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Biomedical subjects

R Brancato

Publications and source records attributed to R Brancato.

At least 37 records · Page 2Linked to original sources
PubMed1999

Axial length in patients with diabetes.

PURPOSE: To investigate the relationship between axial length and retinal involvement in patients with diabetes. METHODS: A total of 157 consecutive patients with diabetes underwent biometry. The patients were divided into three groups, according to retinopathy: 44 without retinopathy, 37 with background retinopathy, and 76 with proliferative retinopathy. To compare axial length in diabetic versus nondiabetic subjects, a control group of 157 healthy subjects with age and sex distribution similar to the diabetic group was selected from an orthopedic clinic. We investigated in the diabetic group whether the axial length was related to specific type of diabetes (non-insulin-dependent or insulin-dependent), duration of disease, presence of retinopathy, or laser treatment. To eliminate the confounding effect of myopia, we excluded all patients with axial length greater than 24 mm from the two groups. Comparison of diabetic patients without retinopathy versus nondiabetic subjects was also performed. RESULTS: Diabetic patients presented shorter axial lengths compared with the controls (mean +/- standard deviation, 22.4+/-1.3 mm versus 23.4+/-1.3 mm; P<0.001). Significantly shorter axial lengths were found in the background and proliferative retinopathy groups compared with the group without retinopathy (22.0+/-1.2 mm and 22.1+/-1.1 mm versus 23.2+/-1.4 mm, respectively; P<0.05). No difference in axial length was found between the diabetic patients without retinopathy and the nondiabetic subjects (P = 0.3). Multivariate analyses showed that retinopathy was negatively correlated with axial length (P<0.01). Including only the patients with axial length under 24 mm, we obtained similar results. CONCLUSION: Axial length is shorter in diabetic patients than in nondiabetic subjects. Within the diabetic group, patients with retinopathy had shorter axial lengths than did patients without retinopathy.

Anthropometry↗
PubMed1999

Ultrasound biomicroscopic evaluation of ciliochoroidal effusion after laser treatment.

We evaluated ciliochoroidal effusion (CE) by ultrasound biomicroscopy (UBM) following diode endophotocoagulation at the end of the vitreoretinal surgery. The aim of our study was to assess any differences in the CE morphology following diode endophotocoagulation or transpupillary krypton photocoagulation, and to demonstrate the influence of diabetes and intravitreal surgery on CE formation. Sixty-six consecutive patients were divided in to four groups. Twenty-nine patients with proliferative retinopathy underwent transpupillary krypton photocoagulation; 11 diabetic patients underwent vitreoretinal surgery and diode endophotocoagulation; 18 nondiabetics underwent vitreoretinal surgery and diode endophotocoagulation; 8 consecutive nondiabetic patients were the control group and underwent vitreoretinal surgery, without laser treatment. UBM was performed in the four groups before and after laser treatment, if performed. We determined, by UBM, not only the presence, but also the thickness of CE. CE was present in all the patients treated by laser, diabetics and nondiabetics, and its thickness was not correlated with the number of laser spots (p = 0.28). CE was seen ultrasonically in all the patients undergoing transpupillary photocoagulation or endophotocoagulation, regardless of diabetes and surgical trauma.

Aged↗
PubMed1999

Treatment of hyperfiltering blebs with Nd:YAG laser-induced subconjunctival bleeding.

PURPOSE: To assess the feasibility of a new technique to manage hyperfiltering blebs after penetrating glaucoma surgery. METHODS: Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser bursts were used to induce bleeding in conjunctival and episcleral vessels in the bleb area to achieve local delivery of autologous blood. RESULTS: In the three cases reported here in which this technique was used, the treatment was successful and safe, leading to resolution of hypotony and reduction of the bleb with no complications. CONCLUSION: Subconjunctival bleeding can be achieved using Nd:YAG laser, and can represent a valuable alternative to autologous blood injection in cases of hyperfiltration after glaucoma surgery.

Adult↗
PubMed1998

Indocyanine green angiography in enlarged blind spot syndrome.

PURPOSE: To report the indocyanine green angiography findings in a case of acute idiopathic blind spot enlargement syndrome. METHOD: The patient underwent ophthalmologic examination with fluorescein angiography and indocyanine green angiography. RESULTS: A monocular enlarged blind spot was found on automated perimetry; fluorescein angiography showed a hypofluorescent peripapillary atrophic area and indocyanine green angiography highlighted diffuse, small hypofluorescent spots scattered throughout the posterior pole. Visual field defects and indocyanine green angiography abnormalities resolved over 4 weeks. CONCLUSION: Indocyanine green angiography in acute idiopathic blind spot enlargement syndrome showed many lesions not visible with fluorescein angiography, indicating a choroidal involvement reaching not only the peripapillary area but the entire posterior pole.

Acute Disease↗
PubMed1998

Keratometric index, videokeratography, and refractive surgery.

PURPOSE: To clarify the confusion resulting from the use of slightly different refractive indices in calculations related to optical modeling of the cornea for refractive surgery, corneal diagnostics, and cataract surgery. SETTING: Scientific Institute H.S. Raffaele, Milan, Italy. METHODS: The cornea is represented as a centered optical system composed by 1, 2, or 3 spherical interfaces, in progression of modeling accuracy. Optical analysis is performed with the usual formulas of paraxial geometrical optics as well as with ray tracing. Simple models are also provided for corneas having both incisional and photoablative refractive surgery. Values of geometrical parameters are taken from the Gullstrand eye model. RESULTS: Using the keratometric index of refraction of 1.3375 is validated for estimating optical power differences on untreated corneas or after incisional keratotomy. It is not as accurate in assigning absolute values of dioptric power, where the value 1.3315 is more appropriate. For photorefractive keratectomy (PRK), however, the proper stromal index of refraction, 1.376, must be used for ablation calculations and dioptric change estimates. CONCLUSION: Videokeratographic instruments should include three distinct values of refraction index (1.3375, 1.376, and 1.3315) for an accurate and complete characterization of dioptric power maps. In cataract surgery, corrections must be introduced in the calculation of intraocular lens power for patients who have previously had PRK.

Cataract Extraction↗
PubMed1998

Nd:YAG laser iridotomy in pigment dispersion syndrome: an ultrasound biomicroscopic study.

AIMS: Ultrasound biomicroscopy was used to study the shape of the iris and the iridolenticular contact in pigment dispersion syndrome (PDS) eyes, to compare them with matched normal eyes, and to assess the morphological effects of laser iridotomy in PDS eyes. METHODS: 50 eyes of 50 patients suffering from PDS (group 1), and 15 normal eyes of 15 subjects matched for age and refraction (group 2), were studied by ultrasound biomicroscopy (UBM, Humphrey-Zeiss). Nd:YAG laser iridotomy was proposed to the 30 PDS patients with concave iris and 18 underwent the treatment. RESULTS: The iris was concave in 27 eyes in group 1, and three more eyes showed a concave iris during accommodation. Among normals, iris concavity was present in two eyes. The height of the iris convexity was -0.15 (0.24) mm (range -0.65 to +0.21), in the eyes of group 1, whereas it was +0.07 (0.10) mm (range -0.21 to +0.16) in group 2 (p < 0.0012). Group 1 had greater iridolenticular contact than group 2: 1.55 (0.78) mm (range 0.30-2.88) and 1.07 (0.61) (range 0.30-2.50; p = 0.0304). After laser iridotomy, only one eye still had a concave iris. Pre- and post-treatment deflections were -0.35 (0.18) mm (range -0.61 to -0.05) and +0.01 (0.06) mm (range -0.12 to +0.17), respectively (p < 0.0001). Pre- and post-treatment iridolenticular contact was 2.10 (0.65) mm (range 0.70-2.88) and 0.93 (0.38) mm (range 0.4-1.75), respectively (p < 0.0001). After laser iridotomy, the treated irises were flatter than normal (p = 0.0207), whereas the iridolenticular contact was not significantly different. CONCLUSIONS: Laser iridotomy can restore a normal iris shape and iridolenticular contact in eyes suffering from PDS.

Adult↗
PubMed1998

Axial length and refraction in retinal vein occlusions.

To assess whether axial length and refraction are risk factors for retinal vein occlusion, we measured these parameters in 88 consecutive patients with unilateral branch retinal vein occlusion (BRVO), in 58 consecutive patients with unilateral central retinal vein occlusion (CRVO) and in 50 patients selected as a control group. Patients and controls were free or affected by systemic or local predisposing factors. We compared eyes with CRVO with control eyes, eyes with BRVO with control eyes, and eyes with CRVO with eyes with BRVO. Comparing CRVO eyes and controls, none of the investigated variables was shown to be significant. From the analysis of BRVO eyes versus controls, it resulted that refraction was the only variable which played the role of an independent prognostic factor. When comparing BRVO eyes with CRVO eyes, we found that age was slightly related to the development of BRVO. In conclusion, faulty refraction appeared to be a risk factor for the development of BRVO. We did not find any influence of axial length on the occlusion of retinal veins.

Adult↗
PubMed1998

Indocyanine green angiography in age-related macular degeneration with occult neovascularization.

This study has been conducted to assess the sensitivity of indocyanine green angiography (ICGA) in detecting choroidal neovascularization (CNV) in patients with age-related macular degeneration (ARMD) with occult CNV at fluorescein angiography (FA) and to establish their eligibility for laser photocoagulation. Three hundred eighty-three eyes of 355 consecutive patients with occult CNV at FA were studied by ICGA; occult CNV with or without pigment epithelial detachment (PED) were detected as well. Eligibility for laser treatment was established on the basis of the ICGA-guided CNV extension and localization. Out of 157 eyes (41%) with occult CNV and PED, 74 (47.1%) showed focal ICGA CNV, 35 eyes (22.3%) had plaque CNV. Thirty-five eyes with PED (22.3%) appeared serous without CNV, and in 13 eyes (8.3%) no CNV was detectable because of large hemorrhages. Out of the 226 eyes (59%) presenting occult CNV without PED, 94 eyes (41.6%) had plaque CNV, and 58 (25.7%) had focal CNV. In 74 eyes (32.7%), there was no detectable CNV or only an ill-defined ICGA appearance. ARMD with PED is closely associated with focal CNV, while plaque CNV is largely found in exudative ARMD without PED (p < 0.001). Considering all the cases examined by ICGA, CNV was evident in 261 eyes (68%) occult at FA. Extrafoveal CNV laser treatment was recommended for 103 eyes (27%). Our results suggest that ICGA may be useful in the diagnosis and management of ARMD with occult CNV at FA increasing the number of patients eligible for laser treatment.

Aged↗
PubMed1998

Fluorescein and indocyanine green angiography in vascular chorioretinal diseases.

Fluorescein angiography allows visualization of blood flow in retinal and choroidal tissues, permitting diagnostic support in many ocular diseases. Particularly, fluorescein angiography has become a very important tool in the study and treatment of chorioretinal diseases. Because of the limitations of fluorescein angiography in imaging the choroidal circulation and associated pathologies, investigators have searched for alternative dyes to improve choroidal angiography, the most promising of which has been indocyanine green dye. The usefulness of indocyanine green angiography to aid in the diagnosis and treatment of a variety of chorioretinal diseases was reported during the last years. The goal of this article is to make an overview on the most frequent Fluorescein and ICGA patterns of vascular diseases of the chorioretina.

Choroid Diseases↗
PubMed1997

Interaction between infrared radiation and vitreous substitutes.

OBJECTIVE: To characterize the interaction between midintrared radiation of cutting lasers used or proposed for vitreoretinal surgery and fluid vitreous substitutes commonly used in vitreoretinal surgery. METHODS: Optical transmittance of vitreous substitutes was measured with a double-beam spectrophotometer. Measurements were performed in a wide spectral range of infrared radiation, including the 2120-nm wavelength of the holmium-YAG laser and the water absorption peaks at 1440, 1930, and 2940 nm. RESULTS: The wavelengths considered have a penetration depth varying from 410 to 1 microns in Ringer's solution, balanced salt citrate-buffered solution, balanced salt bicarbonated-buffered solution, hyaluronate sodium, and hydroxypropyl methylcellulose ophthalmic solution, from 2000 to 13 mm in perfluorocarbon liquid, and from 52 to 2.5 mm in silicone and fluorosilicone oils. CONCLUSIONS: Midinfrared optical radiation exhibits dramatic differences of penetration depth in different vitreous substitutes. High-absorbing liquids should be used mainly with contact laser procedures and could provide a shield for remote structures. Low-absorption vitreous substitutes allow noncontact laser surgical procedures, but they also may cause direct optical damage to remote tissues. The knowledge of wavelength transmittance of vitreous substitutes is necessary to evaluate and optimize the efficacy and safety of cutting laser sources.

Fluorocarbons↗
PubMed1997

Mycobacterium chelonae keratitis after excimer laser photorefractive keratectomy.

This is the first report of a severe case of Mycobacterium chelonae keratitis; it occurred in a 26-year-old man after he had undergone excimer laser photorefractive keratectomy for the correction of severe myopia, once the epithelium was already healed. The diagnosis was made by culture results and acid-fast staining of corneal scrapings. Topical ciprofloxacin sodium, 0.3 mg/mL, plus amikacin sodium, 10 mg/mL, and oral clarithromycin sodium led to remission of the ulceration after 3 months of therapy. Subsequent topical corticosteroid therapy led to complete visual recovery during 1 year of follow-up. There may be an increased risk of severe keratitis during the first postoperative months in eyes that have already undergone photorefractive keratectomy, due to the presence of some microepithelial defects symptomatically negative and not easily detectable by slit-lamp examination.

Adult↗