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Which of the following indicates a convex lens?

  1. Plus lens

  2. Minus lens

  3. Flat lens

  4. Concave lens

The correct answer is: Plus lens

A convex lens is indicated as a plus lens, which means it has a positive optical power. This type of lens converges light rays that are entering it, bringing them to a focal point on the opposite side of the lens. Convex lenses are thicker in the center compared to the edges, and they are commonly used to correct hyperopia (farsightedness) by assisting the eye in focusing light correctly on the retina. In ocular prescriptions, a plus sign (+) is used to characterize the power of a convex lens. This indicates that the lens provides magnification to the objects viewed through it and is suitable for individuals who have difficulty seeing nearby objects clearly because their natural lens does not have enough converging power. Understanding this is essential for anyone pursuing a career in optometry or opticianry, as distinguishing between lens types directly impacts the type of lens chosen for patients based on their vision needs.