Glossary M

M SHAPE MACULA LUTEA The area of the retina that surrounds the fovea, filled with a yellow pigment that is insensitive to light. It resembles a slightly flattened ellipse whose major axis is horizontal and covers about 7° of the visual field (2 mm on the retina). MINERAL LENSES Scratch-resistant and providing excellent optical quality, mineral lenses can be photochromic and are made from silica and a mixture of oxides combined at high temperatures. Disadvantage: They are heavy and breakable. MONOCULAR VISION Vision by a single eye. MYOPIA An irregularity of vision in which the image is formed in front of the retina rather than on it. In myopia, vision for distant objects is poor whereas vision for very near objects is good.