Accuracy of fundus autofluorescence imaging for the diagnosis and monitoring of retinal conditions: a systematic review

Abstract

BackgroundNatural fluorescence in the eye may be increased or decreased by diseases that affect the retina. Imaging methods based on confocal scanning laser ophthalmoscopy (cSLO) can detect this ‘fundus autofluorescence’ (FAF) by illuminating the retina using a specific light ‘excitation wavelength’. FAF imaging could assist the diagnosis or monitoring of retinal conditions. However, the accuracy of the method for diagnosis or monitoring is unclear.ObjectiveTo conduct a systematic review to determine the accuracy of FAF imaging using cSLO for the diagnosis or monitoring of retinal conditions, including monitoring of response to therapy.Data sourcesElectronic bibliographic databases; scrutiny of reference lists of included studies and relevant systematic reviews; and searches of internet pages of relevant organisations, meetings and trial registries. Databases included MEDLINE, EMBASE, The Cochrane Library, Web of Science and the Medion database of diagnostic accuracy studies. Searches covered 1990 to November 2014 and were limited to the English language.Review methodsReferences were screened for relevance using prespecified inclusion criteria to capture a broad range of retinal conditions. Two reviewers assessed titles and abstracts independently. Full-text versions of relevant records were retrieved and screened by one reviewer and checked by a second. Data were extracted and critically appraised using the Quality Assessment of Diagnostic Accuracy Studies criteria (QUADAS) for assessing risk of bias in test accuracy studies by one reviewer and checked by a second. At all stages any reviewer disagreement was resolved through discussion or arbitration by a third reviewer.ResultsEight primary research studies have investigated the diagnostic accuracy of FAF imaging in retinal conditions: choroidal neovascularisation (one study), reticular pseudodrusen (three studies), cystoid macular oedema (two studies) and diabetic macular oedema (two studies). Sensitivity of FAF imaging using an excitation wavelength of 488 nm was generally high (range 81–100%), but was lower (55% and 32%) in two studies using longer excitation wavelengths (514 nm and 790 nm, respectively). Specificity ranged from 34% to 100%. However, owing to limitations of the data, none of the studies provide conclusive evidence of the diagnostic accuracy of FAF imaging.LimitationsNo studies on the accuracy of FAF imaging for monitoring the progression of retinal conditions or response to therapy were identified. Owing to study heterogeneity, pooling of diagnostic outcomes in meta-analysis was not conducted. All included studies had high risk of bias. In most studies the patient spectrum was not reflective of those who would present in clinical practice and no studies adequately reported how FAF images were interpreted.ConclusionsAlthough already in use in clinical practice, it is unclear whether or not FAF imaging is accurate, and whether or not it is applied and interpreted consistently for the diagnosis and/or monitoring of retinal conditions. Well-designed prospective primary research studies, which conform to the paradigm of diagnostic test accuracy assessment, are required to investigate the accuracy of FAF imaging in diagnosis and monitoring of inherited retinal dystrophies, early age-related macular degeneration, geographic atrophy and central serous chorioretinopathy.Study registrationThis study is registered as PROSPERO CRD42014014997.FundingThe National Institute for Health Research Health Technology Assessment programme.

Fundus autofluorescence imaging: systematic review of test accuracy for the diagnosis and monitoring of retinal conditions

“…Instead, we re-ran our original MEDLINE search. 66 and supplemented this with a broad search in Google Scholar using the free text term 'fundus autofluorescence imaging'. The first 200 potentially relevant references identified in Google Scholar, as judged by one reviewer against the inclusion criteria, and all references identified in the MEDLINE search were imported into an Endnote library.…”

“…Full-text articles were screened by one reviewer and checked by a second reviewer. At both steps of the selection process, a standard study selection worksheet listing the inclusion criteria was employed, 66 and any disagreements were resolved by discussion among the two reviewers or, if necessary, by involving a third reviewer. If a study was reported in more than one article at the full-text assessment step, all the articles relating to the study were grouped together for the eligibility assessment.…”

“…Data were extracted from the included studies using a pre-designed and pilot-tested data extraction form 66 to minimise errors. If test accuracy outcomes were not fully reported, missing values were calculated by the reviewers where possible.…”

“…39,41,48,[70][71][72][73][74] Eye Key characteristics of the included studies are summarised in Supplementary Table 2 and are given in detail in the full study report. 66 Although FAF imaging may be used to detect autofluorescence in a wide range of retinal conditions, the eight included studies cover only choroidal neovascularisation in AMD, 70 reticular pseudodrusen in AMD, [71][72][73] cystoid macular oedema, 39,41 and diabetic macular oedema. 48,74 Six of these studies were European, one was conducted in the United States, 72 and one in Japan.…”

“…To determine the accuracy of FAF imaging using cSLO for the diagnosis and/or monitoring of retinal conditions, we conducted a systematic review of studies in a wide range of retinal conditions. Full details of the review are reported by Frampton et al 66 Here, we summarise the key methods and findings of the systematic review, and a review update conducted in October 2016, and we consider the implications of the current evidence for the application of FAF imaging to detect and/or monitor retinal conditions in clinical practice.…”