Proposed international clinical diabetic retinopathy and diabetic macular edema disease severity scales

PURPOSE

To develop consensus regarding clinical disease severity classification systems for diabetic retinopathy and diabetic macular edema that can be used around the world, and to improve communication and coordination of care among physicians who care for patients with diabetes.

DESIGN

Report regarding the development of clinical diabetic retinopathy disease severity scales.

PARTICIPANTS

A group of 31 individuals from 16 countries, representing comprehensive ophthalmology, retina subspecialties, endocrinology, and epidemiology.

METHODS

An initial clinical classification system, based on the Early Treatment Diabetic Retinopathy Study and the Wisconsin Epidemiologic Study of Diabetic Retinopathy publications, was circulated to the group in advance of a workshop. Each member reviewed this using e-mail, and a modified Delphi system was used to stratify responses. At a later workshop, separate systems for diabetic retinopathy and macular edema were developed. These were then reevaluated by group members, and the modified Delphi system was again used to measure degrees of agreement.

MAIN OUTCOME MEASURES

Consensus regarding specific classification systems was achieved.

RESULTS

A five-stage disease severity classification for diabetic retinopathy includes three stages of low risk, a fourth stage of severe nonproliferative retinopathy, and a fifth stage of proliferative retinopathy. Diabetic macular edema is classified as apparently present or apparently absent. If training and equipment allow the screener to make a valid decision, macular edema is further categorized as a function of its distance from the central macula.

CONCLUSIONS

There seems to be a genuine need for consistent international clinical classification systems for diabetic retinopathy and diabetic macular edema that are supported with solid evidence. The proposed clinical classification systems provide a means of appropriately categorizing diabetic retinopathy and macular edema. It is hoped that these systems will be valuable in improving both screening of individuals with diabetes and communication and discussion among individuals caring for these patients.

Increased levels of vascular endothelial growth factor and interleukin-6 in the aqueous humor of diabetics with macular edema

PURPOSE

To investigate the relationship between diabetic macular edema and the levels of vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) in aqueous humor and plasma.

DESIGN

Comparative cross-sectional study.

METHODS

Fifty-four eyes from 54 diabetic patients were used. The concentrations of VEGF and IL-6 in undiluted aqueous specimens (obtained from the eyes during cataract surgery) and in plasma were measured by an enzyme-linked immunosorbent assay. To assess blood-aqueous barrier function, the aqueous flare intensity was measured by a laser flare-cell meter as an estimate of the aqueous protein level.

RESULTS

The aqueous levels of VEGF and IL-6 were significantly correlated with the severity of macular edema (rho = 0.628, P <.001 and rho = 0.517, P <.01, respectively), as well as with the aqueous protein concentration (rho = 0.618, P <.001 and rho = 0.588, P <.001, respectively). Aqueous levels of VEGF and IL-6 were significantly higher than their respective plasma levels (both P <.001). In addition, the aqueous level of VEGF was significantly correlated with that of IL-6 (rho = 0.537, P <.01). Furthermore, the status of the posterior vitreous significantly correlated with the severity of macular edema (rho = 0.618, P <.0001).

CONCLUSIONS

These results suggest that both VEGF and IL-6 are produced together in the intraocular tissues, and are involved in the pathogenesis of macular edema.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy XXIII: the twenty-five-year incidence of macular edema in persons with type 1 diabetes

OBJECTIVE

To examine the 25-year cumulative incidence of macular edema (ME) and its relation to various risk factors.

DESIGN

Population-based study.

PARTICIPANTS

A total of 955 insulin-taking persons living in an 11-county area in southern Wisconsin with type 1 diabetes diagnosed before age 30 years who participated in baseline examinations (1980-1982) and at least 1 of 4 follow-up (4-, 10-, 14-, and 25-year) examinations (n=891) or died before the first follow-up examination (n=64).

METHODS

Stereoscopic color fundus photographs were graded using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme. Competing risk of death was included in statistical models.

MAIN OUTCOME MEASURES

Incidence of ME and clinically significant ME (CSME).

RESULTS

The 25-year cumulative incidence was 29% for ME and 17% for CSME. Annualized incidences of ME were 2.3%, 2.1%, 2.3%, and 0.9% in the first, second, third, and fourth follow-up periods of the study, respectively. In univariate analyses, the incidence of ME was associated with male sex, more severe diabetic retinopathy, higher glycosylated hemoglobin, proteinuria, higher systolic and diastolic blood pressure, and more pack-years of smoking. Multivariate analyses showed that the incidence of ME was related to higher baseline glycosylated hemoglobin (hazard ratio [HR] per 1% 1.17; 95% confidence interval [CI], 1.10-1.25; P<0.001) and higher systolic blood pressure (HR per 10 mmHg 1.15; 95% CI, 1.04-1.26; P=0.004) and marginally to proteinuria (HR 1.43; 95% CI, 0.99-2.08; P=0.06).

CONCLUSIONS

These data show that relatively high 25-year cumulative rates of incidence of ME were related to glycemia and blood pressure. The lower risk of incident ME in the last period of the study may reflect recent improvement in care.

Optical coherence tomographic patterns of diabetic macular edema

PURPOSE

To describe various morphologic patterns of diabetic macular edema (DME) demonstrated by optical coherence tomography (OCT) and correlate them with visual acuity.

DESIGN

Retrospective, observational, case series.

METHODS

A retrospective review of all patients with DME who underwent OCT evaluation and met the study inclusion criteria between May 1998 and December 2002 at the Cole Eye Institute was performed. The OCT scans were evaluated for the presence of diffuse retinal thickening (DRT), cystoid macular edema (CME), posterior hyaloidal traction (PHT), serous retinal detachment (SRD), and traction retinal detachment (TRD). Additionally, the retinal thickness was measured and visual acuity evaluated.

RESULTS

Two hundred seventy-six OCT scans of 164 eyes of 119 patients were identified. OCT revealed five morphologic patterns of DME: DRT (269, 97%), CME (152, 55%), SRD without PHT (19, 7.0%), PHT without TRD (35, 12.7%), and PHT with TRD (8, 2.9%). Mean retinal thickness varied depending on the morphologic pattern. The mean visual acuities (Snellen equivalent) also varied between groups. Increasing retinal thickness in all patterns was significantly correlated with worse visual acuity (P < .005). The OCT patterns containing CME (P = .01) and PHT without TRD (P = .02) were also significantly associated with worse vision.

CONCLUSIONS

DME exhibits at least five different morphologic patterns on OCT. There is a significant correlation between retinal thickness and visual acuity.

The Value of Automated Diabetic Retinopathy Screening with the EyeArt System: A Study of More Than 100,000 Consecutive Encounters from People with Diabetes

Background: Current manual diabetic retinopathy (DR) screening using eye care experts cannot scale to screen the growing population of diabetes patients who are at risk for vision loss. EyeArt system is an automated, cloud-based artificial intelligence (AI) eye screening technology designed to easily detect referral-warranted DR immediately through automated analysis of patient's retinal images. Methods: This retrospective study assessed the diagnostic efficacy of the EyeArt system v2.0 analyzing 850,908 fundus images from 101,710 consecutive patient visits, collected from 404 primary care clinics. Presence or absence of referral-warranted DR (more than mild nonproliferative DR [NPDR]) was automatically detected by the EyeArt system for each patient encounter, and its performance was compared against a clinical reference standard of quality-assured grading by rigorously trained certified ophthalmologists and optometrists. Results: Of the 101,710 visits, 75.7% were nonreferable, 19.3% were referable to an eye care specialist, and in 5.0%, the DR level was unknown as per the clinical reference standard. EyeArt screening had 91.3% (95% confidence interval [CI]: 90.9-91.7) sensitivity and 91.1% (95% CI: 90.9-91.3) specificity. For 5446 encounters with potentially treatable DR (more than moderate NPDR and/or diabetic macular edema), the system provided a positive "refer" output to 5363 encounters achieving sensitivity of 98.5%. Conclusions: This study captures variations in real-world clinical practice and shows that an AI DR screening system can be safe and effective in the real world. This study demonstrates the value of this easy-to-use, automated tool for endocrinologists, diabetologists, and general practitioners to address the growing need for DR screening and monitoring.

Diabetic macular edema: what is focal and what is diffuse?

PURPOSE

To review the available information on classification of diabetic macular edema (DME) as focal or diffuse.

DESIGN

Interpretive essay.

METHODS

Literature review and interpretation.

RESULTS

The terms focal diabetic macular edema and diffuse diabetic macular edema frequently are used without clear definitions. Published definitions often use different examination methods and often are inconsistent. Evaluating published information on the prevalence of focal and diffuse DME, the responses of focal and diffuse DME to treatments, and the importance of focal and diffuse DME in assessing prognosis is hindered because the terms are used inconsistently. A newer vocabulary may be more constructive, one that describes discrete components of the concepts such as extent and location of macular thickening, involvement of the center of the macula, quantity and pattern of lipid exudates, source of fluorescein leakage, and regional variation in macular thickening and that distinguishes these terms from the use of the term focal when describing one type of photocoagulation technique. Developing methods for assessing component variables that can be used in clinical practice and establishing reproducibility of the methods are important tasks.

CONCLUSIONS

Little evidence exists that characteristics of DME described by the terms focal and diffuse help to explain variation in visual acuity or response to treatment. It is unresolved whether a concept of focal and diffuse DME will prove clinically useful despite frequent use of the terms when describing management of DME. Further studies to address the issues are needed.

Four-year incidence and progression of diabetic retinopathy and macular edema: the Los Angeles Latino Eye Study

PURPOSE

To estimate the 4-year incidence and progression of diabetic retinopathy, macular edema (ME) and clinically significant macular edema (CSME) among adult Latinos with diabetes mellitus.

DESIGN

A population-based, longitudinal study of 4658 self-identified Latinos (primarily Mexican Americans), residing in Los Angeles, examined at baseline (2000-2003) and at 4 years (2004-2008).

METHODS

Participants underwent a standardized ophthalmic examination. Diabetic retinopathy (DR) and CSME were detected by grading of stereoscopic fundus photographs using the modified Airlie House classification scheme. chi(2) and trend tests were used to assess differences in incidence when stratifying by age and duration of diabetes.

RESULTS

The 4-year incidence of DR, ME, and CSME was 34.0% (182/535), 5.4% (38/699), and 7.2% (50/699) respectively. Younger persons and those with longer duration of diabetes mellitus had a higher incidence of DR compared to those who were older and had shorter duration of diabetes mellitus. A higher incidence of ME was associated with longer duration of diabetes mellitus (P = .004). Worsening/progression of any DR was found in 38.9% (126/324) and improvement occurred in 14.0% (37/265) of participants. Progression from nonproliferative DR (NPDR) to proliferative DR (PDR) and from NPDR to PDR with high-risk characteristics occurred in 5.3% and 1.9% of participants.

CONCLUSIONS

The 4-year incidence and progression of DR and the incidence of ME and CSME among Latinos are high compared to non-Hispanic whites. These findings support the need to identify and modify risk factors associated with these long-term complications.

OPTICAL COHERENCE TOMOGRAPHY OF CHOROIDAL NEVUS IN 120 PATIENTS

OBJECTIVE

To describe the optical coherence tomography (OCT) findings of choroidal nevi.

METHODS

Retrospective, single-center case series of 120 eyes of 120 consecutive patients with choroidal nevi who were evaluated by OCT. Diagnostic imaging was performed with a Zeiss StratusOCT Model 3000 (Carl Zeiss Ophthalmic Systems, Dublin, CA) using scan acquisition protocols of 6 radial lines and retinal thickness analysis overlying the nevus.

RESULTS

The mean patient age was 59 years (median, 60 years; range, 14-87 years). The choroidal nevus was a mean of 5.2 mm in basal dimension and 1.7 mm in thickness and was located a mean of 2.7 mm from the optic disk and 2.5 mm from the foveola. Related retinal findings by ophthalmoscopic evaluation included overlying retina edema (3%), subretinal fluid (16%), retinal thinning (0%), drusen (58%), and retinal pigment epithelium (RPE) detachment (2%). In comparison, related retinal findings at the site of the nevus by OCT included overlying retina edema (15%), subretinal fluid (26%), retinal thinning (22%), drusen (41%), and RPE detachment (12%). Furthermore, OCT permitted classification of the overlying retinal edema as focal cystoid (3%), diffuse cystoid (8%), coalescent cystoid (3%), and noncystoid edema (1%). By OCT, the overlying retina was normal thickness (32%), thinned (22%), or thickened (45%), and photoreceptor loss or attenuation was noted in 51% of cases. Specific OCT findings of the choroidal nevus were limited to its anterior surface with minimal penetration into the mass. These findings included increased thickness of the RPE/choriocapillaris layer (68%) and optical qualities within the anterior portion of the nevus of hyporeflectivity (62%), isoreflectivity (29%), and hyperreflectivity (9%). Hyporeflectivity was observed in 68% of pigmented nevi and 18% of nonpigmented nevi. When comparing OCT with clinical examination, OCT was more sensitive in the detection of related retinal edema, subretinal fluid, retinal thinning, photoreceptor attenuation, and RPE detachment.

CONCLUSIONS

OCT is a useful diagnostic modality for imaging the retina overlying a choroidal nevus. Numerous overlying changes such as subretinal fluid, retinal edema, retinal thinning, and photoreceptor attenuation are visible by OCT.

Nonmydriatic screening for diabetic retinopathy by ultra-widefield scanning laser ophthalmoscopy (Optomap)

PURPOSE

To compare the diagnostic properties of a nonmydriatic 200 degrees ultra-widefield scanning laser ophthalmoscope (SLO) versus onsite mydriatic ophthalmologic examination for diabetic retinopathy.

METHODS

A consecutive series of 51 eyes of 51 patients with different levels of diabetic retinopathy (DR) was examined. Grading of diabetic retinopathy and macular edema obtained on stereoscopic dilated funduscopy by a retina specialist was compared against grading obtained from Optomap Panoramic200 SLO images. All SLOs were performed with an undilated pupil, and no additional clinical information was used for evaluation of the Optomap images by three independent, masked expert graders.

RESULTS

A total of five images (9.8%) were not gradable due to insufficient quality. Clinically 4 eyes had proliferative diabetic retinopathy (PDR), while 9 had none, 5 mild, 19 moderate and 14 severe nonproliferative diseases (NPDR). Of the gradable 46 images, a clinically significant macular edema (CSME) was present in 28 eyes clinically. On Optomap, all eyes with PDR were detected as being proliferative, and a sensitivity of 94% at a specificity of 100% was obtained for all graders to detect more than mild DR. Agreement between Optomap retinopathy grading and clinical assessment was good with unweighted kappas of 0.68, 0.68 and 0.51. Assessment of CSME yielded sensitivities of 93, 93 and 89% at specificities of 89, 72 and 83%.

CONCLUSIONS

The Optomap Panoramic200 nonmydriatic images are of sufficient quality to assess DR and CSME validly and therefore fulfill the basic requirements for telescreening programs.

High-resolution stereoscopic digital fundus photography versus contact lens biomicroscopy for the detection of clinically significant macular edema

PURPOSE

The purpose of this study was to compare high-resolution stereoscopic digital photography to contact lens biomicroscopy (CLBM) for the diagnosis of clinically significant macular edema.

STUDY DESIGN

Comparative, prospective, observational case series.

PARTICIPANTS

One hundred twenty diabetic patients.

METHODS

Patients underwent clinical retinal examination with CLBM by a retinal specialist. On the same day as clinical grading, patients received high-resolution stereoscopic digital imaging of the macula. The stereoscopic digital images were viewed using liquid crystal shutter goggles at least 2 months after clinical examination by a single masked grader for the presence or absence of diabetic retinopathy.

MAIN OUTCOME MEASURES

Presence or absence of the Early Treatment of Diabetic Retinopathy Study criteria for clinically significant macular edema (CSME) overall, CSME 1, CSME 2, CSME 3, macular edema, microaneurysms, intraretinal hemorrhage, and hard exudate.

RESULTS

Two hundred seven eyes of 105 patients had complete data sets from both diagnostic modalities. Exact agreement was high for all identified pathologic conditions: CSME overall, 83.6%; CSME 1, 83.6%; CSME 2, 96.1%; CSME 3, 88.5%; macular edema, 75.0%; microaneurysms, 77.9%; intraretinal hemorrhage, 83.7%; and hard exudate, 73.1%. Sensitivity ranged from 50.0% (CSME 2) to 90.6% (CSME overall). Specificity ranged from 90.0% (macular edema) to 99.0% (CSME 2).

CONCLUSIONS

High-resolution stereoscopic digital photography is both sensitive and specific when identifying CSME and correlates well with the accepted standard of CLBM for the diagnosis of CSME.

Diabetic macular edema: an OCT-based classification

PURPOSE

More than ten years after ETDRS, Optical Coherence Tomography (OCT) greatly enhanced our ability to detect macular thickening and has brought new insights on the morphology of edema and on the presence of vitreal traction. In this study we propose a new classification of macular edema based on OCT findings to better catalogue and follow this complex clinical entity.

METHODS

Since January 2000 we analysed with OCT 2 (Zeiss Inc.) more than one thousand and two hundred eyes with DME.

RESULTS

The classification takes into account five parameters: retinal thickness, diffusion, volume, morphology and presence of vitreous traction. Standard figures and numerical values for every parameter are given.

CONCLUSION

Although ETDRS guidelines for laser treatment of DME still remain the only proven therapy for this condition, many other strategies are now on trial, and the vast majority of authors use OCT as the best indicator of therapeutic benefit. The amount of information given by OCT demonstrates that macular edema is a complex clinical entity with various morphology and gravity, and disclaimed the limitations of a simple "clinical" definition. As in many other examples such as macular holes and choroidal neovascularization, a uniform and precise definition of macular edema would increase the possibility to compare and judge the result of different therapeutic strategies. Aim of this classification is to implement the ETDRS clinical definition of DME with the precise and useful data given by OCT to better diagnose, catalogue and follow macular edema.

United Kingdom National Ophthalmology Database Study: Diabetic Retinopathy; Report 1: prevalence of centre-involving diabetic macular oedema and other grades of maculopathy and retinopathy in hospital eye services

AIMS

To report estimates of the prevalence of diabetic retinopathy (DR) and maculopathy grades for a large cohort of patients managed by the UK hospital eye service (HES).

METHODS

Anonymised data were extracted from 30 UK NHS hospital trusts using a single ophthalmic electronic medical record (EMR) for the period from April 2000 to November 2010 to create the National Ophthalmology Database (NOD). From 2007, the EMR facilitated capture of a nationally agreed-upon standardised data set (DR Structured Assessment) relating to the presence or absence of clinical signs of DR and maculopathy. An algorithm in the software automatically calculated the Early Treatment of Diabetic Retinopathy Study grades of retinopathy and maculopathy.

RESULTS

Between 2007 and 2010, 307,538 patients had data on the NOD, with 76,127 (24.8%) patients having been recorded as having diabetes. The proportion of patients with diabetes who had a structured assessment increased from 50.7% (2007) to 86.8% (2010). In each NHS year, 12.6-20.6% of eyes with structured assessments had no DR; 59.6-67.3% had non-proliferative DR; and 18.3-20.9% had active or regressed proliferative DR. Clinically significant macular oedema was present in 15.8-18.1% of eyes, and in 8.7-10.0% of eyes, this involved the central macula.

CONCLUSION

This study provides contemporary estimates of the prevalence of retinopathy and maculopathy grades in a large cohort of patients with diabetes managed by the UK HES. Centre-involving diabetic macular oedema, potentially amenable to anti-VEGF therapy, is present in the eyes of almost 10% of these patients. This information is useful for clinicians, health-care economists, and commissioners involved in planning and delivering diabetic eye services.

Role of Inflammation in Classification of Diabetic Macular Edema by Optical Coherence Tomography

Diabetic macular edema (DME) is the abnormal accumulation of fluid in the subretinal or intraretinal spaces in the macula in patients with diabetic retinopathy and leads to severely impaired central vision. Technical developments in retinal imaging systems have led to many advances in the study of DME. In particular, optical coherence tomography (OCT) can provide longitudinal and microstructural analysis of the macula. A comprehensive review was provided regarding the role of inflammation using OCT-based classification of DME and current and ongoing therapeutic approaches. In this review, we first describe the pathogenesis of DME, then discuss the classification of DME based on OCT findings and the association of different types of DME with inflammation, and finally describe current and ongoing therapeutic approaches using OCT-based classification of DME. Inflammation has an important role in the pathogenesis of DME, but its role appears to differ among the DME phenotypes, as determined by OCT. It is important to determine how the different DME subtypes respond to intravitreal injections of steroids, antivascular endothelial growth factor agents, and other drugs to improve prognosis and responsiveness to treatment.

Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) Study system for evaluation of stereoscopic color fundus photographs and fluorescein angiograms: SCORE Study Report 9

OBJECTIVE

To describe the procedures and reproducibility for grading stereoscopic color fundus photographs and fluorescein angiograms of participants in the SCORE Study.

METHODS

Standardized stereoscopic fundus photographs and fluorescein angiograms taken at 84 clinical centers were evaluated by graders at a central reading center. Type of retinal vein occlusion (RVO), area of retinal thickening, and area of retinal hemorrhage are evaluated from fundus photographs; area of fluorescein leakage and area of capillary nonperfusion are measured on fluorescein angiography. Temporal reproducibility consisted of annual regrading of a randomly selected dedicated subset of fundus photographs (60 subjects) and fluorescein angiograms (40 subjects) for 3 successive years. Contemporaneous reproducibility involved monthly regrading of a 5% random selection of recently evaluated fundus photographs (n = 73).

RESULTS

The intergrader agreement for RVO type and presence of retinal thickening was greater than 90% in the 3 annual regrades. The intraclass correlation (ICC) for area of retinal thickening in the 3 years ranged from 0.39 to 0.64 and for area of retinal hemorrhage, 0.87 to 0.96. The ICC for area of fluorescein leakage ranged from 0.66 to 0.75 and for capillary nonperfusion, 0.94 to 0.97. The contemporaneous reproducibility results were similar to those of temporal reproducibility for all variables except area of retinal thickening (ICC, 0.84).

CONCLUSIONS

The fundus photography and fluorescein angiography grading procedures for the SCORE Study are reproducible and can be used for multicenter longitudinal studies of RVO. A systematic temporal drift occurred in evaluating area of retinal thickening.

Automated detection of exudates and macula for grading of diabetic macular edema

Medical systems based on state of the art image processing and pattern recognition techniques are very common now a day. These systems are of prime interest to provide basic health care facilities to patients and support to doctors. Diabetic macular edema is one of the retinal abnormalities in which diabetic patient suffers from severe vision loss due to affected macula. It affects the central vision of the person and causes total blindness in severe cases. In this article, we propose an intelligent system for detection and grading of macular edema to assist the ophthalmologists in early and automated detection of the disease. The proposed system consists of a novel method for accurate detection of macula using a detailed feature set and Gaussian mixtures model based classifier. We also present a new hybrid classifier as an ensemble of Gaussian mixture model and support vector machine for improved exudate detection even in the presence of other bright lesions which eventually leads to reliable classification of input retinal image in different stages of macular edema. The statistical analysis and comparative evaluation of proposed system with existing methods are performed on publicly available standard retinal image databases. The proposed system has achieved average value of 97.3%, 95.9% and 96.8% for sensitivity, specificity and accuracy respectively on both databases.

Agreement between clinician and reading center gradings of diabetic retinopathy severity level at baseline in a phase 2 study of intravitreal bevacizumab for diabetic macular edema

PURPOSE

To evaluate agreement in diabetic retinopathy severity classification by retina specialists performing ophthalmoscopy versus reading center (RC) grading of seven-field stereoscopic fundus photographs in a phase 2 clinical trial of intravitreal bevacizumab for center-involved diabetic macular edema.

METHODS

Clinicians' grading scale used four levels: microaneurysms only, mild/moderate nonproliferative diabetic retinopathy (NPDR), severe NPDR, and proliferative diabetic retinopathy (PDR) or prior panretinal photocoagulation (PRP) or both. The RC scale used eight levels: microaneurysms only, mild NPDR, moderate NPDR, moderately severe NPDR, severe NPDR, mild PDR, moderate PDR, and high-risk PDR. Percent agreement and kappa statistic were defined by collapsing RC categories to match those used by clinicians.

RESULTS

There was agreement in 89/118 eyes (75%) with kappa = 0.55 (95% confidence interval [0.41, 0.68]). In six eyes, disagreements were of potential substantial clinical importance: five eyes with subtle retinal neovascularization and one with a small preretinal hemorrhage identified only in photographs.

CONCLUSIONS

Clinician grading of retinopathy severity had moderate agreement with RC grading and might be useful for placing eyes into broad baseline categories.

Comparison of optical coherence tomography in diabetic macular edema, with and without reading center manual grading from a clinical trials perspective

PURPOSE

To analyze the value of reading center error correction in automated optical coherence tomography (OCT; Stratus; Carl Zeiss Meditec, Inc., Dublin, CA) retinal thickness measurements in eyes with diabetic macular edema (DME).

METHODS

OCT scans (n=6522) obtained in seven Diabetic Retinopathy Clinical Research Network (DRCR.net) studies were analyzed. The reading center evaluated whether the automated center point measurement appeared correct, and when it did not, measured it manually with calipers. Center point standard deviation (SD) as a percentage of thickness, center point thickness, signal strength, and analysis confidence were evaluated for their association with an automated measurement error (manual measurement needed and exceeded 12% of automated thickness). Curves were constructed for each factor by plotting the error rate against the proportion of scans sent to the reading center. The impact of measurement error on interpretation of clinical trial results and statistical power was also assessed.

RESULTS

SD was the best predictor of an automated measurement error. The other three variables did not augment the ability to predict an error using SD alone. Based on SD, an error rate of 5% or less could be achieved by sending only 33% of scans to the reading center (those with an SD >or= 5%). Correcting automated errors had no appreciable effect on the interpretation of results from a completed randomized trial and had little impact on a trial's statistical power.

CONCLUSIONS

In DME clinical trials, the error involved with using automated Stratus OCT center point measurements is sufficiently small that results are not likely to be affected if scans are not routinely sent to a reading center, provided adequate quality control measures are in place.

Progression to proliferative retinopathy and macular oedema requiring treatment. Assessment of the alternative classification of the Wisconsin Study

PURPOSE

To study the ability of the alternative classification of the Wisconsin Study to predict progression to retinopathy requiring laser treatment in patients with diabetes.

METHODS

A total of 1585 diabetic patients were included in the study. Of them, 294 (19%) were diagnosed with diabetes before and 1291 (81%) after age 30 years. Retinopathy was diagnosed on fundus photographs using a modification of the Wisconsin scale, and graded into 6 levels according to the worse eye. The first visit during the study period was used to represent baseline examination. The time points for detection of proliferative retinopathy (PDR) and clinically significant macular oedema (CSME) were recorded during a mean follow-up time of 2.9 years.

RESULTS

Progression to PDR and/or CSME was significantly related to increasing severity of retinopathy at baseline (p<0.001; test for trend). Fifty per cent of patients with severe non-proliferative retinopathy (NPDR) (level 51) at entry progressed within one year to PDR and/or CSME; the 3-year risk for such progression in patients with mild (level 31) and moderate NPDR (level 41) was 25 and 60%, respectively. The incidence of progression to PDR and to CSME was 0.95 and 2.3/100 person-years, respectively. Progression to PDR and/or CSME was furthermore associated with a higher level of glycosylated haemoglobin, longer duration of the diabetes and use of antihypertensive treatment.

CONCLUSION

Increasing severity of retinopathy as recorded by this modification of the alternative classification of the Wisconsin Study was significantly associated with increased risk of progression to retinopathy requiring treatment.

Spectral Domain Optical Coherence Tomography Features and Classification Systems for Diabetic Macular Edema: A Review

Spectral domain optical coherence tomography (SD-OCT) is fast becoming the current standard of care for the detection and assessment of diabetic macular edema. With the application of SD-OCT for imaging of retinal microstructure and measurement of retinal thickness, new information regarding disease characteristics has been gathered, which was unrecognized previously. Retinal thickness measurements on SD-OCT have also been used for deciding the management and monitoring of the disease. Since its development, OCT has enhanced the understanding of retinal anatomical changes in diabetic retinopathy. Several authors have used SD-OCT to classify diabetic macular edema with the purpose of correlating the pathophysiology with disease severity. The classification systems have helped monitor the treatment efficacy and provide prognostic information on the treatment outcome. The following review article summarizes these classifications.

Regional patterns of sight-threatening diabetic macular edema

PURPOSE

To define regional patterns of macular thickening in diabetic macular edema (DME).

DESIGN

Retrospective case series.

METHODS

SETTING

Retina practice.

PATIENT POPULATION

Fifty-two normal eyes of 48 patients and 100 eyes of 80 patients with DME.

EXPERIMENTAL PROCEDURE

We measured retinal thickness for nine zones and total macular volume using the 3.5-mm display of an optical coherence tomograph (OCT). We determined the normal ranges of values for zones, and then normal ranges of values for the difference in thickness between each pair of zones, termed comparisons. main outcome measures: Frequencies of increased zonal thickness, increased total macular volume, and abnormalities in zonal comparisons.

RESULTS

We found the following abnormalities: increased total macular volume 49% (49/100), increased foveal zone thickness 46% (46/100), increased inner parafoveal zone thickness (average 42.2% for the four zones), and increased outer zone thickness (average 34.3% for the four zones). Abnormal two-zone comparisons were found in 1027 of the 7200 possible comparisons (14.3%). Of these abnormal comparisons, the fovea was thicker relative to another zone in 26%; the four inner parafoveal zones were thicker relative to other zones in 8.7% to 15.2% (average 13.0%); and the four outer zones were thicker relative to other zones in 3.9% to 7.6% (average 6%). Eighty-eight percent (88/100) of the eyes chosen on clinical grounds as needing focal laser photocoagulation were detected.

CONCLUSION

A broader concept of OCT abnormality, which includes abnormalities in zonal relationships, may improve automated detection of DME compared with clinical judgment.

Comparison of dilated fundus examinations with seven-field stereo fundus photographs in the Veterans Affairs Diabetes Trial

OBJECTIVE

The Veterans Affairs Diabetes Trial (VADT) is a 20-medical center, prospective, randomized study of 1792 Type 2 diabetic individuals primarily aimed at determining whether intensive glycemic control prevents macrovascular events. We report a comparison of fundus photographs and ophthalmologic examination at baseline, permitting an evaluation of multiple settings similar to common clinical practice.

RESEARCH DESIGN AND METHODS

A 340-patient subset had both local dilated fundus examinations and centrally read seven-field stereo fundus photographs completed within 60 days of each other (median 28 days). Local examiners were unaware of the stereo photographs.

RESULTS

Overall, agreement within one step was 76% and exact agreement between ophthalmoscopy and central gradings of fundus photographs on a five-step retinopathy severity scale was 43% (weighted kappa 0.42, CI 0.35-0.48). In about 90% of disagreements the severity level was higher by photographic grading. The sensitivity for ophthalmoscopy compared to grading of fundus photographs for the detection of any retinopathy was 51% and specificity was 91%. For proliferative diabetic retinopathy (PDR), sensitivity was 61% and specificity 98%. Only one eye was high-risk PDR, and it was detected by both methods. For clinically significant macular edema, these measures were 24% and 98%, respectively. The disagreements were of possible clinical importance in three cases (<1%).

CONCLUSION

Most disagreements occurred in eyes rated near the milder end of a category and/or resulted from small differences between the ophthalmoscopic and photographic definitions used in classifying severity. There were reasonably few disagreements of possible clinical significance.

Classification of aphakic cystoid macular edema with focal macular electroretinograms

We compared the amplitude and implicit times of the a-waves, b-waves, and oscillatory potentials of the focal macular electroretinograms of 30 eyes with aphakic cystoid macular edema and the healthy fellow eyes. Ten affected eyes were characterized by reduced amplitudes of the oscillatory potentials with normal a-wave and b-wave responses (type 1). Nine affected eyes had both reduced amplitudes of the oscillatory potentials and the b-waves (type 2). Ten affected eyes were characterized by reduced amplitude of the oscillatory potentials, the a-waves, and the b-waves (type 3). One eye could not be classified. Visual acuities were as follows: type 1, 0.55 (20/36.4); type 2, 0.31 (20/64.5); and type 3, 0.12 (20/166.7). The mean time between cataract surgery and the electroretinographic testing was significantly longer for type 2 and 3 eyes than for type 1 eyes. The differences in the electroretinographic responses between the affected eye and the normal fellow eye suggested either an increased severity or the stage of the cystoid macular edema.

MHANet: A hybrid attention mechanism for retinal diseases classification

With the increase of patients with retinopathy, retinopathy recognition has become a research hotspot. In this article, we describe the etiology and symptoms of three kinds of retinal diseases, including drusen(DRUSEN), choroidal neovascularization(CNV) and diabetic macular edema(DME). In addition, we also propose a hybrid attention mechanism to classify and recognize different types of retinopathy images. In particular, the hybrid attention mechanism proposed in this paper includes parallel spatial attention mechanism and channel attention mechanism. It can extract the key features in the channel dimension and spatial dimension of retinopathy images, and reduce the negative impact of background information on classification results. The experimental results show that the hybrid attention mechanism proposed in this paper can better assist the network to focus on extracting thr fetures of the retinopathy area and enhance the adaptability to the differences of different data sets. Finally, the hybrid attention mechanism achieved 96.5% and 99.76% classification accuracy on two public OCT data sets of retinopathy, respectively.