Biomedical subjects

D Tognetto

Publications and source records attributed to D Tognetto.

11 recordsLinked to original sources

PubMed2001

Inflammatory cell adhesion and surface defects on heparin-surface-modified poly(methyl methacrylate) intraocular lenses in diabetic patients.

PURPOSE: To evaluate the incidence of surface scratches on heparin-surface-modified (HSM) poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) and the possible influence of these alterations on the biocompatibility of HSM PMMA. SETTING: University Eye Clinic of Trieste, Trieste, Italy. METHODS: Twenty-six diabetic patients had phacoemulsification and implantation of an HSM PMMA IOL (809C, Pharmacia & Upjohn). Patients with proliferative diabetic retinopathy or iridopathy were excluded from the study. On postoperative days 7, 30, 90, and 180, specular microscopy was performed to study and photograph the anterior IOL surface. The presence of scratches on the anterior IOL surface was assessed and the inflammatory cell reaction noted and graded using a semiquantitative scale. Finally, the location of the inflammatory cells in relation to the surface scratches was established. RESULTS: Scratches and other surface defects were found in 88.4% of cases. All patients had small cells on the IOL surface 7 days after surgery. At 30 days, small cells were observed in 88.4% of cases. The inflammatory cells were mainly located inside the scratches rather than throughout the IOL surface. CONCLUSIONS: This in vivo cytology study provides further evidence of the effectiveness of heparin surface modification in improving the biocompatibility of PMMA. In diabetic patients, inflammatory cells adhered to the exposed PMMA surface more than to the HSM surface, suggesting that the use of HSM PMMA in patients with conditions predisposing them to increased postoperative blood-aqueous barrier breakdown is beneficial.

Cell Adhesion↗

PubMed2001

Iris alteration using mechanical iris retractors.

A 74-year-old woman had a 3-port pars plana vitrectomy for a dropped nucleus after complicated phacoemulsification. Flexible nylon iris retractors were positioned to dilate the small pupil. The patient died of a pulmonary embolus 1 day after surgery. The eyeball was removed at autopsy, and pathology of the iris was investigated. Localized damage to the iris where the retractor hooks were positioned was noted, but no other alterations to the iris were observed. These findings may explain the recovery of pupil function that is common after surgery with mechanical iris retractors.

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PubMed2001

Comparative evaluation of corneal epithelial permeability after the use of diclofenac 0.1% and flurbiprofen 0.03% after phacoemulsification.

PURPOSE: To assess the corneal epithelial function after prolonged topical administration of diclofenac 0.1% and flurbiprofen 0.03% single-dose eyedrops. SETTING: University Eye Clinic of Trieste, Trieste, Italy. METHODS: This randomized prospective study comprised 24 patients scheduled for phacoemulsification. The patients were randomly assigned to receive diclofenac or flurbiprofen eyedrops for 2 months after surgery. Corneal epithelial permeability was determined by fluorophotometry 7, 37, and 67 days after surgery. RESULTS: An increase in corneal epithelial permeability was observed in the diclofenac group 37 and 67 days after surgery. No epithelial function alterations occurred in the flurbiprofen group. CONCLUSIONS: Subclinical impairment of the epithelial function was observed during topical treatment with diclofenac 0.1% single-dose eyedrops after phacoemulsification. The mechanism responsible for this effect remains unknown.

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PubMed2000

Pit defects on the anterior surface of hydrophilic foldable intraocular lenses.

A series of pits varying in depth and size appeared on the anterior surface of hydrogel intraocular lenses (IOLs) soon after they were implanted. In all cases, the pits increased in size but not in number during a 1 year follow-up. The origin of the pit defects is unknown and does not seem related to inflammatory or lens epithelial cell activity. Hydration of the IOL could be a cause even if a manufacturing defect were present. This IOL surface alteration did not seem to impair visual function or cause visual disturbances.

Acrylic Resins↗

PubMed1999

Spontaneous dislocation into the vitreous of a poly(methyl methacrylate) disc lens 9 years after surgery.

A 76-year-old woman had sudden visual loss 9 years after an extracapsular cataract extraction with implantation of a poly(methyl methacrylate) disc intraocular lens (IOL) in the capsular bag. Slitlamp examination showed the disc IOL had luxated into the vitreous through a linear inferior opening in the capsular bag; the IOL lay on the retinal surface. A pars plana vitrectomy was performed. The vitreous cavity was filled with perfluorocarbon liquid, floating the IOL to behind the iris. The IOL was removed through a limbal incision, then another type of IOL was implanted in the ciliary sulcus using transscleral fixation. Thirty days after surgery, best corrected visual acuity (BCVA) was 20/20. At 2 months, total retinal detachment appeared with a large superior retinal dialysis. Another pars plana vitrectomy was performed and the scleral-fixated IOL removed through a limbal incision. Internal gas tamponade was used. The eye was left aphakic. Final BCVA was 20/25.

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PubMed1997

Postoperative cellular reaction on various intraocular lens materials.

PURPOSE: The presence of cellular deposits on the surface of intraocular lenses (IOLs) is a manifestation of: (1) the breakdown of the blood-aqueous barrier produced by surgery; and (2) foreign body reaction induced by lens implantation. The purpose of this study was to assess the presence of cellular deposits on the surfaces of various IOL materials. METHODS: Fifty patients scheduled for cataract surgery were randomized into five groups of ten patients each and received IOLs of the following materials: conventional polymethylmethacrylate (PMMA), surface-passivated PMMA, heparin-surface modified PMMA, poly-hydroxyethylmethacrylate (HEMA) hydrogel and silicone. Patients were examined at 7 days, 30 days, 90 days, and 180 days after surgery. All eyes were observed first via slit-lamp and then using a contact specular microscope for photographic documentation. RESULTS: Small, spindle-shaped cells were observed on all IOLs in the early postoperative period. Epithelioid cells appeared approximately 30 days after surgery on all PMMA IOLs, but most particularly on conventional PMMA IOLs. No cells were observed on poly-HEMA and silicone IOLs. CONCLUSIONS: The decreased number of epithelioid cells discovered in the early postoperative period may indicate a reduction in the inflammatory process induced by surgery. The permanence of epithelioid cells on IOL surfaces may be a sign of foreign body reaction. The results of this study indicated that poly-HEMA and silicone IOLs showed fewer cellular deposits than PMMA IOLs, suggesting that they may be better tolerated than PMMA IOLs.

Biofilms↗

PubMed1997

Corneal endothelial function after extracapsular cataract extraction and phacoemulsification.

PURPOSE: To compare the morphology and function of the corneal endothelium in the early postoperative period after extracapsular cataract extraction (ECCE) and phacoemulsification. SETTING: University Eye Clinic of Trieste, Italy. METHODS: In this prospective, randomized study of patients scheduled for cataract surgery, 40 patients were divided into two groups of 20 patients each. Group 1 had ECCE and Group 2, phacoemulsification; both had capsular bag intraocular lens (IOL) implantation. Preoperatively and 7 and 30 days postoperatively, a complete ophthalmological examination, endothelial specular microscopy, ultrasonic pachymetry, and anterior segment fluorophotometry were done. Visual acuity, endothelial cell density, cell size variation coefficient, corneal thickness, endothelial permeability coefficient, and endothelial pump function were studied. RESULTS: Visual acuity was better 7 days after phacoemulsification than after ECCE, but no differences were observed after 30 days. No significant differences in postoperative loss of endothelial cells were found between the two groups. Coefficient of variation in size, corneal thickness, and endothelial permeability significantly increased in both groups 7 days postoperatively, but only in the ECCE group 30 days postoperatively; the differences between the two groups were statistically significant. Endothelial pump function significantly increased after 7 days in only the phacoemulsification group. CONCLUSIONS: Functional endothelial failure occurred in the early period after ECCE. Phacoemulsification seemed to minimize postoperative functional damage to the endothelium.

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PubMed1997

Corneal endothelial protection by different viscoelastics during phacoemulsification.

PURPOSE: To evaluate corneal endothelium morphology and function after phacoemulsification using different viscoelastics. SETTING: Eye Clinic, University of Trieste, Italy. METHODS: This prospective, randomized study included results of preoperative and postoperative (7, 30, and 90 days) examinations of 66 patients scheduled for phacoemulsification without ocular pathology; 8 patients were excluded. Patients were randomly assigned to one of four groups based on type of viscoelastic used: 1% sodium hyaluronate (Healon); 1.4% sodium hyaluronate (Healon GV); 4% sodium chondroitin sulfate-3% sodium hyaluronate (Viscoat); 2% hydroxypropyl methylcellulose (Hymecel). Mean cell density and cell size variation coefficient were determined by specular microscopy; central corneal thickness, by ultrasonic pachymetry; and endothelial permeability coefficient and active pump function, by anterior segment fluorophotometry. RESULTS: There were no significant differences in postoperative mean cell loss among the groups. The cell size variation coefficient was altered in all groups 7 days after surgery and was still impaired at 30 days in the Hymecel group. A significant increase in mean corneal thickness, endothelial permeability, and active pump function occurred in the Healon and Hymecel groups 7 days after surgery. These parameters were still altered 30 days after surgery in the Hymecel group. Endothelial functional alterations did not occur in the Healon GV or Viscoat group. CONCLUSION: Viscoat and Healon GV are effective in minimizing functional damage of endothelial structure in the early medium-term postoperative period.

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PubMed1994

Heparin-surface-modified intraocular lens implantation in eyes with pseudoexfoliation syndrome.

Eyes with pseudoexfoliation syndrome have a greater risk of intraoperative and postoperative complications. Clinical and histopathological studies indicate that heparin-surface-modified intraocular lenses (HSM IOLs) can reduce postoperative anterior segment inflammation. Our study evaluated the blood-aqueous barrier permeability in eyes with pseudoexfoliation syndrome and implanted with an HSM IOL. We examined two groups of 20 patients, one comprising patients with pseudoexfoliation syndrome and one a sex- and age-matched control group with senile cataracts. Each group was divided into two subgroups of ten patients each. In one subgroup, an HSM IOL was implanted; in the other, a conventional poly(methyl methacrylate) IOL. We performed a complete ophthalmologic examination and iris angiography preoperatively and at 30, 90, and 180 days after surgery. Fluorophotometry was performed at the 90-day and 180-day postoperative examinations. The patients with pseudoexfoliation syndrome had a higher blood-aqueous barrier permeability than did the control group. Permeability decreased significantly three and six months after surgery, especially in the HSM IOL group.

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PubMed1994

Corneal endothelial function in diabetes: a fluorophotometric study.

The corneal endothelium in diabetics is particularly susceptible to surgical trauma. This is related to the presence of morphological alterations of endothelial cells and to a supposedly concomitant functional failure of the endothelium in these patients. The aim of our study was to evaluate the corneal endothelial function in diabetics. A fluorophotometric study was performed on 3 groups of diabetic subjects without retinopathy, with nonproliferative retinopathy and with proliferative retinopathy compared with an age-matched control group. We evidenced a significant increase in corneal thickness and in passive corneal permeability in diabetics with severe retinal involvement. These findings are not related with a proportional significant increase in endothelial pump function. We suggest an altered regulation in corneal hydration in diabetic patients depending on the functional failure of endothelial cells that is likely to be connected with corneal biochemical modifications caused by an altered glucidic metabolism.

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PubMedDate not supplied

Capsulorhexis size and posterior capsule opacification.

PURPOSE: Posterior capsule opacification (PCO) after intraocular lens (IOL) implantation has a multifactored pathogenesis. Capsulorhexis and capsular bag implantation of a one-piece, biconvex poly(methyl methacrylate) (PMMA) IOL are likely to reduce the PCO incidence. This study was performed to determine whether an ideal capsulorhexis size able to reduce PCO incidence exists. METHODS: A retrospective study of 107 patients who had extracapsular cataract extraction with capsulorhexis and capsular bag IOL implantation was carried out. The PCO site (central, paracentral, and peripheral) and degree (mild, moderate, and severe) were evaluated in relation to the capsulorhexis edge location relative to the IOL optic. Slitlamp biomicroscopy and photography and examination with a three-mirror Goldmann lens were performed. Patients were divided into three groups. Group 1: capsulorhexis free edge located on the IOL optic for 360 degrees; Group 2: capsulorhexis free edge located asymmetrically on and peripherally to the IOL optic; Group 3: capsulorhexis free edge located peripherally to IOL optic for 360 degrees. Each group was divided into two subgroups; one received polyHema IOLs and the second, PMMA IOLs. RESULTS: In Groups 1 and 2, the capsular transparency was higher than in Group 3 (P < .04). Central opacification percentage was lower in Group 1 than in Groups 2 and 3 (P < .04). No statistically significant differences between the polyHema and the PMMA subgroups were seen. CONCLUSIONS: Capsulorhexis with a slightly smaller diameter than the IOL optic appears to be better than a large-size capsulorhexis in reducing the incidence of PCO.

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