Which of the following is used for treatment of Myopia?
**Core Concept**
Myopia, or nearsightedness, is a refractive error caused by an elongation of the eyeball, resulting in light being focused in front of the retina. Treatment options for myopia include refractive surgeries, contact lenses, and pharmacological agents that slow down the progression of the disease.
**Why the Correct Answer is Right**
Atropine eye drops are used in the treatment of myopia due to their ability to slow down the axial elongation of the eyeball. Atropine, a muscarinic antagonist, blocks the parasympathetic input to the ciliary muscle, leading to a decrease in accommodation and a subsequent reduction in the rate of axial elongation. This mechanism is thought to be mediated through the blockade of the muscarinic M3 receptor, which is responsible for the contraction of the ciliary muscle.
**Why Each Wrong Option is Incorrect**
**Option A:** Orthokeratology is a non-surgical procedure that involves wearing a specialized contact lens at night to reshape the cornea. While it can correct refractive errors, it is not used for the treatment of myopia progression.
**Option B:** Pirenzepine is a selective M1 muscarinic receptor antagonist that is used in the treatment of peptic ulcers, not myopia.
**Option C:** Timolol is a beta-blocker used in the treatment of glaucoma, not myopia.
**Clinical Pearl / High-Yield Fact**
Atropine eye drops are a high-yield treatment for myopia, especially in children, as they have been shown to slow down the progression of the disease without significant side effects.
**Correct Answer:** C. Atropine eye drops.