Biomedical subjects

Giuseppe Ravalico

Publications and source records attributed to Giuseppe Ravalico.

33 records · Page 2Linked to original sources

PubMed2004

Hyperhomocysteinemia and the methylenetetrahydrofolate reductase 677C-T mutation in patients under 50 years of age affected by central retinal vein occlusion.

PURPOSE: To investigate the correlation between increased homocysteine plasma levels and the homozygosity for the 677C-T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in patients aged under 50 years affected by central retinal vein occlusion (CRVO). DESIGN: Prospective, case-control study. PARTICIPANTS AND CONTROLS: Participants included 31 consecutive patients under 50 years and diagnosed with CRVO. Two controls per case were selected. The first control group (group I) included 31 individuals matched for age, gender, laboratory tests, and the main risk factors for atherosclerosis. The second control group (group II) consisted of 31 volunteers matched only for age and gender. METHODS: Fasting (>10 hours) blood samples were obtained from patients and controls. Blood samples were obtained from patients within 1 week after the onset of the vaso-occlusive event. Molecular genetic analysis for the 677C-T mutation in the MTHFR gene was performed in patients and controls. A plasma homocysteine reading of >12 micromol/l was considered an increase. MAIN OUTCOME MEASURES: The total homocysteine plasma level (determined by the high-performance liquid chromatography method with fluorescence detection) and molecular genetic analysis for the 677C-T mutation in the MTHFR gene in patients and controls. RESULTS: Mean ages were 44.5 years in the group comprising the patients and 44.3 and 44.2 years, respectively, in groups I and II. Mean homocysteine plasma levels were 10.60 micromol/l in patients and 10.39 and 9.34 micromol/l, respectively, in groups I and II. There was no statistically significant difference between mean homocysteine plasma levels in patients and group I controls. In fact, the mean homocysteine plasma level was lower in group II than in patients, and the difference was statistically significant. Homozygosity for the 677C-T mutation in the MTHFR gene was found in 4 patients (12.9%), 5 controls in group I (16.1%), and 4 controls in group II (12.9%). CONCLUSION: The results of the present investigation support the hypothesis that the homocysteine plasma level is not to be considered a primary and independent risk factor for CRVO, but is more likely a marker of atherosclerosis and the consequence of other well-established risk factors. Moreover, the importance of the study design is brought out, because the results we obtained differ on the basis of the considered control group. This feature may in part explain the contradictory results reported in the literature.

Adult↗

PubMed2004

Survey of ophthalmic viscosurgical devices.

PURPOSE OF REVIEW: Cataract treatment is evolving, thanks to new phaco systems and innovative surgical techniques. Recent ophthalmic viscosurgical devices (OVDs) play an important role in the development of new approaches to surgery. Knowledge of the new techniques and advances in new OVDs is crucial to performing routine and complicated surgeries. RECENT FINDINGS: Viscoadaptive substances have been introduced as a particular kind of OVD and are distinguished by high viscosity at a low flow rate and a tendency to fracture at higher flow rates, assuming pseudodispersive behavior. The ultimate soft shell technique emphasizes the rheology of viscoadaptive OVDs to perform phacoemulsification procedures, exploiting all the useful properties of these OVDs in terms of space maintenance and tissue protection. Recent studies have highlighted some new and interesting aspects of the use of OVDs. Current reports suggest that the association of lidocaine and OVD seems to be safe and useful in providing anesthesia during cataract surgery. Concern has been expressed in other studies regarding the presence of contaminants, such as endotoxins, which may be responsible for postoperative uveitis-like reactions. Finally, OVDs are widely known to protect the corneal endothelium during cataract surgery. Their role is also assuming relevance in vitreoretinal surgery. SUMMARY: New OVDs and related techniques represent an advancement in cataract surgery.

Biocompatible Materials↗

PubMed2004

Analysis of the optical quality of intraocular lenses.

PURPOSE: To evaluate the optical quality of different intraocular lenses (IOLs). METHODS: An optical test bench and suitable software were used to assist in analysis of the optical Fourier transform (OFT) of a test image and to determine the quality of the lens in terms of spatial frequency response. The OFT was automatically converted, by means of an optical-electronic calibration procedure, into a modulation transfer function (MTF) for each lens. The passband value calculated by computer analysis of the MTF is an objective index of the lens quality. Three randomly acquired samples of 24 different models of foldable IOLs were compared. Statistical analysis was performed with two-way and one-way ANOVA for repeated measurements and with the Ryan-Einot-Gabriel-Welsch multiple F test. RESULTS: The method was demonstrated to be precise and accurate. A large range of passband values was found. Statistically significant differences between the mean passband values for different lenses were found. The lowest passband value (125.60 line pairs [lp]/mm) was measured for the IOL (Lenstec LH3000; Lenstec, Inc., St. Petersburg, FL) and the highest (191.48 lp/mm) for the Acrysof SA30AL (Alcon, Fort Worth, TX). CONCLUSIONS: Different IOLs can transmit different spectra of spatial frequencies. The best frequency response was provided by acrylic IOLs, particularly those with an asymmetrically biconvex profile. This could be due to a reduction of optical degradation provided by this type of profile. A lens with a higher frequency response should determine a better quality of vision once implanted and the frequency response should therefore be considered when choosing the intraocular lens model.

Fourier Analysis↗

PubMed2004

Prismatic correction in patients affected by age-related macular degeneration.

OBJECTIVE: To evaluate by means of a controlled clinical trial the effectiveness and the tolerance of prismatic correction in improving visual function in patients affected by advanced bilateral age-related macular degeneration. SETTING: Department of Ophthalmology, Eye Clinic, University of Trieste. SUBJECTS AND INTERVENTIONS: Each patient underwent an ophthalmologic examination, complete with distance visual acuity measurement using the Standard Early Treatment Diabetic Retinopathy Study chart. Patients were then randomly assigned to the treatment or control group. The treatment group received spectacles lenses with a prismatic correction of low power (5-7 prismatic dioptres) in the better eye. MAIN MEASURES: Visual acuity was measured at baseline and 1, 90, 180 and 360 days after prescription in both groups. RESULTS: The treatment group consisted of 14 patients, while the control group was of 14 patients. The prismatic correction was well tolerated in 85.7% of cases. Visual acuity in the treatment group improved mostly at three-month follow-up, with a slight further improvement at the six- and 12-month follow-ups, showing a statistically significant difference in comparison with the control group. No visual acuity improvement was registered in the control group. CONCLUSION: Monolateral prismatic correction may be considered a viable means to improve visual function in patients affected by bilateral age-related macular degeneration at an advanced stage.

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PubMed2003

Hydrophobic acrylic versus heparin surface-modified polymethylmethacrylate intraocular lens: a biocompatibility study.

BACKGROUND: The implant of intraocular lenses (IOLs) following cataract surgery induces a foreign-body reaction to the IOL and a response on the part of the lens epithelial cells (LECs). The purpose of this study was to compare these aspects after the implantation of two different IOL materials. METHODS: Thirty-six cataract patients were randomised to receive two different foldable lens: an acrylic hydrophobic IOL (Acrysof MA30BA) and a heparin surface-modified (HSM) polymethylmethacrylate IOL (Pharmacia & Upjohn 809C) after phacoemulsification. Slit-lamp biomicroscopy with specular technique was used to assess the inflammatory cell adhesion on the anterior IOL surface, anterior capsule opacification (ACO) and membrane growth from the rhexis edge at 7, 30, 90, 180 and 360 days after surgery. RESULTS: The 809C group showed a higher percentage of patients with slight inflammatory cell adhesion on the anterior cell surface and a higher small cellular density during the whole follow-up period. The epithelioid cell response was greater in the 809C group than the Acrysof group but the difference between the two groups was not statistically significant. The ACO increased during the follow-up in both groups but was significantly higher in the 809C group. CONCLUSION: Acrysof lenses are more biocompatible than HSM IOLs, showing a lower grade of inflammatory cell adhesion and ACO. The implantation of these lenses may be particularly indicated in patients with pathologies predisposing to blood-aqueous barrier damage.

Acrylates↗

PubMed2003

Photodynamic therapy of subfoveal recurrences after laser photocoagulation of extrafoveal choroidal neovascularization in pathologic myopia.

BACKGROUND: Photodynamic therapy with verteporfin (Visudyne; Novartis, Bülach, Switzerland) has been proposed for the treatment of subfoveal choroidal neovascularization secondary to pathologic myopia. We retrospectively evaluated the effects of verteporfin therapy of subfoveal recurrences of extrafoveal myopic CNV previously treated with thermal laser photocoagulation. METHODS: Twelve eyes, previously treated with thermal laser photocoagulation for extrafoveal choroidal neovascularization, received photodynamic therapy with verteporfin for subfoveal recurrence of choroidal new vessels. Thirteen eyes that did not receive photodynamic therapy served as control group. Vision and fluorescein angiography outcomes were analyzed on all study visits (every 3 months) through month 12. Visual acuity was measured in Snellen lines. RESULTS: On average, at the month 12 examination the verteporfin-treated group had gained 2 lines and the untreated group had lost 1 line of vision. Eleven eyes of the verteporfin-treated group compared with nine eyes of the untreated group lost fewer than 3 lines of vision, including four eyes versus none improving at least 1 line of vision. CONCLUSION: Photodynamic therapy with verteporfin might increase the chance of stabilizing or improving vision in patients with subfoveal recurrences of extrafoveal myopic CNV previously treated with thermal laser photocoagulation. A prospective, randomized study on larger series of patients is mandatory.

Adult↗

PubMed2003

Lens epithelial cell reaction after implantation of different intraocular lens materials: two-year results of a randomized prospective trial.

PURPOSE: To determine the influence of intraocular lens (IOL) material on anterior capsular opacification and membrane growth over the anterior IOL surface in patients who have undergone standardized small-incision cataract surgery and foldable IOL implantation in the capsular bag. DESIGN: Randomized controlled trial. PARTICIPANTS: Eighty-eight cataract patients (88 eyes). METHODS: Patients were randomly assigned to receive one of four different foldable IOLs after phacoemulsification: Storz Hydroview H60M, Corneal ACR6D, AMO SI40NB, and Alcon AcrySof MA60BM. Examinations on days 7, 30, 90, 180, 360, and 720 after surgery included ophthalmologic examination, slit-lamp biomicroscopy, and photography using red reflex and focal illumination of the anterior IOL surface. MAIN OUTCOME MEASURES: Best-corrected visual acuity was measured at each examination. In addition, the anterior capsule opacification and the membrane growth on the anterior IOL surface were graded according to a subjective method by the same researcher. RESULTS: The fibrosis of the anterior capsule was more frequently observed in the group using Corneal ACR6D and AMO SI40NB. The Hydroview and ACR6D groups showed a higher percentage of cases with membrane growth from the rhexis edge on the anterior IOL surface. AcrySof showed the lowest presence of fibrosis of the anterior capsule, and no membrane growth was noted. CONCLUSIONS: Anterior capsule opacification is an index of IOL biocompatibility. The natural location of lens epithelial cells (LECs) precludes the possibility of the IOL's design influencing the anterior capsule behavior. The local response of LECs varies according to the IOL studied. This may be related to the chemical and physical properties of the materials used in the different IOLs.

Adult↗

PubMed2003

Retinal detachment after cataract extraction and refractive lens exchange in highly myopic patients.

PURPOSE: To assess the refractive effects and incidence of postoperative complications in patients with high myopia after cataract extraction. SETTING: University Eye Clinic, Trieste, Italy. METHODS: This noncomparative retrospective study comprised all eyes (N = 388) having cataract extraction and implantation of an intraocular lens with a power less than 11.0 diopters (D) between 1986 and 1999. The preoperative and postoperative refractions; preoperative, postoperative, and final best corrected visual acuity (BCVA); and postoperative complications were analyzed. The mean follow-up was 47.16 months +/- 32.83 (SD) (range 8 to 146 months). RESULTS: Phacoemulsification was performed in 237 eyes, extracapsular cataract extraction in 147 eyes, and intracapsular cataract extraction in 4 eyes. The mean preoperative BCVA was 0.20 +/- 0.21 and the mean postoperative BCVA, 0.58 +/- 0.32. At the final evaluation, the mean BCVA was 0.50 +/- 0.33. The mean refraction was -15.95 +/- 5.86 D preoperatively and -2.00 +/- 1.62 D postoperatively. One eye (0.26%) developed a retinal detachment postoperatively. Of the 127 eyes (32.73%) having a neodymium:YAG laser capsulotomy for posterior capsule opacification, 1 had a macular retinal hole. Posterior detachment of the vitreous occurred in 78.6% of cases. Peripheral retinal photocoagulation was required in 8 cases postoperatively. CONCLUSION: Refractive lens exchange led to good functional results and a low incidence of postoperative complications and can thus be regarded as a viable technique to correct high myopia associated with cataract. However, further study is required before it can be routinely recommended for the correction of high myopia in eyes with a transparent crystalline lens.

Adult↗

PubMed2003

Long-term endothelial changes after implantation of anterior chamber intraocular lenses in cataract surgery.

PURPOSE: To determine and quantify corneal endothelial damage after primary or secondary implantation of anterior chamber intraocular lenses (AC IOLs). SETTING: Eye Clinic, University of Trieste, Trieste, Italy. METHODS: This retrospective study comprised 125 patients who had implantation of an AC IOL from January 1987 to December 1998. The mean follow-up was 5.2 years. The IOLs were the Domilens Chiron Vision Z (n = 52), the Iolab U85J (n = 38), and the AMO AC51B (n = 35). The Konan specular microscope was used to perform full morphometric analysis of the corneal endothelium. The values obtained were compared with those in fellow eyes, which were phakic or pseudophakic with a posterior chamber IOL (PC IOL). Two years later, 63 patients (mean follow-up 2.1 years) had another morphometric analysis and the values obtained were compared with those in the same eye at the previous examination. The Student t test for unpaired groups was used to compare the results at a 5% significance level. RESULTS: The mean endothelial cell density (ECD) was significantly lower in eyes with primary or secondary AC IOL implantation than in unoperated phakic eyes (P<.01). Patients who had primary AC IOL implantation in 1 eye and PC IOL implantation in the fellow eye had a difference in ECD that was not statistically significant. The endothelial cell difference was significantly greater in aphakic patients who had a secondary AC IOL implantation (P<.05). The ECD ranged from 1015 to 2980 cells/mm(2). The endothelium in the various groups showed no significant changes in the coefficient of variation (CV) in cell size. The ECD and endothelial CV in the same eyes at the second examination were not significantly different from the values 2 years previously. CONCLUSIONS: Anterior chamber IOL implantation did not appear to alter corneal endothelial function. Results indicate that the endothelial cell loss was related to surgical trauma rather than the presence of an IOL in the anterior chamber.

Aged↗

PubMed2003

Photodynamic therapy for choroidal neovascularization associated with pattern dystrophy.

PURPOSE: To report the results of photodynamic therapy (PDT) for subfoveal choroidal neovascularization (CNV) associated with nine eyes affected by pattern dystrophy of the retinal pigment epithelium. METHODS: Each patient underwent an ophthalmologic examination complete with electroretinogram, electrooculogram, fluorescein angiography, and indocyanine green angiography to define the characteristics of the CNV. PDT was administered according to the TAP protocol. Re-treatment was decided on the basis of the detection of leakage on fluorescein angiography. RESULTS: Classic subfoveal CNV was associated with four cases of reticular dystrophy, one case of butterfly-shaped dystrophy, and one case of pattern dystrophy simulating fundus flavimaculatus. Moreover, three cases of adult-onset foveomacular vitelliform dystrophy showed occult subfoveal CNV. The mean follow-up was 15.6 +/- 2.1 months. Adult-onset foveomacular vitelliform dystrophy has the worst visual outcome, passing from 20/59 to 20/640 (mean variation, -10.7 lines), whereas the other forms of pattern dystrophy overall retain their baseline best-corrected visual acuity of 20/51 (mean variation, +0.17 lines). CONCLUSIONS: Photodynamic therapy for subfoveal CNV associated with pattern dystrophy of the retinal pigment epithelium can stabilize visual acuity, except for occult CNV associated with adult-onset foveomacular vitelliform dystrophy.

Adult↗

PubMed2002

Capsular block syndrome associated with horizontal jerk nystagmus.

A 78-year-old cataract patient with horizontal jerk nystagmus had phacoemulsification and intraocular lens (IOL) implantation in the capsular bag with continuous curvilinear capsulorhexis. One week postoperatively, the posterior capsule ballooned posteriorly, the anterior capsule opening was sealed to the IOL optic, and a transparent liquefied substance accumulated between the lens optic and the posterior capsule. The best corrected visual acuity was 0.6 with a myopic shift compared with the refraction after the first day. A neodymium:YAG laser posterior capsulotomy was performed, and the capsular block syndrome (CBS) resolved. The results confirm the experimental model proposed by Zacharias suggesting that saccadic eye movements contribute to CBS under certain anatomic conditions.

Aged↗

PubMed2002

Biocompatibility of hydrophilic intraocular lenses.

PURPOSE: To assess the biocompatibility of 3 hydrophilic acrylic intraocular lenses (IOLs) by evaluating the postoperative cell reaction on the IOL surface, anterior capsule opacification (ACO) rate, and presence of membrane growth over the anterior IOL surface. SETTING: University Eye Clinic of Trieste, Trieste, Italy. METHODS: In this prospective study, 73 patients were randomized to receive 1 of 3 types of hydrogel IOLs after phacoemulsification: Storz Hydroview H60M, Corneal ACR6D, or Ioltech Stabibag. To analyze and photograph the anterior IOL surface, slitlamp biomicroscopy and specular microscopy were performed 7, 30, 90, and 180 days after surgery. Small, epithelioid, and giant inflammatory cell reaction was evaluated. In addition, ACO and membrane growth on the anterior IOL surface were assessed. RESULTS: Low inflammatory cell adhesion was observed on the anterior surface of all 3 IOLs. The Stabibag group had a significantly higher grade of small inflammatory cell reaction 7 and 30 days after surgery. A significantly higher rate of ACO was observed in the ACR6D group. The Hydroview and ACR6D groups had a significantly higher percentage of membrane growth from the capsulorhexis edge onto the anterior IOL surface than the Stabibag group. CONCLUSIONS: Clinically, the 3 hydrophilic IOLs behaved in a different manner, showing the different forms of biocompatibility. Results indicate that a different chemical composition determines correspondingly different protein absorption on IOL surfaces. This might result in a different adhesion pattern and spreading of lens epithelial and inflammatory cells.

Acrylic Resins↗

PubMed2002

Glistenings in foldable intraocular lenses.

PURPOSE: To evaluate the formation of glistenings in foldable intraocular lenses (IOLs) of various materials after cataract surgery. SETTING: University Eye Clinic of Trieste, Trieste, Italy. METHODS: In this prospective study, 273 patients were randomized to have implantation of 1 of 7 types of foldable IOLs in the capsular bag after phacoemulsification. The IOLs were the CeeOn Edge 911A (Pharmacia & Upjohn Co.), ACR6D (Corneal), AcrySof (Alcon), SI-40NB (AMO), Hydroview H60M (Storz), Sensar (AMO), and Stabibag (Ioltech). The presence of glistenings in the IOL optic was assessed by slitlamp evaluation 7, 30, 90, 180, 360, and 720 days after surgery. The glistenings were graded at each control. RESULTS: Glistenings were observed in all IOL groups. The percentage of patients with glistenings ranged from 40.0% to 67.5%, with the percentage increasing up to 90 days after surgery and then becoming stable in most groups. The AcrySof group had a continuous increase over time. The mean grade of glistenings increased up to 180 days after surgery and then became stable in most groups. The AcrySof and 911A groups had a continuous increase over time. CONCLUSIONS: Glistening formation was observed in 7 different foldable IOLs. The AcrySof group had a higher percentage and a greater density of glistenings.

Acrylic Resins↗

PubMedDate not supplied

Correlation between the retinal nerve fiber layer thickness and the pattern electroretinogram amplitude.

OBJECTIVE: To establish a correlation between the retinal nerve fiber layer (RNFL) thickness measured by a scanning laser polarimeter (GDx) and the pattern electroretinogram (p-ERG) amplitudes in a heterogeneous population sample composed of normal subjects, ocular hypertensive and glaucomatous patients. METHODS: 112 subjects were considered: 40 glaucomatous patients, 39 ocular hypertensive and 33 normal subjects. All were examined with the GDx, and the RNFL thickness was measured. A transient p-ERG was then recorded. RESULTS: A statistically significant correlation was observed between the RNFL thickness and the p-ERG amplitudes (p < 0.001) by means of linear regression analysis. CONCLUSION: We observed a strict correlation between the measurements of the RNFL thickness obtained with the GDx and the amplitude of the p-ERG signal. These techniques represent additional objective tools to detect an early glaucomatous damage.

Adolescent↗

PubMedDate not supplied

Clinical and angiographic features in nasal branch retinal vein occlusion.

PURPOSE: To analyse the epidemiological and clinical characteristics of nasal branch retinal vein occlusion (NBRVO). METHODS: Patients affected by branch retinal vein occlusion observed in the out-patient departments of the Eye Clinic of Trieste between January 1995 and January 1999 were enrolled. RESULTS: Out of 144 patients with branch retinal vein occlusion, 128 (88.9%) were affected by temporal branch retinal vein occlusion (TBRVO), and 16 patients were affected by NBRVO (11.1%). The two groups did not differ as far as systemic hypertension, diabetes mellitus, glaucoma and ischaemic heart disease were regarded. NBRVO cases were characterized by better visual acuity and greater figures of capillary non-perfusion, retinal neovascularization and vitreous haemorrhage. CONCLUSIONS: NBRVO, even though infrequent, shares the same epidemiological characteristics as TBRVO. The higher prevalence of ischaemic cases in the NBRVO group could depend on a bias during the enrolment of patients, because especially symptomatic patients may have been examined in our out-patient departments. The relatively high percentage of epiretinal membrane formation after laser photocoagulation suggests particular caution, especially in cases presenting with vitreous haemorrhage.

Aged↗