Background: Neovascular age-related macular degeneration is a leading cause of sight loss, and early detection and treatment is important. For patients with neovascular age-related macular degeneration in one eye, it is usual practice to monitor the unaffected eye. The test used to diagnose neovascular age-related macular degeneration, fundus fluorescein angiography, is an invasive test. Non-invasive tests are available, but their diagnostic accuracy is unclear.
Objectives: The primary objective was to determine the diagnostic monitoring performance of tests for neovascular age-related macular degeneration in the second eye of patients with unilateral neovascular age-related macular degeneration. The secondary objectives were the cost-effectiveness of tests and to identify predictive factors of developing neovascular age-related macular degeneration.
Design: This was a multicentre, prospective, cohort, comparative diagnostic accuracy study in a monitoring setting for up to 3 years. A Cox regression risk prediction model and a Markov microsimulation model comparing cost-effectiveness of the index tests over 25 years were used.
Setting: This took place in hospital eye services.
Participants: Participants were adults (aged 50-95 years) with newly diagnosed (within the previous 6 weeks) neovascular age-related macular degeneration in one eye and an unaffected second (study) eye who were attending for treatment injections in the first eye and who had a study eye baseline visual acuity of ≥ 68 Early Treatment Diabetic Retinopathy Study letters.
Interventions: The index tests were Amsler chart (completed by participants), fundus clinical examination, optical coherence tomography, self-reported vision assessment (completed by participants) and visual acuity. The reference standard was fundus fluorescein angiography.
Main outcome measures: The main outcome measures were sensitivity and specificity; the performance of the risk predictor model; and costs and quality-adjusted life-years.
Results: In total, 552 out of 578 patients who consented from 24 NHS hospitals (n = 16 ineligible; n = 10 withdrew consent) took part. The mean age of the patients was 77.4 years (standard deviation 7.7 years) and 57.2% were female. For the primary analysis, 464 patients underwent follow-up fundus fluorescein angiography and 120 developed neovascular age-related macular degeneration on fundus fluorescein angiography. The diagnostic accuracy [sensitivity (%) (95% confidence interval); specificity (%) (95% confidence interval)] was as follows: optical coherence tomography 91.7 (85.2 to 95.6); 87.8 (83.8 to 90.9)], fundus clinical examination [53.8 (44.8 to 62.5); 97.6 (95.3 to 98.9)], Amsler [33.7 (25.1 to 43.5); 81.4 (76.4 to 85.5)], visual acuity [30.0 (22.5 to 38.7); 66.3 (61.0 to 71.1)] and self-reported vision [4.2 (1.6 to 9.8); 97.0 (94.6 to 98.5)]. Optical coherence tomography had the highest sensitivity across all secondary analyses. The final prediction model for neovascular age-related macular degeneration in the non-affected eye included smoking status, family history of neovascular age-related macular degeneration, the presence of nodular drusen with or without reticular pseudodrusen, and the presence of pigmentary abnormalities [c-statistic 0.66 (95% confidence interval 0.62 to 0.71)]. Optical coherence tomography monitoring generated the greatest quality-adjusted life-years gained per patient (optical coherence tomography, 5.830; fundus clinical examination, 5.787; Amsler chart, 5.736, self-reported vision, 5.630; and visual acuity, 5.600) for the lowest health-care and social care costs (optical coherence tomography, £19,406; fundus clinical examination, £19,649; Amsler chart, £19,751; self-reported vision, £20,198; and visual acuity, £20,444) over the lifetime of the simulated cohort. Optical coherence tomography dominated the other tests or had an incremental cost-effectiveness ratio below the accepted cost-effectiveness thresholds (£20,000) across the scenarios explored.
Limitations: The diagnostic performance may be different in an unselected population without any history of neovascular age-related macular degeneration; the prediction model did not include genetic profile data, which might have improved the discriminatory performance.
Conclusions: Optical coherence tomography was the most accurate in diagnosing conversion to neovascular age-related macular degeneration in the fellow eye of patients with unilateral neovascular age-related macular degeneration. Economic modelling suggests that optical coherence tomography monitoring is cost-effective and leads to earlier diagnosis of and treatment for neovascular age-related macular degeneration in the second eye of patients being treated for neovascular age-related macular degeneration in their first eye.
Future work: Future works should investigate the role of home monitoring, improved risk prediction models and impact on long-term visual outcomes.
Study registration: This study was registered as ISRCTN48855678.
Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 8. See the NIHR Journals Library website for further project information.
Keywords: ADULT; AMSLER; CHOROID; COST-BENEFIT ANALYSIS; DIAGNOSTIC TESTS, ROUTINE; FLUORESCEIN ANGIOGRAPHY; HUMANS; QUALITY-ADJUSTED LIFE-YEARS; RETINA; RISK FACTORS; SELF-REPORT VISUAL FUNCTION; SENSITIVITY AND SPECIFICITY; TOMOGRAPHY, OPTICAL COHERENCE; VISUAL ACUITY; WET MACULAR DEGENERATION.
Wet age-related macular degeneration is the leading cause of sight loss in older people. It is diagnosed using fundus fluorescein angiography, which involves photographing the retina after the injection of a dye into a vein in the arm, which may result in allergic reactions. Many people with wet age-related macular degeneration in one eye will also develop it in their second eye. To avoid regular fundus fluorescein angiography, non-invasive tests are used to routinely monitor for wet age-related macular degeneration in the second eye of patients with wet age-related macular degeneration already in one eye. We studied five commonly used and easily performed non-invasive tests to see which best detected the onset of wet age-related macular degeneration. The five tests were: self-report of visionself-completion of an Amsler charta standard sight testexamination of the retina by a specialistoptical coherence tomography, which is a non-invasive scan of the central retina. If any tests suggested wet age-related macular degeneration, fundus fluorescein angiography was performed to compare results. In total, 552 hospital eye clinic patients who had wet age-related macular degeneration in only one eye took part. Over a 3-year period, wet age-related macular degeneration developed in the second eye in 145 people (26%), of whom 120 had undergone fundus fluorescein angiography. In 25 people with wet age-related macular degeneration, fundus fluorescein angiography was not carried out for safety reasons or because the patient did not want to undergo it. Of all the tests, only optical coherence tomography was good at detecting wet age-related macular degeneration correctly (92% sensitivity) and at detecting those who did not have wet age-related macular degeneration (88% specificity). All other tests either did not detect wet age-related macular degeneration consistently when it occurred or gave a false positive result when it had not occurred. This study confirmed that optical coherence tomography detected wet age-related macular degeneration correctly in the second eye of people with wet age-related macular degeneration in their first eye, and may offer cost saving for the NHS.