaces. The Aqua-Sense lenses exhibited both patterns simultaneously. The deposits in all cases stained positive with alizarin red and von Kossa method. EDS also demonstrated the presence of calcium and phosphates within the deposits.

CONCLUSION

Differences in the water content of the hydrophilic acrylic materials used in the manufacture of these three lens designs may be responsible for the different patterns of calcium precipitation. Careful clinical follow up of patients implanted with these lenses is necessary to determine if this phenomenon is rare and sporadic or may be more widespread.

Visually significant opacification of hydrophilic acrylic intraocular lenses--a clinico-pathological analysis

PURPOSE

To describe the clinic-pathological analysis of the visually significant opacification of the Cirrus International Hydroflex foldable hydrophilic acrylic intraocular lens (IOL) (model SC600-2, Medical Developmental Research Inc., Clearwater, Florida) and to highlight that this IOL is the same model as the Acryflex SC600-2 IOL, by the same manufacturer.

METHODS

Retrospective review of five eyes of four patients with opacification of their Cirrus International Hydroflex foldable hydrophilic acrylic IOLs (model SC600-2) after uncomplicated phacoemulsification and IOL implantation. Two IOLs were explanted from two patients 14 to 24 months after initial implantation. Each explanted lens was divided into equal halves, one half for scanning electron microscopy (SEM) study and the other half for transmission electron microscopy (TEM) examination. SEM and TEM samples were also subjected to energy dispersive X-ray analysis (EDX).

RESULTS

The IOL opacification was detected 14 to 24 months after uncomplicated phacoemulsification and IOL implantation. EDX analysis showed that the crystals contained calcium and phosphorus, presumably calcium phosphate.

CONCLUSIONS

The Cirrus International Hydroflex foldable hydrophilic acrylic IOL (model SC600-2) is associated with opacification, that appeared worse centrally than peripherally. This is the same model as the Acryflex SC600-2 IOL, made by the same manufacturer. The opacification consists of calcium and phosphate.

Hydrophilic acrylic intraocular lens optic and haptics opacification in a diabetic patient: bilateral case report and clinicopathologic correlation

OBJECTIVE

To report clinicopathologic and ultrastructural features of two opacified single-piece hydrophilic acrylic intraocular lenses (IOLs) explanted from a diabetic patient.

DESIGN

Interventional case report with clinicopathologic correlation.

SETTING

A 64-year-old white female underwent phacoemulsification and implantation of a single-piece hydrophilic acrylic lens (SC60B-OUV; Medical Developmental Research, Inc., Clear Water, FL) in October 1998 in the left eye and in July 1999 in the right eye. The best-corrected visual acuity after surgery was 20/60 in the left eye and 20/50 in the right eye. The patient had a marked decrease in visual acuity in June 2000 as a result of a milky, white opalescence of both lenses. Intraocular lens explantation and exchange was performed in both eyes and the explanted IOLs were submitted to our center for detailed pathologic, histochemical, and ultrastructural evaluation. They were stained with alizarin red and the von Kossa method for calcium, and also underwent scanning electron microscopy and energy dispersive radiograph spectroscopy to ascertain the nature of the deposits leading to opacification.

MAIN OUTCOME MEASURES

Documentation of calcium deposits confirmed by histochemical stains and surface analyses.

RESULTS

Opacification of the IOL was found to be the cause of decreased visual acuity. The opacification involved both the IOL optic and the haptics in the left eye and was confined to the IOL optic in the right eye. Histochemical and ultrastructural analyses revealed that the opacity was caused by deposition of calcium and phosphate within the lens optic and haptics.

CONCLUSIONS

There are two features that distinguish this case from those reported earlier. This is the first clinicopathologic report of lens opacification that has involved completely the lens optic and the haptics. Second, these two explanted IOLs document the first bilateral case. This process of intraoptic and haptic opacification represents dystrophic calcification of unknown cause. Diabetic patients appear to be more severely and more often affected by lens opacification. Long-term follow-up of diabetic patients implanted with this IOL design should be maintained by surgeons and manufacturers.

Complications and clinical outcomes of intraocular lens exchange in patients with calcified hydrogel lenses

PURPOSE

To evaluate the outcomes of intraocular lens (IOL) exchange in patients with calcified hydrogel IOLs.

SETTING

Ophthalmology departments of 2 university hospitals in Hong Kong, China.

METHODS

Fifteen patients developed loss of vision resulting from calcification of hydrogel IOLs. The calcified IOLs were explanted and replaced with new IOLs. The best corrected visual acuity before and after surgery was measured and compared.

RESULTS

The mean visual acuity was 0.03 (range 0.01 to 0.20) before IOL exchange and 0.20 (range 0.01 to 0.50) 3 months after; the difference was significant (P <.001). Acuity improved approximately 5 Snellen lines. Complications included posterior capsule rupture in 2 patients and zonular dehiscence in 3 patients; the secondary IOL was placed in the anterior chamber or ciliary sulcus in these patients. Three patients required cutting of the haptics before the calcified IOL could be removed.

CONCLUSION

Intraocular lens exchange was an effective treatment in patients with calcified hydrogel IOLs.

Opacification of a hydrophilic acrylic intraocular lens with exacerbation of Behçet's uveitis

Behçet's disease is 1 of the most common causes of uveitis in the Eastern world. Its common ocular complications are uveitis, cataract, and obliteration of retinal vessels. Phacoemulsification with intraocular lens (IOL) implantation in patients with Behçet's disease is known to be a safe procedure. We managed a patient with Behçet's disease who had aggravated uveitis and opacification of a hydrophilic acrylic IOL (ACRL-C160, Ophthalmed) 4 months after cataract surgery. Recalcitrant uveitis despite maximum tolerable medication and IOL opacification with vitreous opacity necessitated an IOL exchange and trans pars plana vitrectomy. After the procedure, the eye became quiescent. However, the visual acuity was 20/200 because of the obliteration of retinal vessels.

Survey of intraocular lens material and design

Modern cataract surgery is constantly evolving and improving in terms of lens material and design. Researchers and physicians strive to obtain better refractive correction with smaller wound size and minimizing host cell response to limit the proliferation of lens epithelial cells leading to opacification of the lens capsule. Intraocular lens material varies in water content, refractive index, and tensile strength. Intraocular lens design has undergone revisions to prohibit lens epithelial cell migration and reflection of internal and external light. The evolution of intraocular lens and extracapsular cataract surgery has lead to faster postoperative recovery and better visual outcomes.

Posterior capsule opacification and lens epithelial cell layer formation: Hydroview hydrogel versus AcrySof acrylic intraocular lenses

PURPOSE

To quantitatively compare the incidence of visually significant posterior capsule opacification (PCO) and lens epithelial cell (LEC) layer formation on the anterior surface of Hydroview hydrogel and AcrySof acrylic foldable intraocular lenses (IOLs) after implantation.

SETTING

Single-surgeon ophthalmology practice, Orange Base Hospital, and Dudley Private Hospital, Orange, New South Wales, Australia.

METHODS

This retrospective study comprised 166 eyes of 150 patients (after exclusions) who had cataract extraction and insertion of a foldable IOL in the capsular bag by a single surgeon using a standardized phacoemulsification technique from December 1997 to September 1998. The mean follow-up was 13.1 months (range 6.0 to 23.6 months). The eyes were divided into 2 groups based on the type of IOL implanted: Storz Hydroview H60M (81 eyes) or Alcon AcrySof MA30BA (85 eyes). A neodymium:YAG posterior capsule laser capsulotomy (PC YAG) was performed for an objective decrease in Snellen best corrected visual acuity (BCVA) of more than 1 line, significant visual symptoms, or both. This was used as a measure of visually significant PCO. An Nd:YAG anterior surface clearance (ASC YAG) was done for LEC layer formation anterior to the IOL to better visualize or facilitate treatment of PCO. The rates of PC YAG and ASC YAG after Hydroview and AcrySof IOL implantation were statistically compared.

RESULTS

Forty-five eyes (55.6%) in the Hydroview IOL group and 3 eyes (3.5%) in the AcrySof IOL group required a PC YAG; the risk difference was 52.0% (P <.001). An ASC YAG was required in 27 eyes (33.3%) in the Hydroview group and 1 eye (1.2%) in the AcrySof group; the risk difference was 32.2% (P <.001). Survival analysis demonstrated that the only independent predictor of the incidence of PC YAG and ASC YAG over time was IOL type, with the Hydroview IOL group having a statistically significantly higher incidence of both procedures.

CONCLUSION

There was a greater incidence of visually significant PCO and LEC layer formation on the anterior surface of Hydroview IOLs than of AcrySof IOLs.