Inami M-CHARTS™ are used to quantify metamorphopsia in patients with age-related macular degeneration, macular hole and epiretinal membrane.
In patients with metamorphopsia, a straight line projected onto the retina is recognised as an irregular or curved line. When a dotted line is used and the dot interval changes from fine to coarse, metamorphopsia decreases and finally disappears. Based on this phenomenon, M-CHARTS™ are developed to quantitatively assess metamorphopsia easily and quickly.
M-CHARTS™ include a straight line and 19 kinds of dotted lines with dot intervals ranging from 0.2⁰ to 2.0⁰ of visual angle. The length of the lines, the dot size of the lines and the size of the fixation point are 20⁰, 0.1⁰, and 0.3⁰ of visual angle respectively.
Type I has one line that passes through the fixation point and Type II has two lines which are 1⁰ apart from the fixation point on each side. Type II is designed for patients with central scotoma.
For patients with low vision, M-CHARTS™ with a dot size of 0.5⁰ visual angle are available.