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M A Viana

Publications and source records attributed to M A Viana.

At least 19 recordsLinked to original sources
PubMed1999

The effectiveness of protraction face mask therapy: a meta-analysis.

This study examined the effectiveness of maxillary protraction with orthopedic appliances in Class III patients. A meta-analysis of relevant literature was performed to determine whether a consensus exists regarding controversial issues such as the timing of treatment and the use of adjunctive intraoral appliances. An initial search identified 440 articles relating to Class III malocclusion. Among those articles, 11 studies in English and 3 studies in foreign languages met the previously established selection criteria. Data from the selected studies were categorized by age and appliance groups for the meta-analysis. The sample sizes were comparable between the groups. The statistical synthesis of changes before and after treatment in selected cephalometric landmarks showed no distinct difference between the palatal expansion group and nonexpansion group except for 1 variable, upper incisor angulation, which increased to a greater degree in the nonexpansion group. This finding implies that more skeletal effect and less dental change are produced in the expansion appliance group. Examination of the effects of age revealed greater treatment changes in the younger group. Results indicate that protraction face mask therapy is effective in patients who are growing, but to a lesser degree in patients who are older than 10 years of age, and that protraction in combination with an initial period of expansion may provide more significant skeletal effects. Overall mean values and corresponding standard deviations for the studies selected can also be used to estimate mean treatment effects expected from the use of protraction face mask.

Age Factors↗
PubMed1997

Long-term follow-up of initially successful trabeculectomy.

OBJECTIVE: The purpose was to study the long-term outcomes of primary trabeculectomies that were successful at 1 year. DESIGN: A retrospective study of patients with various types of glaucoma who had trabeculectomies that were successful at 1 year and who had a follow-up of at least 10 years. PARTICIPANTS: There were 40 patients (40 eyes) who had primary trabeculectomies that were successful at 1 year and who had a follow-up range of 10 to 21 years. INTERVENTION: Control of intraocular pressure (IOP) and disease progression was evaluated at 5, 10, and 15 years and at the last obtainable follow-up. MAIN OUTCOME MEASURES: Successful control of IOP was defined as IOP less than 21 mmHg or a reduction of 33% if preoperative IOP was less than 21 mmHg. Successful control of disease progression was defined as stable cup-disc ratios determined by examination, or color photographs or both, as well as stable visual fields. RESULTS: If an eye was considered successful by IOP at 1 year, the probability of successful control of IOP was 82% at 5 years and 67% at 10 and 15 years. If an eye was considered successful by IOP at 1 year, the probability of successful control of disease progression at 5 years was 77%, at 10 years 61%, and at 15 years 48%. If an eye did not require further glaucoma surgery at 1 year, the probability that it still would not need further surgery at 5 years was 90%, at 10 years 75%, and at 15 years 67%. Forty percent of eyes had cataract extraction by the time of last follow-up examination. CONCLUSIONS: Loss of IOP control and progression of glaucomatous damage occurs over time despite initial success at 1 year.

Adolescent↗
PubMed1997

The effect of hyperthyroidism on Müller's muscle contractility in rats.

The objective of this study was to determine if hyperthyroidism affects the responses of Müller's muscle to alpha-1 adrenoceptor agonists and consequently, if these responses might explain thyroid eyelid retraction. Sprague-Dawley adult rats (n = 37) were divided into control and treated groups and given either placebo or intraperitoneal triiodothyronine (250 micrograms/kg/d) for 1, 2, or 3 weeks. A suture was passed through their upper eyelid and connected to a force transducer that measured Müller's muscle contractions. Responses to phenylephrine (0.015-0.61 mmol) were compared with respect to peak amplitude and 50% duration of action. Mean maximum force values [+/-1 standard error of the mean (SEM)] in response to phenylephrine were 1.254 +/- 0.071 gr for controls and 0.963 +/- 0.062 gr for thyroid-treated subjects (p = 0.005). Mean 50% duration of response values (+/-1 SEM) were 9.143 +/- 1.108 min for controls and 5.763 +/- 0.973 min for thyroid-treated subjects (p = 0.014). Hyperthyroid rats had a significantly lower Müller's muscle response amplitude than control rats; however, duration of response was not significantly different between the groups. We believe that hyperthyroidism caused intrinsic changes in Müller's muscle that resulted in eyelid retraction. Based on hypotheses discussed in this article, we expect that further studies will localize these changes to the thyroid hormone receptor on Müller's muscle or calcium-triggered intracellular second messengers. Clinical significance would then be the ability to treat hyperthyroid eyelid retraction with drugs. This study provides the first evidence of functional impairment of Müller's muscle due to hyperthyroidism in an animal model.

Adrenergic alpha-Agonists↗
PubMed1997

[De novo absence status: case report].

There are few descriptions about middle-aged patients who have nonconvulsive status epilepticus, absence status. We reported the clinical case of a woman, 52-year-old, diabetic, referred to the emergency room in a confusional state. Initial electroencephalogram showed continuous typical, bilateral, symmetric and synchronous spike-and-wave discharges. Clinical and electroencephalogram normalization occurred immediately following intravenous injection of benzodiazepine. Computerized axial tomography was normal. The recognition of this entity is essential because of its similarity to psychiatric disturbance and its prompt response to proper treatment.

Diabetes Complications↗
PubMed1996

Differential care of corneal ulcers in the community based on apparent severity.

PURPOSE: To describe current practice patterns in treating infectious keratitis. METHODS: A questionnaire was designed that asked ophthalmologists to describe the diagnostic equipment accessible to their practice for performing smears and obtaining scrapings for microbial culture and sensitivity testing. The questionnaire also presented two hypothetical cases of patients with infectious keratitis. Bacterial keratitis was relatively early and less severe in the first patient, and it was more advanced and more severe in the second patient. Recipients were asked about their diagnostic and therapeutic approach. The survey was mailed to 300 ophthalmologists in Florida, Illinois, and New York. RESULTS: One hundred twenty-four completed surveys (45%) were returned. Six surveys were from cornea specialists, who were excluded from the analysis. Only 18 practices (15%) maintained access to Gram stain supplies, and 58 (50%) maintained culture supplies. Whereas 56% of respondents would treat the patient with the less severe bacterial keratitis without obtaining samples for cultures, only 13% would treat the patient with the more severe condition in this manner (P<0.00001). Of the respondents, 82% would treat the patient with the less severe bacterial keratitis with a fluoroquinolone, compared with 62% for the patient with the more severe infection (P=0.002). The mean frequency of fluoroquinolone administration for the patient with more-severe bacterial keratitis was one drop every 0.88 hours, compared with one drop every 1.48 hours for the patient with the less severe infection. CONCLUSIONS: Ophthalmologists appear to treat suspected infectious keratitis differently, depending on perceived severity; they choose different antibiotic regimens; and are more likely to forgo scrapings for Gram staining and cultures for ulcers that appear less severe. The justification for this approach should be established.

Adult↗
PubMed1996

Recovery from induced corneal edema and endothelial morphology after long-term PMMA contact lens wear.

PURPOSE: To study the effect of long-term polymethyl methacrylate (PMMA) contact lens wear (CLW) on corneal endothelial morphology and corneal hydration control (CHC). METHODS: Sixteen long-term PMMA CL wearers (mean duration of wear 20.8 +/- 8.39 SD years; mean age 40.37 years +/- 10.47 SD) served as subjects and 14 age-matched, non-lens wearing subjects (mean age 41.29 years +/- 10.15 SD) served as controls. Corneal function was assessed by measuring the corneal thickness recovery rate (PRPH) after induced edema from a hypoxic stress load. Endothelial morphology was assessed by taking specular microscopy photographs, digitizing the images, and calculating the cell density, size, and coefficient of variation of cell size (CV). RESULTS: Morphologic analysis showed a significant decrease in mean endothelial cell density (2147 vs. 2865, p < 0.01), an increase in mean cell size (582 vs. 381, p = 0.001), and an increase in polymegethism (CV, 0.32 vs. 0.26, p < 0.01) for PMMA lens wearers compared to agematched controls. Corneal function as measured by PRPH was not significantly different for PMMA lens wearers compared to controls when taken as a whole. However, a subgroup of PMMA lens wearers (seven eyes, four subjects) did show a substantial reduction in PRPH. These subjects also showed a strong relation between reduced PRPH, morphology, and years of lens wear (r2 = 0.99). CONCLUSIONS: Longterm PMMA CLW leads to increased polymegethism in most, if not all, cases and results in a substantial decrease in corneal function in some cases.

Adult↗
PubMed1994

Ocular manifestations of leprosy in a noninstitutionalized community in the United States.

OBJECTIVE: Our goal was to delineate the epidemiologic and clinical patterns of ocular leprosy in an outpatient setting in the United States. DESIGN: Examinations were performed in 61 consecutive outpatients seen in a Midwestern leprosy clinic. PATIENTS: Forty-three male and 18 female patients were examined. The patients' origins included Southeast Asia (24 patients [39%]), Latin America (23 patients [38%]), India (nine patients [15%]), Europe or North America (two patients [3%]), Africa (two patients [3%]), and the Middle East (one patient [2%]). RESULTS: Thirty-nine percent of patients were classified as having polar lepromatous leprosy; 18%, borderline lepromatous leprosy; 3%, borderline borderline leprosy; 36%, borderline tuberculoid leprosy; 2%, polar tuberculoid leprosy; and 2%, indeterminate leprosy. Ninety-six percent of patients had a best-corrected visual acuity of 20/40 or better. Ocular findings included madarosis (28 patients [46%]), subconjunctival fibrosis (18 patients [30%]), punctate epithelial keratopathy (17 patients [28%]), posterior subcapsular cataract (10 patients [16%]), corneal hypesthesia (10 patients [16%]), lagophthalmos (seven patients [11%]), corneal pannus (six patients [10%]), entropion (five patients [8%]), prominent or beaded corneal nerves (four patients [7%]), iridocyclitis (four patients [7%]), focal avascular keratitis (three patients [5%]), scleritis (three patients [5%]), interstitial keratitis (two patients [3%]), iris pearls (two patients [3%]), and ocular clofazimine crystals (two patients [3%]). Madarosis, corneal hypesthesia, and posterior subcapsular cataracts were significantly associated with disease duration (P < .05). CONCLUSION: We report herein a relatively low frequency of visual impairment attributable to leprosy in our series compared with that seen among institutionalized leprous patients. However, since 48% of subjects had one or more sight-threatening complications as a result of their disease, a program of regular ophthalmic follow-up is strongly advocated for all patients with leprosy.

Adolescent↗
PubMed1994

Predictors of occult scleral rupture.

PURPOSE: To determine which signs are sensitive and specific in the setting of trauma to establish the diagnosis of an occult scleral rupture. METHODS: The charts of patients with presumed scleral rupture were identified retrospectively. The ocular findings among the patients who had a rupture based on findings at surgery were compared with those patients who were noted to have normal findings at surgery. RESULTS: Visual acuity worse than 20/400, decreased intraocular pressure, intraocular pressure less than that in the nontraumatized eye, and an afferent pupillary defect were all significant indicators of an open globe. CONCLUSION: Determining the likelihood of an occult rupture can be facilitated by noting the presence or absence of those indicators that are significant and carry a high specificity.

Adolescent↗
PubMed1994

Dynamic shifts in corneal topography after radial and transverse keratotomy.

PURPOSE: The authors aimed to quantitate the dynamic patterns of change in corneal topography after multistaged radial and transverse keratotomy using digitized video-keratography. METHODS: Single and paired radial and transverse keratotomies, with videokeratoscopy between each stage and at the end of the procedure, were performed on fresh animal cadaver eyes using an artificial orbit system. RESULTS: All incisions led to central flattening. A single radial keratotomy caused flattening adjacent to the incision, and steepening 180 degrees away. A paired radial keratotomy caused increased flattening in the meridian of the incisions, and less flattening 90 degrees away. A single transverse incision caused steepening adjacent to the incision and diffuse flattening elsewhere. A paired transverse incision caused flattening near the optical center along the meridian bisecting the incisions and steepening 90 degrees away. CONCLUSION: The authors have demonstrated that computerized videokeratography can be used successfully to systematically quantitate dioptric shifts in multiple hemimeridians and measurement zone diameters after refractive surgery.

Animals↗
PubMed1994

Effect of methazolamide on chronic macular edema in patients with retinitis pigmentosa.

PURPOSE: To determine the effectiveness of methazolamide for improving visual acuity and macular edema in patients with retinitis pigmentosa. METHODS: Seventeen subjects with retinitis pigmentosa and chronic macular edema participated in a prospective, placebo-controlled, double-masked, crossover design study in which either methazolamide or a placebo was taken for 3 weeks. Visual acuity, fluorescein angiograms, and subjective impressions were obtained at baseline and after 3 weeks of treatment with each substance. A subgroup of subjects were enrolled in a more extended period of methazolamide treatment for an additional 3 months. RESULTS: Methazolamide resulted in the improvement of angiographic macular edema in 9 of 17 subjects. As a group, visual acuity statistically improved with methazolamide. However, improvement in at least one eye, of between two and four lines more than while taking placebo, occurred in only three (undilated pupils) or four (dilated pupils) subjects. Subjective improvement during treatment with methazolamide but not placebo occurred in only one subject. An extended period of methazolamide treatment for an additional 3 months in a subgroup of patients did not result in additional beneficial effects on visual acuity. In fact, a partial rebound in the extent of macular edema was found. CONCLUSIONS: Although angiographic improvement of macular edema can occur in patients with retinitis pigmentosa treated with methazolamide, notable (between 3 and 4 lines) or even moderate (between 2 and 3 lines) visual acuity improvement was seen in relatively few patients. When methazolamide was administered in a placebo-controlled fashion, subjective improvement in visual function also was not readily apparent. A more substantial subjective improvement in visual function had occurred with the use of acetazolamide in five of six subjects who also had participated in a previous treatment trial with the use of acetazolamide.

Adolescent↗
PubMed1994

Invasive and noninvasive methods to predict the long-term efficacy of amiodarone: a compilation of clinical observations using meta-analysis.

BACKGROUND: The method of choice to predict the long-term efficacy of amiodarone in the treatment of complex ventricular arrhythmias is unknown. Whether electrophysiological testing or Holter monitoring better predicts long-term outcome is controversial. METHODS AND RESULTS: We performed a meta-analysis of trials using electrophysiological testing or electrocardiographic monitoring to predict the efficacy of amiodarone in patients with sustained ventricular tachycardia. Arrhythmia recurrence data were combined after homogeneity testing across trials. Bayesian estimates and 95% credibility intervals were constructed to compare the arrhythmia-free probability among groups. Nine studies using electrophysiological testing (351 patients) and three using Holter monitoring (167 patients) met criteria for inclusion determined a priori. The combined arrhythmia-free probability estimate and credibility intervals were 0.86 (0.78-0.92) for patients rendered noninducible and 0.81 (0.73-0.87) for patients with abolition of ventricular tachycardia during Holter monitoring on amiodarone. With this primary analysis, there was no significant difference between the predictive value of noninducibility during electrophysiological testing and abolition of ventricular tachycardia with Holter. However, if only those electrophysiological studies using at least triple extrastimuli were included, arrhythmia-free probability for patients rendered noninducible increased to 0.96 (0.88-0.99), significantly better than noninvasive testing. CONCLUSIONS: Noninducible ventricular tachycardia during electrophysiological testing and abolition of ventricular tachycardia during electrocardiographic monitoring on amiodarone appear equally predictive of long-term amiodarone success, but this conclusion seems dependent on the stimulation protocol used. Although the yield is lower (compared to Holter monitoring), ventricular tachycardia rendered noninducible with a stimulation protocol using triple extrastimuli is the most highly predictive test of long-term amiodarone efficacy.

Aged↗
PubMed1994

Combined maximum likelihood estimates for the equicorrelation coefficient.

Combined maximum likelihood estimates for equicorrelation covariance matrices are considered. The case of a common equicorrelation rho and possibly different standard deviations sigma 1, ..., sigma k among k experimental groups is examined first, and the estimation of (rho, sigma 1, ..., sigma k) is discussed. Second, under the assumption of a common standard deviation and possibly different equicorrelations, the estimation of (rho 1, ..., rho k, sigma) is considered. In each case, maximum likelihood solutions and corresponding large-sample variances are presented.

Biometry↗
PubMed1993

Spontaneous and traumatic vitreous hemorrhage.

PURPOSE: The authors sought to provide relevant data regarding the demographic and clinical aspects of spontaneous and traumatic vitreous hemorrhages to guide clinicians in better delineating the expected etiologic patterns of these hemorrhages in an urban environment. METHODS: The records of 253 consecutive patients with newly diagnosed vitreous hemorrhage seen in a general eye clinic were selected for retrospective analysis. To minimize selection bias of a tertiary care center, patients who were referred to the clinic by outside ophthalmologists for vitreoretinal consultation or those with a history of recent intraocular surgery, postoperative complications, or loss to follow-up were excluded from study. Demographic, ocular, and general medical variables were tabulated for the 200 patients (230 eyes) who met our inclusion criteria. RESULTS: Fifty percent of the patients were black, 26% were white, 23% were Hispanic, and 1% was Oriental. The causes of vitreous hemorrhage were proliferative diabetic retinopathy (PDR) (35.2%), trauma (18.3%), retinal vein occlusion (7.4%), retinal tear without a detachment (7.0%), posterior vitreous detachment (6.5%), proliferative sickle retinopathy (5.7%), retinal tear with a detachment (4.8%), subretinal neovascularization from macular degeneration (2.2%), hypertensive retinopathy (1.7%), unknown (2.5%), and other causes (8.7%). Among black patients with spontaneous vitreous hemorrhage, sickle cell retinopathy and retinal vein occlusion were major causes, each accounting for more than 15% of the cases. Systemic hypertension was associated with vitreous hemorrhage from retinal vein occlusion. CONCLUSION: The authors propose that despite the wide array of causative factors of vitreous hemorrhage, the evaluation of demographic, ocular, and medical variables can significantly aid clinicians in identifying its etiologic patterns.

Adolescent↗
PubMed1993

Can the concentration of timolol or the frequency of its administration be reduced?

BACKGROUND: There is evidence that the ocular hypotensive effect of topical beta-blockers persists for at least 24 hours once beta-blockade has been achieved. In previous studies, the highest concentration of drug generally has been used for this purpose. METHOD: Home tonometry was performed with a self-tonometer by 14 patients to study the intraocular pressure (IOP) reduction of 0.5% timolol administered once daily in the morning or in the evening and of 0.25% timolol administered in the morning. The study was masked and included washout periods before and between the different regimens. At the end of each treatment period, the IOP was monitored five times daily for 3 days. RESULTS: No significant difference in mean reduction of IOP was found between the morning instillation of once daily 0.5% timolol compared with evening instillation of 0.5% timolol. In addition, there was no statistically significant difference in the mean IOP reduction between once daily administration of 0.25% versus 0.5% timolol. CONCLUSION: This study indicates that a lower concentration of timolol maleate used once daily may achieve maximum IOP reduction. The time of the single administration appears not to make any difference.

Adult↗
PubMed1993

Saccadic eye movements as a measure of the effect of low vision rehabilitation on reading rate.

We assessed saccadic eye movements and reading capabilities in individuals with macular disease by a masked clinical study to determine whether changes in saccadic frequency were correlated to changes in reading rates or number of errors for a reading task. We used a measure of eye movement characteristics in the form of a saccadic frequency score (SFS). Twelve subjects with macular disease were tested before and after an intense 6-week inpatient vision rehabilitation program. The mean age was 70.9 years (63 to 77 years). Mean visual acuity was 10/100 (10/40 to 10/200). Mean reading rates at entry and discharge were 8.5 words/min and 20.9 words/min, respectively (p = 0.02). SFS improved from 2.709 to 2.022 (p = 0.07). Reading errors improved from 5.60 to 4.00 (p = 0.03). Reading rates and SFS's were highly inversely correlated both pre- and post-treatment (Pearson r = -0.892 and -0.896, respectively). SFS and the number of reading errors were highly correlated with both pre- and post-treatment as well (Pearson r = 0.782 and 0.601, respectively). Interestingly the data appeared to cluster into two groups, one showing improvement and the other showing none. Cluster analysis revealed a strong association among reading rate, saccade scores, and reading errors. Membership in the two clusters is consistent pre- and post-rehabilitation in all but one case. Clustering is most evident for reading rate and reading errors and less so for saccade scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Multivariate assessment of computer-analyzed corneal topographers.

Methodological aspects of multivariate statistical models to describe and to assess data from computer-analyzed corneal topographers (CACT) are considered. The data generated by repeated curvature mappings of calibrated steel balls are discussed in detail with the objective of formulating the basic questions and suggesting directions to assess data from clinical applications of CACT. The interpretation of seemingly straightforward concepts such as accuracy and precision is revisited with the objective of understanding its meaning in future clinical and experimental applications of CACT. Some of the statistical problems related to the analysis of corneal astigmatism based on CACT data are also discussed.

Astigmatism↗
PubMed1992

Contact lens failure in keratoconus management.

PURPOSE: Surgery is indicated for keratoconus when management with contact lenses fails. The authors sought to determine the relative contribution of various preoperative patient and ocular factors to the ultimate causes of contact lens failure. METHODS: The records of unoperated eyes of keratoconus patients whose contact lenses were managed intensively before undergoing penetrating keratoplasty (PK) at the authors' institution between 1981 and 1990 were selected for study. Univariate and multivariate analyses were performed to identify risk factors for early contact lens failure. RESULTS: The records of 99 keratoconic eyes of 75 patients with an average age of 34 years and average keratometry readings of 57.5 diopters at presentation were studied. Cases had been followed for an average of 27 months before PK. The primary reasons for PK were a best-corrected visual acuity of under 20/40 (despite good contact lens fit) causing disability for the patient (43%), contact lens intolerance (32%), frequent lens displacement (13%), and significant peripheral thinning of the cornea (12%). The referral source of the patient, sex, a history of PK in the fellow eye, or of contact lens wear in either eye did not alter the relative contributions of these parameters to surgery. CONCLUSION: Poor best-corrected visual acuity at presentation, higher keratometry readings (greater than or equal to 55 D), age (greater than or equal to 40 years), and duration of disease (greater than 5 years) were significantly associated with failure due to poor functional acuity and peripheral thinning, frequently leading to surgery within the first 12 months after presentation.

Adolescent↗