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Piero Barboni

Publications and source records attributed to Piero Barboni.

17 recordsLinked to original sources
PubMed2006

Intraocular lens power calculation after myopic refractive surgery: theoretical comparison of different methods.

OBJECTIVE: To evaluate the reliability of different methods developed to calculate intraocular lens (IOL) power after corneal refractive surgery. DESIGN: Retrospective observational case series. PARTICIPANTS: Preoperative and postoperative data of all eyes that underwent myopic excimer laser surgery in a private practice (Centro Salus, Bologna, Italy) between 1999 and 2004 were reviewed. INTERVENTION: The following methods were analyzed: videokeratography, clinical history, Shammas' refraction-derived and clinically derived methods, Rosa's correcting factor, Ferrara's variable refractive index, separate consideration of anterior and posterior corneal curvature (with and without preoperative data), Feiz-Mannis' formula and nomogram, and Latkany's regression formulas (based on both average and flattest postrefractive surgery keratometry). The Holladay 1 formula was used for eyes with an axial length between 22 and 24.49 mm and the SRK-T for eyes longer than 24.49 mm. Double-K formulas were also evaluated, when applicable. Each IOL power determined with these methods was compared to a benchmark value, calculated using the preoperative axial length and corneal power and aiming for the preoperative spherical equivalent. MAIN OUTCOME MEASURE: Mean error in IOL power prediction. RESULTS: Ninety-eight eyes of 98 patients were analyzed. The double-K clinical history method, Feiz-Mannis' formula, double-K method based on separate consideration of anterior and posterior corneal curvature (with and without preoperative data), and both Latkany's regression formulas were the only methods resulting in a mean IOL power not statistically different (P>0.05) from the benchmark used for comparative purposes. CONCLUSIONS: When prerefractive surgery data are available, IOL power should be calculated using the double-K clinical history method. Alternative choices may be represented by the Feiz-Mannis' formula, Latkany's regression formulas based on average and flattest postrefractive surgery keratometry, and the double-K method based on separate consideration of anterior and posterior corneal curvatures. A variant of the latter can be used to calculate IOL power when prerefractive surgery data are not available. Further prospective studies based on patients undergoing phacoemulsification after refractive surgery are needed to validate the results of this theoretical comparison.

Adult↗
PubMed2006

Detection and quantification of retinal nerve fiber layer thickness in optic disc edema using stratus OCT.

OBJECTIVE: To investigate the ability of optical coherence tomography (OCT) to assess changes in retinal nerve fiber layer (RNFL) thickness in optic disc edema. METHODS: Prospective observational case series in a private eye clinic (Centro Salus). Twelve consecutive eyes (9 patients) with optic disc edema were analyzed, including 6 patients with anterior ischemic optic neuropathy, 1 patient with multiple sclerosis-associated papillitis, and 2 patients with bilateral papilledema. Peripapillary scans of the RNFL were obtained using Stratus OCT (software version 3.0; Carl Zeiss Meditec, Dublin, Calif). Repeated measurements were performed in 7 patients during a follow-up ranging from 8 to 30 weeks. The main outcome was RNFL thickness measurement. RESULTS: Optical coherence tomography detected and quantified diffuse thickening of the RNFL. Compared with eyes in a control group of 75 healthy subjects, eyes with optic disc edema showed a significant increase in the mean RNFL thickness in all quadrants (temporal, P = .002; superior, P<.001; nasal, P<.001; and inferior, P<.001). In patients who were followed up, progressive thinning was observed as the disease evolved toward optic atrophy or clinical resolution. CONCLUSIONS: Optical coherence tomography can identify and measure RNFL edema. This ability of OCT may help elucidate pathophysiological mechanisms in optic disc edema and provide a valuable aid to clinicians.

Adult↗
PubMed2006

Corneal melting associated with topical diclofenac use after laser-assisted subepithelial keratectomy.

We report a case of corneal melting associated with topically applied preservative-free diclofenac (Voltaren Ofta) after laser-assisted subepithelial keratectomy. Keratolysis was detected on day 5; further progression toward perforation was arrested by immediate suspension of diclofenac and prescription of topical dexamethasone with 24-hour patching. At the last follow-up, the visual acuity had improved from counting fingers to 20/20. Preservative-free diclofenac instillation had never been associated with keratolysis. Topical steroids may be useful in treating corneal melting associated with nonsteroidal antiinflammatory drugs.

Administration, Topical↗
PubMed2006

Influence of pupil size and cataract on retinal nerve fiber layer thickness measurements by Stratus OCT.

AIM: To investigate whether retinal nerve fiber layer (RNFL) thickness, as measured by optical coherence tomography (OCT), is influenced by pupil size and cataract. METHODS: RNFL thickness was measured by means of Stratus OCT (RNFL Thickness 3.4 acquisition protocol) in a group of consecutive patients undergoing phacoemulsification and intraocular lens implantation. Measurements were taken preoperatively without pupil dilation (PR1), preoperatively with pupil dilation (PR2), and 1 month postoperatively without pupil dilation. RESULTS: Twenty-five eyes of 25 patients were enrolled in the study and underwent statistical analysis. Pupil dilation caused RNFL thickness measurements to increase slightly in PR2 compared with PR1; the difference showed to be statistically significant in the 360-degree average measurement (P=0.0456) and in the nasal quadrant (P=0.032), but not in the remaining quadrants. Postoperative measurements were higher than those of PR1 in all quadrants (temporal P=0.011; superior P=0.0098; nasal P<0.0001; inferior P=0.0081) and in 360 degrees average (P<0.0001), suggesting that the presence of cataract significantly influences RNFL thickness as measured by Stratus OCT. More advanced degrees of lens opacity were correlated to a higher decrease in RNFL thickness values (r=0.4071, P=0.0434). CONCLUSIONS: While pupil size only marginally affects RNFL measurements performed by Stratus OCT, the presence and degree of cataract seem to have a significant impact. This effect should be taken in consideration when using this technology for the diagnosis of glaucoma and other neuro-ophthalmologic disorders possibly affecting the RNFL.

Aged↗
PubMed2006

Leber's hereditary optic neuropathy with childhood onset.

PURPOSE: To characterize the clinical features of childhood-onset Leber's hereditary optic neuropathy (LHON) as defined by a pathogenic mtDNA mutation and age at onset equal to or less than 10 years of age. METHODS: Fifty-six LHON Italian pedigrees including 180 affected individuals were reviewed, and 14 of 18 patients with childhood LHON were enrolled. LHON was classified as acute bilateral, acute unilateral, slowly progressive, and subclinical, according to disease features. All patients underwent a complete ophthalmic examination and optical coherence tomography (OCT), including retinal nerve fiber layer (RNFL) and optic nerve head analysis (ONH), and were compared with age- and optic disc size-matched control groups. RESULTS: The prevalence of childhood LHON in this case series was 11.5%. Five patients had an acute bilateral course, three an acute unilateral course with subclinical signs in the fellow eye, and six a slowly progressive course. Four of five acute patients with acute bilateral disease experienced visual recovery. Slowly progressive cases presented a better visual acuity and visual field outcome than acute cases. A significant diffuse reduction of RNFL was evident in children with acute LHON compared with the control group, whereas a significant reduction of the temporal quadrant was present in the slowly progressive and subclinical LHON cases. Acute LHON children had a smaller disc area and vertical disc diameter than did the control subjects. CONCLUSIONS: This study systematically characterized for the first time the subgroup of LHON with childhood onset. The peculiar clinical and anatomic features of childhood LHON offer insights for the understanding of LHON's pathophysiology as well as a basis for the differential diagnosis of visual loss in childhood.

Acute Disease↗
PubMed2005

Retinal nerve fiber layer evaluation by optical coherence tomography in Leber's hereditary optic neuropathy.

PURPOSE: To study retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (StratusOCT) in patients with Leber's hereditary optic neuropathy (LHON). DESIGN: Cross-sectional study. PARTICIPANTS AND/OR CONTROLS: Thirty-eight patients with LHON were analyzed and compared with an age-matched control group of 75 patients. Patients with LHON were classified as having early LHON (E-LHON, n = 8) when the duration of the disease was shorter than 6 months and atrophic LHON (A-LHON, n = 30) when the duration was longer than 6 months. METHODS: The fast RNFL thickness (3.4) scan acquisition protocol was used. MAIN OUTCOME MEASURE: Retinal nerve fiber layer thickness as measured by StratusOCT. RESULTS: Compared with the control group, eyes with E-LHON showed a thicker RNFL in the 360 degrees average measurement (P<0.01) and in the superior (P<0.01), nasal (P<0.05), and inferior quadrants (P<0.05); no significant changes were detected in the temporal quadrant. Eyes with A-LHON revealed a thinner RNFL in all measurements (P<0.001); the fibers of the nasal quadrant showed the lowest amount of reduction (38% vs. 42%-49.8% in the other quadrants). In cases with A-LHON and visual recovery, RNFL was significantly thicker in all measurements (P<0.001), except the temporal quadrant, with respect to A-LHON without visual recovery. CONCLUSIONS: On the basis of OCT data, the RNFL is thickened in E-LHON and severely thinned in A-LHON. RNFL is likely to be partially preserved in A-LHON with visual recovery. The temporal fibers (papillomacular bundle) are the first and most severely affected; the nasal fibers seem to be partially spared in the late stage of the disease.

Acute Disease↗
PubMed2005

Retinal nerve fiber layer evaluation by optical coherence tomography in unaffected carriers with Leber's hereditary optic neuropathy mutations.

PURPOSE: To study retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) in unaffected carriers with Leber's hereditary optic neuropathy (LHON) mutations. DESIGN: Cross-sectional study. PARTICIPANTS: Sixty-six unaffected carriers (44 females and 22 males) were analyzed and compared with an age-matched control group of 70 patients (40 females and 30 males). The statistical analysis was performed after grouping both the patients and the control group on the basis of gender and, for unaffected carriers only, mitochondrial DNA mutation. METHODS: The Fast RNFL Thickness (3.4) scan acquisition protocol was used. MAIN OUTCOME MEASURE: Retinal nerve fiber layer thickness as measured by OCT. RESULTS: With respect to the control group, unaffected male carriers showed a thicker RNFL in the temporal and inferior quadrants and in the 360 degrees average measurement (P = 0.025, P = 0.03, and P = 0.018, respectively). These differences reached statistical significance in subjects carrying the 11778 mutation, whereas only a trend was detected in those with the 3460 mutation. Unaffected female carriers had an increased thickness in the temporal quadrant when compared with the control group (P = 0.003) and no differences in the other measurements. The increase in temporal sectors was statistically significant in females with the 11778 mutation, whereas a trend was detected in those with the 3460 mutation. CONCLUSIONS: A thickening of the temporal fibers was detected in all subgroups of unaffected carriers. This is the first evidence indicating the preferential involvement of the papillomacular bundle in subclinical LHON. This notion previously was based on the early loss of fibers from the temporal quadrant in acute LHON and the selective loss of small-caliber fibers at histopathology. Our study also revealed that males have a more diffuse involvement than females.

Adolescent↗
PubMed2005

Filtering blebs imaging by optical coherence tomography.

PURPOSE: To assess the ability of standard optical coherence tomography to visualize filtering blebs after glaucoma surgery. METHODS: A prospective interventional case series was conducted in a private practice. Twenty-nine eyes of 24 patients (21 with good, 2 with fair and 6 with poor intraocular pressure [IOP] control) were investigated. After the focus was manually adjusted on the conjunctiva, blebs were scanned perpendicularly to the limbus. RESULTS: Hyporeflective fluid-filled spaces were detected in 19 out of the 21 eyes with good IOP. Within this group, blebs were classified into three different categories according to their optical coherence tomography pattern: type A (featuring a thick wall and a single large fluid-filled space), type B (featuring a thin wall and multiple large fluid-filled spaces) and type C (featuring multiple, irregular and flattened fluid-filled spaces). Fluid-filled spaces were not observed in three out of the six eyes with poor IOP control. Trabeculectomy without antimetabolites was associated with type A blebs (P = 0.015, Fisher's exact test), mitomycin-C trabeculectomy with type B blebs (P = 0.0025) and mitomycin-C phacotrabeculectomy with type C blebs (P = 0.0173). CONCLUSIONS: Although it was not developed to evaluate the anterior segment of the eye, standard optical coherence tomography can visualize filtering blebs and reveal interesting details of their morphology. Clinicians using optical coherence tomography to diagnose glaucoma can take advantage of this ability of the instrument to obtain more information about their patients in the postoperative course of trabeculectomy and phacotrabeculectomy.

Adolescent↗
PubMed2004

Ocular findings in mitochondrial neurogastrointestinal encephalomyopathy: a case report.

PURPOSE: To describe the ocular features of a patient with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) due to a homozygous G1443A mutation in the thymidine-phosphorylase gene. METHODS: A case report with extensive ophthalmological investigation over a 9-year period, until death at age 38 years. Measures used included standard ophthalmological examination, visual field examination and optical coherence tomography (OCT). RESULTS: Ptosis and external ophthalmoplegia progressively worsened during the follow-up, as did the neurological and general status. Corneal and optic disc alterations were also observed at the last visit. Glaucomatous changes of the optic disc were confirmed by the visual field examination and OCT. CONCLUSION: In addition to previously described alterations such as ptosis and external ophthalmoplegia, MNGIE may be associated with glaucomatous-like optic neuropathy.

Adult↗
PubMed2004

The ND1 gene of complex I is a mutational hot spot for Leber's hereditary optic neuropathy.

A novel mitochondrial DNA (mtDNA) transition (3733G-->A) inducing the E143 K amino acid change at a very conserved site of the NADH dehydrogenase subunit 1 (ND1) was identified in a family with six maternally related individuals with Leber's hereditary optic neuropathy (LHON) and in an unrelated sporadic case, all negative for known mutations and presenting with the canonical phenotype. The transition was not detected in 1,082 control mtDNAs and was heteroplasmic in several individuals from both pedigrees. In addition, the mtDNAs of the two families were found to belong to different haplogroups (H and X), thus confirming that the 3733G-->A mutation occurred twice independently. Phosphorus magnetic resonance spectroscopy disclosed an in vivo brain and skeletal muscle energy metabolism deficit in the four examined patients. Muscle biopsy from two patients showed slight mitochondrial proliferation with abnormal mitochondria. Biochemical investigations in platelets showed partially insensitive complex I to rotenone inhibition. We conclude that the 3733G-->A transition is a novel cause of LHON and, after those at positions 3460 and 4171, is the third ND1 mutation to be identified in multiple unrelated families. This finding shows that, in addition to ND6, the ND1 subunit gene is also a mutational hot spot for LHON.

Adult↗
PubMed2004

Deficit of in vivo mitochondrial ATP production in OPA1-related dominant optic atrophy.

Dominant optic atrophy has been associated with mutations in the OPA1 gene, which encodes for a dynamin-related GTPase, a mitochondrial protein implicated in the formation and maintenance of mitochondrial network and morphology. We used phosphorus magnetic resonance spectroscopy to assess calf muscle oxidative metabolism in six patients from two unrelated families carrying the c.2708-2711delTTAG deletion in exon 27 of the OPA1 gene. The rate of postexercise phosphocreatine resynthesis, a measure of mitochondrial adenosine triphosphate production rate, was significantly delayed in the patients. Our in vivo results show for the first time to our knowledge a deficit of oxidative phosphorylation in OPA1-related DOA.

Adenosine Triphosphate↗
PubMed2002

Mitochondrial DNA nucleotide changes C14482G and C14482A in the ND6 gene are pathogenic for Leber's hereditary optic neuropathy.

A novel mitochondrial DNA nucleotide transversion, C14482A (M64I), different from the previously reported C14482G (M64I), was found to cause Leber's hereditary optic neuropathy with visual recovery in an Italian family. These equivalent changes are the fifth pathogenic mutation for pure Leber's hereditary optic neuropathy. This confirms that the ND6 gene of complex I is a mutational hot spot and suggests that different amino acid substitutions at residue 64, as induced by C14482G or C14482A (M64I) and the common T14484C (M64V) mutations, are associated with visual recovery.

Adolescent↗
PubMed2002

First application of extremely high-resolution magnetic resonance imaging to study microscopic features of normal and LHON human optic nerve.

PURPOSE: To apply new methods in magnetic resonance imaging (MRI) in resolving the histoarchitecture of the human optic nerve obtained from normal individuals and a Leber's hereditary optic neuropathy (LHON) case. DESIGN: Small case series--clinicopathologic correlation. METHOD: Three optic nerves were obtained from two normal subjects, aged 69 and 70, and a LHON/3460 patient, aged 75. The posterior pole of the eye with attached optic nerves was fixed in buffered paraformaldehyde and placed into a 10-mm quartz tube. Images were acquired in a Bruker AMX500 12 Tesla microimaging system. The three-dimensional data were acquired with 512 x 256 x 256 points, yielding a final isotopic resolution of 30 microm. RESULTS: The sclera, choroids, and retina were easily distinguished. The nerve fiber layer was seen to enter the optic disc and traverse the lamina cribrosa (LC). The resolution of the image of the optic nerve head was such that the LC was visualized as multiple stacked plates. The fibers emerged from glial columns in the LC as distinct fascicles and could be made out to change appearance as they became myelinated and expanded in the more posterior nerve. The ophthalmic artery and vein were visualized, as were the optic nerve arachnoid and dural sheaths. In the Leber's case, the LC plates seemed collapsed or compressed. The axonal bundles were atrophic and the pial-collagen septae markedly thickened. The entire nerve had shrunk, creating space under the arachnoid, down and around the central ophthalmic artery and vein. CONCLUSIONS: These results demonstrate the feasibility of using extremely high-resolution magnetic resonance imaging (microMRI) to examine the three-dimensional (30 microm) images of the human optic nerve. Several atrophic lesions, normally visible only by histopathologic examination, were visualized in the Leber's optic nerve. microMRI may eventually permit the in vivo visualization of lesions in or about the optic nerve.

Aged↗
PubMedDate not supplied

Ocular surface changes in laser in situ keratomileusis-induced neurotrophic epitheliopathy.

PURPOSE: To evaluate the ocular surface changes in patients with laser in situ keratomileusis (LASIK)-induced neurotrophic epitheliopathy. METHODS: Seven consecutive patients with LASIK-induced neurotrophic epitheliopathy were studied prospectively and compared to a control group (seven consecutive patients who had LASIK- but without neurotrophic epitheliopathy). Bilateral sequential LASIK was performed at a 1-week interval; the first operated eye of each patient was considered for statistical analysis. Blinking, corneal sensitivity, tear break-up time, tear secretion and clearance were measured preoperatively (T0) and postoperatively at 1 week after surgery on the first eye (T1), and 1 week (T2), 1 month (T3), and 3 months (T4) after surgery was performed on the second eye. RESULTS: Laser in situ keratomileusis-induced neurotrophic epitheliopathy occurred bilaterally in all patients. During follow-up, patients with LASIK-induced neurotrophic epitheliopathy showed a significant decrease in blinking (P = .0002), which was not observed in cases without LASIK-induced neurotrophic epitheliopathy [corrected] Compared to eyes without LASIK-induced neurotrophic epitheliopathy, those with LASIK-induced neurotrophic epitheliopathy revealed lower values of sensitivity in the central cornea preoperatively and early postoperatively (T0, P = .004; T1, P = .003; T2, P = .003). A trend towards reduced sensitivity was also detected in the central cornea in late follow-up and in the superior, temporal, and nasal sectors of the flap at all examinations. No significant differences were observed in break-up time, tear secretion, or clearance within or between the two groups. CONCLUSION: Decreased blinking seems to be involved in the pathogenesis of LASIK-induced neurotrophic epitheliopathy. The reduction probably depends on the lower levels of corneal sensitivity and induces the epitheliopathy by increasing the ocular surface exposure.

Adult↗
PubMedDate not supplied

Tear meniscus evaluation by optical coherence tomography.

BACKGROUND AND OBJECTIVE: To assess the ability of optical coherence tomography to visualize the inferior tear meniscus and measure its height. PATIENTS AND METHODS: Twenty-seven eyes (27 patients) with aqueous tear deficiency were compared with 20 eyes (20 patients) with normal tear secretion (control group). After the instrument was focused on the ocular surface, a 4-mm long vertical scan, centered on the lower tear meniscus at corneal 6 o'clock hours, was obtained using optical coherence tomography. Tear meniscus height was measured by means of an external application. RESULTS: Mean tear meniscus height was significantly lower (P < .0001) in patients with aqueous tear deficiency (mean +/- standard deviation: 0.13 +/- 0.07 mm) than in the control group (mean +/- standard deviation: 0.25 +/- 0.08 mm). CONCLUSION: Optical coherence tomography can be used to noninvasively visualize the inferior tear meniscus. This method seems able to discriminate between patients with normal and dry eyes when measuring tear meniscus height.

Adult↗