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Andrew P Schachat

Publications and source records attributed to Andrew P Schachat.

At least 19 recordsLinked to original sources
PubMed2006

Nine-year incidence of diabetic retinopathy in the Barbados Eye Studies.

OBJECTIVE: To estimate the 9-year incidence of diabetic retinopathy (DR) in a population with the same ancestry as African Americans. METHODS: Participants with diabetes mellitus and gradable photographs at the 9-year examination were evaluated (n = 436). The incidences of minimum/moderate/severe DR, clinically significant macular edema (CSME), and sight-threatening DR (severe DR plus CSME) were defined by the development of specific diabetic changes in persons without those conditions at baseline. Progression was defined as the development of severe/proliferative DR in persons with minimum/moderate DR at baseline. RESULTS: The 9-year DR incidence was 39.6% (38.0% for minimum, 9.0% for moderate, and 2.6% for severe/proliferative DR). Incidence tended to increase with diabetes duration and treatment. Of persons with preexisting DR at baseline, 8.2% progressed to proliferative DR. The CSME incidence was 8.7%, and it increased with diabetes duration, accounting for most of the overall incidence of sight-threatening DR. CONCLUSIONS: The study provides new data on long-term incidence among persons of African origin. Results suggest a possible lower risk of severe/proliferative DR than in whites, while CSME incidence seems comparable or higher. The main component of sight-threatening DR was CSME, highlighting the importance of DR as a cause of vision loss in this population.

Adult↗
PubMed2006

Hemoglobin A1c awareness among patients receiving eye care at a tertiary ophthalmic center.

PURPOSE: To describe awareness of hemoglobin A1c (HbA1c) among patients receiving eye care at a tertiary ophthalmic center for diabetic eye disease. DESIGN: Prospective, nonrandomized clinical case series. METHODS: One hundred-fifty adult patients with diabetes mellitus (DM) examined between July and October of 2003 for diabetic retinopathy (DR) were surveyed about HbA1c knowledge. RESULTS: Seventy-six (51%) understood HbA1c, 25 (17%) were not sure if they understood, and 49 (33%) did not understand. Patients who understood HbA1c based on duration of DM were as low as two (29%) of seven with DM < 5 years and as high as 17 (55%) of 31 with DM > 15 years. Seventy-six (51%) had proliferative DR, among whom 33 (43%) understood HbA1c, 69 (46%) had nonproliferative DR, among whom 39 (57%) understood HbA1c, and five (3%) had no DR, among whom four (80%) understood HbA1c. CONCLUSION: Approximately half of diabetic patients surveyed understood HbA1c.

Adult↗
PubMed2005

Nine-year incidence of age-related macular degeneration in the Barbados Eye Studies.

OBJECTIVE: To provide 9-year incidence estimates of age-related macular degeneration (AMD) in a population of African descent. DESIGN: Population-based cohort study. PARTICIPANTS: Two thousand seven hundred ninety-three participants (81% of eligible) after 9 years' follow-up. MAIN OUTCOME MEASURES: Nine-year incidence of AMD-related features, based on fundus photographic gradings and/or clinical examinations. RESULTS: The overall incidence rate of early AMD was 12.6% (95% confidence interval [CI], 11.0%-14.1%), and that of late AMD was 0.7% (95% CI, 0.4%-1.1%). Both increased with age (P<0.05). For early AMD, incidence ranged from 10.7% at 40 to 49 years of age to 16.8% at > or =70 years. For late AMD, incidence increased from 0.1% to 2.3% in the same age groups. Late AMD was more likely to develop in eyes with pigment changes (risk ratio [RR], 5.8; 95% CI, 2.0-16.8) and retinal pigment epithelial atrophy (RR, 5.4; 95% CI, 1.9-15.8) at baseline. Crude RRs indicated significant associations of late AMD to elevated systolic blood pressure and diabetes history, but only the diabetes relationship was suggested after adjusting for age, with borderline statistical significance (age-adjusted RR, 2.7; P = 0.054). CONCLUSIONS: Nine-year data on natural history indicate that early AMD is common in this population of African origin, although late AMD is infrequent. These long-term observations provide further evidence for the lower AMD risk in black populations compared with white populations.

Adult↗
PubMed2005

The Open Access initiative in scientific and biomedical publishing: fourth in the series on editorship.

PURPOSE: To provide basic information about the Open Access concept and its historical development, define the benefits and challenges inherent in this new model, and identify the value of the traditional print model and its movement towards more open access. DESIGN: Review of current information on the subject from numerous sources. METHODS: Medline search and Internet search engines on the topic of Open Access Publishing. RESULTS: The Open Access initiative derives from several premises: medical libraries can no longer afford journal subscriptions; society benefits from the open exchange of ideas; society has in large part already paid for this research; the Internet provides an available venue. The traditional journal publishers model, however, has functioned well over many years with a robust peer review system and increasing Internet digital components permitting search and cross referencing, including elements of the Open Access model. CONCLUSIONS: It will be difficult to maintain the costs of both the traditional journal system and the fully implemented Open Access model. Any decisions that are made must ensure that the archive of prior medical knowledge is not lost, that financial barriers do not restrict publication, and that research continues to be available to those who need it, in the media that they prefer.

Access to Information↗
PubMed2005

Primary lymphoma of the central nervous system.

This article discusses primary lymphoma of the central nervous system, which is a variant of extranodal non-Hodgkin's lymphoma that arises from specific sites such as the brain, spinal cord, meninges, or eyes.

Central Nervous System↗
PubMed2005

Hyperglycemia, blood pressure, and the 9-year incidence of diabetic retinopathy: the Barbados Eye Studies.

OBJECTIVES: To evaluate factors related to the incidence of diabetic retinopathy (DR) in a population of African descent, after 9 years of follow-up. DESIGN: Population-based cohort study; 81% participation after 9 years. PARTICIPANTS: Three hundred twenty-four participants of the Barbados Eye Studies, with diabetes mellitus (DM) at baseline and at risk for developing DR during follow-up. METHODS: Diabetes-related changes were assessed by masked gradings of baseline and follow-up photographs using a standardized system. The 9-year cumulative incidence of DR was based on participants with DM and free of retinopathy at baseline; incidence rates were estimated by the product-limit approach. Cox regression models for discrete-time data were used to evaluate risk factors associated with the 9-year incidence of DR. RESULTS: Multivariate analyses revealed that older age at DM onset decreased the 9-year risk of DR development; for each 10 years of older age at onset, the risk of DR decreased by 30% (risk ratio [RR], 0.7; 95% confidence interval [CI], 0.56-0.96). The risk of DR doubled among persons with DM duration between 5 and 9 years (RR, 2.1; 95% CI, 1.2-3.6) versus those with shorter durations; it also doubled in those treated with oral medications or insulin at baseline versus those treated with diet only. Antihypertensive treatment halved the risk of DR versus no treatment (RR, 0.5; 95% CI, 0.3-0.9) and high systolic or diastolic blood pressure (BP) increased risk. Thus, DR risk increased by 30% for every 10 mmHg of higher systolic BP at baseline (RR, 1.3; 95% CI, 1.1-1.4) or of BP increase from baseline to the 4-year follow-up (RR, 1.3; 95% CI, 1.1-1.4). Diabetic retinopathy risk similarly increased with each 1% of higher glycosylated hemoglobin level at baseline (RR, 1.3; 95% CI, 1.2-1.5). CONCLUSIONS: The long-term follow-up of persons with DM in this population of African origin, where disease prevalence is high, identified important potentially modifiable risk factors for DR. Findings suggest that efforts to achieve optimal glycemic and BP control may reduce the vision-threatening complications of DM.

Adult↗
PubMed2004

Detection of diabetic foveal edema: contact lens biomicroscopy compared with optical coherence tomography.

OBJECTIVE: To compare contact lens biomicroscopy with optical coherence tomography (OCT) for the detection of diabetic foveal edema. METHODS: Study participants consisted of a convenient cohort of consecutive patients with diabetes mellitus seen at the Wilmer Eye Institute's Retinal Vascular Center, Baltimore, MD. Case characteristics were recorded and eyes were examined by 1 of 4 retina specialists by means of contact lens biomicroscopy. Edema involving the center of the macula was assessed as definitely present, questionably present, or definitely not present. The OCT testing was performed and interpreted by trained technicians, masked to the physicians' assessment of foveal edema. Agreement between OCT and contact lens examination for the absence or presence of foveal edema was evaluated. RESULTS: One hundred seventy-two eyes of 95 patients with diabetes were enrolled in August and September 2002. Foveal thickness was objectively measured by OCT in 170 (99%) of 172 cases. We found excellent agreement between OCT and contact lens examination for the absence or presence of foveal edema when OCT thickness was normal ( 300 microm). However, agreement was poor when foveal thickness was mildly increased on OCT (201-300 microm). CONCLUSIONS: Agreement between contact lens examination and OCT for the detection of diabetic foveal edema is poor when OCT thickening is mild. This suggests that contact lens biomicroscopy is relatively insensitive for the detection of mild foveal thickening apparent on OCT. Additional studies are needed to investigate the natural course of cases with mildly increased foveal thickness on OCT that do not appear thickened clinically.

Adult↗
PubMed2004

Four-year incidence of visual impairment: Barbados Incidence Study of Eye Diseases.

OBJECTIVE: To describe the 4-year incidence of visual impairment and causes of blindness among black participants of the Barbados Eye Studies. DESIGN: Population-based incidence study. SETTING AND PARTICIPANTS: The Barbados Incidence Study of Eye Diseases (BISED) followed the cohort of the Barbados Eye Study (BES), a prevalence study based on a simple random sample of Barbadians 40 to 84 years of age. BISED included 3193 black participants from the original cohort (85% of those eligible). MAIN OUTCOME MEASURES: Best-corrected visual acuity (Ferris-Bailey chart) at baseline and follow-up was measured according to a modified Early Treatment of Diabetic Retinopathy Study protocol. By use of World Health Organization (WHO) criteria, low vision and blindness for an individual were defined as visual acuity (VA) <6/18 to 6/120 and <6/120, respectively, in the better eye. By commonly used US criteria, low vision and blindness were defined as VA < or = 20/40 and < or = 20/200, respectively. Vision loss was defined as a doubling of the visual angle (i.e., decrease of 15 letters or more read correctly between baseline and follow-up examinations). Progression was defined as vision loss among those with low vision at baseline. RESULTS: On the basis of WHO criteria, the overall 4-year incidence was 3.6% (95% confidence interval [CI], 3.0%-4.4%) for low vision and 0.6% (95% CI, 0.4%-1.0%) for blindness. Incidence rates were higher using US criteria: 5.3% (95 % CI, 4.5%-6.2%) and 1.5% (95% CI, 1.1%-2.0%), respectively, reaching 21.5% and 7.3% for persons aged 70 years or older at baseline. One tenth of the cohort had vision loss, and 28.6% of those with low vision progressed. About one half of incident blindness was due to age-related cataract. Nearly one fifth was caused by open-angle glaucoma (OAG) alone or combined with cataract, and approximately 10% was caused by diabetic retinopathy (DR). CONCLUSIONS: The incidence of visual impairment was high in this Afro-Caribbean population, particularly in older age groups, indicating the public health significance of visual loss for this and similar black populations. Cataract, OAG, and DR were among the leading causes of incident blindness, paralleling their high prevalence in this population.

Adult↗