Correlation of optical coherence tomography, with or without additional colour fundus photography, with stereo fundus fluorescein angiography in diagnosing choroidal neovascular membranes

Associations of ARMS2 and CFH Gene Polymorphisms with Neovascular Age-Related Macular Degeneration

Purpose

This study aimed to determine the association of ARMS2 A69S, ARMS2 del443ins54, and CFH Y402H polymorphisms with neovascular age-related macular degeneration (nAMD) for the first time in an Indonesian population.

Patients and Methods

Our case–control study involved 104 nAMD and 100 control subjects. AMD diagnosis was evaluated by retinal specialists based on color fundus photography and optical coherence tomography. The polymorphisms on CFH Y402H and ARMS2 A69S were analyzed by PCR-restriction fragment length polymorphism (PCR-RFLP), whereas ARMS2 del443ins54 was evaluated by PCR-based assay.

Results

Significant allelic associations with nAMD were detected on all polymorphisms (P<0.05), with stronger association with the ARMS2 A69S (OR 3.13; 95% CI 2.08–4.71; P<0.001) and ARMS2 del443ins54 (OR 3.28; 95% CI 2.17–4.95; P<0.001) polymorphisms than with CFH Y402H (OR 2.08; 95% CI 1.08–3.99; P=0.028). Genotype analysis showed a statistical difference between nAMD and the control group for all polymorphisms (P<0.05). However, the association with nAMD was weaker for CFH Y402H (P=0.043) than for ARMS2 A69S and ARMS2 del443ins54 (P<0.001). A significant interaction between ARMS2 A69S and hypertension was documented (OR 9.53; 95% CI 3.61–25.1; P<0.001).

Conclusion

Our findings indicate that ARMS2 A69S and ARMS2 del443ins54 polymorphisms are strongly associated with the risk of nAMD for the first time in an Indonesian population. The risk of nAMD increased when the presence of risk alleles from ARMS2 A69S was combined with the presence of hypertension.

OPTICAL COHERENCE TOMOGRAPHY, FLUORESCEIN ANGIOGRAPHY, AND DIAGNOSIS OF CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION

In a prospective study, spectral domain optical coherence tomography and fluorescein angiography, combined with color fundus photograph used as a first diagnostic test in patients aged 50 years or older, had a similar sensitivity and specificity for the diagnosis of choroidal neovascularization in age-related macular degeneration.

To determine the sensitivity and specificity of different retinal imaging combinations for the diagnosis of choroidal neovascularization (CNV) in age-related macular degeneration.

Fluorescein Angiography Does Not Alter the Initial Clinical Management of Choroidal Neovascularization in Age-Related Macular Degeneration

PURPOSE

Fundus fluorescein angiography (FFA) is the standard modality to diagnose and manage choroidal neovascularization (CNV). However, FFA is costly and has considerable morbidity from allergic reactions and a mortality of 1 per 220 000. Since the advent of anti-vascular endothelial growth factor (VEGF) therapy for CNV, OCT has been used extensively to manage CNV, but FFA is still widely used. One recent study found the sensitivity and specificity of OCT compared with FFA in diagnosis of CNV were 100% and 80.8%, respectively. We hypothesize that FFA does not affect the management of patients initially suspected of having CNV to a clinically significant degree.

DESIGN

Evaluation of diagnostic test using vignettes.

PARTICIPANTS

A total of 99 patients (99 eyes) who had an initial presentation of later confirmed CNV.

METHODS

We retrospectively extracted in de-identified form the FFA, OCT, and clinical histories of the subjects. Vignettes were created with a standard narrative clinical history, posterior-pole color fundus image, central B-scan OCT of the initial visit, and early, mid, and late FFA of the affected eye. Four masked retinal specialists reviewed, in randomized order, these vignettes without FFA images (FFA- arm) and answered a forced choice management question: observation, 3 consecutive anti-VEGF injections, or other. After re-randomization, experts again reviewed the vignettes with the addition of the FFA images (FFA+ arm).

MAIN OUTCOME MEASURES

Intraobserver and interobserver concordance and reliability statistics within and between specialists.

RESULTS

Among our retina specialists, intraobserver concordances were 89.7%, 88.7%, 88.7%, and 95.9% (average 90.7%, 95% confidence interval [CI], 83.7-97.6). The average interobserver concordance for the FFA- arm was 84.0% (95% CI, 72.6-95.4), and for the FFA+ arm, 81.8% (95% CI, 68.5-95.2); paired t testing demonstrated no significant difference between the FFA- and FFA+ arms: t = 0.6, P = 0.55.

CONCLUSIONS

Our data suggest a high degree of agreement in clinical decision making whether FFA was used or not. There was a similar level of agreement among specialists in the FFA- and FFA+ groups, albeit at higher, not statistically significant, variability. We believe these findings further support deferring the use of FFA in the initial management of CNV in AMD, except in treatment failures and nonstandard cases.

Investigation of artifacts in retinal and choroidal OCT angiography with a contrast agent

Optical coherence tomography angiography (OCTA) has recently emerged for imaging vasculature in clinical ophthalmology. Yet, OCTA images contain artifacts that remain challenging to interpret. To help explain these artifacts, we perform contrast-enhanced OCTA with a custom-designed wide-field ophthalmoscope in rats in vivo. We choose an intravascular contrast agent (Intralipid) with particles that are more isotropically scattering and more symmetrically shaped than red blood cells (RBCs). Then, by examining how OCTA artifacts change after contrast agent injection, we attribute OCTA artifacts to RBC-specific properties. In this work, we investigate retinal and choroidal OCTA in rats with or without melanosomes, both before and after contrast agent injection, at a wavelength at which scattering dominates the image contrast (1300 nm). First, baseline images suggest that high backscattering of choroidal melanosomes accounts for the relatively dark appearance of choroidal vessel lumens in OCTA. Second, Intralipid injection tends to eliminate the hourglass pattern artifact in OCTA images of vessel lumens and highlights vertical capillaries that were previously faint in OCTA, showing that RBC orientation is important in determining OCTA signal. Third, Intralipid injection increases lumen signal without significantly affecting the tails, suggesting that projection artifacts, or tails, are due to RBC multiple scattering. Fourth, Intralipid injection increases the side-to-top signal ratio less in choroidal vessel lumens of pigmented rats, suggesting that melanosome multiple scattering makes the hourglass artifact less prominent. This study provides the first direct experimental in vivo evidence to explain light scattering-related artifacts in OCTA.

Prevalence and treatment patterns of ranibizumab and photodynamic therapy in a tertiary care setting in Malaysia

AIM

To describe the prevalence and changes in treatment patterns of ranibizumab and photodynamic therapy (PDT) among retinal disease patients who attended the Ophthalmology Clinic in the tertiary care Hospital Selayang from 2010 to 2014.

METHODS

Study subjects were recruited retrospectively using the Electronic Medical Record (EMR) database software in Hospital Selayang. Demographic data, medical history, diagnostic procedure, treatments and diagnosis of patients were recorded.

RESULTS

The five-year analysis included 821 patients with a mean age of 65.9±11.73y. Overall, there were a higher number of males (63.1%) and a higher number of Chinese (47.4%) patients. Among the 821 patients, 62.9% received ranibizumab injection followed by 19.2% PDT therapy and 17.9% had ranibizumab combined with PDT therapy. Age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) were the most common retinal eye diseases reported, recording prevalence of 25.0% and 45.6%, respectively. The trend in ranibizumab treatment was reported to increase while PDT showed a decrease in trend from year 2010 to 2014. In terms of treatment, following multiple logistic regression, AMD was associated with the subjects being more likely to have received ranibizumab monotherapy (P<0.001) while PCV was associated with more likely to have received PDT (P<0.001) and PDT combined with ranibizumab therapy (P<0.001).

CONCLUSION

The tertiary care setting in Malaysia is consistent with management of patients from other countries whereby ranibizumab is the most common treatment given to patients with AMD, while PCV patients most commonly receive PDT and ranibizumab combined with PDT therapy.

Morphologic Criteria of Lesion Activity in Neovascular Age-Related Macular Degeneration: A Consensus Article

Intravitreal antivascular endothelial growth factor drugs represent the current standard of care for neovascular age-related macular degeneration (nAMD). Individualized treatment regimens aim at obtaining the same visual benefits of monthly injections with a reduced number of injections and follow-up visits, and, consequently, of treatment burden. The target of these strategies is to timely recognize lesion recurrence, even before visual deterioration. Early detection of lesion activity is critical to ensure that clinical outcomes are not compromised by inappropriate delays in treatment, but questions remain on how to effectively monitor the choroidal neovascularization (CNV) activity. To assess the persistence/recurrence of lesion activity in patients undergoing treatment for nAMD, an expert panel developed a decision algorithm based on the morphological features of CNV. After evaluating all current retinal imaging techniques, the panel identified optical coherent tomography as the most reliable tool to ascertain lesion activity when funduscopy is not obvious.

Multi-categorical deep learning neural network to classify retinal images: A pilot study employing small database

Deep learning emerges as a powerful tool for analyzing medical images. Retinal disease detection by using computer-aided diagnosis from fundus image has emerged as a new method. We applied deep learning convolutional neural network by using MatConvNet for an automated detection of multiple retinal diseases with fundus photographs involved in STructured Analysis of the REtina (STARE) database. Dataset was built by expanding data on 10 categories, including normal retina and nine retinal diseases. The optimal outcomes were acquired by using a random forest transfer learning based on VGG-19 architecture. The classification results depended greatly on the number of categories. As the number of categories increased, the performance of deep learning models was diminished. When all 10 categories were included, we obtained results with an accuracy of 30.5%, relative classifier information (RCI) of 0.052, and Cohen's kappa of 0.224. Considering three integrated normal, background diabetic retinopathy, and dry age-related macular degeneration, the multi-categorical classifier showed accuracy of 72.8%, 0.283 RCI, and 0.577 kappa. In addition, several ensemble classifiers enhanced the multi-categorical classification performance. The transfer learning incorporated with ensemble classifier of clustering and voting approach presented the best performance with accuracy of 36.7%, 0.053 RCI, and 0.225 kappa in the 10 retinal diseases classification problem. First, due to the small size of datasets, the deep learning techniques in this study were ineffective to be applied in clinics where numerous patients suffering from various types of retinal disorders visit for diagnosis and treatment. Second, we found that the transfer learning incorporated with ensemble classifiers can improve the classification performance in order to detect multi-categorical retinal diseases. Further studies should confirm the effectiveness of algorithms with large datasets obtained from hospitals.

The Role of mf-ERG in the Diagnosis and Treatment of Age-Related Macular Degeneration: Electrophysiological Features of AMD

INTRODUCTION

Age-related macular cegeneration (AMD) is the leading cause of visual dysfunction worldwide, affecting 9-25% of individuals between 65 and 75 years old.

METHODS

We have reviewed the published articles investigating the role of multifocal electroretinogram (mf-ERG) in the diagnosis and treatment of AMD.

RESULTS

Visual evoked potentials have revealed decreased amplitudes and higher latencies in patients with AMD, while the degeneration of photoreceptors and abnormalities of retinal pigment epithelium can be identified by electro-oculogram recordings. Moreover, ERG can detect the functional abnormalities observed in AMD and evaluate each therapeutic approach. The record of local electrophysiological responses coming from different retinal areas can be accurately performed by mfERG.

CONCLUSION

The accuracy of mfERG in detecting the degeneration of photoreceptors, as well the disturbances of macular function, could be useful both in the early diagnosis of AMD and the assessment of treatment efficacy.

Optical coherence tomography for the diagnosis, monitoring and guiding of treatment for neovascular age-related macular degeneration: a systematic review and economic evaluation

BACKGROUND

Age-related macular degeneration is the most common cause of sight impairment in the UK. In neovascular age-related macular degeneration (nAMD), vision worsens rapidly (over weeks) due to abnormal blood vessels developing that leak fluid and blood at the macula.

OBJECTIVES

To determine the optimal role of optical coherence tomography (OCT) in diagnosing people newly presenting with suspected nAMD and monitoring those previously diagnosed with the disease.

DATA SOURCES

Databases searched: MEDLINE (1946 to March 2013), MEDLINE In-Process & Other Non-Indexed Citations (March 2013), EMBASE (1988 to March 2013), Biosciences Information Service (1995 to March 2013), Science Citation Index (1995 to March 2013), The Cochrane Library (Issue 2 2013), Database of Abstracts of Reviews of Effects (inception to March 2013), Medion (inception to March 2013), Health Technology Assessment database (inception to March 2013).

REVIEW METHODS

Types of studies: direct/indirect studies reporting diagnostic outcomes.

INDEX TEST

time domain optical coherence tomography (TD-OCT) or spectral domain optical coherence tomography (SD-OCT).

COMPARATORS

clinical evaluation, visual acuity, Amsler grid, colour fundus photographs, infrared reflectance, red-free images/blue reflectance, fundus autofluorescence imaging, indocyanine green angiography, preferential hyperacuity perimetry, microperimetry. Reference standard: fundus fluorescein angiography (FFA). Risk of bias was assessed using quality assessment of diagnostic accuracy studies, version 2. Meta-analysis models were fitted using hierarchical summary receiver operating characteristic curves. A Markov model was developed (65-year-old cohort, nAMD prevalence 70%), with nine strategies for diagnosis and/or monitoring, and cost-utility analysis conducted. NHS and Personal Social Services perspective was adopted. Costs (2011/12 prices) and quality-adjusted life-years (QALYs) were discounted (3.5%). Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

In pooled estimates of diagnostic studies (all TD-OCT), sensitivity and specificity [95% confidence interval (CI)] was 88% (46% to 98%) and 78% (64% to 88%) respectively. For monitoring, the pooled sensitivity and specificity (95% CI) was 85% (72% to 93%) and 48% (30% to 67%) respectively. The FFA for diagnosis and nurse-technician-led monitoring strategy had the lowest cost (£ 39,769; QALYs 10.473) and dominated all others except FFA for diagnosis and ophthalmologist-led monitoring (£ 44,649; QALYs 10.575; incremental cost-effectiveness ratio £ 47,768). The least costly strategy had a 46.4% probability of being cost-effective at £ 30,000 willingness-to-pay threshold.

LIMITATIONS

Very few studies provided sufficient information for inclusion in meta-analyses. Only a few studies reported other tests; for some tests no studies were identified. The modelling was hampered by a lack of data on the diagnostic accuracy of strategies involving several tests.

CONCLUSIONS

Based on a small body of evidence of variable quality, OCT had high sensitivity and moderate specificity for diagnosis, and relatively high sensitivity but low specificity for monitoring. Strategies involving OCT alone for diagnosis and/or monitoring were unlikely to be cost-effective. Further research is required on (i) the performance of SD-OCT compared with FFA, especially for monitoring but also for diagnosis; (ii) the performance of strategies involving combinations/sequences of tests, for diagnosis and monitoring; (iii) the likelihood of active and inactive nAMD becoming inactive or active respectively; and (iv) assessment of treatment-associated utility weights (e.g. decrements), through a preference-based study.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012001930.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The diagnostic accuracy of spectral-domain optical coherence tomography for neovascular age-related macular degeneration: a comparison with fundus fluorescein angiography

PURPOSE

To evaluate the diagnostic accuracy of spectral-domain optical coherence tomography (SD-OCT) for neovascular age-related macular degeneration (nAMD): a comparison against fundus fluorescein angiography (FFA).

METHODS

A retrospective review of SD-OCT, colour fundus photographs (FP), and FFA of 411 consecutive patients referred to a rapid access Macular Clinic over a 4-year period was performed. FFA images were reviewed non-stereoscopically. SD-OCT images were acquired using the Topcon 3D OCT-1000 instrument. All FFA and OCT images were graded by at least two ophthalmologists independently. Side-by-side grading took place with immediate open discussion and adjudication. If there was disagreement between the two grading ophthalmologists or they were not 90% confident of their assigned grade, then adjudication by a third ophthalmologist was performed.

RESULTS

A total of 278 eyes were graded as having choroidal neovascularisation (CNV) with SD-OCT and 231 diagnosed with FFA. The main diagnostic CNV classifications on FFA were: classic no occult in 27 eyes, predominantly classic in 16, minimally classic in 50, occult in 129, and 9 peripapillary membranes. There were a total of 47 false positives with SD-OCT: a rate of 16.9%. The sensitivity and specificity of SD-OCT alone for detecting CNV was 100 and 80.8%, respectively.

CONCLUSION

Our study confirms SD-OCT in comparison to the reference standard of non-stereoscopic FFA is highly sensitive at detecting newly presenting nAMD in the setting of a specialist AMD clinic where the investigations are interpreted by trained specialists. However, it does not seem accurate enough to replace FFA in the diagnosis on nAMD in current practice.

Two week, OCT-based follow-up as guidance for retreatment with ranibizumab for CNV apparently refractory to therapy

PURPOSE

To assess the value of 2-week optical coherence tomography (OCT) follow-up for re-treatment decision-making in patients receiving monthly ranibizumab injections for choroidal neovascular membrane (CNV), which was apparently refractory to treatment.

METHODS

A total of 25 eyes of 25 consecutive patients with refractory CNV were included. Patients were classified as having refractory disease if no visual acuity (VA) change and no change in the pattern of macular fluid was noticed on OCT after at least 3 consecutive monthly injections, excluding the loading doses. Repeat injection was given and reassessment with VA and OCT was undertaken at 2, 4, 8, and 12 weeks.

RESULTS

Complete resolution or marked reduction of macular fluid was noted in 19 patients at 2 weeks (responders). In 18 responders, the fluid increased on 4- and persisted on 8- and 12-week follow-ups, so that further injections were given at these time points. In 6 patients, no significant change was noted at 2 weeks (nonresponders). In all of them, VA and OCT were stable on 4-, 8-, and 12-week follow-ups, without further injections.

CONCLUSIONS

As some patients are responding for at least part of the month, injections may be worth continuing or possibly more frequent injections, tailored to the individual's response, may need to be considered. Alternative therapies such as aflibercept may also need to be considered. In nonresponding eyes, other cytokines except for vascular endothelial growth factor are probably involved in the pathogenesis or such cases may have structural damage that will not respond to therapy.

Optical coherence tomography for the diagnosis of neovascular age-related macular degeneration: a systematic review

The purpose is to study the diagnostic performance of optical coherence tomography (OCT) and alternative diagnostic tests for neovascular age-related macular degeneration (nAMD). Methods employed are as follows:systematic review and meta-analysis;

INDEX TEST

OCT including time-domain (TD-OCT) and the most recently developed spectral domain (SD-OCT); comparator tests: visual acuity, clinical evaluation (slit lamp), Amsler chart, colour fundus photographs, infra-red reflectance, red-free images/blue reflectance, fundus autofluorescence imaging (FAF), indocyanine green angiography (ICGA), preferential hyperacuity perimetry (PHP), and microperimetry; reference standard: fundus fluorescein angiography. Databases searched included MEDLINE, MEDLINE In Process, EMBASE, Biosis, SCI, the Cochrane Library, DARE, MEDION, and HTA database. Last literature searches: March 2013. Risk of bias assessed using QUADAS-2. Meta-analysis models were fitted using hierarchical summary receiver operating characteristic (HSROC) curves. Twenty-two studies (2 abstracts and 20 articles) enrolling 2124 participants were identified, reporting TD-OCT (12 studies), SD-OCT (1 study), ICGA (8 studies), PHP (3 studies), Amsler grid, colour fundus photography and FAF (1 study each). Most studies were considered to have a high risk of bias in the patient selection (55%, 11/20), and flow and timing (40%, 8/20) domains. In a meta-analysis of TD-OCT studies, sensitivity and specificity (95% CI) were 88% (46-98%) and 78% (64-88%), respectively. There was insufficient information to undertake meta-analysis for other tests. TD-OCT is a sensitive test for detecting nAMD, although specificity was only moderate. Data on SD-OCT are sparse. Diagnosis of nAMD should not rely solely on OCT.

Optical coherence tomography imaging of macular oedema

Macular oedema (ME) occurs in a wide variety of pathological conditions and accounts for different degrees of vision loss. Early detection of ME is therefore critical for diagnosis and therapeutic management. Optical coherence tomography (OCT) is a non-contact, diagnostic method that uses infrared light, which allows the analysis of the retinal structure by means of high-resolution tomographic cross sections. The identification, localisation, quantification and long-term follow-up of fluid collections are the most important capabilities of OCT. Since the introduction of OCT in clinical practice, it has become an invaluable diagnostic tool and different patterns of ME have been reported. The purpose of this manuscript is to review OCT profiles of ME according to the aetiology and describe what has been reported regarding intraretinal features in vivo.

Correlation of fundus fluorescein angiography and spectral-domain optical coherence tomography in identification of membrane subtypes in neovascular age-related macular degeneration

AIMS

To assess the sensitivity and specificity of spectral-domain optical coherence tomography (SDOCT) for the determination of choroidal neovascularization (CNV) subtypes in neovascular age-related macular degeneration (AMD) compared to fundus fluorescein angiography (FFA) and also the agreement between the two procedures.

DESIGN

This was a retrospective, observational study.

METHODS

We evaluated and compared the CNV subtypes on FFA and OCT in 100 eyes initiated on ranibizumab for neovascular AMD.

RESULTS

SDOCT showed high sensitivity (85.7-98.3%) and specificity (84.2-100%) compared to FFA in the diagnosis of the CNV subtype. The area under the receiver-operating characteristic curve ranged from 0.9 to 0.93 (p value <0.0001) for the different CNV subtypes. Weighted kappa statistics showed a near-perfect agreement of 0.85 between the procedures.

CONCLUSION

SDOCT is a reliable tool for the diagnosis of CNV subtypes in neovascular AMD obviating the need for an invasive procedure such as FFA.

Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia - fluorescein angiography versus spectral-domain optical coherence tomography

BACKGROUND

To compare ability of fluorescein angiography (FFA) and spectral-domain optical coherence tomography (SD-OCT) to diagnose subretinal neovascularization (SRNV) secondary to idiopathic juxtafoveal retinal telangiectasia (IJRT) type 2A.

METHODS

Two masked observers evaluated FFA and SD-OCT images separately to diagnose the presence of SRNV in 65 eyes of 36 patients. A third masked observer diagnosed SRNV on color fundus photo. Presence of SRNV on color fundus photo was defined as presence of subretinal hemorrhage, thickening of retina, and/or visible membrane at the macula. Presence of SRNV on FFA was defined when there was hyperfluorescence in early phase with increase in intensity and size in the late phase; presence of membrane, large irregular lesion, hypofluorescence due to subretinal haemorrhage. SRNV on SD-OCT was defined as the presence of thickening of the retinal pigment epithelium-choriocapillaris complex with or without intraretinal fluid or subretinal fluid and associated with intraretinal hyperreflective area with retinal thickening.

RESULTS

Interobserver agreement (Kappa) for diagnosis of SRNV on FFA and SD-OCT was 0.373 (95 % CI, 0.106-0.617) and 0.775 (95 % CI, 0.612-0.899) respectively. The sensitivity and specificity of FFA were 52.3 % and 70.0 % respectively. With regard to SD-OCT, the sensitivity and specificity were 72.7 % and 64.1 % respectively in reference to color photograph. The negative predictive value (NPV) of SD-OCT (80.6 %) was higher than FFA (73.7 %). When we considered only the presence of subretinal hemorrhage on color photograph as a confirmed diagnosis of SRNV and compared the diagnostic ability of FFA and SD-OCT, we found that the FFA had poor sensitivity (58.3 %) but a better specificity (71.8 %) than SD-OCT, which had sensitivity of 75 % and specificity of 64 % (Tables 1 and 2). However, the negative predictive value (NPV) of SD-OCT (89.29 %) was slightly better than FFA (84.85 %).

CONCLUSION

Interobserver agreement between the observers was better for SD-OCT than for FFA in making the diagnosis of SRNV. SD-OCT is a better diagnostic modality than FFA for ruling out the presence of SRNV.

Choroidal neovascularization regression on fluorescein angiography after VEGF blockade

Background

Intravitreal vascular endothelial growth factor (VEGF) inhibitors stabilize vision in a majority of patients with neovascular age-related macular degeneration (AMD) and can improve vision in almost 40% of patients. However, some individuals who respond to anti-VEGF treatment still lose vision due to the formation of geographic atrophy (GA). While optical coherence tomography is often the primary imaging modality used, fluorescein angiography (FA) can provide useful information on GA development after choroidal neovascularization (CNV) regression.

Methods

A retrospective chart review was conducted to evaluate the changes seen on FA over a 47-month period for 3 patients with neovascular AMD treated with anti-VEGF inhibitors.

Results

All 3 patients were initially noted to have subfoveal CNV due to AMD at baseline; they were followed up monthly and treated on an as needed basis for at least 47 months with intravitreal VEGF inhibitors. All subjects had regression of their CNV lesions after VEGF blockade. Two subjects developed foveal atrophy.

Conclusions

This case series depicts the changes on FA seen over a 4-year period and shows that GA can occur with regression of CNV after treatment with VEGF inhibitors.

Information used to decide on retreatment of exudative age-related macular degeneration with anti-VEGF in clinical practice

Purpose. To record the information used in order to make a retreatment decision in patients with exudative age-related macular degeneration (AMD) and to assess if an optical coherence tomography (OCT)-only follow-up clinic would suffice.
Methods. Two hundred patients under treatment with intravitreal anti-vascular endothelial growth factor injections (anti-VEGF) for exudative AMD were included. Each patient had previously received at least 3 intravitreal anti-VEGF injections (loading dose) (range 3-24 injections). Clinicians seeing the patients beyond the third injection were asked to document the criteria used to make a retreatment decision.
Results. Overall, in 171 (85.5%) cases the retreatment decision was based on OCT findings of intraretinal or subretinal fluid alone. Diagnosis of recurrence requiring treatment would have been missed in 12 cases (6%), if OCT-only data had been used and funduscopy or visual function criteria had been omitted. Decision was based solely on functional criteria in only 2% of the cases. The retreatment decision was based on evaluation of morphologic funduscopic or OCT criteria in 187 (93.5%) cases.
Conclusions. With the increasing number of patients having follow-up after anti- VEGF treatment, efficient systems of follow-up are required. Although most retreatment decisions could have been made by qualitative assessment of OCT images alone, the examination has considerable limitations. Optical coherence tomography in combination with color fundus photography could serve as screening tools for a rational implementation of other invasive imaging techniques such as fundus fluorescein angiography and indocyanine green angiography in decision-making.

Imaging in neovascular age-related macular degeneration

Imaging plays an essential role in the diagnosis and treatment of age-related macular degeneration (AMD). This review describes the imaging modalities most commonly employed by ophthalmologists caring for patients with neovascular AMD. Imaging modalities discussed include fluorescein angiography, optical coherence tomography, indocyanine green angiography, and fundus autofluorescence.

Optical coherence tomography for age-related macular degeneration and diabetic macular edema: an evidence-based analysis

OBJECTIVE

The purpose of this evidence-based review was to examine the effectiveness and cost-effectiveness of spectral-domain (SD) optical coherence tomography (OCT) in the diagnosis and monitoring of patients with retinal disease, specifically age-related macular degeneration (AMD) and diabetic macular edema (DME). Specifically, the research question addressed was: What is the sensitivity and specificity of spectral domain OCT relative to the gold standard?

CLINICAL NEED

TARGET POPULATION AND CONDITION The incidence of blindness has been increasing worldwide. In Canada, vision loss in those 65 years of age and older is primarily due to AMD, while loss of vision in those 18 years of age and older is mainly due to DME. Both of these conditions are diseases of the retina, which is located at the back of the eye. At the center of the retina is the macula, a 5 mm region that is responsible for what we see in front of us, our ability to detect colour, and fine detail. Damage to the macula gives rise to vision loss, but early detection of asymptomatic disease may lead to the prevention or slowing of the vision loss process. There are two main types of AMD, 'dry' and 'wet'. Dry AMD is the more prevalent of the two, accounting for approximately 85% of cases and characterized by small deposits of extracellular material called "drusen" that build up in Bruch's membrane of the eye. Central vision loss is gradual with blurring and eventual colour fading. Wet AMD is a less prevalent condition (15% of all AMD cases) but it accounts for 90% of severe cases. It's characterized by the appearance of retinal fluid with vision loss due to abnormal blood vessels/leakage within weeks to months of diagnosis. In 2003, the Canadian National Institute for the Blind (CNIB) prevalence estimate for AMD was 1 million Canadians, including approximately 400,000 affected Ontarians. The incidence in 2003 was estimated to be 78,000 new cases in Canada, with approximately one-third of these cases arising in Ontario (n=26,000). Over the next 25 years, the number of new cases is expected to triple. DME is caused by complications of diabetes mellitus, both Type 1 and Type 2. It is estimated that 1-in-4 persons with diabetes has this condition, though it occurs more frequently among those with type 2 diabetes. The condition is characterized by a swelling of the retina caused by leakage of blood vessels at the back of the eye. In early stages of the disease, vision may still be normal but it can degrade rapidly in later stages. In 2003, the CNIB prevalence estimate for DME was 0.5 million Canadians, with approximately 200,000 Ontarians affected. The incidence of DME is more difficult to ascertain; however, based on an annual incidence rate of 0.8% (for those 20 years of age or older) and the assumption that 1-in-4 persons with diabetes is affected, the incidence of DME in Ontario is estimated to be 21,000 new cases per year. OPTICAL COHERENCE TOMOGRAPHY: Prior to the availability of OCT, the standard of care in the diagnosis and/or monitoring of retinal disease was serial testing with fluorescein angiography (FA), biomicroscopy (BM), and stereo-fundus photography (SFP). Each of these is a qualitative measure of disease based on subjective evaluations that are largely dependent on physician expertise. OCT is the first quantitative visual test available for the diagnosis of eye disease. As such, it is allows for a more objective evaluation of the presence/absence of retinal disease and it is the only test that provides a measure of retinal thickness. The technology was developed at the Michigan Institute of Technology (MIT) in 1991 as a real-time imaging modality and is considered comparable to histology. It's a light-wave based technology producing cross-sectional images with scan rates and resolution parameters that have greatly improved over the last 10 years. It's also a non-invasive, non-contact visual test that requires just 3 to 5 minutes to assess both eyes. There are two main types of OCT system, both licensed by Health Canada as class II devices. The original patent was based on a time domain (TD) system (available from 1995) that had an image rate of 100 to 400 scans per second and provided information for a limited view of the retina with a resolution in the range of 10 to 20 μm. The newer system, spectral domain (SD) OCT, has been available since 2006. Improvements with this system include (i) a faster scan speed of approximately 27,000 scans per second; (ii) the ability to scan larger areas of the retina by taking six scans radially-oriented 30 degrees from each other; (iii) increased resolution at 5μm; and (iv) 'real-time registration,' which was not previously available with TD. The increased scan speed of SD systems enables the collection of additional real-time information on larger regions of the retina, thus, reducing the reliance on assumptions required for retinal thickness and volume estimates based on software algorithms. The faster scan speed also eliminates image distortion arising from patient movement (not previously possible with TD), while the improvement in resolution allows for clearer and more distinguishable retinal layers with the possibility of detecting earlier signs of disease. Real-time registration is a new feature of SD that enables the identification of specific anatomical locations on the retina, against which subsequent tests can be evaluated. This is of particular importance in the monitoring of patients. In the evaluation of treatment effects, for example, this enables the same anatomic retinal location to be identified at each visit.

METHODS

LITERATURE SEARCH

A literature search was performed on February 13, 2009 using Ovid MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from January 2003 to February 2009. The subject headings and keywords searched included AMD, DME, and OCT (the detailed search strategy can be viewed in Appendix 1). Excluded were case reports, comments, editorials, non-systematic reviews, and letters. Abstacts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. In total, 542 articles were included for review. Inclusion CriteriaExclusion CriteriaEnglish-language articles and health technology assessments.RCTs and observational studies of OCT and AMD or DME.Studies focusing on either diagnosis or monitoring of disease.Studies in which outcomes were not specific to those of interest in this report.Studies of pediatric populations.Studies on OCT as a screening tool.Studies that did not assess comparative effectiveness of OCT with a referent, as specified below in "Comparisons of Interest".

OUTCOMES OF INTEREST

Studies of sensitivity, specificity. COMPARISONS OF INTEREST: Evidence exists for the following comparisons of interest: OCT compared with the reference "fluorescein angiography" for AMD.OCT compared with the reference "biomicroscopy" or "stereo or fundus photography" for DME. SUMMARY OF EXISTING EVIDENCE: No evidence for the accuracy of SD OCT compared to either FA, BM or SFP was published between January 2006 to February 2009; however, two technology assessments were found, one from Alberta and the other from Germany, both of which contain evidence for TD OCT. Although these HTAs included eight studies each, only one study from each report was specific to this review. Additionally, one systematic review was identified for OCT and DME. It is these three articles, all pertaining to time and not spectral domain OCT, as well as comments from experts in the field of OCT and retinal disease, that comprise the evidence contained in this review. Upon further assessment and consultations with experts in the methodology of clinical test evaluation, it was concluded that these comparators could not be used as references in the evaluation of OCT. The main conclusion was that, without a third test as an arbiter, it is not possible to directly compare the sensitivity and specificity of OCT relative to either FA for AMD and stereo- or fundus - photography for DME. Therefore, in the absence of published evidence, it was deemed appropriate to consult a panel of experts for their views and opinions on the validity of OCT and its utility in clinical settings. This panel consisted of four clinicians with expertise in AMD and/or DME and OCT, as well as a medical biophysicist with scientific expertise in ocular technologies. This is considered level 5 evidence, but in the absence of an appropriate comparator for further evaluation of OCT, this may be the highest level of evidence possible.

SUMMARY OF FINDINGS

The conclusions for SD OCT based on Level 5 evidence, or expert consultation, are as follows: OCT is considered an essential part of the diagnosis and follow-up of patients with DME and AMD.OCT is adjunctive to FA for both AMD and DME but should decrease utilization of FA as a monitoring modality.OCT will result in a decline in the use of BM in the monitoring of patients with DME, given its increased accuracy and consistency.OCT is diffusing rapidly and the technology is changing. Since FA is still considered pivotal in the diagnosis and treatment of AMD and DME, and there is no common outcome against which to compare these technologies, it is unlikely that RCT evidence of efficacy for OCT will ever be forthcoming.In addition to the accuracy of OCT in the detection of disease, assessment of the clinical utility of this technology included a rapid review of treatment effects for AMD and DME. The treatment of choice for AMD is Lucentis®, with or without Avastin® and photodynamic therapy. (ABSTRACT TRUNCATED)

[Optical coherence tomography for macula diagnostics. Review of methods and standardized application concentrating on diagnostic and therapy control of age-related macula degeneration]

BACKGROUND

Optical coherence tomography (OCT) has gained increasing relevance for follow-up after the treatment of macular diseases especially after anti-VEGF therapy. Therefore it seemed reasonable to develop standardized evaluation strategies and OCT examination guidelines for Stratus OCT III.

MATERIALS AND METHODS

Basic guidelines for the Stratus OCT III examination of macular diseases were developed. The first part contains basic advice for the OCT examination with respect to the examiner, patients, image quality, movement artefacts, algorithms, archiving and interpretation of OCT images. The second part consists of the relevance and indications for OCT examination especially in age-related macular degeneration (AMD), subgroups of AMD and follow-up after treatment. The third part demonstrates a brief outlook on future developments, such as the digital integration method (DIM), which provides identical scan localization in follow-up and eliminates any movement artefacts.

CONCLUSION

The application of standardized routine scanning and analysis protocols in Stratus OCT III for macular diseases and follow-up examinations provides an optimized, time-saving and comparable use of OCT. Therefore, the relevance and quality of OCT is increased for routine use in outpatient departments, hospitals and also for clinical studies.

Age-related macular degeneration: experimental and emerging treatments

Purpose:

This essay reviews the experimental treatments and new imaging modalities that are currently being explored by investigators to help treat patients with age-related macular degeneration (AMD).

Design:

Interpretative essay.

Methods:

Literature review and interpretation.

Results:

Experimental treatments to preserve vision in patients with exudative AMD include blocking vascular endothelial growth factor (VEGF), binding VEGF, and modulating the VEGF receptors. Investigators are also attempting to block signal transduction with receptor tyrosine kinase inhibitors. Experimental treatments for non-exudative AMD include agents that target inflammation, oxidative stress, and implement immune-modulation. The effectiveness of these newer pharmacologic agents has the potential to grow exponentially when used in combination with new and improved imaging modalities that can help identify disease earlier and follow treatment response more precisely.

Conclusion:

With a better understanding, at the genetic and molecular level, of AMD and the development of superior imaging modalities, investigators are able to offer treatment options that may offer unprecedented visual gains while reducing the need for repetitive treatments.

Recent progress in macular function self-assessment

BACKGROUND

Patients that are deemed to be at risk for the development of choroidal neovascularization are frequently instructed to self-monitor their vision for symptoms that may signal the presence of choroidal neovascularization. Traditionally, the Amsler grid has been used for this purpose, but recent technological innovations have resulted in a number of potential alternatives that offer important advantages, including greater sensitivity, the ability to differentiate exudative from non-exudative disease, and quantitative analysis of test results.

METHODS

The following technologies that could be employed for patient self-assessment of macular function in a home setting are reviewed: computerized Amsler grid, preferential hyperacuity perimetry, macular mapping test and noise-field campimetry.

CONCLUSIONS

A number of technologies are currently available that could significantly improve the ability of patients at risk for the development of choroidal neovascularization to self-monitor their central visual field.

Quantitative optical coherence tomography findings in various subtypes of neovascular age-related macular degeneration

PURPOSE

To compare the volume of various spaces visible on optical coherence tomography (OCT) images in different angiographic lesion subtypes of neovascular age-related macular degeneration (AMD).

METHODS

Sixty-six cases of previously untreated, active subfoveal choroidal neovascularization (CNV) associated with AMD were retrospectively collected. CNV lesions were classified as occult with no classic CNV, minimally classic CNV, predominantly classic CNV, or CNV lesions with associated retinal angiomatous proliferation (RAP). Corresponding OCT image sets were analyzed by trained graders using previously validated custom software that allows manual placement of boundaries on OCT B-scans. Spaces delineated by these boundaries included the neurosensory retina, subretinal fluid, subretinal tissue, and pigment epithelial detachments (PEDs). Volume measurements were calculated by the software and compared among groups.

RESULTS

Minimally and predominantly classic CNV membranes demonstrated subretinal tissue on OCT in all cases and appeared to show a significantly greater volume of subretinal tissue than did the occult membranes. Subretinal fluid was present in all the predominantly classic cases. A PED was visible in all the occult CNV cases in our study, demonstrating less retinal thickening and significantly greater PED volumes than minimally and predominantly classic CNV lesions. Lesions associated with RAP showed the highest percentage of cystoid spaces.

CONCLUSIONS

OCT and angiography provide complementary information regarding CNV lesions. Quantitative analysis of OCT images allows for an improved understanding of the anatomic characteristics of angiographically defined CNV lesion subtypes.

Optical coherence tomography identification of occult choroidal neovascularization in age-related macular degeneration

PURPOSE

To evaluate and describe the various optical coherence tomography (OCT) features of occult choroidal neovascularization (CNV) in age-related macular degeneration (AMD) at the time of diagnosis.

DESIGN

Prospective, consecutive, observational case series.

METHODS

One hundred and fifty-three eyes of 130 consecutive patients with subfoveal occult CNV diagnosed on scanning laser ophthalmoscope (SLO) fluorescein angiography (FA) and SLO indocyanine green angiography (ICGA) were evaluated with OCT. The diagnostic criteria for occult CNV on angiography were heterogeneous hyperfluorescence with late leakage in the macular region associated with pigment epithelial detachment (PED), stippled hyperfluorescent dots, and signs of deterioration. OCT findings were evaluated and described.

RESULTS

A PED was observed on OCT in 98% (150 eyes) either as a limited retinal pigment epithelium (RPE) elevation (54 eyes [35.3%]) or a complete detachment (96 eyes [62.7%]). Occult CNV corresponded to zones of hyperreflectivity in contact with the RPE band and was detected in 62.7% of eyes. In fibrovascular PED (63 eyes [65.5%]), the elevated RPE was highlighted posteriorly by a moderately reflective band overlying a hyporeflective cavity. In serous PED, the cavity remained optically empty. The RPE in the detached zone showed changes such as fragmentation (137 eyes [89.5%]). OCT also showed intraretinal (122 eyes [79.7%]) and subretinal (64 eyes [41.8%]) fluid.

CONCLUSIONS

Analysis of the various OCT features observed in this study confirms the polymorphic nature of occult CNV in AMD, their exudative reactions, the almost constant presence of PED, and the different changes in the RPE band. OCT examination, therefore, provides valuable data to confirm the features of subepithelial occult CNV.

Optical coherence tomography findings during pegaptanib therapy for neovascular age-related macular degeneration

BACKGROUND

To evaluate macular thickness measured by optical coherence tomography (OCT) during pegaptanib therapy for neovascular age-related macular degeneration (AMD).

METHODS

For this prospective, nonrandomized, observational case series, 41 eyes from 41 patients with neovascular AMD received intravitreous pegaptanib (1 mg) injections repeated every 6 weeks. The primary outcome measure was central foveal thickness measured by OCT. Secondary outcomes were fluorescein angiographic leakage and visual acuity.

RESULTS

Mean thickness of the central area on OCT decreased from 340 +/- 24 microm to 299 +/- 14 microm after 12 weeks of pegaptanib injections. This represents a reduction in thickening of 32%. Fluorescein angiograms with definite leakage decreased from 100% to 81%, and mean visual acuity decreased from 20/116 to 20/120.

CONCLUSIONS

Intravitreal injections of pegaptanib at 6-week intervals result in a moderate reduction of central foveal thickness in eyes with subfoveal neovascular AMD. This presents a modest effect relative to that reported with other anti-angiogenic agents.

VARIABILITY AMONG RETINA SPECIALISTS IN EVALUATING FLUORESCEIN ANGIOGRAMS OF PATIENTS WITH NEOVASCULAR AGERELATED MACULAR DEGENERATION

PURPOSE

To determine the rate of agreement among five retina specialists in classifying various angiographic features of subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD), as evaluated on printed digital fluorescein angiogram (FA) frames, as well as determination of eligibility for photodynamic treatment (PDT) according to established guidelines.

METHODS

Ninety-two digital FAs demonstrating subfoveal CNV secondary to AMD were evaluated independently by five retina specialists. The pattern of classic component could be classified as no classic component, minimally classic, predominantly classic, or classic only. Each grader was asked to determine eligibility of each case to PDT according to established treatment guidelines, national health insurance guidelines, and one's own personal judgment.

RESULTS

The kappa coefficient of concordance calculated for all five observers regarding CNV localization was 0.285, indicating fair overall agreement, and was 0.295, indicating fair agreement, regarding classification of leakage pattern. The kappa coefficient of agreement calculated for all five graders regarding eligibility for treatment according to established international guidelines, national health insurance, and each grader's own personal judgment was 0.163, 0.33, and 0.164, respectively, indicating slight to fair overall agreement.

CONCLUSION

Considerable variability may exist among retina specialists interpreting FAs and should be considered in the assessment of treatment guidelines.

Diabetic macular oedema: a clinical overview

Diabetic retinopathy is the leading cause of blindness in working aged-adults in westernised countries. Diabetic macular oedema (DMO) is a manifestation of diabetic retinopathy and is the leading cause of the visual impairment that occurs with diabetic retinopathy. There are multiple ways of classifying DMO; however, none appear to be wholly satisfactory. DMO occurs more frequently in type 2 diabetes mellitus, and appears to be more prevalent as the duration of diabetes increases, and as the severity of diabetic retinopathy worsens. There are multiple risk factors in common with diabetic retinopathy, such as hyperglycaemia, hypertension and dyslipidaemia; however, specific factors such as the presence of renal disease appear to be more significantly associated with DMO. Whereas the gold standard for diagnosis of DMO is via clinical examination, there is considerable variability involved, and hence, this has led to the advent of more objective methods of quantifying the degree of retinal thickness, such as optical coherence tomography. Laser photocoagulation appears to be the only universally acceptable treatment of choice to date; however, this is a destructive therapy, and its side effects coupled with the suboptimal efficacy has led to the advent of potential new therapies which will undoubtedly compliment the existing approaches, in the future management of a patient with DMO.

Use of optical coherence tomography, fluorescein angiography and indocyanine green angiography in a screening clinic for wet age-related macular degeneration

AIMS

To assess the utility of optical coherence tomography (OCT) in a nurse-led, fast-track clinic for new age-related macular degeneration (AMD) referrals, and to see how often indocyanine green angiography (ICGA) led to an additional diagnosis to that provided by fundus fluorescein angiography (FFA).

METHOD

Retrospective audit of a consecutive series of 134 new patients referred with suspected wet AMD. When visual acuity was >or=6/60 an OCT was performed. If the OCT was consistent with "wet" AMD, the patient underwent simultaneous FFA/ICGA. The sensitivity and specificity of this clinic was calculated. The number of additional diagnoses made using ICGA was recorded.

RESULTS

23/134 (17.16%) patients had OCT only and were not subsequently found to have wet AMD. FFA/ICGA was performed in 111 patients, showing wet AMD in 90 (81%) patients. OCT as used in our clinic had a sensitivity of 1 and a specificity of 0.65 for detecting wet AMD. ICGA provided additional diagnoses in 19 (14.17%) patients. ICGA detected a specific vascular abnormality in 58% of the occult lesions.

CONCLUSIONS

OCT proved to be an effective screening tool for wet AMD in this clinic, with excellent sensitivity and reasonable specificity. ICGA provided an additional diagnosis in a significant number of cases, but did not define a vascular abnormality in all occult cases.

Retinal assessment using optical coherence tomography

Over the 15 years since the original description, optical coherence tomography (OCT) has become one of the key diagnostic technologies in the ophthalmic subspecialty areas of retinal diseases and glaucoma. The reason for the widespread adoption of this technology originates from at least two properties of the OCT results: on the one hand, the results are accessible to the non-specialist where microscopic retinal abnormalities are grossly and easily noticeable; on the other hand, results are reproducible and exceedingly quantitative in the hands of the specialist. However, as in any other imaging technique in ophthalmology, some artifacts are expected to occur. Understanding of the basic principles of image acquisition and data processing as well as recognition of OCT limitations are crucial issues to using this equipment with cleverness. Herein, we took a brief look in the past of OCT and have explained the key basic physical principles of this imaging technology. In addition, each of the several steps encompassing a third generation OCT evaluation of retinal tissues has been addressed in details. A comprehensive explanation about next generation OCT systems has also been provided and, to conclude, we have commented on the future directions of this exceptional technique.

Correlation of optical coherence tomography and fundus fluorescein angiography following photodynamic therapy for choroidal neovascular membranes

AIMS

To assess the correlation between optical coherence tomography (OCT) and leakage on fundus fluorescein angiography (FFA) following photodynamic therapy (PDT) with verteporfin for choroidal neovascularisation (CNV).

METHODS

Retrospective comparative observational case series of patients who were treated with PDT for CNV from one centre. All patients had 3 monthly FFA and OCT following initial PDT to assess if further treatment was required. A pair of FFA and OCT images from the same visit at a random follow up date were taken from each patient's series and assessed separately by different observers. The presence of pigment epithelial detachment, subretinal fluid, vitreomacular traction, intraretinal fluid, absence of foveal depression, and the retinal thickness on OCT were correlated with presence of leaks on FFA.

RESULTS

A total of 121 eyes of 121 patients were included. The presence of subretinal fluid, gross cystoid macular oedema, sponge-like retinal thickening and retinal thickness of more than 350 mum on OCT correlated well with leak on FFA (p value <0.01). The likelihood ratios were 3.0, 5.7, 2.7, and 3.6, respectively. The presence of a solitary foveal cyst did not correlate well with leaks on FFA.

CONCLUSIONS

The presence of subretinal fluid, intraretinal fluid in the form of gross cystoid macular oedema, or sponge-like retinal thickening, or a retinal thickness more than 350 mum correlates with leaks on FFA and so suggests the need for repeat PDT.