Effect of image compression and resolution on retinal vascular caliber.

Purpose: Changes in retinal vascular caliber measured from digital color fundus photographs have been independently associated with systemic outcomes in epidemiologic studies, but the effect of image resolution and compression on vascular measurements has not been previously evaluated.

Methods: To explore image compression, 40 natively digital fundus images were selected with good photo quality, high spatial resolution, and no previous image compression. Using Adobe Photoshop, these images were compressed at progressively higher levels up to 147:1, and then retinal vascular caliber was measured at each level using semiautomated software.

Retinal vessel caliber among people with acquired immunodeficiency syndrome: relationships with disease-associated factors and mortality.

Purpose: To evaluate relationships between retinal vessel caliber, AIDS-related factors, and mortality.

Design: Longitudinal, observational cohort study.

Methods: We evaluated data for participants without ocular opportunistic infections at initial examination (baseline) in the Longitudinal Studies of the Ocular Complications of AIDS (1998-2008).

Retinal vessel caliber among people with acquired immunodeficiency syndrome: relationships with visual function.

Purpose: To evaluate relationships between retinal vessel caliber and tests of visual function among people with AIDS.

Design: Longitudinal, observational cohort study.

Methods: We evaluated data for participants without ocular opportunistic infections at initial examination (baseline) in the Longitudinal Studies of the Ocular Complications of AIDS (1998-2008).

Suboptimal image focus broadens retinal vessel caliber measurement.

Purpose: Studies have used central retinal arteriolar (CRAE) and central retinal venular (CRVE) calibers, measured from images produced with computerized image analysis, to detect risk factors for systemic diseases. The authors explored suboptimal image focus as a possible contributing factor to artificially larger vascular caliber measurements.

Methods: From the reading center image collections, 30 digital retinal images were selected for optimum quality.

Transition from film to digital fundus photography in the Longitudinal Studies of the Ocular Complications of AIDS.

Purpose: To describe the transition to digital imaging and assess any impact on ocular disease classification.

Methods: Film and digital images, acquired by certified photographers, were evaluated independently according to standard procedures for the following: image quality, presence of cytomegalovirus retinitis lesions, and their extent and proximity from disk and macula. Intergrader agreement within the digital medium was also assessed.

Comparison of digital and film grading of diabetic retinopathy severity in the diabetes control and complications trial/epidemiology of diabetes interventions and complications study.

Objective: To compare diabetic retinopathy (DR) severity as evaluated by digital and film images in a long-term multicenter study, as the obsolescence of film forced the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC) to transition to digital after 25 years.

Methods: At 20 clinics from 2007 through 2009, 310 participants with type 1 diabetes with a broad range of DR were imaged, per the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol, with both film and digital cameras. Severity of DR was assessed centrally from film and tonally standardized digital cameras.

Imaging of diabetic retinopathy and diabetic macular edema.

Imaging of the retinal complications of diabetes mellitus is rapidly changing from the emergence of new technology such as optical coherence tomography. In particular, the characterization of diabetic macular edema is much easier for the clinician and there are new, more sensitive clinical research end points. However, our understanding of structure-functional relationships remains suboptimal and the classification of macular edema by optical coherence tomography continues to evolve.

Mosaics versus Early Treatment Diabetic Retinopathy seven standard fields for evaluation of diabetic retinopathy severity.

Purpose: To compare agreement between mosaicked and seven field photographs for classification of the diabetic retinopathy (DR) severity.

Methods: Mosaic digital (MosD) images were compared with seven field stereo film (7FF) and stereo digital (7FD) photographs from a 152-eye cohort with full-spectrum Early Treatment of Diabetic Retinopathy severity levels for agreement on severity level, DR presence with ascending severity thresholds, DR index lesion presence, and classification repeatability.

Results: There was a substantial agreement classifying the Early Treatment Diabetic Retinopathy Study DR severity level between MosD and 7FF (kunweighted = 0.

Long-term renal outcomes of patients with type 1 diabetes mellitus and microalbuminuria: an analysis of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort.

Background: Microalbuminuria is a common diagnosis in the clinical care of patients with type 1 diabetes mellitus. Long-term outcomes after the development of microalbuminuria are variable.

Methods: We quantified the incidence of and risk factors for long-term renal outcomes after the development of microalbuminuria in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study.

Comparability of digital photography with the ETDRS film protocol for evaluation of diabetic retinopathy severity.

Purpose: To evaluate digital photography parameters affecting comparability with the Early Treatment Diabetic Retinopathy Study (ETDRS) film protocol for diabetic retinopathy (DR) severity grading.

Methods: ETDRS protocol photographs and four variations of digital images (uncompressed stereoscopic, compressed stereoscopic, uncompressed monoscopic, and uncompressed monoscopic wide-angle mosaic) of 152 eyes were independently evaluated by using ETDRS classifications. Digital formats were compared to film and each other for agreement on severity level, DR presence at ascending threshold, presence of the DR index lesion, and repeatability of grading.

Grading diabetic retinopathy severity from compressed digital retinal images compared with uncompressed images and film.

Purpose: To compare research grading of diabetic retinopathy (DR) severity level from compressed digital images versus uncompressed images and film.

Methods: Compressed (JPEG2000, 37:1) digital images (C) were compared with uncompressed digital (U) and film (F) stereoscopic photographs from a 152-eye cohort with full-spectrum Early Treatment Diabetic Retinopathy Study severity levels for agreement on severity level, DR presence with ascending severity threshold, presence of DR index lesions, and repeatability of grading.

Results: Classification of Early Treatment Diabetic Retinopathy Study severity levels from C images agreed substantially with results from F images (κ = 0.

Comparison of multiple stereoscopic and monoscopic digital image formats to film for diabetic macular edema evaluation.

Purpose: To assess agreement between evaluations of monoscopic and stereoscopic digital images versus stereo film photographs in diabetic macular edema (DME).

Methods: A 152-eye group of digital monoscopic macular images (seven-field sets and wide-angle mosaics) were compared with digital stereoscopic images (uncompressed and compressed seven-field sets) and stereo 35-mm film photos (Early Treatment Diabetic Retinopathy Study protocol) for the presence of hard exudates (HE), retinal thickening (RT), clinically significant macular edema (CSME), and RT at the center of the macular (RTCM).

Results: Agreement, according to the κ statistic, was almost perfect in identifying HE and RT between all digital formats and stereo film (HE, κ = 0.

Evaluation of the age-related eye disease study clinical lens grading system AREDS report No. 31.

Purpose: To examine the grading (interrater) reliability of the Age-Related Eye Disease Study (AREDS) Clinical Lens Grading System (ARLNS).

Design: Evaluation of diagnostic test or technology.

Participants: One hundred fifty volunteers (284 eyes).

Digital versus film Fundus photography for research grading of diabetic retinopathy severity.

Purpose: To assess agreement between digital and film photography for research classification of diabetic retinopathy severity.

Methods: Digital and film photographs from a 152-eye cohort with a full spectrum of Early Treatment Diabetic Retinopathy Study (ETDRS) severity levels were assessed for repeatability of grading within each image medium and for agreement on ETDRS discrete severity levels, ascending severity thresholds, and presence or absence of diabetic retinopathy index lesions, between digital and 35-mm slides (film). Digital photographs were color balanced to match film.

Monoscopic versus stereoscopic retinal photography for grading diabetic retinopathy severity.

Purpose: To assess agreement between monoscopic and stereoscopic photography for research classification of the severity of diabetic retinopathy (DR).

Methods: Monoscopic digital (MD) images were compared with stereo digital (SD) and film (SF) photographs from a 152-eye cohort with full-spectrum Early Treatment Diabetic Retinopathy Study (ETDRS) severity levels for agreement on severity level, DR presence with ascending severity threshold, presence of DR index lesions, and repeatability of grading.

Results: There was substantial agreement classifying ETDRS DR severity levels between MD and SF (kappa = 0.

Prolonged effect of intensive therapy on the risk of retinopathy complications in patients with type 1 diabetes mellitus: 10 years after the Diabetes Control and Complications Trial.

Objective: To examine the persistence of the original treatment effects 10 years after the Diabetes Control and Complications Trial (DCCT) in the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. In the DCCT, intensive therapy aimed at near-normal glycemia reduced the risk of microvascular complications of type 1 diabetes mellitus compared with conventional therapy.

Methods: Retinopathy was evaluated by fundus photography in 1211 subjects at EDIC year 10.

Calibration of fundus images using spectral domain optical coherence tomography.

Background And Objective: Measurements performed on fundus images using current software are not accurate. Accurate measurements can be obtained only by calibrating a fundus camera using measurements between fixed retinal landmarks, such as the dimensions of the optic nerve, or by relying on a calibrated model eye provided by a reading center. However, calibrated spectral domain OCT (SD-OCT) could offer a convenient alternative method for the calibration of any fundus image.

A severity scale for diabetic macular edema developed from ETDRS data.

Purpose: To develop a severity scale for diabetic macular edema (DME) and to assess relationships between severity and duration of DME and visual acuity (VA).

Methods: From the Early Treatment Diabetic Retinopathy Study (ETDRS), mean baseline VA scores were tabulated for 7422 eyes cross-classified by (1) location of retinal thickening (RT) and its area within 1 disc diameter of the macular center, and (2) degree of RT at the center. Adjacent (row, column, and off-diagonal) cells with the greatest similarity in baseline VA (mean and SD) based on a Gaussian (normal) likelihood were merged.

Brightness, contrast, and color balance of digital versus film retinal images in the age-related eye disease study 2.

Purpose: To analyze brightness, contrast, and color balance of digital versus film retinal images in a multicenter clinical trial, to propose a model image from exemplars, and to optimize both image types for evaluation of age-related macular degeneration (AMD).

Methods: The Age-Related Eye Disease Study 2 (AREDS2) is enrolling subjects from 90 clinics, with three quarters of them using digital and one quarter using film cameras. Image brightness (B), contrast (C), and color balance (CB) were measured with three-color luminance histograms.

Intake of zinc and antioxidant micronutrients and early age-related maculopathy lesions.

Background: Macular degeneration, the end stage of age-related maculopathy (ARM), is the leading cause of legal blindness worldwide, and few modifiable risk factors are known. The high concentration of carotenoids in the macula, plus evidence linking oxidative stress to ARM and carotenoids to antioxidation, generated the hypothesis that higher antioxidant intakes can prevent ARM. Results of observational and intervention studies have been inconsistent.

Progression of diabetic macular edema: correlation with blood retinal barrier permeability, retinal thickness, and retinal vessel diameter.

Purpose: To study the progression of diabetic macular edema (DME) in relation to baseline retinal thickness, retinal vascular leakage, and retinal trunk vessel diameters.

Methods: In this single-center study, 45 patients were enrolled with 62 eligible eyes defined as having DME of a grade less than clinically significant macular edema (CSME). From the start, the patients were included in a multicenter study exploring the effect of ruboxistaurin versus placebo for 3.

Three-year incidence and cumulative prevalence of retinopathy: the atherosclerosis risk in communities study.

Purpose: To describe the three-year incidence and cumulative prevalence of retinopathy and its risk factors.

Design: Population-based, prospective cohort study in four US communities.

Methods: In the Atherosclerosis Risk in Communities (ARIC) Study, 981 participants had retinal photography of one randomly selected eye at the third examination (1993 to 1995) and three years later at the fourth examination (1996).

Apolipoprotein e gene and age-related maculopathy in older individuals: the cardiovascular health study.

Objective: To examine the association between the apolipoprotein E (APOE) gene and age-related maculopathy (ARM) in an older population.

Methods: Two thousand one hundred seventy persons 65 years and older sampled from 4 US communities had ARM signs assessed from retinal photographs using a modified Wisconsin Age-Related Maculopathy Grading System. DNA extracted from blood samples was analyzed for common APOE alleles.

Age-related macular degeneration and risk for stroke.

Background: Age-related macular degeneration (AMD) affects 7 million persons 40 years of age and older in the United States. Risk factors for the disease are similar to those for stroke.

Objective: To determine what relationship, if any, exists between AMD and incident clinical stroke.