Macular function surveillance revisited

BackgroundThe Amsler grid is a widely used means of evaluating the central 20° diameter visual field. It is a common practice to have patients who are at risk for exudative maculopathy evaluate their macular function daily using the Amsler grid. The goal is to make the patient aware of the earliest symptoms of choroidal neovascularization at a time when therapeutic intervention has the greatest chance for success. There are, however, several important shortcomings of self-monitoring macular function with the Amsler grid, including low sensitivity and low compliance.MethodsThe history of macular function surveillance is reviewed. The following techniques that are either currently available or under development for home self-monitoring of macular function are discussed: Amsler grid, red Amsler grid, threshold Amsler grid, environmental Amsler techniques, entoptic perimetry, preferential hyperacuity perimetry, and Internet-based interventions.ConclusionThere is compelling evidence that several currently available technologies are superior to the conventional Amsler grid in detecting the earliest symptoms of macular disease. Threshold Amsler grid, entoptic perimetry, and preferential hyperacuity perimetry each have been found to be more sensitive than the conventional Amsler grid in detecting vision disturbances caused by macular disease. Any one of these diagnostic tests could conceivably be utilized by patients at home for self-monitoring of macular function if the technology were suitably deployed for this purpose, such as over the Internet.