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Suresh K Pandey

Publications and source records attributed to Suresh K Pandey.

46 records · Page 3Linked to original sources
PubMed2002

Rates and causes of intraoperative removal of foldable and rigid intraocular lenses: clinicopathological analysis of 100 cases.

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.

Device Removal↗
PubMed2002

Evaluation of 3 modern single-piece foldable intraocular lenses: clinicopathological study of posterior capsule opacification in a rabbit model.

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.

Acrylic Resins↗
PubMed2002

Loop memory of haptic materials in posterior chamber intraocular lenses.

PURPOSE: To compare the shape recovery ratios after compression of haptic materials used in the manufacture of intraocular lenses (IOLs). SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: The loop memory of 40 silicone-optic posterior chamber IOLs was studied. All the IOLs had modified-C haptics made of poly(methyl methacrylate) (PMMA; n = 10), polyimide (n = 10), polyvinylidene fluoride (PVDF; n = 10), and polypropylene (PP; n = 10). After the overall diameter of each lens was measured (day 0), the lenses were inserted into plastic wells (9.5 mm in diameter) and immersed in water (37 degrees C) for 1 month. They were then placed on an open plate and allowed to reexpand for 2 months. Overall diameter measurements were performed within 5 minutes of the IOLs' removal from the wells and at subsequent time points (days 14, 28, 30, 60, 74, 88, and 95). RESULTS: The loop memory of each lens was expressed as the difference between the initial overall diameter measurement (pretest) and the measurement at each time point; the lower the value, the higher the memory. The overall difference among the 4 groups was statistically significant at each time point (P < or = .001). From days 30 to 95, silicone-PMMA, silicone-elastimide, and silicone-PVDF IOLs had similar loop memory mean values, which were significantly lower than the mean value of silicone-PP IOLs (P <.05). The latter design tended to be deformed after removal from the wells, with increased optic-haptic angulation. CONCLUSION: Studying the loop memory of haptic materials (PMMA, polyimide, PVDF, and PP) used in the manufacture of posterior chamber IOLs can help surgeons choose an appropriate IOL for each patient.

Lenses, Intraocular↗
PubMed2002

A first comparative study of purpurinimide-based fluorinated vs. nonfluorinated photosensitizers for photodynamic therapy.

A first report on the synthesis and comparative in vitro-in vivo photosensitizing efficacy of various fluorinated and the corresponding nonfluorinated, purpurinimide-based photosensitizers is discussed. In preliminary in vivo screening, compared with the nonfluorinated analogs, purpurinimides bearing trifluoromethyl substituents showed enhanced photosensitizing efficacy. Among compounds (isomers) with similar lipophilicity, the position of the substituents was found to play a decisive role in biological efficacy.

Animals↗
PubMedDate not supplied

Aqueous infiltration into an implantable miniaturized telescope.

The implantable miniaturized telescope (IMT) is the first intraocular magnifying system proposed for optical correction in patients with age-related macular degeneration (ARMD). The optical component is embedded in a carrying device designed as an intraocular lens that is implanted after cataract surgery. In this study, we report findings on an IMT that was explanted because of aqueous infiltration into its optic and describe the configuration of this device and the surgical technique required for its implantation. The patient, a 75-year-old male with bilateral cataract and nonexudative ARMD, underwent phacoemulsification with implantation of an IMT in the right eye. The rigid device, weighing 46.1 mg in aqueous, has an overall diameter of 13.5 mm and requires implantation through a large limbal incision. It is fixated at the 6 to 12 o'clock meridian. Follow-up examination revealed the presence of numerous droplets inside the IMT optic. The device was explanted and sent to our center for evaluation. A large fissure was found on the carrying device. However, it was unlikely the site for aqueous infiltration. Microdefects at the level of the sealing of the optical cylinder appeared to provide the opening for the inflow of aqueous that formed droplets. Based on the findings of this report the manufacturer has modified the sealing technique to avoid this complication. Current clinical trials are now ongoing to assess the efficacy of this device in providing visual rehabilitation for ARMD patients.

Aged↗
PubMedDate not supplied

Silicone plate-haptic posterior chamber intraocular lens implanted in the anterior chamber: report of a bilateral case and potential complications.

BACKGROUND AND OBJECTIVE: To evaluate possible complications associated with implantation of a posterior chamber (PC) intraocular lens (IOL) in the anterior chamber. MATERIALS AND METHODS: We analyzed a plate-haptic silicone IOL that had been explanted from the anterior chamber of an 83-year-old female. Additionally, the lens was experimentally reimplanted into the anterior chambers of 3 human cadaver eyes. After fixation of the eyes (Karnovsky's solution), the anterior-posterior length, the white-to-white diameter, the angle-to-angle diameter, and the sulcus-to-sulcus diameter were measured. Two different techniques to cut the eyes were used: sagittal section and corneal buttonhole technique. The plate-haptic silicone lens was then implanted in the anterior chamber and sulcus ciliaris of the eyes. A Kelman multiflex IOL was used as a control for anterior chamber implantation. RESULTS: This experiment demonstrated that the plate-haptic silicone IOL lens is too small and thick for implantation in the anterior chamber and in the sulcus. The lens could easily rotate in the anterior chamber and also dislocate inferiorly, obstructing the visual axis by its edge. The thickness of the lens theoretically could also cause endothelial cell damage and mechanical iris irritation resulting in chronic uveal inflammation. CONCLUSION: This case and experiment should help surgeons realize the risk and potential for IOL-missizing complications that may be caused if a lens design for the capsular bag is implanted in the anterior chamber, especially if a plate-haptic PC-IOL design is used.

Aged↗
PubMedDate not supplied

Opacification of two hydrophilic acrylic intraocular lenses 3 months after implantation.

BACKGROUND AND OBJECTIVE: To report clinical, pathologic, histochemical, ultrastructural, and spectrographic analyses of explanted hydrophilic acrylic intraocular lenses (IOLs) obtained from two patients who had early visual disturbances caused by postoperative opacification of the lens optic. MATERIALS AND METHODS: Two hydrophilic IOLs were explanted from patients with decreased visual acuity. The patients became symptomatic 3 months after uneventful phacoemulsification and lens implantation. IOL optic opacification was associated with a fine granularity within the substance of the lens optic. The IOLs were examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red (a special stain for calcium). Some sections were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: Microscopic analyses revealed the presence of multiple fine, granular deposits of variable sizes within the optics of the lenses distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optics' surface. Extension of the opacification into the haptics of the IOLs could also be observed. The deposits stained positive with alizarin red. Energy dispersive x-ray spectroscopy of the internal substance of the IOLs also demonstrated the presence of calcium within the deposits. CONCLUSIONS: This is the first clinicopathologic report of optic and haptic opacification occurring with this hydrophilic acrylic IOL model only 3 months postoperatively. Further studies on other similar cases with this lens should be done to determine the incidence and possible mechanisms of this phenomenon.

Acrylic Resins↗