Spectroscopic study of explanted opacified hydrophilic acrylic intraocular lenses

Purpose: To report a detailed spectroscopic analysis of explanted hydrophilic acrylic intraocular lenses (IOLs) that were removed because of postoperative opacification of the lens optic. Methods: Thirteen Hydroview H60M (Bausch & Lomb Surgical) IOLs were explanted from 13 different patients on average 56 months after phacoemulsification and IOL implantation. All patients had decreased visual acuity because of a fine granularity of the optical surface of the IOLs. The surface was investigated by gross, microscopic, histochemical and scanning electron microscopic analysis, and the elemental composition of the opacified IOLs was determined by X‐ray fluorescence spectroscopy (XRF). The spectrograms were compared to three different originally packed and never‐implanted hydrophilic acrylic IOLs. Results: Light and scanning electron microscopy of the optical surface of explanted IOLs revealed multiple fine granular deposits varying in size and shape that were positive for alizarin red. XRF confirmed that the explanted IOLs contained not only the previously reported calcium and phosphorous (calcium apatite), chlorine, silicone, sodium, aluminum and magnesium but also iron, sulfur, potassium as well as lesser amounts of iodine, zinc, strontium and yttrium. Conclusion: This is the first spectroscopic analysis determining the content of more than 10 elements of explanted and originally packed never‐implanted hydrophilic acrylic IOLs. The possible origin of the different elements obtained from the spectrograms and their implications are discussed.     

Multiple elements in the deposits of opacified Hydroview intraocular lens

PURPOSE: To report the ultrastructural and elemental features of two opacified intraocular lenses (IOLs). DESIGN: Histopathologic case series. METHODS: Two opaque hydrophilic acrylic IOLs (Hydroview H60M, Bausch & Lomb Surgical Clearwater, Florida, USA) explanted from two Chinese patients in Taiwan. The explanted IOLs were evaluated by light microscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. RESULTS: Brownish granular and scattered crystal-like deposits were found in case 2, whereas only fine white granular deposits were found in case 1. Using EDX spectroscopy, the elements of deposits on IOL optics were calcium and phosphorus in case 1, but in case 2, fluorine, magnesium, and sodium were demonstrated in addition to calcium and phosphorus. CONCLUSIONS: Our study indicated a difference in morphology and elements of deposits on opaque IOL optics between these two cases. It was suggested that multiple elements may contribute to the formation of deposits.     

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.     

Intraoperative explantation of two single-piece hydrophobic acrylic intraocular lenses due to surface deposits

PURPOSE: To report clinical, pathological, and laboratory analyses of two cases of single-piece hydrophobic acrylic intraocular lenses (IOLs), which presented with significant surface deposits during implantation. METHODS: The lenses were implanted with the manufacturer's recommended injector (loaded with Viscoat and Healon GV, respectively). Immediately after injection into the anterior chamber, areas on the lenses' surfaces were covered by deposits, which could not be entirely removed by irrigation/aspiration. The lenses were explanted and replaced with lenses of the same design. They underwent gross analyses, light microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy for analysis of the elemental composition of the deposits. Liquid chromatography/mass spectroscopy was also performed to identify the presence of proteins. RESULTS: The deposits on the first lens had a granular appearance, forming a homogeneous layer mostly on the posterior lens surface. Larger crystal-like deposits were present mostly on the anterior surface of the second lens. Elemental analyses of the deposits in both cases revealed the presence of peaks of sodium, chloride, phosphate, and potassium, in addition to the peaks of carbon and oxygen (normal constituents of the lens material). Only protein components normally found in the anterior chamber during surgery, such as haemoglobin and albumin, were identified. CONCLUSIONS: The results obtained suggest that the deposits in both cases may have resulted from crystallization of the ophthalmic viscosurgical device normally used during the loading of the IOLs into the cartridges.     

Dense opacification of the optical component of a hydrophilic acrylic intraocular lens: a clinicopathological analysis of 9 explanted lenses

PURPOSE: To report clinical, pathological, histochemical, ultrastructural, and spectrographic analyses of explanted hydrophilic acrylic intraocular lenses (IOLs) obtained from patients who had visual disturbances caused by postoperative opacification of the lens optic. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA, and Ege University, Alsancak Izmir, Turkey. METHODS: Nine hydrophilic IOLs (SC60B-OUV, MDR Inc.) were explanted from 9 patients with decreased visual acuity. Most patients became symptomatic approximately 24 months after uneventful phacoemulsification and IOL implantation. Opacification was noted and appeared clinically to be associated with a fine granularity within the substance of the IOL optic. The IOLs were forwarded to the center and examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red and the von Kossa method (special stains for calcium). Some were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: Microscopic analyses revealed multiple fine, granular deposits of variable sizes within the lens optics, usually distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optic surface. The deposits stained positive with alizarin red and the von Kossa method. Energy dispersive x-ray spectroscopy of the internal substance of sectioned IOLs demonstrated the presence of calcium within the deposits. CONCLUSION: This is the first clinicopathological report of optic opacification occurring with this hydrophilic acrylic IOL model. Studies of similar cases with this lens should be done to determine the incidence and possible mechanisms of the phenomenon.     

Hydrophilic acrylic intraocular lens clouding: a clinicopathological review

PURPOSE: An analysis is made of a serious late complication (opacification) of different models of hydrophilic acrylic intraocular lenses (IOLs). METHODS: Seven lenses were explanted from seven patients treated for cataracts with phacoemulsification and implantation of different types of hydrophilic acrylic IOLs (five SC60B-OUV from MDR, one Aquasense from OII, and one H60M Hydroview lens from Bausch & Lomb) who developed important vision impairment in the late postoperative period (1 to 3 years) due to lens opacification. The explanted lenses were subjected to exhaustive study involving photographic analysis, scanning electron microscopy, and energy dispersive X-ray spectroscopy. RESULTS: Light and scanning electron microscopy revealed diffuse, variable-size granular deposits within the optic of the SC60B-OUV lens, and on the anterior and posterior optic surfaces of the H60M Hydroview lens, though without affecting the haptics in any of the models. Dispersive energy X-ray spectroscopy of the deposits revealed the presence mainly of calcium and phosphorus salts. CONCLUSIONS: Hydrophilic acrylic IOL opacification is a serious late complication of unknown etiology. The condition is more frequent among diabetic patients, and the only management option is IOL explantation and replacement with a lens of some other material. More frequent and longer follow-up is required of those patients wearing lenses for which cases of opacification have been documented, particularly in the presence of predisposing factors (diabetes, uveitis). Caution is required with new lenses, avoiding their generalized use until they have successfully passed the test of time.     

Postoperative deposition of calcium on the surfaces of a hydrogel intraocular lens

OBJECTIVE: To report clinical, pathological and histochemical features of 5 Hydroview intraocular lenses (IOLs) explanted from five patients who had visual disturbances caused by postoperative deposits on the lens surfaces. DESIGN: Noncomparative small case series with clinicopathologic and histochemical correlations. PARTICIPANTS: Five hydrophilic IOLs explanted from five different patients. All patients presented with decreased visual acuity and glare circa 12 months after uneventful phacoemulsification and IOL implantation, associated with a red-brown granularity on the optical surfaces of the IOLs. METHODS: The lenses were explanted, fixed in buffered formaldehyde and examined by gross and light microscopy. MAIN OUTCOME MEASURES: Staining of the IOLs with 1% alizarin red and with the von Kossa method (both stains for calcium). Two additional IOLs were also stained and included as controls. RESULTS: The optical surfaces of all five IOLs were covered by a layer of irregular granular deposits, composed of multiple fine, translucent spherical-ovoid granules. The deposits stained positive for calcium in all cases. No deposit or positive staining was observed on the IOLs haptics. Staining of the control IOLs was also negative. CONCLUSION: This is the first histopathological report of calcified deposits on the surfaces of this hydrogel IOL model. Further studies on other similar cases with this lens should be done to determine the incidence and possible mechanisms of this phenomenon.     

Postoperative surface deposits on intraocular lenses in children

PURPOSE: To report the clinicopathologic features of 4 intraocular lenses (IOLs) composed of 3 different hydrophilic biomaterials explanted from children who had postoperative opacification of the IOL optic. SETTING: David J Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: The IOLs were explanted 20, 11, 22, and 25 months postoperatively from children aged 10, 3, 36, and 20 months old, respectively, at IOL implantation. Clinical data were obtained to correlate the findings with possible associated risk factors. The explanted IOLs were examined by gross and light microscopy. They were further analyzed with a stain for calcium, alizarin red 1%. Scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) were also performed. RESULTS: The primary reason for cataract surgery in Case 1 and Case 2 was persistent hyperplastic primary vitreous (PHPV); 1 patient received a B-Lens IOL (Hanita) and the other a Centerflex IOL (Rayner). The primary reason in Case 3 was familial bilateral congenital cataract and in Case 4, rubella cataract; both patients received a Hydroview IOL (Bausch & Lomb). All 4 IOLs had surface deposits on the optic, but the morphology of the deposits on the B-Lens and Centerflex IOLs was different than that in previously reported cases. The deposits in all four cases stained positive with alizarin red and consisted of calcium and phosphorus when imaged with EDS. CONCLUSIONS: Calcified deposits on 2 Hydroview IOLs explanted from children were similar to those seen in adults with the same IOL. The deposits on the B-Lens and Centerflex IOLs were probably secondary to a breakdown of the blood-aqueous barrier caused by preexisting PHPV.     

Two opacification patterns of the same hydrophilic acrylic polymer: case reports and clinicopathological correlation

We report 2 intraocular lenses (IOLs) manufactured from the same hydrophilic acrylic polymer by Ioltech that developed optic opacification. In both cases, the postoperative course after implantation of the IOLs was complicated by significant inflammatory reaction with fibrin formation in the anterior chamber. Pathologic analyses of the explanted IOLs were consistent with dystrophic calcification leading to optic opacification, but the pattern was different between the 2 IOL designs. Patient-related factors might have been responsible for this complication.     

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.     

Role of silicon contamination on calcification of hydrophilic acrylic intraocular lenses

PURPOSE: To verify the presence of the element silicon on hydrophilic acrylic intraocular lenses (IOLs) explanted because of calcification. DESIGN: Interventional case series with clinicopathological correlation. METHODS: Twenty explanted IOLs with surface deposits (MemoryLens), and 20 with deposits mostly within their optic substance (SC60B-OUV and Aqua-Sense; 10 each) were used. After gross, microscopic, and histochemical analyses to confirm the presence of deposits, the lenses underwent scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) for elemental composition, on the external surface of MemoryLens IOLs, and on the surface and internal substance of SC60B-OUV and Aqua-Sense IOLs. The weight percentage of the element silicon was obtained at the level of deposits, and at adjacent deposit-free areas in all lenses. RESULTS: Scanning electron microscopy (SEM) coupled with EDS confirmed that the composition of the deposits was calcium/phosphate in all cases. The element silicon was found in all 40 lenses, on all areas analyzed. The silicon weight percentage was higher at the level of the deposits. The presence of aluminum on five MemoryLens IOLs, and in most of the SC60B-OUV and Aqua-Sense lenses might be related to scattering from the aluminum mounting stubs used for surface analyses. CONCLUSIONS: Silicone compounds have been implicated in the calcification of another hydrophilic acrylic design (Hydroview). They may also have a role in the calcification of other hydrophilic acrylic IOLs. Further investigation on the relationship between the presence of the element silicon and the silicone compounds found on calcified hydrophilic acrylic lenses is necessary.     

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.     

Progressive opacification of hydrophilic acrylic intraocular lenses in diabetic patients

Four patients with diabetes mellitus had cataract extraction with implantation of a hydrophilic acrylic intraocular lens (IOL) (ACRL-C160, Ophthalmed). The IOLs showed progressive and generalized opacification 10 to 20 months after implantation, decreasing visual acuity. All 4 IOLs were removed. By light microscopic examination, the IOL surfaces were wrinkled and encrusted with microspheres. Electron microscopy revealed the material to be crystalline in nature. Energy dispersive x-ray spectrum analysis showed that the deposits were mainly composed of calcium and phosphate.     

Primary IOL implantation in children: a risk analysis of foldable acrylic v PMMA lenses

BACKGROUND:/aims: To compare the relative risks of poly (methylmethacrylate) (PMMA) and soft acrylic (AcrySof) primary intraocular lens (IOL) implantation in paediatric cataract surgery. METHODS: A retrospective analysis of clinical data was performed on eyes of 61 infants and children who underwent cataract surgery with primary IOL implantation. Age at operation ranged from 3 weeks to 15 years. Mean follow up duration was 24.5 months (range 0.5-68 months). Factors examined included type of IOL (PMMA, acrylic), performance of a primary posterior continuous curvilinear capsulorhexis (PCCC) or capsulotomy with limited anterior vitrectomy, perioperative complications, and subsequent intervention for posterior capsule opacification (PCO). Risk factors for perioperative complications were examined with 2x2 tables to give odds ratios (OR) as measures of association. A survival analysis was performed to assess risk of subsequent intervention for PCO with different IOL types. Relative risks (hazards) and confidence intervals (CI) were calculated with Cox regression to adjust for potential confounding. RESULTS: Compared to acrylic, PMMA IOLs were significantly associated with perioperative complications (OR 5.2, 95% CI 1.4 to 19, p = 0.01). However, IOL and type of section were highly correlated factors, and this finding may reflect risks associated with larger scleral wounds used for PMMA IOLs. No statistically significant difference in risk of subsequent intervention for PCO was found between different IOL types. Mean times till intervention for PMMA and acrylic IOLs were 30.1 months (95% CI 22 to 38) and 19.8 months (95% CI 12 to 27) respectively (log rank test statistic 1.53, one degree of freedom, p = 0.22). At 12 months post-implant surgery, 76% (95% CI 59 to 93) of PMMA cases and 54% (95% CI 35 to 72) of acrylic cases had not required intervention for PCO; these proportions fell to 55% (95% CI 35 to 75) and 38% (95% CI 14 to 61) for PMMA and acrylic cases respectively at 2 years post-surgery. After adjustment for age at surgery, primary posterior capsulorhexis, and perioperative complications relative risk of intervention after acrylic IOL implantation was 1.6 (95% CI 0.66 to 3.9, p = 0.29). CONCLUSION: Primary implantation of foldable soft acrylic IOLs in paediatric eyes may allow fewer perioperative complications than rigid PMMA IOLs. Short term safety profiles of primary implantation in paediatric cataract surgery are otherwise comparable for PMMA and soft acrylic IOLs.     

Laboratory analyses of two explanted hydrophobic acrylic intraocular lenses

Two three-piece hydrophobic acrylic intraocular lenses (IOLs) were explanted from two patients at 7 and 9 years, respectively, after implantation, because of poor fundus visualisation and/or a clinically significant decrease in visual acuity related to their opacified IOLs. In addition to light microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, confocal laser scanning microscopy was used for the first time to observe the explanted IOLs. The clinical aspect seemed to correspond to the phenomenon of surface light scattering, while laboratory analyses showed dense glistenings in the central layer of the IOL optic, which had no change next to the surface. Further studies on these phenomena are needed.     

Transforming growth factor-beta isoform proteins in cell and matrix deposits on intraocular lenses

PURPOSE: To determine whether the cells that adhere to poly(methyl methacrylate) (PMMA) posterior chamber intraocular lenses (PC IOLs) implanted in human eyes produce transforming growth factor-beta (TGF-beta) isoforms and whether the acellular proteinaceous deposits on these IOLs contain TGF-beta. SETTING: Department of Ophthalmology, Wakayama Medical College, Japan. METHODS: Thirty-two PMMA PC IOLs explanted from Japanese patients were immunostained for TGF-beta1, -beta2, or -beta3, and observed under light microscopy. RESULTS: Cell deposits were observed on 12 IOLs and proteinaceous deposits on 16. Components of the cell deposits were mainly of macrophage origin. The cell and matrix deposits tested positive for each isoform of TGF-beta. CONCLUSION: The cells that adhered to implanted PMMA PC IOLs produced TGF-beta, and the extracellular matrix that accumulated on the surface of the IOLs contained TGF-beta. Transforming growth factor-beta from the cells on IOLs may influence the healing process of residual lens capsules after cataract surgery with IOL implantation.     

Is chronic intraocular inflammation after lens implantation of bacterial origin?

In an effort to better understand the cause of chronic intraocular inflammation after intraocular lens (IOL) implantation, both scanning and transmission electron microscopy were used to compare 1 anterior chamber, 1 iris-fixated, and 3 posterior chamber IOLs removed for this condition between 2 and 16 months after implantation with 8 IOLs explanted for other reasons (decentration in 4 cases, bullous keratopathy in 4 cases). Colonization with non-slime-producing, as well as slime-producing bacteria (1 case) in the presence of a thin membranous structure of cellular origin (multinucleated giant cells and macrophage-like cells) was demonstrated on all of the 5 IOLs explanted from inflamed eyes. Neither bacteria nor membranous structures could be identified on the IOLs removed because of dislocation or from eyes with bullous keratopathy. These observations indicate that bacterial colonization and the consequent host response may be characteristic features of many otherwise unexplained cases of intraocular inflammation after IOL implantation.     

Bilateral spontaneous anterior dislocation of intraocular lens with the capsular bag in a patient with pseudoexfoliation

We report a rare case of bilateral spontaneous anterior partial in-the-bag intraocular lens (IOL) dislocation in a 75-year-old man with pseudoexfoliation (PXF). He underwent uneventful phacoemulsification in both eyes with in-the-bag IOL implantation 9 years back. In the right eye, single piece poly (methyl methacrylate) (PMMA) IOL (+19 D) and in the left eye, single piece acrylic foldable IOL (+19 D) were implanted. An attempt at pharmacological IOL repositioning was unsuccessful. The dislocated IOLs were explanted and exchanged with scleral suture fixated PMMA IOLs. Vision improved to 20/30 in both eyes following surgery, without any associated ocular morbidity. We believe that zonular weakness secondary to PXF, capsular contraction, and myopia together were the predisposing factors for partial anterior dislocation of IOLs and IOL exchange with scleral suture fixation of IOL is a safe and effective treatment option.     

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.     

Single-piece acrylic intraocular lens implantation in children

PURPOSE: To assess the short-term outcomes of single-piece acrylic intraocular lens (IOL) implantation in children by determining the incidence of postoperative visual axis opacification and the need for a second procedure to clear the axis, cell deposits on the IOL optic, posterior synechias, and IOL decentration. SETTING: Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This retrospective case review comprised 43 consecutive implantations (33 patients) of a single-piece hydrophobic acrylic IOL (AcrySof SA30AL or SA60AT, Alcon). An analysis of 42 eyes with posterior capsulectomy and vitrectomy was performed. Eyes with traumatic cataract and secondary IOLs were excluded. RESULTS: Single-piece acrylic IOLs were implanted in 42 eyes. The mean age was 33.5 months +/- 28.9 (SD) (range 0.5 to 110 months) and the mean follow-up, 12.0 +/- 8.2 months (range 1.0 to 27.5 months). Postoperative opacification of the visual axis occurred in 7 eyes (16.7%). Secondary surgical procedures were required in 5 eyes (11.9%). Lens deposits were observed in 8 eyes (19.0%) and synechias, in 5 eyes (11.9%). All IOLs were well centered postoperatively. CONCLUSION: The short-term data suggest implantation of the AcrySof single-piece hydrophobic acrylic IOL is safe in the pediatric eye.