Diagnostic Accuracy of the Amsler Grid Test for Detecting Neovascular Age-Related Macular Degeneration

Abstract

Patients with nonneovascular age-related macular degeneration (AMD) are encouraged to use the Amsler grid test for self-assessment to facilitate early diagnosis. The test is widely recommended, suggesting a belief that it signals worsening AMD, warranting its use in home monitoring. To systematically review studies of the diagnostic test accuracy of the Amsler grid in the diagnosis of neovascular AMD and to perform diagnostic test accuracy meta-analyses. A systematic literature search was conducted in 12 databases for relevant titles from database inception until May 7, 2022. Studies included those with groups defined as having (1) neovascular AMD and (2) either healthy eyes or eyes with nonneovascular AMD. The index test was the Amsler grid. The reference standard was ophthalmic examination. After removal of obviously irrelevant reports, 2 authors (J.B. and M.S.) independently screened the remaining references in full text for potential eligibility. Disagreements were resolved by a third author (Y.S.). Two authors (J.B. and I.P.) independently extracted all data and evaluated quality and applicability of eligible studies using the Quality Assessment of Diagnostic Accuracy Studies 2. Disagreements were resolved by a third author (Y.S.). Sensitivity and specificity of the Amsler grid for detecting neovascular AMD with comparators being either healthy control participants or patients with nonneovascular AMD. Of 523 records screened, 10 studies were included with a total of 1890 eyes (mean participant age ranging from 62 to 83 years). Sensitivity and specificity to diagnose neovascular AMD were 67% (95% CI, 51%-79%) and 99% (95% CI, 85%-100%), respectively, when comparators were healthy control participants and 71% (95% CI, 60%-80%) and 63% (95% CI, 49%-51%), respectively, when control participants were patients with nonneovascular AMD. Overall, potential sources of bias were low across studies. Although the Amsler grid is easy and inexpensive to use for detection of metamorphopsia, its sensitivity may be at levels typically not recommended for monitoring. Coupling this lower sensitivity with only moderate specificity to identify neovascular AMD in a population at risk, these findings suggest that such patients typically should be encouraged to undergo ophthalmic examination regularly, regardless of any results of Amsler grid self-assessment.