Evaluation of optical coherence tomography in the diagnosis of age related macula degeneration compared with fluorescence angiography.

Abstract

Background: In industrialised nations age-related macular degeneration (AMD) is the most common cause of blindness and severe visual impairment. AMD is a disease of the retina characterized by the accumulation of metabolic products in the macula. In early stages drusen and pigment disorders occur, in late stages a dry form is distinguished from the exsudative form with choroidal neovascularisation. AMD causes vision disorders such as blurred vision of the central part of the visual field, leading finally to a dark spot. Several therapies are available for the exsudative form, however an exact diagnosis is partially essential. The gold standard for the diagnosis of AMD is fluorescein angiography (FA), an invasive investigation with intravenous application of a dye. Optical coherence tomography (OCT) is a more recent non-invasive procedure.

Objectives: The aim of this HTA report is to investigate the efficacy and efficiency of OCT compared to FA. Ethical, societal and legal aspects are also considered.

Methods: A systematic literature search was performed in 34 international databases which yielded 2324 articles. Eight publications were included for assessment, according to predefined selection criteria.

Results: The number of studies investigating OCT compared to FA in patients with AMD is presently very limited and the quality of the studies is generally low. The number of investigated patients is below 35 in four publications and in only one publication it is above 100. Moreover in most of the articles very selected patient groups are studied. Economic studies concerning the efficiency of OCT compared to FA cannot be identified.

Discussion: Even though the patient groups investigated and the objectives of the studies are very heterogenous, all publications uniformly show that OCT cannot replace FA. However, OCT yields additional diagnostic findings and may verify unclear findings of FA. Therefore the application of OCT in addition to FA is useful in many cases. With regard to costs German patients on average currently have to pay more for performing OCT than for performing FA.

Conclusion: Future studies have to show whether OCT may give diagnostic information essential for therapeutic decisions in addition to FA and whether it can replace FA in selected cases. The number of patients included in these studies should be high enough to answer relevant questions with sufficient statistical power. An economic model calculation can be built upon the resulting findings.