Evaluating persistent and recurrent choroidal neovascularization. The role of indocyanine green angiography

Imaging Biomarkers and Their Impact on Therapeutic Decision-Making in the Management of Neovascular Age-Related Macular Degeneration

These recommendations, produced by a group of Canadian retina experts, have been developed to assist both retina specialists and general ophthalmologists in the management of vision-threatening neovascular age-related macular degeneration (nAMD). The recommendations are based on published evidence as well as collective experience and expertise in routine clinical practice. We provide an update on practice principles for optimal patient care, focusing on identified imaging biomarkers, in particular retinal fluid, as well as current and emerging therapeutic approaches. Algorithms for delivering high-quality care and improving long-term patient outcomes are provided, with an emphasis on timely and appropriate treatment to preserve and maintain vision. In the context of nAMD, increasing macular fluid or leakage on fluorescein angiography (FA) may indicate disease activity regardless of its location. Early elimination of intraretinal fluid (IRF) is of particular relevance as it is a prognostic indicator of worse visual outcomes. Robust referral pathways for second opinion and peer-to-peer consultations must be in place for cases not responding to intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy.

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.

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

TOPIC

To compare the accuracy of optical coherence tomography (OCT) with alternative tests for monitoring neovascular age-related macular degeneration (nAMD) and detecting disease activity among eyes previously treated for this condition.

CLINICAL RELEVANCE

Traditionally, fundus fluorescein angiography (FFA) has been considered the reference standard to detect nAMD activity, but FFA is costly and invasive. Replacement of FFA by OCT can be justified if there is a substantial agreement between tests.

METHODS

Systematic review and meta-analysis. The index test was OCT. The comparator tests were visual acuity, clinical evaluation (slit lamp), Amsler chart, color fundus photographs, infrared reflectance, red-free images and blue reflectance, fundus autofluorescence imaging, indocyanine green angiography (ICGA), preferential hyperacuity perimetry, and microperimetry. We searched the following databases: MEDLINE, MEDLINE In-Process, EMBASE, Biosis, Science Citation Index, the Cochrane Library, Database of Abstracts of Reviews of Effects, MEDION, and the Health Technology Assessment database. The last literature search was conducted in March 2013. We used the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) to assess risk of bias.

RESULTS

We included 8 studies involving more than 400 participants. Seven reported the performance of OCT (3 time-domain [TD] OCT, 3 spectral-domain [SD] OCT, 1 both types) and 1 reported the performance of ICGA in the detection of nAMD activity. We did not find studies directly comparing tests in the same population. The pooled sensitivity and specificity of TD OCT and SD OCT for detecting active nAMD was 85% (95% confidence interval [CI], 72%-93%) and 48% (95% CI, 30%-67%), respectively. One study reported ICGA with sensitivity of 75.9% and specificity of 88.0% for the detection of active nAMD. Half of the studies were considered to have a high risk of bias.

CONCLUSIONS

There is substantial disagreement between OCT and FFA findings in detecting active disease in patients with nAMD who are being monitored. Both methods may be needed to monitor patients comprehensively with nAMD.

Does context or color improve object recognition in patients with low vision?

Most studies on people with age-related macular degeneration (AMD) have been focused on investigations of low-level processes with simple stimuli like gratings, letters, and in perception of isolated faces or objects. We investigated the ability of people with low vision to analyze more complex stimuli like photographs of natural scenes. Fifteen participants with AMD and low vision (acuity on the better eye <20/200) and 11 normally sighted age-matched controls took part in the study. They were presented with photographs of either colored or achromatic gray level scenes in one condition and with photographs of natural scenes versus isolated objects extracted from these scenes in another condition. The photographs were centrally displayed for 300 ms. In both conditions, observers were instructed to press a key when they saw a predefined target (a face or an animal). The target was present in half of the trials. Color facilitated performance in people with low vision, while equivalent performance was found for colored and achromatic pictures in normally sighted participants. Isolated objects were categorized more accurately than objects in scenes in people with low vision. No difference was found for normally sighted observers. The results suggest that spatial properties that facilitate image segmentation (e.g., color and reduced crowding) help object perception in people with low vision.

Recognition of facial emotion in low vision: a flexible usage of facial features

Age-related macular degeneration (AMD) is a major cause of visual impairment in people older than 50 years in Western countries, affecting essential tasks such as reading and face recognition. Here we investigated the mechanisms underlying the deficit in recognition of facial expressions in an AMD population with low vision. Pictures of faces displaying different emotions with the mouth open or closed were centrally displayed for 300 ms. Participants with AMD with low acuity (mean 20/200) and normally sighted age-matched controls performed one of two emotion tasks: detecting whether a face had an expression or not (expressive/non expressive (EXNEX) task) or categorizing the facial emotion as happy, angry, or neutral (categorization of expression (CATEX) task). Previous research has shown that healthy observers are mainly using high spatial frequencies in an EXNEX task while performance at a CATEX task was preferentially based on low spatial frequencies. Due to impaired processing of high spatial frequencies in central vision, we expected and observed that AMD participants failed at deciding whether a face was expressive or not but categorized normally the emotion of the face (e.g., happy, angry, neutral). Moreover, we observed that AMD participants mostly identified emotions using the lower part of the face (mouth). Accuracy did not differ between the two tasks for normally sighted observers. The results indicate that AMD participants are able to identify facial emotion but must base their decision mainly on the low spatial frequencies, as they lack the perception of finer details.

Angiographic pattern of recurrent choroidal neovascularization in age-related macular degeneration

PURPOSE

To evaluate the angiographic characteristics of recurrent choroidal neovascularization (R-CNV) in age-related macular degeneration (AMD).

METHODS

A prospective investigation on 107 consecutive patients with exudative AMD and CNV not involving the fovea was conducted. Fluorescein angiography (FA) and indocyanine green angiography (ICGA) were planned before krypton laser treatment, and after 3 weeks, 2, 3, 4, 6, 9, 12, 18, and 24 months from photocoagulation. Laser treatment was FA-guided in eyes with classic CNV, and ICGA-guided in eyes with occult CNV on FA.

RESULTS

At baseline on FA, 23.3% had classic CNV, whereas, 76.6% showed occult CNV. On ICGA, CNV assumed a focal and a plaque pattern in 81.3 and 18.6% of cases, respectively. Overall, post-laser CNVs occurred in 56 eyes. FA identified well-defined and ill-defined R-CNV in 25 and 75% of cases, respectively. ICGA identified three different R-CNV patterns: focal, annular, and plaque. Focal R-CNV was defined as a single dot-like hyperfluorescence, which was detected in 69.6% of cases, with subfoveal location in half of them. Annular R-CNV was identified by a hyperfluorescent lesion, partially or completely encircling treated area, which was visible in 19.6% of cases, all with subfoveal involvement. Plaque R-CNV was defined as a hyperfluorescent lesion larger than 1 disc diameter in size, and was seen in 10.7% of cases, all with subfoveal location.

CONCLUSIONS

ICGA is able to improve R-CNV visualization identifying three different R-CNV patterns. Focal R-CNV is the most frequent pattern and can be re-treated in half of the cases.

Changes in confocal indocyanine green angiography through two years after photodynamic therapy with verteporfin

PURPOSE

To evaluate vascular changes documented by confocal indocyanine green angiography (ICGA) through 2 years after photodynamic therapy (PDT) with verteporfin of neovascular age-related macular degeneration (AMD).

DESIGN

Single-center, 2-year, randomized, double-masked, interventional, placebo-controlled trial (subset from Treatment of AMD with PDT Study [TAP]).

PARTICIPANTS

Sixty patients with subfoveal choroidal neovascularization (CNV) resulting from AMD.

INTERVENTION

Patients were randomized in a ratio of 2:1 to a standard regimen using verteporfin therapy at a drug dose of 6 mg/m(2) body surface area and a light dose of 50 J/cm(2) or a sham treatment with placebo infusion and light exposure. Retreatments, if persistent fluorescein leakage from CNV was documented, were scheduled at 3-month intervals for up to 2 years. Confocal ICGA with tomographic sections was performed at baseline and continuously at the month 3, 6, 12, and 24 examinations using a standardized protocol.

MAIN OUTCOME MEASURES

Analysis included the size of the neovascular net, the area of late hyperfluorescence, and choroidal hypofluorescence during early- and late-phase imaging.

RESULTS

In the verteporfin-treated group, the mean size of the CNV and the mean area of late leakage consistent with active leakage or staining showed no further enlargement at month 12 and were reduced at month 24. In the placebo-treated group, new vessels grew threefold compared with baseline and exhibited persistent late hyperfluorescence resulting from leakage at 24 months. Associated choroidal hypofluorescence within the treated area was significantly increased in eyes treated with verteporfin PDT compared with the control group during the first year, persisted during all ICGA phases, and was irreversible during follow-up. Image analysis revealed choroidal hypoperfusion with choriocapillary dropout, which correlated with chorioretinal atrophy clinically. Progressive destruction of choroidal integrity by fibrosis in control eyes led to a similar extent of collateral hypofluorescence in both groups through the 24-month examination.

CONCLUSIONS

Indocyanine green angiography is an important adjunct in the identification of vascular effects associated with verteporfin PDT. Repeated treatments effectively arrested CNV growth and reduced leakage activity. The collateral impairment of choroidal perfusion appears to influence the visual outcome of the treatment.

Treatment of age-related macular degeneration

Age-related macular degeneration (AMD), while rapidly becoming more prevalent due to an aging population, is still poorly understood and treatment modalities are limited. Fortunately, advances are being made in the treatment of AMD that may greatly alter the outcome of this debilitating disease. Treatments for both wet and dry AMD are reviewed.

The present role of indocyanine green angiography in ophthalmology

Recent developments in the clinical application of indocyanine green angiography have mainly concerned refining its role as an adjunct to fluorescein angiography in detecting and guiding the treatment of choroidal neovascularization. We now have a better understanding of the different patterns of abnormal hyperfluorescence seen with indocyanine green angiography in eyes with both wet and dry forms of macular degeneration. In exudative cases, the success rate of laser treatment guided by indocyanine green angiographic findings can vary considerably, and it is now known which angiographic presentations are not as likely to benefit. In dry macular degeneration, indocyanine green angiography appears to add clinically useful information, such as helping to identify plaques in fellow eyes with choroidal neovasculrization or watershed zones that may be predictive of future exudative transformation. In certain circumstances, indocyanine green angiography can be valuable in detecting choroidal neovascularization in other macular diseases or in helping to diagnose other choroidal conditions, especially when the clinical presentation is atypical, such as central serous chorioretinopathy in elderly patients.