Biomedical subjects

George A Cioffi

Publications and source records attributed to George A Cioffi.

At least 19 recordsLinked to original sources

PubMed2007

The results of screening frequency doubling technology perimetry in different locations of the community.

PURPOSE: To determine the effect of screening location on the frequency of abnormal test results with Frequency Doubling Technology (FDT) perimetry. DESIGN: Retrospective cross-sectional study. METHODS: The Vision Screening Outreach Project conducted FDT testing in community sites surrounding Portland, Oregon. The sites were separated into a specific location type: health care clinics, work sites, senior centers, festivals/fairs, food banks/shelters, and other locations. These locations were compared for differences in the proportion of screening failures. MAIN OUTCOME MEASURES: Screening failure (defined as a repeatable, abnormal FDT result in either eye). RESULTS: There were 9052 participants from 211 locations in Oregon and Washington. On initial FDT testing, the right and left eye had abnormal results in 18% (1654/9052) and 21% (1918/9052) of participants. Of those with abnormal FDT results, approximately 30% of eyes reverted to normal on repeat testing. Overall, 13% of participants were screening failures. Screening failure was highly associated with age (P<0.001). After controlling for age, participants at senior centers (P<0.001) were most likely to be screening failures and participants at work sites (P=0.006) were least likely to be screening failures when compared with health clinics. CONCLUSIONS: An investigator should repeat an initially abnormal FDT result when screening with FDT. Age and the location of testing influence the probability of a screening failure. Screening in senior centers is most likely to result in screening failure. However, only a randomized controlled trial can determine the true benefit of FDT screening in these locations.

Adolescent↗

PubMed2006

Microspheres method for ocular blood flow measurement in rats: size and dose optimization.

This study modified the microspheres method by optimizing the dose and size of microspheres (MS) to enable accurate ocular blood flow measurement in rats. Fluorescent MS, either 6, 8, 10 or 15 microm diameter, were administered into the left ventricle of anesthetized adult Brown Norway rat in a dose of either 10(6), 5x10(6), or 10(7). The total number of MS entrapped in retina, choroid and optic nerve (Ntissue) was quantified and compared between size and dose groups. The MS distribution in the retina and their reentry into systemic circulation were evaluated for different sized MS. The results showed that at the 5x10(6) dose, the Ntissue of 8 microm MS was significantly more than either 6 or 10 microm MS in the retina (P<0.02) and optic nerve (P<0.03). The 10 microm MS produced the highest Ntissue for the choroid, as compared with either 8 or 6 microm MS (P<0.03). At the 10(6) dose, no difference of N(tissue) was found between 8, 10, and 15 microm MS in the retina. The 10 microm MS yielded the highest Ntissue in the choroid as compared to 8 and 15 microm MS (P<0.003). The Ntissue for 8 microm MS was higher than both 10 and 15 microm (P<0.01) MS in the optic nerve. No MS (>or=8 microm) reentered the systemic circulation. The 15 microm MS tended to lodge in pre-capillary arterioles and caused significant blood pressure increase during the injection. The blood flow measured with the optimal size MS (mean+/-SE) were 19+/-3.4 and 170+/-35 microl/min in the retina and choroid, respectively; and 0.18+/-0.03 microl/min per mm optic nerve. It is concluded that the 8 microm MS are the optimal size for both retinal and optic nerve blood flow estimation; the 10 microm for the choroid. The optimal dose for the retina was approximately 2.5x10(6), 0.5x10(6) for the choroid, and 5x10(6) approximately 10(7) for the optic nerve. The 15 microm MS are inappropriate for ocular blood flow measurements in rats.

Animals↗

PubMed2006

Endothelin B receptor in human glaucoma and experimentally induced optic nerve damage.

OBJECTIVE: To assess endothelin B receptor (ETbR) expression in human glaucomatous optic nerves and the spatial relationship between ETbR and astrocytes. METHODS: Twenty-six eyes from 16 glaucoma patients and 10 normal control subjects were immunohistochemically labeled with antibodies to ETbR. The immunoreactivity was quantified and compared between normal and glaucomatous eyes with an image analysis system. Tissues were also double-labeled for ETbR and astrocytes. In addition, the optic nerve of a monkey with regional degeneration induced by laser coagulation was examined with the same techniques. RESULTS: The frequency of positive ETbR immunoreactivity was higher in human glaucomatous optic nerves as compared with age-matched controls (9/16 vs 1/10, P = .02). The ETbR immunoreactivity colocalized with astrocytic processes and was quantitatively higher in the glaucomatous eyes (P = .02). In the monkey, the regions of degeneration showed increased ETbR associated with reactive astrocytes and was highest at the borders between normal areas and degeneration. CONCLUSION: Increased ETbR immunoreactivity in diseased optic nerves and its association with astrocytes suggest that the glia-endothelin system may be involved in the pathologic mechanisms of neuronal degeneration. Clinical Relevance The study supports the clinical observation of endothelin involvement in glaucoma and provides direct evidence that the endothelin system is associated with glaucomatous pathologic abnormalities.

Aged↗

PubMed2006

The probability of glaucoma from ocular hypertension determined by ophthalmologists in comparison to a risk calculator.

OBJECTIVE: To investigate the ability of ophthalmologists to estimate an individual's risk of converting from ocular hypertension to glaucoma, and to compare these estimates to a risk calculator. DESIGN: Cross-Sectional Survey. METHODS: Fifty-one ophthalmologists estimated the probability of developing glaucoma of 4 factitious patients with ocular hypertension, after a didactic review of the Ocular Hypertension Treatment Study (OHTS) results. We compared the physician estimates to the probability estimates of a risk calculator on the basis of the multivariate Cox proportional hazard model of the OHTS results. RESULTS: The average estimates given by the ophthalmologists (mean probability+/-SD) of developing glaucoma in 5 years for patient no. 1, patient no. 2, patient no. 3, and patient no. 4 were 6.5%+/-8.4 (range 1 to 50), 30.6%+/-20.5 (range 1 to 100), 7.1%+/-5.1 (range 0 to 20), and 21.1%+/-17.3 (range 1 to 80), respectively. The risk calculator estimated the probability of glaucoma in these same patients to be 13.7%, 53.8%, 5.1%, and 41.9%, respectively. CONCLUSIONS: The ophthalmologists showed a high range of estimates for the probability of developing glaucoma in the same ocular hypertensive patients. This may lead to either under or over treatment of patients. Clinicians need a more exact method to determine the probability of glaucoma from ocular hypertension.

Aged↗

PubMed2005

Baseline topographic optic disc measurements are associated with the development of primary open-angle glaucoma: the Confocal Scanning Laser Ophthalmoscopy Ancillary Study to the Ocular Hypertension Treatment Study.

OBJECTIVE: To determine whether baseline confocal scanning laser ophthalmoscopy (CSLO) optic disc topographic measurements are associated with the development of primary open-angle glaucoma (POAG) in individuals with ocular hypertension. METHODS: Eight hundred sixty-five eyes from 438 participants in the CSLO Ancillary Study to the Ocular Hypertension Treatment Study with good-quality baseline CSLO images were included in this study. Each baseline CSLO parameter was assessed in univariate and multivariate proportional hazards models to determine its association with the development of POAG. RESULTS: Forty-one eyes from 36 CSLO Ancillary Study participants developed POAG. Several baseline topographic optic disc measurements were significantly associated with the development of POAG in both univariate and multivariate analyses, including larger cup-disc area ratio, mean cup depth, mean height contour, cup volume, reference plane height, and smaller rim area, rim area to disc area, and rim volume. In addition, classification as "outside normal limits" by the Heidelberg Retina Tomograph classification and the Moorfields Regression Analysis classifications (overall, global, temporal inferior, nasal inferior, and superior temporal regions) was significantly associated with the development of POAG. Within the follow-up period of this analysis, the positive predictive value of CSLO indexes ranged from 14% (Heidelberg Retina Tomograph classification and Moorfields Regression Analysis overall classification) to 40% for Moorfields Regression Analysis temporal superior classification. CONCLUSIONS: Several baseline topographic optic disc measurements alone or when combined with baseline clinical and demographic factors were significantly associated with the development of POAG among Ocular Hypertension Treatment Study participants. Longer follow-up is required to evaluate the true predictive accuracy of CSLO measures.

False Positive Reactions↗

PubMed2005

Psychophysical investigation of ganglion cell loss in early glaucoma.

PURPOSE: To evaluate ganglion cell loss in early glaucoma using a variety of psychophysical tests and to identify optimal perimetric technique(s) for detection of early glaucomatous visual function loss. METHODS: Five perimetric tests, short wavelength automated perimetry (SWAP), temporal modulation perimetry (TMP), frequency doubling technology perimetry (FDT), detection acuity perimetry (DAP), and resolution acuity perimetry (RAP) were compared in their ability to discriminate between normal individuals and patients with early glaucoma or glaucoma suspects. Comparisons were also made by their ability to produce repeatable defects. The tests examined different visual functions that are likely to be mediated by different retinal ganglion cell subpopulations, thereby permitting examination of hypotheses of ganglion cell death in early glaucoma. RESULTS: All visual field tests demonstrated high performance in separating glaucoma patients from normal individuals. SWAP, TMP, FDT, and DAP provided the greatest discrimination between normal individuals and high- and low-risk glaucoma suspects. However, SWAP, TMP, and FDT obtained better consistency across the various analysis approaches (global indices and pointwise) than DAP and RAP. Of all the test types, FDT exhibited the highest proportion of repeatable abnormal test locations, with poor confirmation rates achieved by DAP and RAP. CONCLUSION: The performance of SWAP, FDT, and TMP suggests that these test types may all be suitable for detection of early loss of visual function in glaucoma. Ganglion cell subpopulations with lower levels of redundancy and/or those with larger cell sizes offer the most parsimonious explanation for earliest ganglion cell losses occurring in glaucoma.

Cell Death↗

PubMed2005

Predictive value of frequency doubling technology perimetry for detecting glaucoma in a developing country.

PURPOSE: To determine the feasibility and diagnostic precision of Frequency Doubling Technology (FDT) perimetry as a method to detect glaucoma in rural villages of a developing country. DESIGN: Cross-sectional study. METHODS: Testing included FDT perimetry (C-20-5 screening protocol), tonometry, anterior segment biomicroscopy, and dilated ophthalmoscopy in 296 rural, non-English speaking residents of Southern India over 35 years old. Participants repeated the FDT if they had a location with reduced sensitivity or an unreliable result. We defined an abnormal FDT as one location of reduced sensitivity present on both the initial and repeat examination. We determined the diagnostic precision of FDT separately for a glaucomatous optic disc, a cup to disc ratio (C/D) > or = 0.7, and a C/D > or = 0.8. RESULTS: Ninety-three percent of subjects were able to complete the test satisfactorily. With repeat FDT testing, 37% of eyes with abnormal FDT results subsequently converted to normal and 67% of eyes with unreliable results subsequently became reliable. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for a glaucomatous optic disc were 7%, 87%, 13%, 76%, and 69%, respectively; for a C/D > or = 0.7, they were 0%, 87%, 0%, 91%, and 81%, respectively; and for a C/D > or = 0.8, they were 0%, 87%, 0%, 99%, and 87%, respectively. CONCLUSION: Clinicians can use FDT perimetry to rapidly screen for glaucoma in rural villages of a developing country. FDT testing had high specificity and negative predictive value, but low sensitivity and positive predictive value. The low sensitivity suggests that FDT has limited applicability as the sole test for glaucoma screening in this population. Repeat testing of FDT results that are unreliable or suspected of being abnormal is beneficial for this screening procedure.

Adult↗

PubMed2005

The gradient of retinal functional changes during acute intraocular pressure elevation.

PURPOSE: To characterize retinal function during a period of acutely elevated intraocular pressure (IOP) across a wide range of IOPs, including those typically observed in animals with experimental glaucoma. METHODS: Unilateral elevation of IOP was achieved manometrically in adult Brown Norway rats (nine experimental groups; n=4-7 in each; 10-100 mmHg and sham control). Full-field ERGs were recorded simultaneously from treated and control eyes, beginning 75 minutes after IOP elevation. Scotopic ERG stimuli were brief white flashes (-6.1 to 2.7 log cd-s/m2). Photopic ERGs were recorded (1.2-2.7 log cd-s/m2) after 15 minutes of light adaptation (150 cd/m2). Relative amplitude (treated/control, %) of ERG components versus IOP was described with a cumulative normal function. RESULTS: Resting IOP was 12.1 +/- 2.8 mmHg and mean femoral artery pressure was 97.6 +/- 10.7 mmHg. ERG components showed a graded effect dependent on IOP. Systematic delays in the timing of the scotopic threshold response (STR) and photopic b-wave were observed between IOPs of 30 and 40 mmHg. Analysis of amplitudes revealed that the negative STR component (nSTR) and the photopic OPs were the most sensitive to acute IOP elevation. These components were first significantly affected at 50 mmHg, whereas all parameters of middle and outer retinal function (scotopic P2 and P3) remained normal. The nSTR and photopic OPs declined by 50% at IOP <61 mmHg. The scotopic P2, OPs, and positive STR (pSTR) had intermediate sensitivity, such that they were reduced by 50% at IOPs between 61 and 66 mmHg. Scotopic P2 amplitude, but not sensitivity, was significantly reduced by 60 mmHg. At 60 and 70 mm Hg, the decline in P2 amplitude was not attributable to changes in photoreceptor response (P3) amplitude or sensitivity. The least sensitive component was the scotopic a-wave (RmP3) showing a 50% reduction at an IOP of 71 mmHg. CONCLUSIONS: During acute IOP elevation, functional changes progress from the proximal to the distal retina. Alterations in ganglion-cell-related ERG potentials occurred at IOPs (30-50 mmHg) commonly observed in rat experimental glaucoma models. Nonspecific functional changes were observed at acute IOP above 50 mmHg, suggesting that IOP should be maintained below this level in experimental glaucoma models if selective ganglion cell injury is to be sought. Repeated IOP spikes above this level may cause permanent, nonspecific damage, perhaps via ischemic mechanisms. Thus, IOP should be monitored frequently in these models.

Acute Disease↗

PubMed2005

Idiopathic bilateral optic atrophy in the rhesus macaque.

PURPOSE: To document the existence of idiopathic bilateral optic atrophy (BOA) in rhesus macaque monkeys and to characterize the structural and functional consequences of this condition. METHODS: In vivo assessment of retinal and optic nerve structure included fundus biomicroscopy and stereophotography. Functional analyses included transient pattern-reversal electroretinography (PERG) and full-field flash ERG, with both white flashes while dark adapted and red flashes on a blue background used to assess the photopic negative response (PhNR). Also measured were visual evoked cortical potentials (VEPs) and multifocal (mf)ERGs, with both a standard fast and slowed (7F) stimulation sequence. Post mortem histologic evaluation was performed on a subset of five animals with BOA and compared with data from 22 healthy normal animals. Blood tests, including vitamin E, B(12), folate, lead, and complete blood cell count with differential were obtained on the four animals that remained alive. RESULTS: Animals with BOA showed temporal pallor of the optic nerve head and thinning of the retinal nerve fiber layer (RNFL) between the temporal vascular arcades (i.e., of the papillomacular bundle). Severity of optic atrophy and RNFL loss varied between animals from mild to severe, but was similar in the two eyes of each animal. Functional changes included greater loss of the PERG N95, compared with the P50 component and substantial reduction of mfERG high-frequency components. The mfERG low-frequency components were slightly larger than normal. None of the full-field flash ERG amplitudes (a-wave, b-wave, oscillatory potentials, or PhNR) was significantly different from normal. There were no consistent abnormalities found in the results of any blood test. Histologic findings included axonal loss and gliosis limited to the temporal optic nerve, reduction of nuclei within the retinal ganglion cell layer, and thinning of the temporal retinal RNFL. CONCLUSIONS: The existence of BOA in nonhuman primates warrants caution on the part of investigators who use these animals in experimental models of ophthalmic disease.

Animals↗

PubMed2005

Evaluation of the structure-function relationship in glaucoma.

PURPOSE: While glaucoma is evaluated on the basis of structural and functional test results, the spatial relationship between structure and function is not well defined. This study produces a topographical map to demonstrate how sectors of the optic nerve head (ONH) are related to locations in the visual field, using empiric cross-sectional patient data. METHODS: One hundred nine subjects with healthy eyes and 166 subjects with diagnosed or suspected glaucoma (one test per patient) were evaluated using a retina tomograph and white-on-white standard automated perimetry (SAP). The tomograph ONH images were divided into 36 sectors; and the sector rim areas normalized to account for changes in the total rim area. These were then correlated with SAP thresholds. For each visual field location, a map was produced indicating the strength of correlation between the normalized sector rim areas and thresholds. RESULTS: The highest correlation between a sector's normalized rim area and a SAP location's sensitivity was 0.520. Twenty-seven of the 52 non-blind spot SAP locations exhibited a correlation greater than 0.2 with at least one ONH sector. Locations in the superior hemifield were usually best correlated with the polar inferior temporal sectors of the ONH; locations in the inferior hemifield were usually best correlated with the polar superior temporal sectors of the ONH. CONCLUSIONS: A map relating regions of the ONH to SAP test locations has been produced. This map may be useful in elucidating the structure-function relationship, particularly for cases of localized glaucomatous loss.

Aged↗

PubMed2005

Causes of visual impairment and common eye problems in Northwest American Indians and Alaska Natives.

OBJECTIVES: Little information exists regarding the causes of visual impairment and the most common eye problems in American Indians/Alaska Natives. METHODS: We randomly sampled American Indians/Alaska Natives older than 40 years from 3 tribes within the Northwest region. RESULTS: We found a higher prevalence of visual impairment and normal-tension glaucoma, as well as a lower prevalence of ocular hypertension, in American Indians/Alaska Natives compared with previous results in other racial/ethnic groups. CONCLUSIONS: American Indians/Alaska Natives have a need for vision correction. Future interventions in American Indians/Alaska Natives should include providing spectacles for refractive error, detecting glaucoma, and preventing visual impairment from age-related maculopathy and cataracts.

Adult↗

PubMed2005

Ischemic model of optic nerve injury.

PURPOSE: It is proposed that the anterior optic nerve is specifically susceptible to microcirculatory compromise contributing to the development of glaucomatous optic neuropathy. METHODS: Ischemic optic neuropathy was induced by delivering endothelin-1 (ET-1) to the retrobulbar space in one eye of 12 primates for 6 to 12 months. Regional ganglion cell axonal sizes and densities were compared with the normal, contralateral eyes. RESULTS: Without changes of intraocular pressure, mean axonal density was significantly decreased in ET-1 eyes compared to controls (P = .03, paired t test). Two-way matched-pair analysis of variance showed a significant effect of ET-1 on overall axonal density (P < .0001). Among the animals with significant axonal loss, the mean axonal loss was 11.6%, and loss varied from 4% to 21%. Axonal loss was commonly localized within specific quadrants. Five animals were examined for preferential axonal size loss. As a group, there appears to be a tendency toward preferential large axonal loss, but the mean axonal loss of large and small axons did not meet significant differences (P = .1) However, examination of individual animals with significant loss shows significantly greater loss of large axons as compared to the small axons in three of the animals. CONCLUSIONS: Chronic optic nerve ischemia causes demonstrable and localized damage of the optic nerve, without intraocular pressure elevation. There is preferential loss of large retinal ganglion cell axons in animals with significant axonal loss. Ischemia-induced focal axonal loss is similar to human glaucoma and may represent a differential regional vulnerability.

Analysis of Variance↗

PubMed2004

Racial differences in optic disc topography: baseline results from the confocal scanning laser ophthalmoscopy ancillary study to the ocular hypertension treatment study.

OBJECTIVE: To examine racial differences in optic disc topography among ocular hypertensive participants in the Ocular Hypertension Treatment Study. METHODS: Four hundred thirty-nine participants from 7 Ocular Hypertension Treatment Study centers who had good-quality baseline images obtained using a quantitative 3-dimensional confocal scanning laser ophthalmoscope, the Heidelberg Retina Tomograph (Heidelberg Engineering, Dossenheim, Germany), were included in this study. The first 10 degrees- or 15 degrees-field of view mean topographic image acquired was included in all analyses. Differences in Heidelberg Retina Tomograph topographic optic disc parameter measurements by self-identified race were assessed using a mixed-effects linear model to control for confounders and for the use of both eyes in the model. RESULTS: By self-attribution, 74 (17%) of the 439 participants were of African origin, 329 (75%) were white, 24 (5%) were Hispanic, and 12 (3%) were Native American, Native Alaskan, Asian, Pacific Islander, or unknown. The African American participants had statistically significantly (P<.001) larger mean (SD) optic disc areas than the other participants, 2.17 (0.41) mm(2) vs 1.87 (0.38) mm(2), respectively. African American participants had a larger cup area, cup volume, cup depth, neuroretinal rim area, rim volume, and smaller rim-optic disc area ratios than the other participants. No difference between African American and the other participants was found for cup shape and retinal nerve fiber layer thickness. After controlling for optic disc area, none of the differences between African American and the other participants found in the univariate analysis remained statistically significant (P>.10). CONCLUSIONS: This study demonstrated in a large cohort of subjects with ocular hypertension, that African Americans have significantly larger optic discs, optic cups, neuroretinal rims, and cup-disc ratios than other racial groups. Furthermore, this study found that differences in topographic optic disc parameters between African Americans with ocular hypertension and other racial groups are largely explained by the larger optic disc area in the African Americans. These results highlight the need to consider race and optic disc size when evaluating the appearance of the optic disc in glaucoma.

Antihypertensive Agents↗

PubMed2004

Chronic ischemia induces regional axonal damage in experimental primate optic neuropathy.

OBJECTIVES: To evaluate the effects of chronic optic nerve ischemia in a nonhuman primate model and to evaluate the regional variability of axonal loss. METHODS: Unilateral ischemic optic neuropathy was induced by administration of endothelin-1 to the retrobulbar space via osmotic pumps in 12 primates for 6 to 12 months. The transversely cut sections were stained and divided into 16 regions. Average axonal density in each region was quantified and compared with the untreated contralateral control eyes. RESULTS: Mean axonal density was 208 310/mm(2) and 220 661/mm(2) in treated and control eyes, respectively (P = .03, 1-tailed paired t test), for the entire group. Two-way analysis of variance showed a significant effect of endothelin-1 on overall axonal density for the experimental group (P<.001). Among the nerves with significant axonal loss, the mean axonal loss was 11.6% (4%-21%). Regional mapping of the damage showed the axonal loss varied in the damaged nerves; the damaged regions often clustered within specific quadrants. CONCLUSION: Chronic ischemia induced by local administration of endothelin-1 causes significant loss of optic nerve axons with varying regional susceptibility. Clinical Relevance Localized damage occurs in other types of optic neuropathy, such as glaucoma, and may result from regional differences in anatomy, metabolism, or vasculature of the primate optic nerve.

Animals↗

PubMed2004

The confocal scanning laser ophthalmoscopy ancillary study to the ocular hypertension treatment study: study design and baseline factors.

PURPOSE: To describe the study design of the Confocal Scanning Laser Ophthalmoscopy (CSLO) Ancillary Study to the Ocular Hypertension Treatment Study (OHTS) and to examine the associations between optic disk topography, and baseline demographic, clinical, and ocular factors at study entry. DESIGN: A randomized clinical trial. METHODS: Participants in this ancillary study were recruited from seven of the 22 OHTS clinical centers. Each participant completed imaging annually using a CSLO, the Heidelberg Retina Tomograph (HRT). Associations between HRT topographic optic disk measurements and intraocular pressure (IOP), baseline photographic estimates of horizontal and vertical cup-to-disk diameter ratios by the OHTS Optic Disk Reading Center, baseline visual field indices, and demographic and clinical factors were assessed using linear mixed effects models. RESULTS: Four hundred thirty-nine participants had good quality images and were included in this baseline analysis. No associations between HRT topographic optic disk measurements and diabetes, systemic hypertension, cardiovascular disease, IOP, or visual function were found. The HRT topographic optic disk measurements were associated with baseline stereophotographic estimates of horizontal and vertical cup-to-disk diameter ratios. The strongest associations were found between stereophotographic assessment of horizontal and vertical cup-to-disk diameter ratios, and HRT cup-to-disk area ratio (r =.85 and.84, respectively), rim-to-disk area ratio (r = -.85 and -.84, respectively), mean cup depth (r =.84 and.83, respectively), and cup area (r =.83 and.80, respectively). After adjusting for optic disk area, all HRT topographic optic disk measurements remained associated with stereophotographic assessment of horizontal and vertical cup-to-disk diameter ratios. CONCLUSIONS: The CSLO ancillary study to the OHTS is the first multicenter clinical trial to use CSLO imaging to monitor changes in the optic disk. At study entry, HRT topographic measurements corresponded well with both horizontal and vertical stereophotographic-based estimates of cup-to-disk diameter ratio in ocular hypertensive participants.

Female↗

PubMed2004

Risk assessment in the management of patients with ocular hypertension.

PURPOSE: To develop a model for estimating the global risk of disease progression in patients with ocular hypertension and to calculate the "number-needed-to-treat" (NNT) to prevent progression to blindness as an aid to practitioners in clinical decision making. DESIGN: Development of a mathematical model for estimating risk of glaucoma progression. METHODS: Population-based studies of patients with ocular hypertension and glaucoma were reviewed by a panel of glaucoma specialists. Measures of disease progression risks derived from three long-term studies and assumptions based on the available data were used to estimate the risk of progression from ocular hypertension to glaucoma and glaucoma to unilateral blindness for untreated and treated patients over a 15-year period. Using these estimates, the NNT (1/absolute risk reduction on treatment) to prevent unilateral blindness in one patient with ocular hypertension was calculated. RESULTS: In untreated patients, the estimated risk of progression from ocular hypertension to unilateral blindness was 1.5% to 10.5% and in treated patients, the estimated risk of progression was 0.3% to 2.4% over 15 years. From these estimates, between 12 and 83 patients with ocular hypertension will require treatment to prevent one patient from progressing to unilateral blindness over a 15-year period. CONCLUSION: Global risk assessment that incorporates all available data plays a vital role in managing patients with ocular hypertension. A more precise understanding of long-term vision loss should be factored into decisions pertaining to the initiation of glaucoma therapy. Undoubtedly, these estimates will evolve and change with the availability of new population-based epidemiologic information and improvements in multivariable model testing.

Blindness↗

PubMed2004

Applying an evidence-based approach to the management of patients with ocular hypertension: evaluating and synthesizing published evidence.

PURPOSE: The use of evidence-based medicine in managing patients with ocular hypertension has been constrained by the limited availability of high-quality data from controlled clinical trials and by limited formal training of clinicians in evaluating published evidence. This article will provide strategies and techniques to evaluate critically the quality of published research, synthesize the findings, and integrate published evidence in the care of patients with ocular hypertension. DESIGN: Review of the published literature and consensus of a panel of experts. METHODS: The published literature on evidence-based medicine was reviewed. Strategies and techniques in evaluating the quality of evidence and how to integrate evidence into the practice setting using the following three major questions were discussed by a panel of experts: Are the results of the study valid? What are the results? Do the study outcomes apply to individual patient care? RESULTS: Approaches to assessing study validity and the importance of considering the size of the treatment effect and precision of the effect size were detailed. The importance of using the "number-needed-to-treat" as a tool for translating results of clinical trials to individual patient care and the "number-needed-to-harm" as a method of comparing the potential benefit and harm of a given therapy was acknowledged. CONCLUSION: As the volume of high-quality data increases, the information provided herein may help ophthalmologists apply evidence-based medicine techniques as they seek to optimize the care of individual patients with ocular hypertension.

Evidence-Based Medicine↗

PubMed2004

Gold standard medical therapy for glaucoma: defining the criteria identifying measures for an evidence-based analysis.

BACKGROUND: Over the past decade, several new medical therapies have become available for the treatment of primary open-angle glaucoma (POAG). A systematic evidence-based approach for identifying an optimal therapeutic agent is lacking. OBJECTIVES: The aims of this review were to critically evaluate published treatment recommendations for POAG and, based on a systematic review of the literature, to develop criteria that would define a "gold standard" medical therapy that reflects new treatment advances and established therapeutic goals. METHODS: A MEDLINE search spanning the years 1966 to 2002 and using the search terms gold standard, drug of choice, agent of choice, benchmark, ophthalmology, eye, and glaucoma was conducted and the results reviewed by a panel of 15 experts in the field of glaucoma. Published treatment recommendations for POAG were discussed. Criteria, anchored to medical evidence, for distinguishing a standard of medical therapy for POAG were defined. RESULTS: The terms connoting a gold standard therapy were found in only 258 of approximately 368,000 ophthalmology-related citations and 53 of almost 23,000 glaucoma citations, validating the need to define therapeutic standards. The lack of recommendations for the use of new classes of ocular hypotensive agents was acknowledged. Criteria identified to evaluate intraocular pressure (IOP)-lowering agents as gold standards included the following: efficacy in reducing IOP consistently over a 24-hour period to a level that will preserve the visual field and protect the optic nerve without inducing tachyphylaxis and tolerance, paucity of local and systemic adverse effects, promotion of patient compliance, and applicability in diverse patient populations. CONCLUSIONS: These criteria should be employed as measures for evidence-based analyses to evaluate available and future IOP-lowering medical therapies for POAG. The conceptual framework presented may be applicable to other therapeutic areas.

Adrenergic beta-Antagonists↗