Marcela Escobar-Gomez

Medical University of South Carolina, Charleston, SC, United States

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Publications (66)137.56 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We summarize information, based on clinicopathologic studies over the past decade, on various cataract intraocular lens (IOL) procedures and modern "specialized" IOLs, that will help surgeons continuously improve long-term results for cataract patients. Although most operations do initially provide excellent refractive correction and visual rehabilitation, late complications occur. These sometimes are missed because they are outside of the routine period of follow-up care. We have tried to determine if the various techniques and IOLs truly deliver the long-term results that we desire. Most safety and efficacy information is derived from the manufacturer and is passed through the U.S. Food and Drug Administration (FDA). This is often based on limited, relatively short-term observations made by the manufacturer. After a lens receives FDA approval, there are few means to assess the outcome of each procedure and lens years later. We rarely hear of a 10- or 20-year follow-up study. We have found that one of the best means to assess long-term results is pathologic analyses. We discuss recently studied aspects of pathologic reactions, such as posterior capsule opacification, intracapsular fibrosis, glistenings, intralenticular opacification, and other issues with the various IOL platforms; we then present a clinicopathological overview of tissues and IOLs from our database. These include hydrophobic and hydrophilic acrylic designs, plate lenses, and a dual optic lens.
    Survey of Ophthalmology 01/2011; 56(6 Suppl):S3-53. · 2.86 Impact Factor
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    ABSTRACT: To assess the in vitro effectiveness of preservative-free lidocaine 1% in removing lens epithelial cells (LECs) from the anterior capsule and to evaluate the effect of lidocaine on the LECs. Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Eight rabbits (16 eyes) were used in the study. After the rabbits were killed, the eyes were enucleated and divided into 2 groups. In Group 1 (n = 8 eyes), LECs were exposed to preservative-free lidocaine 1% or balanced salt solution (BSS) for 1, 2, or 5 minutes. The anterior capsules were then stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken and analyzed for LEC damage. In Group 2 (n = 8 eyes), hydrodissection was performed with 1 of the agents, followed by phacoemulsification and cortical cleanup. The LEC attachment to the anterior capsule was evaluated by histopathology. Anterior capsule fragments irrigated with BSS showed no LEC nuclear staining; ie, no direct toxic effect. In those irrigated with preservative-free lidocaine 1%, the LECs showed mild toxicity; some cells showed blue nuclear staining. After hydrodissection with lidocaine, the capsules were almost free of LECs; after hydrodissection with BSS, the capsules showed a normal layer of LECs attached to the anterior capsule. Preservative-free lidocaine 1% may help diminish the amount of live LECs by facilitating cortical cleanup, by loosening the desmosomal area of cell-cell adhesion with decreased cellular adherence, or by a direct toxic effect. The use of this agent may help prevent posterior capsule opacification.
    Journal of Cataract and Refractive Surgery 09/2003; 29(8):1585-92. · 2.53 Impact Factor
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    ABSTRACT: We describe different methods to prepare postmortem human or animal eyes used at the Center for Research in Ocular Therapeutics and Biodevices at the Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA. These techniques have been utilized for performing different surgical procedures (phacoemulsification, extracapsular cataract extraction, etc.), and for training of surgeons in-transition. Performing these techniques in the wet-laboratory contributed to improve surgical skills to perform the critical steps of the phacoemulsification surgery. Pathological evaluation of pseudophakic postmortem human eyes using the Miyake-Apple posterior view and histology was helpful to analyze postoperative complications of cataract surgery (anterior capsule opacification and posterior capsule opacification) secondary to postoperative proliferation of lens epithelial cells into the capsular bag. Modifications in the surgical techniques and/or lens design may be helpful to reduce these postoperative complications. Implantation of various aphakic and phakic intraocular lenses in postmortem human eyes as well as animal eyes was helpful to analyze the sizing and fitting of new lens designs within the eye.
    Archivos de la Sociedad Espanola de Oftalmologia 03/2003; 78(2):73-89.
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    ABSTRACT: To evaluate the properties of the AcrySof(R) SA30AL (Alcon Laboratories, Inc.) single-piece foldable posterior chamber intraocular lens (IOL). Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Two nonimplanted clinical-quality AcrySof IOLs were examined by gross, light, and scanning electron microscopy (SEM). In addition, 2 eyes implanted with this IOL obtained post-mortem, the first such eyes accessioned in our laboratory and the first described to date, were examined using the Miyake-Apple posterior photographic technique and by histologic sections. Scanning electron microscopy of the SA30AL IOL showed excellent surface finish. The edge of the optic was square (truncated) and had a matte (velvet or ground-glass) appearance, a feature that may minimize edge glare and other visual phenomena. A well-fabricated square or truncated optic edge was demonstrated. Miyake-Apple analysis revealed that the SA30AL IOL showed appropriate fit and configuration within the capsular bag. Histologic correlation of the IOL's square edge and its relation to the capsular bag and adjacent Soemmering's ring were noted. The AcrySof SA30AL IOL is a well-fabricated lens that situates well in the capsular bag. The truncated optic and its relationship to adjacent structures show a morphological profile that has been shown to be highly efficacious in reducing the rate of posterior capsule opacification.
    Journal of Cataract and Refractive Surgery 02/2003; 29(1):164-9. · 2.53 Impact Factor
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    ABSTRACT: To report two cases of diffuse epithelial downgrowth after clear cornea phacoemulsification and to review the different treatment options for this ominous disease. Two interventional case reports. Retrospective review of two eyes from two different patients in whom epithelial downgrowth developed 7 and 3 months after uneventful clear cornea phacoemulsification. In the first case, the epithelial invasion seemed to be growing from the temporal incision site onto the corneal endothelium toward the visual axis. Cryotherapy was applied to the affected cornea, with control of the growing membrane. A penetrating keratoplasty was performed to restore visual function. In the second patient, the membrane was attached to the iris and posterior cornea and was confirmed by diagnostic argon laser photocoagulation. This case was surgically treated with en bloc excision and a corneoscleral graft. Visual acuity at the final follow-up visit. Surgical treatment of the epithelial downgrowth was different for both patients. In the postoperative period, a best-corrected visual acuity of 20/60 and 20/30 was achieved in each case. No regrowth of the membrane was observed. Treatment of epithelial downgrowth is controversial. We present two cases of epithelialization of the anterior chamber with either clinical or histologic confirmation after clear cornea sutureless phacoemulsification. Surgical treatment should be attempted promptly to obtain a good visual prognosis.
    Ophthalmology 01/2003; 109(12):2331-5. · 5.56 Impact Factor
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    ABSTRACT: Describimos las técnicas para preparar ojos humanos o animales obtenidos postmortem empleados en el Centro de Investigaciones en Terapéutica Ocular y Bio-implantes, Storm Eye Institute, Medical University of South Carolina, Charleston, SC, EE.UU. Estas técnicas han sido utilizadas para prácticar diferentes procedimientos quirúrgicos (facoemulsificación, extracción extracapsular de cristalino, etc.), y para el entrenamiento de cirujanos en transición. La práctica de estas técnicas en el laboratorio ha contribuido a mejorar la habilidad quirúrgica para realizar los pasos críticos de la cirugía de facoemulsificación. La evaluación patológica de los globos humanos pseudofáquicos obtenidos postmortem mediante la técnica posterior de Miyake-Apple, y el análisis histológico han sido fundamentales en el estudio de complicaciones postoperatorias de cirugía de catarata (opacidad de cápsula anterior, opacidad de cápsula posterior) secundarias a proliferación postoperatoria de células epiteliales del cristalino dentro del saco capsular. Las modificaciones en las técnicas quirúrgicas y en el diseño de las lentes intraoculares han ayudado a disminuir estas complicaciones postoperatorias. El implante de diferentes tipos de lentes afáquicos y fáquicos en ojos humanos y animales obtenidos postmortem ha permitido un mejor análisis del tamaño y la posición de nuevos diseños de lentes dentro del ojo.
    Archivos de la Sociedad Espanola de Oftalmologia 01/2003; 78(2).
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    ABSTRACT: PurposeTo evaluate the properties of the AcrySof® SA30AL (Alcon Laboratories, Inc.) single-piece foldable posterior chamber intraocular lens (IOL).
    Journal of Cataract and Refractive Surgery - J CATARACT REFRACT SURG. 01/2003; 29(1):164-169.
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    ABSTRACT: To report 25 cases of gradual, but sometimes progressive, late-postoperative degeneration of polymethyl methacrylate (PMMA) optics of posterior chamber (PC) intraocular lens (IOL) implants, often resulting in a clinically significant visual decrease long after the implantation, sometimes to a severity that required IOL explantation/exchange. Analysis of explanted PC IOLs, clinical histories, and photographs. We analyzed 25 case histories/photographs and/or explants from 18 patients implanted in the 1980s to mid-1990s with three-piece PC IOLs with PMMA optics and with polypropylene or PMMA haptics. The IOL optic from each case had characteristic snowflake or crystalline opacifications. This condition occurred with more than one manufacturer and in some cases was restricted to certain lot numbers. The explanted IOLs (n = 10) were studied by gross inspection and by light and scanning electron microscopy, as well as confocal and energy dispersive spectroscopy. The snowflake lesions were noted within the IOL optics. The nature of these lesions was investigated. Assimilation of clinical information with pathologic and morphologic profiles of all cases suggested that the snowflake opacification was a small spherical lesion surrounded by an outer pseudocapsule composed of compressed, degenerated PMMA, with a central core containing convoluted fragments of PMMA. The lesions were classified into four clinical and pathologic grades according to their density and severity. This is the first clinicopathologic correlative report on this complication. We postulate that manufacturing variations in some IOL models fabricated in the 1980s and early 1990s are responsible. The snowflake lesions seem to represent a destruction of the PMMA material. The cluster of lesions in implanted lenses manufactured by Surgidev was less progressive than some other models, including lenses made by IOPTEX Research Corporation. This identification of a condition previously unreported is important to alert clinicians regarding these perplexing lesions that may otherwise be considered idiopathic, with no obvious clinical hint as to their origin. The prevalence noted thus far is still too low to in any way suggest that this condition would occur in 100% of PMMA IOLs from these manufacturers. However, these late-occurring lesions, present in lens models that were implanted in hundreds of thousands of patients in the last decade or so, could have constituted a true epidemic, except that many of the patients are now deceased.
    Ophthalmology 10/2002; 109(9):1666-75. · 5.56 Impact Factor
  • Der Ophthalmologe 10/2002; 99(9):732-3. · 0.53 Impact Factor
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    ABSTRACT: As of December 31, 2000, the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy rate for the Alcon AcrySof intraocular lens (IOL) as measured in our database was 3.3%. This was the lowest of any IOL model used in the United States. Only 12 of 361 cases required treatment. We analyzed possible surgical reasons that may have been responsible for the posterior capsule opacification (PCO) in this small group. Special attention was given to the three surgical factors that we had previously identified as being important for PCO reduction: (1) quality of cortical clean up, (2) type of haptic fixation, and (3) continuous curvilinear capsulorhexis (CCC) size and shape. Comparative autopsy tissue analysis. Three hundred sixty-one human eyes obtained postmortem with Alcon AcrySof IOLs, accessioned between January 1995 and December 2000 from Lions Eye Banks. The eyes were evaluated by the Miyake-Apple posterior photographic technique. The area and intensity of Soemmering's ring and type of fixation were studied in 361 eyes. The size and shape of the CCC and relation of the CCC edge to the IOL's optic rim were analyzed in 168 eyes. The amount of Soemmering's ring formation was significantly larger in the group of IOLs requiring Nd:YAG capsulotomy (Nd:YAG group). The not in-the-bag fixated IOLs required more Nd:YAG capsulotomies. Although the trend was clear, the number of specimens was not large enough to acquire statistical significance. The Nd:YAG group showed a highly significant difference compared with the No Nd:YAG group with regard to the amount of clock hours of the CCC edge on the optic rim's surface (P < 0.001). Mean CCC diameters were significantly larger in the Nd:YAG group (P < 0.05). The amount of Soemmering's ring correlates with the quality of cortical clean up. Cells within the Soemmering's ring are the direct precursors of PCO. This study confirms our previous laboratory studies and the clinical assumption that the incidence of PCO and thus the need for Nd:YAG capsulotomy is correlated with the cortical clean up. A second clinical assumption, that poor IOL fixation increases the risk of PCO, is also strongly suggested in this study. This study also verifies the relation of the CCC to PCO and the Nd:YAG laser, namely that a relatively small CCC without tears is best to prevent this complication. Use of a high-quality IOL combined with diligent attention to these three surgical factors should lower further the incidence of PCO.
    Ophthalmology 09/2002; 109(8):1421-6. · 5.56 Impact Factor
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    ABSTRACT: To analyze the rates of and reasons for intraoperative explantation of foldable and rigid intraocular lenses (IOLs) to determine the complication profile of each IOL design. Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. The study comprised data analysis of foldable (n = 85) and rigid (n = 15) IOL specimens that were explanted immediately after primary implantation. Eighty-five foldable intraoperative explants were accessioned. These comprised 14.5% of the 586 foldable IOL explants received between January 1988 and September 2000. There were 15 rigid poly(methyl methacrylate) (PMMA) intraoperative explants out of 2077 rigid explant specimens (0.7%). Fifty-one (60%) of the foldable IOLs requiring intraoperative explantation were the 1-piece silicone plate-haptic large-hole design, and 29 (34.1%) were the 3-piece silicone polyimide-haptic design. The most frequent reason for explantation of both designs was optic damage, 37.3% in the large-hole design and 55.2% in the polyimide design. Optic damage did not occur in rigid PMMA IOLs. Some foldable IOL designs have a higher risk of damage during surgical insertion than rigid designs. Two modern foldable IOLs, the silicone plate-haptic large-hole and the silicone polyimide-haptic, appear to be more prone to damage during folding, loading, and implantation than other IOLs.
    Journal of Cataract and Refractive Surgery 08/2002; 28(7):1223-8. · 2.53 Impact Factor
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    ABSTRACT: To analyze the effect of different haptic angulations on posterior capsule opacification (PCO) in a modern foldable intraocular lens (IOL) with a square-edged optic designed to reduce the incidence of PCO. Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Ten Dutch Belted, serum Pasteurella-free pigmented rabbits of the same age and sex had bilateral phacoemulsification with endocapsular IOL implantation. The eyes were implanted with Centerflex IOLs (Rayner) with haptic angulations of 0 degree (n = 8), 5 degrees (n = 4), 10 degrees (n = 4), or 15 degrees (n = 4). There was no statistical difference in central PCO, peripheral PCO, and measured IOL decentration among the angulation groups. With the Centerflex IOL, haptic angulation did not seem to be a significant factor influencing PCO. It appears that the barrier effect of the IOL's truncated, square-edged optic overrides the angulation factor in preventing PCO.
    Journal of Cataract and Refractive Surgery 08/2002; 28(7):1251-5. · 2.53 Impact Factor
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    ABSTRACT: To assess the development of posterior capsule opacification (PCO) with 3 modern single-piece foldable intraocular lenses (IOLs) in a histopathological study and to compare the potential preventive effects of the IOL design and biomaterial in retarding PCO. Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Thirty-one rabbit eyes were randomly operated on with phacoemulsification and implantation of 3 single-piece foldable lenses: a hydrophilic acrylic design, the Rayner Centerflex 570H (n = 11); a hydrophobic acrylic design, the Alcon AcrySof SA30AL (n = 10); and a silicone large-hole plate design, the Staar AA-4203VF (n = 10). Central PCO (CPCO), peripheral PCO (PPCO), and Soemmering's ring formation were evaluated 3 weeks after surgery using the Miyake-Apple posterior photographic technique. Histological sections of each globe were prepared to document capsular bag status and performance of IOL geometry. The acrylic IOLs (Centerflex and AcrySof) had lower CPCO and PPCO scores than the silicone plate IOL (P <.05). There was no significant difference in Soemmering's ring formation among the 3 models. Pathological evaluations revealed effective blockage of migrating lens epithelial cells (LECs) at the site of the truncated optic edge of the Centerflex and AcrySof IOLs, even in the presence of large amounts of retained/regenerative cortical material. The AcrySof IOL has a hydrophobic surface and the Centerflex a hydrophilic surface, but no correlation to these characteristics could be identified. The single-piece AcrySof optic geometry created a clear-cut barrier effect equal to that of its 3-piece predecessor. The anatomic profile of the Centerflex IOL shows the same characteristics. The optics of both acrylic lenses have square truncated edges that functionally block ingrowth of migrating LECs toward the central visual axis, leaving clear posterior capsules. The square optic edge was an appropriate geometric configuration to create a barrier effect. There was no effect of the biomaterial on PCO prevention.
    Journal of Cataract and Refractive Surgery 07/2002; 28(7):1241-50. · 2.53 Impact Factor
  • Ophthalmologe. 01/2002; 99(9):732-733.
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    ABSTRACT: Purpose: To analyze the effect of different haptic angulations on posterior capsule opacification (PCO) in a modern foldable intraocular lens (IOL) with a square-edged optic designed to reduce the incidence of PCO.Setting: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.Methods: Ten Dutch Belted, serum Pasteurella-free pigmented rabbits of the same age and sex had bilateral phacoemulsification with endocapsular IOL implantation. The eyes were implanted with Centerflex® IOLs (Rayner) with haptic angulations of 0 degree (n = 8), 5 degrees (n = 4), 10 degrees (n = 4), or 15 degrees (n = 4).Results: There was no statistical difference in central PCO, peripheral PCO, and measured IOL decentration among the angulation groups.Conclusion: With the Centerflex IOL, haptic angulation did not seem to be a significant factor influencing PCO. It appears that the barrier effect of the IOL’s truncated, square-edged optic overrides the angulation factor in preventing PCO.
    Journal of Cataract and Refractive Surgery - J CATARACT REFRACT SURG. 01/2002; 28(7):1251-1255.
  • Source
    S Arthur, L L Steed, D J Apple, Q Peng, G Howard, M Escobar-Gomez
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    ABSTRACT: Scedosporium prolificans is a soil saprophyte that is associated with a large variety of infectious processes and with respiratory colonization in immunocompetent and immunocompromised patients. We report the first described case of S. prolificans keratouveitis associated with the intraocular long-term retention of a contact lens in a 76-year-old female patient.
    Journal of Clinical Microbiology 01/2002; 39(12):4579-82. · 4.07 Impact Factor
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    ABSTRACT: Purpose: To analyze the rates of and reasons for intraoperative explantation of foldable and rigid intraocular lenses (IOLs) to determine the complication profile of each IOL design.Setting: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.Methods: The study comprised data analysis of foldable (n = 85) and rigid (n = 15) IOL specimens that were explanted immediately after primary implantation.Results: Eighty-five foldable intraoperative explants were accessioned. These comprised 14.5% of the 586 foldable IOL explants received between January 1988 and September 2000. There were 15 rigid poly(methyl methacrylate) (PMMA) intraoperative explants out of 2077 rigid explant specimens (0.7%). Fifty-one (60%) of the foldable IOLs requiring intraoperative explantation were the 1-piece silicone plate-haptic large-hole design, and 29 (34.1%) were the 3-piece silicone polyimide-haptic design. The most frequent reason for explantation of both designs was optic damage, 37.3% in the large-hole design and 55.2% in the polyimide design. Optic damage did not occur in rigid PMMA IOLs.Conclusion: Some foldable IOL designs have a higher risk of damage during surgical insertion than rigid designs. Two modern foldable IOLs, the silicone plate-haptic large-hole and the silicone polyimide-haptic, appear to be more prone to damage during folding, loading, and implantation than other IOLs.
    Journal of Cataract and Refractive Surgery - J CATARACT REFRACT SURG. 01/2002; 28(7):1223-1228.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To assess the development of posterior capsule opacification (PCO) with 3 modern single-piece foldable intraocular lenses (IOLs) in a histopathological study and to compare the potential preventive effects of the IOL design and biomaterial in retarding PCO.Setting: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.Methods: Thirty-one rabbit eyes were randomly operated on with phacoemulsification and implantation of 3 single-piece foldable lenses: a hydrophilic acrylic design, the Rayner Centerflex® 570H (n = 11); a hydrophobic acrylic design, the Alcon AcrySof® SA30AL (n = 10); and a silicone large-hole plate design, the Staar AA-4203VF (n = 10). Central PCO (CPCO), peripheral PCO (PPCO), and Soemmering’s ring formation were evaluated 3 weeks after surgery using the Miyake−Apple posterior photographic technique. Histological sections of each globe were prepared to document capsular bag status and performance of IOL geometry.Results: The acrylic IOLs (Centerflex and AcrySof) had lower CPCO and PPCO scores than the silicone plate IOL (P < .05). There was no significant difference in Soemmering’s ring formation among the 3 models. Pathological evaluations revealed effective blockage of migrating lens epithelial cells (LECs) at the site of the truncated optic edge of the Centerflex and AcrySof IOLs, even in the presence of large amounts of retained/regenerative cortical material.Conclusions: The AcrySof IOL has a hydrophobic surface and the Centerflex a hydrophilic surface, but no correlation to these characteristics could be identified. The single-piece AcrySof optic geometry created a clear-cut barrier effect equal to that of its 3-piece predecessor. The anatomic profile of the Centerflex IOL shows the same characteristics. The optics of both acrylic lenses have square truncated edges that functionally block ingrowth of migrating LECs toward the central visual axis, leaving clear posterior capsules. The square optic edge was an appropriate geometric configuration to create a barrier effect. There was no effect of the biomaterial on PCO prevention.
    Journal of Cataract and Refractive Surgery - J CATARACT REFRACT SURG. 01/2002; 28(7):1241-1250.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective To report two cases of diffuse epithelial downgrowth after clear cornea phacoemulsification and to review the different treatment options for this ominous disease.
    Ophthalmology 01/2002; 109(12):2331-2335. · 5.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective To report 25 cases of gradual, but sometimes progressive, late-postoperative degeneration of polymethyl methacrylate (PMMA) optics of posterior chamber (PC) intraocular lens (IOL) implants, often resulting in a clinically significant visual decrease long after the implantation, sometimes to a severity that required IOL explantation/exchange.
    Ophthalmology 01/2002; 109(9):1666-1675. · 5.56 Impact Factor

Publication Stats

850 Citations
137.56 Total Impact Points

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Institutions

  • 2001–2003
    • Medical University of South Carolina
      • • Department of Ophthalmology
      • • Storm Eye Institute
      Charleston, SC, United States