Optical Coherence Tomographic Assessment of Diabetic Macular Edema: Comparison with Fluorescein Angiographic and Clinical Findings

Difference of central foveal thickness measurement in patients with macular edema using optical coherence tomography in different display modes

Purpose

To assess the differences in the measurement of central foveal thickness (CFT) in patients with macular edema (ME) between two display modes (1:1 pixel and 1:1 micron) on optical coherence tomography (OCT).

Design

This is a retrospective, cross-sectional study.

Methods

Group A consisted of participants with well-horizontal OCT B-scan images and group B consisted of participants with tilted OCT B-scan. We manually measured the CFT under the two display modes, and the values were compared statistically using the paired t-test. Spearman's test was used to assess the correlations between the OCT image tilting angle (OCT ITA) and the differences in CFT measurement. The area under the curve (AUC) was calculated to define the OCT ITA cutoff for a defined CFT difference.

Results

In group A, the mean CFT in the 1:1 pixel display mode was 420.21 ± 130.61 µm, similar to the mean CFT of 415.27 ± 129.85 µm in the 1:1 micron display mode. In group B, the median CFT in the 1:1 pixel display mode is 409.00 μm (IQR: 171.75 μm) and 368.00 μm (IQR: 149.00 μm) in the 1:1 micron display mode. There were significant differences between the two display modes with the median (IQR) absolute difference and median (IQR) relative difference of 38.00 μm (75.00 μm) and 10.19% (21.91%) (all p = 0.01). The differences in CFT measurement between the two display modes were correlated with the OCT ITA (absolute differences, r = 0.88, p < 0.01; relative differences, r = 0.87, p < 0.01). The AUC for a predefined CFT difference was 0.878 (10 μm), 0.933 (20 μm), 0.938 (30 μm), 0.961 (40 μm), 0.962 (50 μm), and 0.970 (60 μm).

Conclusion

In patients with DM, when the OCT B-scan images were well-horizontal, manual CFT measurements under the two display modes were similar, but when the B-scan images were tilted, the CFT measurements were different under the two display modes, and the differences were correlated to the OCT ITA.

Speckle Contrast as Retinal Tissue Integrity Biomarker in Patients with Type 1 Diabetes Mellitus with No Retinopathy

PURPOSE

To study the retinal and choroidal layers in type 1 diabetes mellitus (DM1) without diabetic retinopathy (DR), using speckle contrast of optical coherence tomography (OCT) images as a tissue biomarker in comparison with healthy subjects.

METHODS

OCT Spectralis images of 148 eyes, 84 from DM1 patients without DR signs, and 64 belonging to the control group, were collected. The speckle contrast and thickness of the inner retinal layer (IRL), the outer retinal layer (ORL), and the choroidal layer in the nasal parafoveal area (N3), were prospectively analyzed.

RESULTS

A statistically significant difference (p = 0.001) in the IRL thickness between groups was observed, being thicker in the DM1 group. There were no differences in the ORL and choroidal thicknesses between groups. A statistically significant difference (p = 0.02) in the IRL speckle contrast was obtained, being lower in the DM1 group. The maximum speckle contrast was reached in the ORL for both groups, although in the DM1 group, it occurs closer to the choroid, at 64 ± 8 μm (p = 0.008).

CONCLUSIONS

Statistically significant differences were found in speckle contrast and thickness between the control and the DM1 group, suggesting an IRL alteration of DM1 patients, supporting the retinal neurodegeneration before DR signs are observed.

Contrast Sensitivity Testing in Age-Related Macular Degeneration Using Motion Diamond Stimulus

Purpose

This study was performed to characterize changes in contrast sensitivity (CS) that occur in patients with age-related macular degeneration (AMD) using a novel test, the motion diamond stimulus (MDS).

Methods

This was a cross-sectional study in which 20 subjects with unilateral exudative AMD (eAMD) and contralateral dry AMD received 3 assessments: the Pelli-Robson (PR) CS Chart, the MDS test, and a visual function questionnaire-25 (VFQ-25). CS results from the PR, and MDS tests were compared across 3 groups: eyes with eAMD vs dry AMD, eAMD vs control, dry AMD vs control. Healthy, undilated eyes from another study served as the control group. Significance was determined using ANOVA analysis for the MDS output parameters (α: overall contrast threshold, β: adaptability of the visual system) and PR logCS. Patients were also administered the VFQ-25 to assess vision-related quality of life.

Results

The ANOVA of the MDS data demonstrated a significant difference in visual function according to the β parameter of the 3 groups, but no significant difference in the α parameter. PR CS results for the 3 groups were significantly different, further supporting the MDS results. Post-hoc analysis showed a significant difference in β and PR log CS between the eAMD and control eyes.

Conclusion

The MDS test is valuable in discerning CS impairments in patients with AMD. It can provide further insight into the visual changes experienced by patients with AMD and has potential to quantify visual function changes that are not found on visual acuity testing alone.

The validity of diabetic retinopathy screening using nonmydriatic fundus camera and optical coherence tomography in comparison to clinical examination

PURPOSE:

To evaluate the use of non-mydriatic fundus camera as a screening modality for diabetic retinopathy in a sample of population in Riyadh, Saudi Arabia.

METHODS:

Patients coming, from April 2015 till September 2018, for their diabetic check up at the diabetic center clinics in King Abdul-Aziz University hospital were screened using a non-mydriatic fundus camera (NMFC). Photos were graded by retina specialist and compared to the findings of dilated fundus examination (DFE) by retina specialists.

RESULTS:

The grading results of NMFC and DFE were compared and the overall sensitivity and specificity for detection of diabetic retinopathy within one grade of retinopathy was 98.7% and 80% respectively. The sensitivity for detection of sight threatening conditions such as proliferative diabetic retinopathy, severe non-proliferative diabetic retinopathy, and diabetic macular edema (by Ocular Coherence Tomography) was found to be 86.7%, 90.3% and 100% respectively; while the specificity was found to be 96.5%, 93%, and 100% respectively.

CONCLUSION:

Non-mydriatic fundus camera has a high sensitivity and specificity in screening for diabetic retinopathy. It is a great screening tool, which is user friendly and can be operated by trained nurses in primary clinics during patient's regular routine diabetic checkups. It aids in early detection of sight threatening conditions which need urgent referral to ophthalmologists.

Changes in retinal layers in type 1 diabetes mellitus without retinopathy measured by spectral domain and swept source OCTs

To evaluate changes in inner retinal layer (IRL) thicknesses in patients with type 1 diabetes mellitus (DM1) with no diabetic retinopathy (DR) using two different optical coherence tomography (OCT) devices. Ninety DM1 and 60 healthy eyes were evaluated using spectral domain (SD)-OCT and swept source (SS)-OCT to measure changes in the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL) and inner nuclear layer (INL) thicknesses in all Early Treatment of Diabetic Retinopathy Study (ETDRS) macular areas. Functional tests were performed in both groups, including ETDRS with 100, 2.5 and 1.25% contrast, and color vision. The mean ages were 42.93 ± 13.62 and 41.52 ± 13.05 years in the diabetic and control groups, respectively. Visual acuity (VA) with ETDRS 1.25% was lower in the DM1 patients. Both ETDRS 2.5% and color vision were lower in the DM1 group but did not reach statistical significance. Retinal thicknesses in the central area and in the vertical outer areas were higher in the DM1 group. Differences were found in the IRL with no changes in the outer ones. Long-term DM1 patients with no DR maintained visual function, with a decrease in VA with 1.25% ETDRS contrast. Macular thickness measurements were higher using Spectralis SD-OCT than DRI Triton SS-OCT, and DM1 patients had a decrease in IRL thickness, especially in the GCL at the parafoveal level, generating thinning of the RNFL in the peripheral areas. There were no differences in outer retinal layer (ORL) thickness.

Optical Coherence Tomographic Patterns as Predictors of Structural Outcome After Intravitreal Ranibizumab in Diabetic Macula Edema

Background/Objectives

The purpose of this study was to present an association between the treatment response of diabetic macular edema (DME) to intravitreal ranibizumab (IVR) injections and different morphology patterns using spectral domain optical coherence tomography (SD-OCT).

Subjects/Methods

This retrospective study included 216 eyes of 142 subjects who received IVR for DME and were observed for at least 2 years. Medical charts and SD-OCT images of consecutive patients were reviewed at baseline, 1, 3, 6, 12, and 24 months after first IVR treatment. The OCT patterns were characterized as diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD), and vitreomacular interface abnormalities (VMIAs). All patients were classified into four groups based on the OCT findings.

Results

For a total of 216 eyes, 36 eyes were classified into the DRT group, 76 in the CME group, 42 in the SRD group, and 62 in the VMIA group. There were significant central macula thickness (CMT) improvements in all groups at the 1st month and the 2nd year, except for the DRT group at the 2nd year. Patients with OCT findings of hyperreflective dots (HRDs), metabolic parameters of hyperlipidemia, and coronary artery disease (CAD) had significantly less improvements in CMT at 2-year follow-up (P=0.029, 0.007, <0.001, respectively).

Conclusion

A trend toward decreased effectiveness after long-term IVR treatment was observed in the DRT group. Consistent IVR treatment could still achieve favorable improvement in the reduction of CMT in 2-year follow-up in the VMIA group. Different OCT patterns in DME may affect the therapeutic role of anti-VEGF agents and predict the structure outcome.

ASSOCIATION BETWEEN EARLY ANATOMIC RESPONSE TO ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY AND LONG-TERM OUTCOME IN DIABETIC MACULAR EDEMA: An Independent Analysis of Protocol i Study Data

This retrospective analysis of Protocol I study data demonstrates a significant positive association between early (Week 12) retinal anatomical response and long-term (1- and 3-year) anatomical response with ranibizumab in center-involved diabetic macular edema. By contrast, early anatomical response was not significantly associated with long-term visual acuity response.

Purpose:

This post hoc analysis explores the relationship between early retinal anatomical response and long-term anatomical and visual outcomes with ranibizumab in center-involved diabetic macular edema.

Methods:

Eyes randomized to the ranibizumab plus prompt laser and ranibizumab plus deferred laser treatment arms in the Protocol I study were categorized according to their proportional reduction (<20 vs. ≥20%) in central retinal thickness (CRT) after 12 weeks. Adjusted and unadjusted analyses assessed the association between early (Week 12) anatomical response and long-term (Weeks 52 and 156) anatomical and best-corrected visual acuity outcomes.

Results:

Of 335 study eyes, 118 showed limited (<20%) and 217 showed strong (≥20%) CRT reduction at Week 12. In unadjusted and adjusted analyses, limited early CRT response was negatively and significantly associated with strong CRT response at Weeks 52 and 156. Sensitivity analyses indicated that this association was robust and unrelated to any “floor effect.” In unadjusted analyses, a strong early CRT response was associated with greater long-term improvement in best-corrected visual acuity; after controlling for confounders, the association lost statistical significance.

Conclusion:

Early CRT response to ranibizumab is a significant prognostic indicator of medium- to long-term anatomical outcome in center-involved diabetic macular edema.

Quantitative Ultra-Widefield Angiographic Features and Associations with Diabetic Macular Edema

PURPOSE

To examine the relationship between diabetic macular edema (DME) and quantitative ultra-widefield fluorescein angiography (UWFA) metrics of ischemia, leakage, and microaneurysms.

DESIGN

Retrospective image analysis study.

PARTICIPANTS

Eyes with diabetic retinopathy that had undergone spectral-domain OCT, UWFA, and ultra-widefield fundus photography.

METHODS

OCT images were analyzed to determine the presence or absence of DME, central subfield thickness (CST), and subretinal fluid. Using a semiautomated analysis platform, UWFA images were segmented for ischemia, leakage, and microaneurysms with manual correction as needed. Clinical variables, including age, gender, race, hemoglobin A1C levels, blood pressure, cholesterol levels, use of blood thinners, smoking status, and lens status also were evaluated.

MAIN OUTCOME MEASURES

Factors associated with the presence and severity of DME.

RESULTS

A total of 304 eyes (156 right eyes, 148 left eyes) from 178 diabetic patients were analyzed in the study. Panretinal leakage index, microaneurysm count, and ischemic index were not significantly different between eyes with and without DME in univariate assessment. Zonal assessments of macular microaneurysms and macular leakage index values revealed that eyes with DME showed a significantly higher microaneurysm count (P = 0.001) and leakage index (P < 0.0001) in the posterior pole compared with eyes without DME. Severity of macular thickening (i.e., CST) was associated significantly with macular leakage index and posterior pole microaneurysm count (P = 0.0002 and P = 0.03, respectively). In addition to posterior pole leakage index and microaneurysm count, DME was associated with older age (P < 0.01), higher systolic blood pressure (P < 0.001), and white race (P = 0.03). Multivariate assessment confirmed the independent association of presence of DME with macular leakage index and macular microaneurysm count (P < 0.01).

CONCLUSIONS

Quantitative measures of leakage index and microaneurysm count in the posterior pole on UWFA images were associated with the presence and severity of DME. Panretinal analyses were not linked to DME as strongly. Additional research is needed to determine the role of quantitative UWFA in predicting DME development and characterizing patient prognosis.

Prevalence and severity of diabetic retinopathy in patients attending the endocrinology diabetes clinic at Mulago Hospital in Uganda

AIMS

The epidemiology for diabetic retinopathy (DR) has been well described in the western population. Countries in Sub-Saharan Africa have attempted to identify the prevalence of diabetic eye disease, however, there still remains a degree of paucity across the continent due to inadequacy in health system organisations and resource poor settings. We aimed to identify the severity and prevalence of DR and maculopathy of patients attending the diabetes clinic at Mulago Hospital, Kampala, Uganda.

METHODS

A cross-sectional observational study of 44 patients who attended a diabetes clinic at Mulago Hospital in April 2016. Parameters measured included visual acuity (VA) using a Snellen chart, blood glucose (mmol/l) and blood pressure (mmHg). Screening for DR grading was carried out with indirect fundoscopy and retinal photograph. Only the highest graded eye of retinopathy of each patient was included.

RESULTS

A total of 41 eyes from 41 patients were included. Of these patients 15 were male. The average age of patients was 50.4 years. Six eyes (14.6%) had a VA < 6/18. Prevalence of DR was 19.5% (8 eyes) and 14.6% (6 eyes) had maculopathy. Of all eyes 14.6% had sight-threatening retinopathy, which was 85.7% of total cases of retinopathy in our study.

CONCLUSIONS

We observed a high prevalence of DR and maculopathy, particularly sight threatening retinopathy, considering the proportion of patients screened. There is a need for a co-ordinated diabetes screening service through integration of the diabetes clinic and eye clinic at Mulago Hospital to better identify and treat this sight-threatening condition.

Analysis of Changes in Retinal Thickness in Type 2 Diabetes without Diabetic Retinopathy

OBJECTIVE

To examine the changes in retinal thickness of patients with diabetes without DR.

DESIGNS

A randomization, crossover, retrospective practice.

PARTICIPANTS

43 diabetic patients and 43 ethnic-, age-, and sex-matched controls.

METHODS

Full retinal thicknesses of ten areas were assessed using spectral domain optical coherence tomography. Confounding variables, such as age, gender, and glycated haemoglobin (HbA1c) level, were assessed by regression analysis.

MAIN OUTCOME MEASURES

Mean retinal thickness of ten areas.

RESULTS

The mean thickness of the fovea was 215.8 ± 18.9 μm in the diabetes group and 222.0 ± 18.6 μm in the control group (p = 0.04). The mean thickness of the temporal parafovea was 319.9 ± 16.7 μm in the diabetes group and 326.0 ± 14.4 μm in the control group (p = 0.01). The mean thickness of the temporal perifovea was 276.4 ± 27.9 μm in the diabetes group and 284.8 ± 17.4 μm in the control group (p = 0.02). There were no significant differences in retinal thickness between groups in other areas (p > 0.05). Regression analysis revealed that decreased retinal thickness of the temporal perifovea was associated with a higher HbA1c level (>8.7%) (p = 0.04).

CONCLUSION AND RELEVANCE

Subtle structural changes in the retina may occur in diabetes without DR. Decreased retinal thickness appeared to begin in the fovea and temporal areas. A high HbA1c level was the main factor influencing retinal thickness.

Automatic detection of Hyperreflective Foci in optical coherence tomography B-scans using Morphological Component Analysis

Hyperreflective Foci (HF) is one of the most common complications distributed in cross-sectional images of patients with Diabetic Macular Edema (DME). Scanning Laser Ophthalmoscope (SLO) images usually consists of several B-scans that represent a cross-sectional reconstruction of a plane through the anterior or posterior regions of retina. In each B-scan, HFs are geometrically distinct constituents in different retinal layers. Since the intensity levels of HFs and many other subjects in B-scans are the same, in this paper we try to separate HFs from other objects by detection of the point and curve singularities in each B-scan. The decomposition algorithm presented in this paper is based on sparse image representation of B-scans using Morphological Component Analysis (MCA) technique. By using curvelet transform and Daubechies wavelet basis, two different over-complete dictionaries are constructed which represent two various aspects of B-scans. The HFs are more distinguished in reconstructed image with wavelet dictionary and other objects are mostly detectable by curvelet dictionary. So, HFs can be detected by applying an optimum threshold criterion on reconstructed image by wavelet atoms. Finally, the false positive points are reduced by removing the candidate points in RNFL and RPE layers, which are automatically segmented based on ridgelet transform. Our simulation results on 1924 HFs show that sensitivity and specificity for HF detection is 91.0% and 100%, respectively.

Selective and complementary use of Optical Coherence Tomography and Fluorescein Angiography in retinal practice

The current field of posterior pole and retinal imaging of the human eye has expanded into detailed analyses of the macula, retinal periphery, individual retinal layers, vitreoretinal interface, imaging of the choroid and the optic nerve head. The challenge in retinal imaging is the enduring pursuit of deeper penetration into tissues, increased resolution to the cellular level, and interpretation of observations. How much deeper can we go and with what resolution and reproducibility? These are fundamental questions for experts in search of novel imaging modalities. New discoveries may resolve existing controversies, but inevitably stimulate new questions. Emerging technologies in retinal imaging include adaptive optics retinal imaging and optical coherence tomography-based retinal angiography.

In this review, the focus of our discussion will be the discrepancy between the findings (interpretation) of one imaging technology that do not agree or are not even found with a complementary technology. If a clearly seen abnormality is present with one technology but absent in another, what are the possible explanations? Following is a summary of key concepts of retinal and optic nerve imaging modalities and current controversies regarding their interpretation and/or limitations.

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.

Diabetic Retinopathy Clinical Practice Guidelines: Customized for Iranian Population

Purpose:

To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population.

Methods:

Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology [Preferred Practice Pattern 2012], and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefits, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9.

Results:

Agreed recommendations were accepted as the final recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence.

Conclusion:

This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy.

Optical coherence tomography (OCT) for detection of macular oedema in patients with diabetic retinopathy

BACKGROUND

Diabetic macular oedema (DMO) is a thickening of the central retina, or the macula, and is associated with long-term visual loss in people with diabetic retinopathy (DR). Clinically significant macular oedema (CSMO) is the most severe form of DMO. Almost 30 years ago, the Early Treatment Diabetic Retinopathy Study (ETDRS) found that CSMO, diagnosed by means of stereoscopic fundus photography, leads to moderate visual loss in one of four people within three years. It also showed that grid or focal laser photocoagulation to the macula halves this risk. Recently, intravitreal injection of antiangiogenic drugs has also been used to try to improve vision in people with macular oedema due to DR.Optical coherence tomography (OCT) is based on optical reflectivity and is able to image retinal thickness and structure producing cross-sectional and three-dimensional images of the central retina. It is widely used because it provides objective and quantitative assessment of macular oedema, unlike the subjectivity of fundus biomicroscopic assessment which is routinely used by ophthalmologists instead of photography. Optical coherence tomography is also used for quantitative follow-up of the effects of treatment of CSMO.

OBJECTIVES

To determine the diagnostic accuracy of OCT for detecting DMO and CSMO, defined according to ETDRS in 1985, in patients referred to ophthalmologists after DR is detected. In the update of this review we also aimed to assess whether OCT might be considered the new reference standard for detecting DMO.

SEARCH METHODS

We searched the Cochrane Database of Systematic Reviews (CDSR), the Database of Abstracts of Reviews of Effects (DARE), the Health Technology Assessment Database (HTA) and the NHS Economic Evaluation Database (NHSEED) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2013), EMBASE (January 1950 to June 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1990 to June 2013), BIOSIS Previews (January 1969 to June 2013), MEDION and the Aggressive Research Intelligence Facility database (ARIF). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 25 June 2013. We checked bibliographies of relevant studies for additional references.

SELECTION CRITERIA

We selected studies that assessed the diagnostic accuracy of any OCT model for detecting DMO or CSMO in patients with DR who were referred to eye clinics. Diabetic macular oedema and CSMO were diagnosed by means of fundus biomicroscopy by ophthalmologists or stereophotography by ophthalmologists or other trained personnel.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data on study characteristics and measures of accuracy. We assessed data using random-effects hierarchical sROC meta-analysis models.

MAIN RESULTS

We included 10 studies (830 participants, 1387 eyes), published between 1998 and 2012. Prevalence of CSMO was 19% to 65% (median 50%) in nine studies with CSMO as the target condition. Study quality was often unclear or at high risk of bias for QUADAS 2 items, specifically regarding study population selection and the exclusion of participants with poor quality images. Applicablity was unclear in all studies since professionals referring patients and results of prior testing were not reported. There was a specific 'unit of analysis' issue because both eyes of the majority of participants were included in the analyses as if they were independent.In nine studies providing data on CSMO (759 participants, 1303 eyes), pooled sensitivity was 0.78 (95% confidence interval (CI) 0.72 to 0.83) and specificity was 0.86 (95% CI 0.76 to 0.93). The median central retinal thickness cut-off we selected for data extraction was 250 µm (range 230 µm to 300 µm). Central CSMO was the target condition in all but two studies and thus our results cannot be applied to non-central CSMO.Data from three studies reporting accuracy for detection of DMO (180 participants, 343 eyes) were not pooled. Sensitivities and specificities were about 0.80 in two studies and were both 1.00 in the third study.Since this review was conceived, the role of OCT has changed and has become a key ingredient of decision-making at all levels of ophthalmic care in this field. Moreover, disagreements between OCT and fundus examination are informative, especially false positives which are referred to as subclinical DMO and are at higher risk of developing clinical CSMO.

AUTHORS' CONCLUSIONS

Using retinal thickness thresholds lower than 300 µm and ophthalmologist's fundus assessment as reference standard, central retinal thickness measured with OCT was not sufficiently accurate to diagnose the central type of CSMO in patients with DR referred to retina clinics. However, at least OCT false positives are generally cases of subclinical DMO that cannot be detected clinically but still suffer from increased risk of disease progression. Therefore, the increasing availability of OCT devices, together with their precision and the ability to inform on retinal layer structure, now make OCT widely recognised as the new reference standard for assessment of DMO, even in some screening settings. Thus, this review will not be updated further.

Spectral-domain optical coherence tomography for macular edema

Optical coherence tomography (OCT) is a rapid noncontact method that allows in vivo imaging of the retina and it has become an important component in clinical practice. OCT is a useful ancillary tool for assessing retinal diseases because of its ability to provide cross-sectional retinal images and quantitatively analyze retinal morphology. The introduction of spectral-domain OCT provided major improvements in image acquisition speed and image resolution. Future studies will address how these major technologic advances will impact the use of OCT in research and clinical practice.

Association of systemic and ocular risk factors with neurosensory retinal detachment in diabetic macular edema: a case-control study

Background

Diabetic macular edema (DME) with neurosensory retinal detachment (NSD) remains an important cause of visual loss in patients with diabetes. The aim of the study was to elucidate the association of systemic and ocular risk factors with NSD in DME.

Methods

In a retrospective case–control study, we reviewed clinical records of all the subjects with DME seen between January 2010 and December 2010. Cases and controls were selected based on optical coherence tomography and stereoscopic biomicroscopy review. NSD was defined as subfoveal fluid accumulation under detached retina with or without overlying foveal thickening. The association between the presence of NSD, blood pressure, lipid status and various other biochemical parameters was evaluated.

Results

Group I (cases) included 37 eyes of 33 patients having DME with NSD and Group II (controls) included 30 eyes of 21 patients having DME without NSD. Patients ranged in age (mean ± SD) from 50 to 62 years (56.6 +/-6.78) for cases and from 51 to 65 years (58.4+/-7.84) for controls. The duration of diabetes ranged from 4 to 15 year (mean 9.45+/-6.08) among cases and 4 to 14 years (9.7+/-5.12) among controls. Significant risk factors for NSD were high values of systolic and diastolic blood pressure (p = 0.039 and 0.043 respectively).

Conclusion

High systolic and diastolic blood pressures are independent and significant risk factors for NSD in DME.

Correlation of morphological pattern of optical coherence tomography in diabetic macular edema with systemic risk factors in middle aged males

To study correlation of different optical coherence tomography (OCT) patterns of diabetic macular edema (DME) with systemic risk factors. Institutional cross-sectional double-masked non-interventional study with 330 eyes of middle-aged male type 2 diabetes patients with DME. Various systemic parameters were measured. Diffuse retinal thickening (DRT), cystoid and serous patterns of DME were identified on OCT. Comparison between DRT versus non-DRT and serous versus non-serous eyes was done in respect to systemic parameters. Correlation of serous and DRT pattern was tested with systemic parameters above and below specified values. Mean age was 54.4 ± 7.1 years. Mean duration of diabetes was 8.7 ± 4.2 years. Mean serum globulin level was significantly higher (p = 0.018) in serous compared to non-serous group. Prevalence of serous DME was significantly high in those with serum globulin level >3.5 gm/dl (prevalence ratio = 3.01, p = 0.040). Significant correlation of central macular thickness was observed with duration of diabetes (p = 0.002, r = 0.440).Visual acuity (logMAR) was correlated significantly with HbA1C (p = 0.031, r = 0.305). Increased serum globulin, a positive phase reactant of inflammation, was found significant independent risk factor for development of serous DME. This study did not identify any modifiable systemic factor for any of the OCT patterns in DME.

Safety and efficacy of oral fluorescein angiography in detecting macular edema in comparison with spectral-domain optical coherence tomography

PURPOSE

To evaluate the safety of oral fluorescein angiography (FA) and to compare its efficacy in detection of macular edema (ME) with spectral-domain optical coherence tomography (SD-OCT).

METHODS

Results of imaging studies for 1,928 eyes of 1,019 patients who had simultaneously undergone both oral FA and SD-OCT by a confocal laser ophthalmoscope were reviewed. Sensitivity in detecting ME, discrepancy rate, and "kappa" agreement were determined for both the techniques and with eyes stratified by disease diagnosis.

RESULTS

No allergic reactions occurred after oral FA. Mild gastric discomfort was noted in <1% of the patients; 1,840 eyes (95.4%) showed concordance between the two techniques, and kappa agreement was 90.3%. For ME, oral FA showed an overall sensitivity of 0.97 and SD-OCT of 0.91. Equivalent sensitivity was found in cases of wet age-related macular degeneration (0.99). Oral FA was more sensitive than SD-OCT in cases of retinovascular diseases. The SD-OCT showed higher sensitivity in cases of macular holes. Detection of ME by SD-OCT was significantly higher in cases of intense leakage on oral FA (P < 0.001).

CONCLUSION

Oral FA proved to be a safe and an adequate technique to evaluate ME. It is more sensitive than SD-OCT in detection of ME in cases of retinovascular diseases but can fail to detect ME in cases of macular holes. A noninvasive examination with simultaneous oral FA and SD-OCT may be considered to obtain a comprehensive evaluation of the presence of ME from different pathologies.

Communications between intraretinal and subretinal space on optical coherence tomography of neurosensory retinal detachment in diabetic macular edema

Background:

The pathogenesis of development and progression of neurosensory retinal detachment (NSD) in diabetic macular edema (DME) is not yet fully understood. The purpose of this study is to describe the spectral domain optical coherence tomography (SD-OCT) morphological characteristics of NSD associated with DME in the form of outer retinal communications and to assess the correlation between the size of communications and various factors.

Materials and Methods:

This was an observational retrospective nonconsecutive case series in a tertiary care eye institute. We imaged NSD and outer retinal communications in 17 eyes of 16 patients having NSD associated with DME using SD-OCT. We measured manually the size of the outer openings of these communications and studied its correlation with various factors. Statistical analysis (correlation test) was performed using the Statistical Package for Social Sciences (SPSS) software (version 14.0). The main outcome measures were correlation of the size of communications with dimensions of NSD, presence of subretinal hyper-reflective dots, and best-corrected visual acuity (BCVA).

Results:

The communications were seen as focal defects of the outer layers of elevated retina. With increasing size of communication, there was increase in height of NSD (r = 0.701, P = 0.002), horizontal diameter of NSD (r = 0.695, P = 0.002), and the number of hyper-reflective dots in the subretinal space (r = 0.729, P = 0.002). The minimum angle of resolution (logMAR) BCVA increased with the increasing size of communications (r = 0.827, P < 0.0001).

Conclusions:

Outer retinal communications between intra and subretinal space were noted in eyes having NSD associated with DME. The size of communications correlated positively with the size of NSD and subretinal detachment space hyper-reflective dots, and inversely with BCVA.

Can optical coherence tomography replace fluorescein angiography in detection of ischemic diabetic maculopathy?

Background

We studied the association between (1) the retinal thickness, volume and structure assessed by optical coherence tomography (OCT), and (2) vascular changes around the fovea in FA to define the role of these methods in the detection of ischemic diabetic maculopathy.

Methods

This retrospective observational study included 51 eyes of 51 patients with severe non-proliferative and proliferative diabetic retinopathy, considering that they present advanced ischemic retinal changes. Based on the clinical examination and presence of leakage on FA, patients with clinically significant macular edema were excluded.

On FA, foveal avascular zone (FAZ) corresponds to capillary loss and reflects ischemic processes. Its outline and size were assessed according to the ETDRS standards. Patients were divided in two groups according to the severity of damage of the FAZ outline: ≤ grade 2 (n = 28) and ≥ grade 3 (n = 23).

As we expected ischemia-related damage, SD-OCT images were evaluated for retinal structure, volume, total thickness with division into the outer and inner retina (to assess the influence of two, non-overlapping blood sources) and ganglion cell layer thickness.

Results

The comparisons revealed that at least currently with described methods:

1. There is no significant association between FAZ outline and retinal volume, total thickness, and thickness of the outer and inner retina and ganglion cell layer.

2. There is no significant association between FAZ outline and following retinal structure characteristics: continuity of the external limiting membrane and inner segment/outer segment junction, and identification of the inner/outer retina boundary.

3. The identification of ganglion cell layer boundaries was significantly more difficult in more advanced FAZ outline grades.

4. FAZ size is not correlated with the retinal thickness and volume.

Conclusions

In patients with severe non-proliferative and proliferative diabetic retinopathy, it is not possible to predict FAZ outline/size based solely on the measurements assessing volume and thickness or retinal structure evaluation on OCT. Consequently, at present OCT cannot replace FA in the detection of ischemic diabetic maculopathy.

Macular edema in the era of spectral-domain optical coherence tomography

The development of spectral-domain optical coherence tomography (OCT) allows for the highest commercially available resolution of in vivo retinal anatomic details to date. The ability to see the macula with ever increasing detail is dramatically improving our understanding of the pathogenesis of retinal disease. However, the only prospective study that partially evaluated spectral-domain OCT versus time-domain OCT failed to show any clinical benefit of increased OCT resolution. Clinical outcomes, eg, best-corrected visual acuity, central macular thickness and number of injections, with “newer” OCT technologies remain an unproven advantage.

Optical coherence tomography classification of diabetic cystoid macular edema

Purpose

To propose a new classification of diabetic cystoid macular edema (CME) based on optical coherence tomography (OCT) findings and cover all new important findings.

Patients and methods

A retrospective study was carried out in the El-Minia Investigation Eye Center between January 2012 and November 2012. It included 104 eyes of 86 patients, aged between 50 and 71 years, all with type II diabetes mellitus of duration from 5 to 20 years. All patients were diagnosed to have CME, as assessed by OCT, with measurement of the vertical size of the largest macular cyst and maximum macular thickness, and the relation between them.

Results

Patients were divided into four groups. Eyes with cysts less than 30% of macular thickness were considered to have CME I (n = 4, 3.84%), while those between 30% and 60% were considered to have CME II (n = 62, 59.62%). Eyes with cysts between 60% and 90% of macular thickness were considered to have CME III (n = 36, 34.62%). CME IV was diagnosed when the size of the cyst became more than 90% of the macular thickness, and this was encountered in two eyes (1.92%).

Conclusions

OCT is a useful technique for quantitative measurement and helps in better anatomical characterization of CME, and this classification of diabetic CME may be of value in classification of CME due to causes other than diabetes.

Association of systemic comorbidity in diabetic serous macular detachment and comparison of various combination therapies in its management

BACKGROUND

The purpose of this research was to study the association between systemic comorbidity in diabetic serous macular detachment (DSMD) and the effect of different forms of combination therapies in its management.

METHODS

In this prospective analysis, 34 eyes from 34 patients with DSMD were investigated for the presence of systemic comorbidity including anemia, dyslipidemia, nephropathy, and cardiac disease, and treated with combination therapy of either intravitreal bevacizumab + laser (group 1, n = 14) or intravitreal triamcinolone + laser (group 2, n = 20). Sequential macular laser was done 2 weeks after intravitreal pharmacotherapy in both groups. Outcome measures included visual acuity and central foveal thickness at 1 and 3 months.

RESULTS

The mean age of the patients was 55.6 ± 7.6 years. The commonest systemic association was nephropathy (82.3%). In group 1, mean visual acuity improved marginally from 6/17 at baseline to 6/16 at 1 month (P = 0.0001) and was maintained at 3 months (P = 0.008); and mean central foveal thickness decreased from 488.7 μm to 318.7 μm at 1 month (P = 0.0001) but increased to 414.4 μm at 3 months (P = 0.049). In group 2, mean visual acuity improved from 6/22 at baseline to 6/19 at 1 month (P = 0.0001) and 6/12 at 3 months (P = 0.0001); and mean central foveal thickness decreased from 428.8 μm to 323.8 μm at 1 month (P = 0.0001) to 269.2 μm at 3 months (P = 0.0001).

CONCLUSION

Nephropathy should be ruled out in patients with DSMD. Although at 1 month both intravitreal triamcinolone and bevacizumab improved vision and decreased central foveal thickness in eyes with DSMD when administered along with focal laser treatment, the former had a more long-lasting effect in maintaining this gain at 3 months.

Effect of panretinal photocoagulation on macular morphology and thickness in eyes with proliferative diabetic retinopathy without clinically significant macular edema

Background

The purpose of this study was to investigate the effect of panretinal photocoagulation (PRP) on macular morphology and thickness in eyes with proliferative diabetic retinopathy (PDR) and without clinically significant macular edema.

Methods

This was a prospective study of 76 eyes from 68 patients diagnosed to have PDR without clinically significant macular edema. Baseline and post PRP visual acuity, morphological changes on optical coherence tomography (OCT), and central foveal thickness were evaluated at one week, one month, and 3 months.

Results

The mean patient age was 56.47 ± 6.55 years. Sixty-two eyes (81.58%) had stable or improved vision, while 14 eyes (18.42%) had worsened visual acuity at 3 months. Compared with baseline, mean visual acuity dropped as early as one week but was regained by 3 months. Mean preoperative central foveal thickness was 222.05 ± 59.11 μm, which increased significantly to 266.84 ± 84.67 μm at one week (P = 0.001), and remained higher at 264.05 ± 102.56 μm by one month (P = 0.01) and 256 ± 101.38 μm by 3 months (P = 0.04). Thirty-four percent of eyes with a normal macula showed morphological changes following PRP. The most common morphological change on OCT after PRP was spongy edema, seen in 48 eyes (31.6%), followed by cystoid macular edema in 36 eyes (23.7%), vitreomacular traction in 28 eyes (18.4%), epiretinal membrane in 24 eyes (15.8%), and subfoveal serous detachment in 16 eyes (10.5%).

Conclusion

PRP may cause a temporary drop in vision in the early post laser phase, and causes macular morphology/thickness changes in eyes with PDR and without clinically significant macular edema. In this study, the change in central foveal thickness did not correlate with a change in visual acuity, and the type of diabetic macular edema on OCT appeared more relevant and correlated better with the visual outcome.

Factors associated with visual recovery after sub-Tenon injection of triamcinolone acetonide in diabetic macular edema

Background

The purpose of this retrospective chart review was to evaluate factors associated with improvement of visual acuity after a single sub-Tenon injection of triamcinolone acetonide in patients with diabetic macular edema.

Methods

We reviewed the medical records for 63 consecutive eyes with diabetic macular edema treated by sub-Tenon injection of triamcinolone acetonide and assessed at 2 months postoperatively. We evaluated changes in morphology, foveal photoreceptor status, and parafoveal cystic change, and also measured the central retinal thickness and macular volume. The association of these factors with improvement of vision (logarithm of the minimum angle of resolution, logMAR) was investigated.

Results

Eyes were classified as having cystoid macular edema (CME, n = 52), serous retinal detachment (n = 24), or diffuse diabetic macular edema (n = 4). In eyes with CME, the mean logMAR of visual acuity improved significantly (P = 0.003) from 0.35 ± 0.31 at baseline to 0.29 ± 0.29 after 2 months. However, there was no significant improvement of visual acuity in the eyes with serous retinal detachment or diffuse diabetic macular edema after sub-Tenon injection of triamcinolone acetonide (P = 0.549 and P = 0.545, respectively). The central retinal thickness and macular volume were both reduced significantly after sub-Tenon injection of triamcinolone acetonide in eyes with CME and serous retinal detachment. However, improvement of visual acuity in the eyes with CME was not correlated with the reduction of central retinal thickness or macular volume. Parafoveal cystic changes showed significant improvement after sub-Tenon injection of triamcinolone acetonide in eyes with CME. Photoreceptor status was significantly associated with the visual prognosis in eyes with CME, but not in eyes with serous retinal detachment.

Conclusion

Visual acuity improved significantly after sub-Tenon injection of triamcinolone acetonide without photoreceptor recovery in eyes with CME. Improvement of parafoveal cystic changes in the eyes with CME suggests that bipolar cells or their accessory cells might have displayed functional recovery.

Optical coherence tomographic patterns in diabetic macula edema can predict the effects of intravitreal bevacizumab injection as primary treatment

PURPOSE

To identify optical coherence tomography (OCT) patterns in diabetic macular edema (DME) that were predictive of visual outcomes after intravitreal bevacizumab (IVB) injection.

METHODS

This was a retrospective study. We examined 31 eyes (24 patients) with clinically significant macular edema that received IVB injections along with macular OCT data. The eyes were categorized into 4 groups by using OCT features: diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD), and vitreomacular interface abnormalities (VMIAs). Changes in retinal thickness, retinal volume, and visual acuity (VA) after IVB injection were compared on the basis of OCT patterns.

RESULTS

After IVB injections, changes in VA logarithm of the minimum angle of resolution were -0.06±0.36, -0.26±0.26, 0.09±0.13, and -0.08±0.15, respectively, for DRT, CME, SRD, and VMIA patterns. Central macular thickness decreased by 70.5±105.5, 110.67±97.28, 181±125.87, and 24.25±77.12 μm for the DRT, CME, SRD, and VMIA patterns, respectively. The CME group was associated with a greater reduction in retinal thickness (P=0.009) and volume (P=0.027) with superior VA improvement (P=0.012) as compared with the DRT, SRD, and VMIA groups.

CONCLUSIONS

Patients with CME gained greater improvement in visual acuity and macular thickness and volume after IVB injection had been administered as the primary treatment for DME, as compared with other patients. The OCT patterns of DME may indicate the appropriate treatment; we consider these patterns to be prognostic of the response to IVB injection for macular edema.

Optical coherence tomography (OCT) for detection of macular oedema in patients with diabetic retinopathy

BACKGROUND

Diabetic macular oedema (DMO) is a thickening of the central retina, or the macula, and is associated with long-term visual loss in people with diabetic retinopathy (DR). Clinically significant macular oedema (CSMO) is the most severe form of DMO. Almost 30 years ago, the Early Treatment Diabetic Retinopathy Study (ETDRS) found that CSMO, diagnosed by means of stereoscopic fundus photography, leads to moderate visual loss in one of four people within three years. It also showed that grid or focal laser photocoagulation to the macula halves this risk. Recently, intravitreal injection of antiangiogenic drugs has been investigated to try to improve vision in people with macular oedema due to DR.Optical coherence tomography (OCT) is based on optical reflectivity and is able to image retinal thickness and structure producing cross-sectional and three-dimensional images of the central retina. It is already widely used because it provides objective and quantitative assessment of macular oedema unlike the subjectivity of fundus biomicroscopic assessment, which is routinely used by ophthalmologists instead of photography. Optical coherence tomography is also used for quantitative follow up of the effects of treatment of CSMO. Disadvantages of using OCT are the cost to purchase it and the need for trained personnel to perform the examinations.

OBJECTIVES

To determine the diagnostic accuracy of OCT for detecting macular oedema in people with DR. A secondary objective is to compare the diagnostic accuracy by study-specific characteristics, such as factors related to methodology, patients or OCT.

SEARCH STRATEGY

We searched the Cochrane Database of Systematic Reviews (CDSR), the Database of Abstracts of Reviews of Effects (DARE), the Health Technology Assessment Database (HTA) and the NHS Economic Evaluation Database (NHSEED) (The Cochrane Library 2011, Issue 5), MEDLINE (January 1950 to May 2011), EMBASE (January 1950 to May 2011), ISI Web of Science (January 1970 to May 2011), BIOSIS Previews (January 1969 to May 2011), MEDION and the Aggressive Research Intelligence Facility database (ARIF). There were no date or language restrictions in the electronic search for trials. The electronic databases were last searched on 16 May 2011. We checked bibliographies of relevant studies for additional references.

SELECTION CRITERIA

We selected studies that assessed the diagnostic accuracy of any OCT model for detecting DMO or CSMO in patients with DR who were referred to eye clinics. Diabetic macular oedema and CSMO were diagnosed by means of fundus biomicroscopy by ophthalmologists or stereophotography by ophthalmologists or other trained personnel.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data on study characteristics and measures of accuracy. We assessed data using random-effects hierarchical sROC meta-analysis models.

MAIN RESULTS

Nine studies (768 participants, 1325 eyes) were included. Prevalence of CSMO was 19% to 65% (median 50%). Study quality was good for half the QUADAS items, whereas unclear or inadequate quality was found in some studies regarding selection criteria, index and reference test masking (blinding), availability of clinical information, uninterpretable results and withdrawals. There was a specific 'unit of analysis' issue because both eyes of the majority of participants were included in the analyses as if they were independent.Central CSMO was the target condition in all but one study and thus our results cannot be applied to non-central CSMO. In eight studies providing data on CSMO (697 participants, 1241 eyes), pooled sensitivity was 0.78 (95% confidence interval (CI) 0.72 to 0.83) and specificity was 0.86 (95% CI 0.76 to 0.93). The median central retinal thickness cut-off we selected for data extraction was 250 µm (range 230 µm to 300 µm).Data from three studies reporting accuracy for detection of DMO (180 participants, 343 eyes) were not pooled. Sensitivities and specificities were about 0.80 in two studies and were both 1.00 in the third study.

AUTHORS' CONCLUSIONS

Central retinal thickness measured with OCT cannot be used as a stand-alone test to diagnose the central type of CSMO and decide on the use of laser photocoagulation in patients who are referred to retina clinics. In fact, there is a substantial disagreement of OCT with the ETDRS definition of CSMO based on clinical examination. Some researchers have observed that OCT can detect macular thickening earlier than clinical examination, but also found that such cases did not necessarily progress to CSMO and need photocoagulation.Care should be taken in applying the conclusions of this review to other test-treatment pathways. In fact, OCT will become an essential tool to manage antiangiogenic therapy, an expanding therapeutic option for patients with macular oedema due to DR, because OCT is a component of the diagnostic algorithms of studies on this new treatment.

Association of fluorescein angiographic features with visual acuity and with optical coherence tomographic and stereoscopic color fundus photographic features of diabetic macular edema in a randomized clinical trial

BACKGROUND

Fluorescein angiography (FA) has been performed as part of the management of diabetic macular edema for many years. Its current role relative to the role of optical coherence tomography (OCT) is not well defined.

PURPOSE

To evaluate the associations of FA features with visual acuity (VA) and with OCT and fundus photographic characteristics in eyes with diabetic macular edema.

METHODS

In a clinical trial, conducted by the Diabetic Retinopathy Clinical Research Network to compare two methods of laser photocoagulation to treat diabetic macular edema, FA (film and digital), color photographs, OCT, and VA measurements were obtained at baseline and at 1 year. Grading of morphologic features was performed at a reading center. Reproducibility of FAs was assessed, and the correlations of FA features with VA, OCT, and color photograph features were computed.

RESULTS

From 79 clinical sites, data of 323 study eyes and 203 fellow nonstudy eyes were analyzed. Fluorescein leakage area at baseline was associated with reduced VA, increased OCT measures of retinal thickness and volume, and color photographic measurements of retinal thickening (r = 0.33-0.58). No important associations were found with changes from baseline to 12 months in these parameters or with any of the other variables analyzed.

CONCLUSION

Fluorescein leakage is associated with VA and some OCT and color photographic variables. We did not identify any unique FA variables that had a stronger association with VA than OCT measures of retinal thickness. These data may be useful to investigators planning future diabetic macular edema clinical trials.

Correlation of leaking microaneurysms with retinal thickening in diabetic retinopathy

AIM

To investigate the contribution of fluorescein angiographic leaking microaneurysms (leak-MA) versus non-leaking microaneurysms (non-leak-MA) to retinal thickening in diabetic retinopathy.

METHODS

A consecutive series of 38 eyes from 24 patients with diabetic retinopathy was included. Leak-MA and non-leak-MA in each eye were selected in pairs at corresponding topographic location. Leaking was defined by late phase fluorescein angiograms compared to early phase. Retinal thickness was measured with Heidelberg Spectralis OCT topographically aligned on early phase angiograms at the MA site and within a 1 mm circle.

RESULTS

In all eyes, significant retinal thickening at the site of leaking compared to non-leaking microaneurysms was observed (356±69µm vs 318±56µm, P<0.001), showing a mean increase in thickness in the areas of leak-MA vs non-leak-MA of 38±39µm (95% confidence interval 25-51µm, P<0.001). All 1mm area measurements also showed significant (P<0.001) thickening of the leak-MA with average thickness of leak-MA vs non-leak-MA as 351±67µm vs 319±59µm; minimum thickness 311±62µm vs 284±60µm; maximum thickness 389±78µm vs 352±66µm; and retina volume 26.4±6.0mm vs 23.6±3.7mm(3), respectively.

CONCLUSION

Leaking of microaneurysms on fluorescein angiography appears to cause focal thickening of retina, which can be measured with high-resolution OCT. Therefore, targeting leaking microaneursyms in diabetic retinopathy has the potential to reduce retinal thickening.

Detection of cystoid macular edema with three-dimensional optical coherence tomography versus fluorescein angiography

PURPOSE

To compare the sensitivity and reproducibility of three-dimensional optical coherence tomography (3D-OCT) and fluorescein angiography (FA) for the detection of cystoid macular edema (CME).

METHODS

Data were retrospectively collected from all patients who underwent digital FA and 512 × 128 horizontal raster 3D-OCT scans on the same day in a retina subspecialty clinic. Images were reviewed independently by four reading center graders and adjudicated as a group to render a single result for each eye and each imaging modality. The κ statistic was used to determine the level of agreement between graders for each modality. The sensitivity of each imaging modality for CME detection was calculated by using the presence of CME on either modality as the ground truth; subgroup analysis was performed according to disease diagnosis and lens status.

RESULTS

Four hundred thirteen eyes of 207 patients were included in the analysis. Intergrader agreement was higher for 3D-OCT than for FA both before (κ(OCT) = 0.61, κ(FA) = 0.43) and after adjudication (κ(OCT) = 0.74, κ(FA) = 0.58).The sensitivity for detection of definite CME was higher for 3D-OCT (95%, 144/151 cases) than for FA (44%, 67/151 cases). Definite FA (+) 3D-OCT (-) CME was identified in 1 eye (0.2%), whereas definite FA (-) 3D-OCT (+) CME was identified in 40 eyes (10%). No significant associations between CME detection and lens examination or disease diagnosis were observed.

CONCLUSIONS

In this study, 3D-OCT was more sensitive and had better intergrader agreement than did FA for the detection of CME.

Correlation between morphologic features on spectral-domain optical coherence tomography and angiographic leakage patterns in macular edema

PURPOSE

The purpose of this study was to determine the morphologic patterns of angiographic macular edema using simultaneous colocalization of fluorescein angiography and spectral-domain optical coherence tomography (SD-OCT) images in diabetes, epiretinal membrane, uveitic and pseudophakic cystoid macular edema, and vein occlusion.

METHODS

Eighty-seven consecutive patients (107 eyes) with macular edema from 5 different etiologies were imaged by simultaneous scanning laser ophthalmoscopy/OCT to study the morphologic patterns of edema on SD-OCT and then correlated/colocalized with the fluorescein angiographic patterns of leakage. Statistical analysis was done to analyze the differences in the morphologic OCT pattern by different diseases.

RESULTS

Spectral-domain OCT characteristics of macular edema showed a significant difference across different diseases (P = 0.037). Cystic fluid pockets were found to be more commonly seen in patients with diabetic macular edema and retinal vein occlusions, whereas those cases with macular edema secondary to epiretinal membrane showed noncystic changes on OCT. Seventy of the 107 eyes had diffuse angiographic leakage, and the remaining 37 eyes had cystoid leakage on angiography. Of the 70 eyes with diffuse leakage, 24.28% showed microcysts on SD-OCT in the area of edema, and 70% eyes had diffuse thickening or distorted architecture without cyst. All 37 eyes with cystoid leakage showed cysts in the area of edema by SD-OCT. A total of 3.73% of eyes with fluorescein angiographic leakage had no abnormalities on SD-OCT.

CONCLUSION

Eyes with diabetic macular edema and retinal vein occlusions have a significantly higher incidence of cyst formation on SD-OCT. There was no correlation between visual acuity and cyst formation. Diffuse noncystoid angiographic macular edema may show microcysts on SD-OCT, but diffuse edema is more commonly associated with thickening or distortion of the retinal layers without cyst formation. Cystoid leakage on fluorescein angiography is always associated with cystic changes on SD-OCT.

Diabetic retinopathy and peripapillary retinal thickness

PURPOSE

To assess the diagnostic efficacy of macular and peripapillary retinal thickness measurements for the staging of diabetic retinopathy (DR) and the prediction of disease progression.

METHODS

In this prospective study, 149 diabetic patients (149 eyes) and 50 non-diabetic control subjects were included. Baseline optical coherence tomography was employed to measure retinal thickness in the macula (horizontal, vertical, and central) and the peripapillary zone (superior, inferior, nasal, and concentric to the optic disc). Seven baseline parameters were correlated with the DR stages identified by fluorescein angiography. Baseline retinal thickness was compared between groups of patients requiring panretinal photocoagulation (PRP) within 6 months (PRP group) and patients not requiring PRP (No-PRP group).

RESULTS

Macular and peripapillary retinal thicknesses in diabetic subjects were significantly greater than that in normal controls (p<0.05). All retinal thickness parameters, and particularly peripapillary circular scans, tended to increase with increasing DR severity (p<0.05). The baseline thicknesses of the peripapillary circular scans were greater in the PRP group than in the no-PRP group (p<0.05).

CONCLUSIONS

Peripapillary retinal thickness may prove to be a useful criterion for DR severity and may also serve as an indicator of disease progression.

Optical coherence tomographic hyperreflective foci: a morphologic sign of lipid extravasation in diabetic macular edema

PURPOSE

To analyze hyperreflective foci typically seen in diabetic macular edema (DME) in optical coherence tomography (OCT).

DESIGN

Prospective clinical trial.

PARTICIPANTS

Twelve consecutive patients with treatment-naïve, clinically significant DME.

METHODS

During a same-day examination, a standardized visual acuity assessment (Early Treatment of Diabetic Retinopathy Study protocol), infrared fundus imaging, color fundus photography, and biomicroscopy were performed. Additionally, all patients were scanned using Stratus, Cirrus, and Spectralis OCT and results correlated.

MAIN OUTCOME MEASURES

Morphologic changes secondary to DME.

RESULTS

In all eyes with DME, distinct hyperreflective foci distributed throughout all retinal layers were found in the OCT scans of all 3 OCT devices. These deposits could not be identified by infrared imaging, fundus photography, or biomicroscopy as long as they were not confluent. Accumulations of such foci at the border of the outer nuclear and in the outer plexiform layer were recognizable clinically as hard exudates showing the same hyperreflective features in OCT. The hyperreflectivity of these foci did not correspond with intraretinal hemorrhage, nor did the lesions cause the characteristic OCT laser beam scattering phenomena typically seen secondary to intraretinal bleedings or microaneurysms. Further, they were detected within the walls of intraretinal microaneurysms.

CONCLUSIONS

Well-demarcated, hyperreflective foci were identified in the retina of patients with DME. The deposits were located within walls of intraretinal microaneurysms and scattered throughout all retinal layers, forming confluent plaques in the outer plexiform layer. It is suggested that the foci represent extravasated lipoproteins and/or proteins being a very early subclinical barrier breakdown sign in DME.

Analysis of the effect of intravitreal bevacizumab injection on diabetic macular edema after cataract surgery

PURPOSE

To determine the feasibility and clinical effectiveness of intravitreal bevacizumab combined with cataract surgery for management of the postoperative increase of retinal thickness in patients with diabetic maculopathy.

DESIGN

Prospective, randomized, masked cohort study.

PARTICIPANTS

Forty-two eyes with diabetic macular edema (DME) of 42 patients with type 2 diabetes mellitus.

METHODS

Patients were randomly assigned to receive either cataract surgery only (control; 21 eyes) or combined with intravitreal injection of 1.25 mg bevacizumab (21 eyes). Efficacy measures included best-corrected visual acuity (BCVA) testing, optical coherence tomography (OCT), and ophthalmoscopic examination.

MAIN OUTCOME MEASURES

Retinal thickness (RT) on OCT and BCVA were measured at baseline and 1 and 3 months after surgery.

RESULTS

There were no significant differences in RT, BCVA, severity of cataract, or systemic condition between the control and bevacizumab groups at the baseline. One and 3 months after surgery, the control group showed a significant increase in RT, whereas the bevacizumab group showed a significant decrease. Although postoperatively the eyes in both groups showed a significant improvement of BCVA, bevacizumab-treated eyes showed significantly better results (mean logarithm of the minimum angle of resolution, 0.38) than the control group (0.51) at month 3. There was a significant relationship between RT and visual acuity (VA) postoperatively in the control (P = 0.0001) and bevacizumab (P = 0.0141) groups. No systemic or ocular adverse events were observed.

CONCLUSIONS

Short-term results suggest that intravitreal bevacizumab has the potential not only to prevent the increase in RT, but also reduce the RT of eyes with DME after cataract surgery. Further improvement of VA in bevacizumab-treated eyes may be dependent on a reduction in central RT.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Discrepancy between fluorescein angiography and optical coherence tomography in detection of macular disease

PURPOSE

To compare high-resolution optical coherence tomography (OCT) and fluorescein angiography (FA) in detection of macular edema (ME) of various etiologies.

METHODS

In a retrospective study over a 12-month period at one retina center, data for consecutive eyes that had undergone simultaneous conventional FA (HRA; Heidelberg Engineering, Vista, CA) and StratusOCT (Carl Zeiss Meditec, Dublin, CA) to rule out ME were reviewed. A subset of patients underwent additional examination with extremely high-resolution (6-microm)/ultrahigh-speed spectral OCT/scanning laser ophthalmoscopy (OTI, Inc., Toronto, Ontario, Canada).

RESULTS

Of 1,272 eyes, 1,208 (94.97%) had the finding of ME or subretinal fluid confirmed by both techniques. There were 49 eyes (3.86%) for which FA showed dye leakage in the macular area and OCT showed normal foveal contour. Of 10 eyes in this group that underwent imaging with ultrahigh-speed spectral OCT/scanning laser ophthalmoscopy, 8 had subtle diffuse lucencies in the retina. For 15 eyes (1.17%), OCT showed intraretinal and subretinal fluid, which was missed by FA.

CONCLUSIONS

Both FA and high-resolution OCT are highly sensitive techniques and correlate well in detection of ME. However, there is a small chance that when performed alone they might miss existing subtle ME.

Correlation between intraretinal changes in diabetic macular oedema seen in fluorescein angiography and optical coherence tomography

PURPOSE

To study the relationship between intraretinal optical coherence tomography (OCT) and fluorescein angiography (FA) findings in eyes with diabetic macular oedema (DMO).

METHODS

We carried out a retrospective observational case series. Thirty eyes with previously untreated DMO underwent FA and OCT. The same ETDRS template was overlaid on the FA images in order to compare OCT and FA. Transfoveal linear high-resolution OCT scans (at the 0- and 90-degree meridians) and FA pictures were compared according to the ETDRS rings.

RESULTS

Six distinct patterns of intraretinal changes in OCT correlated with changes in FA: (a) focal angiographic leakage did not correspond to any obvious intraretinal abnormality in OCT in four eyes; (b) localized thickening of the outer nuclear layer in OCT corresponded to focal leaking microaneurysm (focal oedema) in FA in 11 eyes; (c) diffuse thickening of the outer nuclear layer in OCT corresponded to diffuse angiographic leakage in 21 eyes; (d) cystoid expansion of the outer nuclear layer was found in seven eyes with a petaloid angiographic pattern of leakage; (e) cystoid expansion of the inner nuclear layer was found in relation to honeycomb angiographic oedema in five eyes, and (f) serous detachment of the fovea in OCT did not correspond to any distinct finding in FA in four eyes.

CONCLUSIONS

Intraretinal abnormalities found in OCT correlate systemically with changes in FA. Very early DMO morphological changes may be seen better with FA than with OCT. Serous detachment of the fovea is seen in OCT, but not in FA. The combination of OCT and FA is useful in facilitating understanding of the pathophysiological changes that occur in DMO.

Three-dimensional Imaging of Cystoid Macular Edema in Retinal Vein Occlusion

OBJECTIVE

To study the pathomorphologic features of cystoid macular edema (CME) associated with retinal vein occlusion by three-dimensional (3D) optical coherence tomography (OCT) and to study the relationship of the ocular findings to visual function.

DESIGN

Observational case series.

PARTICIPANTS

Twenty eyes of 20 patients with retinal vein occlusion.

METHODS

A prototype 3D OCT system based on Fourier-domain OCT technology was fabricated for patient examination in this study. This system uses a superluminescent diode, which has a center wavelength of 830 nm and a bandwidth of 50 nm, as the light source, resulting in 4.3-microm axial resolution in tissue. Data acquisition rates of approximately 18 700 axial scans per second and a sensitivity of 98 dB were achieved. Three-dimensional imaging was performed by volume rendering based on the 3D data set acquired with a raster scan of 256x256 axial scans.

MAIN OUTCOME MEASURES

Images of CME pathologic features obtained by 3D OCT and by Stratus OCT (Carl Zeiss, Dublin, CA).

RESULTS

The 3D OCT imaging system generates a realistic 3D image of CME with high resolution. In 16 eyes, 3D OCT showed large foveal cystoid spaces, most of which were accompanied by small cystoid spaces in the parafoveal region. Cystoid spaces were seen often in the inner nuclear layer and outer plexiform layer, but were detected to some extent in all retinal layers. The 3D OCT showed clearly a thin back-reflecting line corresponding to the external limiting membrane (ELM) in 18 eyes; of these, cystoid spaces were located on the inside of the ELM in 7 eyes and appeared to be in contact with the ELM in 9 eyes. In 2 eyes, the ELM line could not be seen clearly beneath the large foveal cystoid spaces. Integrity of the ELM in the foveal region had a direct correlation with visual acuity.

CONCLUSIONS

Observation of CME using 3D OCT enabled visualization of its spatial extent in each retinal layer and discernment of its relationship to the ELM. The use of 3D OCT thus may improve the monitoring of CME progression and its response to treatment.

Clinical applications and new developments of optical coherence tomography: an evidence-based review

Optical coherence tomography (OCT) is a new imaging modality that has increasingly become an indispensable tool in clinical practice for the diagnosis and management of ocular diseases involving the macula, optic nerve and anterior segment. The instrument is an advanced imaging technique that provides unprecedented high resolution and cross-sectional tomographic images of the ocular microstructure in situ, and in real time. Since its introduction about four years ago, a multitude of advantages has made OCT an essential instrument in ophthalmic imaging. The technique has fast image acquisition speed and non-contact, non-invasive applicability, allowing a non-excisional 'optical biopsy' to be performed. The purpose of this paper is to provide an evidence-based review of the increasing role of OCT in the diagnosis and management of ocular disorders, particularly in age-related macular degeneration, diabetic macular oedema, macular hole, epiretinal membrane and glaucoma. Being one of the first users of OCT in Australia, our clinical experiences will be highlighted and clinical examples of various conditions will be presented to provide an overview of the immense implications of OCT in practice. The latest developments of the OCT revolution, in relation to combining OCT with fundus photography and scanning laser ophthalmoscopy, will also be described. New developments of three-dimensional visualisation of tissue morphology with future models of ultra-high speed, ultra-high resolution OCT may further enhance the early diagnosis, monitoring of disease progression and assessment of treatment efficacy, facilitated by this powerful technology.

Anti-VEGF agents in the treatment of neovascular age-related macular degeneration: applying clinical trial results to the treatment of everyday patients

PURPOSE

The vision gains reported with monthly intravitreal ranibizumab in the MARINA and ANCHOR trials led to an immediate paradigm shift in the treatment of neovascular AMD with retina physicians universally switching to the pan-VEGF blocking agents ranibizumab and bevacizumab, and patients expecting visual improvement. As these agents are primarily used on a pro re nata (PRN) dosing schedule (because neither patients nor physicians want monthly injections), the factors involved in making the treatment and retreatment decisions are very important in any attempt to maximize vision gain.

DESIGN

Analysis of literature, ongoing clinical trials, and the clinical assessments that can aid clinicians in treatment and retreatment decisions.

METHODS

Literature review and perspective.

RESULTS

If a monthly injection protocol is not used, clinicians should use both functional and anatomic criteria to attempt to guide treatment and retreatment decisions. Qualitative optical coherence tomography (OCT) appears to be the most sensitive and practical assessment tool to determine anatomic response to treatment but should be used in conjunction with clinical examination.

CONCLUSIONS

If monthly intravitreal injections are not performed, a combination of clinical examination (looking for new hemorrhage) and qualitative OCT (to assess response to treatment and early signs of recurrent leakage) can be used to guide anti-vascular endothelial growth factor (anti-VEGF), treatments with the goal of maintaining a "normal" retinal anatomy in an attempt to maximize the benefit (visual acuity gains) to risk (number of injections required) ratio.

Optical Coherence Tomography Use in Evaluation of the Vitreoretinal Interface: A Review

Optical coherence tomography (OCT) is a valuable tool for assessment of the vitreoretinal interface. This article reviews the normal process of age-related posterior vitreous detachment as viewed by OCT. Abnormalities of the vitreoretinal interface as imaged by OCT are described including vitreomacular traction syndrome, cystoid macular edema/ diabetic macular edema, epiretinal membranes, full thickness macular holes, lamellar holes, pseudoholes, microholes, and schisis from myopia or optic pits/colobomas. This tool has given us new insights into the pathogenesis of these retinal abnormalities.

Association between integrity of foveal photoreceptor layer and visual acuity in branch retinal vein occlusion

AIM

To study the correlation between integrity of the photoreceptor layer after resolution of macular oedema (MO) associated with branch retinal vein occlusion (BRVO) and final visual acuity (VA), and to determine prognostic factors for visual outcome.

METHODS

We retrospectively studied 46 eyes from 46 patients with resolved MO secondary to BRVO, the foveal thickness of which was less than 250 microm at final observation. We assessed the status of the third high reflectance band (HRB) in the fovea using optical coherence tomography (OCT) at final observation, and studied OCT images taken at the initial visit in the hope of identifying a factor that would be prognostic of visual outcome.

RESULTS

No differences were found in initial VA or in foveal thickness between eyes with or without complete third HRB at final observation. However, final VA in eyes without a complete HRB was significantly poorer (p<0.002). Additionally, initial status of the third HRB in the parafoveal area of unaffected retina was associated with final VA; lack of visualisation of the third HRB at 500 microm (p = 0.0104) or 1000 microm (p = 0.0167) from the fovea on initial OCT images was associated with poor visual recovery after resolution of the MO.

CONCLUSION

Integrity of the photoreceptor layer in the fovea is associated with VA in resolved MO, and status of the third HRB before treatment might be predictive of visual outcome.